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Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

A dynamic disorder-linked reversible phase transition in a new chloro­form solvate of cis-di­chloridobis(tri­ethyl­phosphane)platinum(II)

aChemistry Department, Durham University, Science Site, South Road, Durham DH1 3LE, England, and bLaboratoire de Chimie de Coordination, CNRS UPR8241, F-31077 Toulouse, France
*Correspondence e-mail: m.r.probert@durham.ac.uk

(Received 18 January 2011; accepted 4 March 2011; online 10 March 2011)

The title compound, cis-dichloridobis(triethyl­phosphane)platinum(II) chloro­form monosolvate, [PtCl2(C6H15P)2]·CHCl3, has been obtained from ligand scrambling in the cis-[PtCl2(Cyp2PCl)(PEt3)] (Cyp = cyclo­pent­yl) system in CHCl3 solvent. Unlike the two previously reported unsolvated polymorphs, which are both monoclinic, the compound crystallizes in an ortho­rhom­bic setting. Furthermore, the system exhibits a reversible tem­perature-dependent structural phase transition, coupling a reduction in anisotropic displacement parameters and a reduction in crystallographic symmetry on cooling. The high-temperature phase adopts space group Pnma with the complex and solvent mol­ecules sitting across a crystallographic mirror plane (Z′ = 0.5). The low-temperature phase adopts the space group P212121 with Z′ = 1.

Comment

As part of our studies on hydrolysis/hy­droxy­lation of chloro­phosphane ligands in situ on platinum(II) centres (Cornet et al., 2011[Cornet, S. M. M., Dillon, K. B., Dyer, P. W., Goeta, A. E., Howard, J. A. K., Monks, P. K., Shepherd, H. J., Thompson, A. L. & Wright, W. R. H. (2011). In preparation.]), we have prepared in solution the complex cis-[PtCl2(Cyp2PCl)(PEt3)] (Cyp = cyclo­pent­yl) and allowed it to hydrolyse slowly by exposure to air. During the hydrolysis process, however, the 31P NMR solution-state spectra of the reaction mixture demonstrated that ligand scrambling was occurring. Crystals suitable for single-crystal X-ray diffraction were isolated from the reaction mixture which proved to be a new 1:1 solvate of cis-[PtCl2(PEt3)2] with CHCl3, (1).

Analysis of the variation of the length of the crystallographic c axis of (1) with temperature (Fig. 1[link]) clearly demonstrates the onset of a phase transition at 149 K. Data for the calculation of these unit-cell parameters were collected during continuous very slow cooling (2 K h−1); the data collections were such that equal amounts of reciprocal space were sampled for each data point, with the temperature of the data point being assigned to that at the mid-point of the scan. Each point on the graph therefore represents data recorded over 1 K. Full data collections and structural determinations were then carried out above and below the phase-transition temperature at 220 K, (1a), and 120 K, (1b), respectively.

[Scheme 1]

At 220 K, the space group of the solvated complex, (1a), is Pnma, with a mirror plane bis­ecting both the Pt complex and the solvent mol­ecule, resulting in a structure with Z′ = 0.5. The CHCl3 mol­ecule shows dynamic disorder, rotating about the C—H bond axis in a symmetrical fashion with respect to the mirror plane.

Upon cooling below the phase transition, the rotation of the solvent mol­ecule ceases, with respect to the time scale of the diffraction experiment, and appears to `lock' into place. The CHCl3 mol­ecule is subsequently no longer symmetrical about a mirror plane, causing a reduction in the symmetry of the system. The structure of (1b) thus adopts the space group P212121 with Z′ = 1 at 120 K. This transition is illustrated in Figs. 2[link] and 3[link]. A whole-mol­ecule twist, of both the complex and solvent mol­ecules, with respect to the unit cell appears to be driven by a decrease in inter­molecular distances, causing stronger Cl⋯H inter­actions. This results in movements of the ethyl `arms', further breaking the higher-temperature symmetry, as seen from the positions of atoms C32A/B in Fig. 2[link]. The system reverts to the Pnma setting on returning to higher temperatures, demonstrating that the transition is fully reversible within the constraint that the temperature ramping rates are ≤ 120 K h−1.

Electron-density maps (Fobs) through the mean plane defined by the Cl atoms of the chloro­form mol­ecule at the two temperatures are shown in Fig. 4[link], highlighting the decrease in dynamic disorder across the phase transition.

Selected bond distances and angles for (1a) and (1b) are listed in Table 1[link], together with data for one of the previously identified unsolvated monoclinic polymorphs, (2), at 293 K (space group Cc; Otto & Muller, 2001[Otto, S. & Muller, A. J. (2001). Acta Cryst. C57, 1405-1407.]) for which atomic coordinates are available. The second reported unsolvated polymorph (Caldwell et al., 1977[Caldwell, A. N., Manojlovic-Muir, L., Muir, K. W. & Solomun, T. (1977). Eur. Crystallogr. Meet., Oxford, 30 August-3 September, Abstract PI.57, p. 210.]) is not included in Table 1[link] as no three-dimensional coordinates are available, although Otto & Muller describe it as being isostructural with their cis-[PtCl2(AsEt3)2] complex. The known unsolvated polymorphs differ from the title compound (1)[link] not only by the absence of the solvent molecule but also in the relative configuration of the PEt3 groups (see Scheme[link]).

The difference in orientation of the PEt3 ligands around the Pt—P bonds may be better understood by considering the ethyl moiety that lies close to the PtP2Cl2 plane of the Pt atom. As in the case of the previously reported structures, there is one substituent on each P atom in (1) that lies very near the PtP2Cl2 plane. However, unlike in the previously reported structures, these in-plane substituents point towards one another, as shown in the Scheme. It may be expected that this arrangement of the ethyl groups will be somewhat sterically unfavourable, although it does give rise to an increased number of C—H⋯Cl inter­actions, made possible by the presence of the CHCl3 solvent.

The packing motifs of the solvated and unsolvated structures are dominated by C—H⋯Cl inter­actions. In the case of (2), the only short inter­molecular inter­action is C121—H12B⋯Cl1i [H⋯Cl = 2.905 Å; symmetry code: (i) x + [{1\over 2}], −y + [{1\over 2}], z + [{1\over 2}]], which forms one-dimensional chains along the [101] direction. In contrast, (1a) and (1b) form extended hydrogen-bonding networks (Tables 2[link] and 3[link]); (1a) forms two-dimensional sheets which, upon cooling, inter­link to give rise to the three-dimensional hydrogen-bonding network found in (1b), shown in Fig. 5[link].

The Pt—Cl distances (Table 1[link]) are almost identical in (1a), (1b) and (2), although the Pt—P bond lengths show some variation and are shorter in both forms of (1). The most instructive differences between (1) and (2) lie in the bond angles in the approximately square-planar coordination geometry. While the Cl—Pt—Cl angles are very similar, the P—Pt—P angle is over 5° larger in the new polymorphs, reflecting the increased steric repulsion between the PEt3 groups. There is far less variation in the Cl—Pt—P angles found in the polymorphs of (1) (all within 1°) compared with the monoclinic form, where they differ by greater than 6°, a result explained by the differing steric demands on the positions of the two Cl atoms in these structures. These effects may arise from the difference in alignment of the ethyl substituents on the PEt3 ligands, compared with that in (2) described by Otto & Muller (2001[Otto, S. & Muller, A. J. (2001). Acta Cryst. C57, 1405-1407.]). The geometric parameters for (1a) and (1b) are similar to the literature data for other cis-[PtCl2(PR3)2] complexes (Table 4[link]).

[Figure 1]
Figure 1
Graph showing the evolution of the c-axis length of (1) with temperature.
[Figure 2]
Figure 2
The mol­ecular structure of (1a) at 220 K (left, the mirror plane runs through atoms Pt1, Cl1S and C1S) and (1b) at 120 K (right). Atomic displacement parameters are shown at 50% probability in all crystallographic figures. [Symmetry code: (′) x, −y + [1 \over 2], z.]
[Figure 3]
Figure 3
Projection of the crystal packing along the [100] direction of (1a) and (1b) (left and right, respectively), showing the shift in relative mol­ecular orientations as well as the layered motif exhibited in both structures. H atoms have been omitted for clarity.
[Figure 4]
Figure 4
Electron-density maps (Fobs) through the mean plane defined by the Cl atoms of the chloro­form solvent mol­ecule in the structures at 220 K (left) and 120 K (right). Contour lines are displayed at 0.5 e Å−3 inter­vals (higher contour levels have been omitted for clarity for the 120 K data).
[Figure 5]
Figure 5
Hydrogen-bonding networks of (1a) at 220 K (left) and (1b) at 120 K (right). The displayed inter­molecular inter­actions were identified using the same threshold delta function in OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]) of 1.68 Å to highlight the difference between the structures either side of the phase transition. H atoms not involved in inter­molecular contacts have been omitted for clarity.

Experimental

During the synthesis of cis-[PtCl2(PCyp2Cl)(PEt3)], all manipulations, including NMR sample preparation, were carried out either under an inert atmosphere of dry nitro­gen or in vacuo, using standard Schlenk line or glove-box techniques. Chemicals of the best available commercial grade were used, in general without further purification. The 31P NMR spectra of all phospho­rus-containing starting materials were recorded, to verify that no major impurities were present. The synthesis of trans-[PtCl(μ-Cl)(PEt3)]2 was carried out according to the literature procedure of Dillon et al. (2010[Dillon, K. B., Goeta, A. E., Monks, P. K. & Shepherd, H. J. (2010). Polyhedron, 29, 606-612.]). 31P NMR spectra were obtained on a Varian Mercury 400 Fourier-transform spectrometer at 161.91 MHz; chemical shifts are referenced to 85% H3PO4, with the high-frequency direction taken as positive.

Cyp2PCl (0.042 ml, 0.22 mmol) was added via syringe to a solution of trans-[PtCl(μ-Cl)(PEt3)]2 (0.0840 g, 0.11 mmol) in CDCl3 (1 ml). Formation of cis-[PtCl2(PBCyp2Cl)(PAEt3)] was confirmed using 31P NMR spectroscopy: δPA 13.6 p.p.m. (singlet + satellites, 1JPt—P = 3506 Hz, 2JP—P = 13 Hz), δPB 113.0 p.p.m. (singlet + satellites, 1JPt—P = 4024 Hz, 2JP—P = 13 Hz). Attempted hydrolysis of this complex resulted in ligand scrambling to afford compound (1), cis-[PtCl2(PEt3)2] [31P NMR: δ10.2 p.p.m. (singlet + satellites, 1JPt—P = 3514 Hz)], and also cis-[PtCl2(PCyp2Cl)2] [31P NMR: δ108.1 p.p.m. (singlet + satellites, 1JPt—P = 4037 Hz)]. Colourless crystals of (1) were obtained by slow evaporation of solvent from the reaction mixture. Crystals of (1) were also isolated from hydrolysis reactions of cis-[PtCl2(PCy2Cl)(PEt3)] and cis-[PtCl2(PCyCl2)(PEt3)] (Cy = cyclo­hex­yl).

A crystal of (1) was mounted in inert oil and placed in the cold gas stream of an N2 cryostream device (Cosier & Glazer, 1986[Cosier, J. & Glazer, A. M. (1986). J. Appl. Cryst. 19, 105-107.]) at 220 K. Data were collected at this temperature before ramping at a rate of 120 K h−1 to 120 K, where the diffraction experiment was repeated. The temperature was again ramped at 120 K h−1 to 220 K where a short data collection was performed to assess the reversibility of the transition.

Compound (1a)[link]

Crystal data
  • [PtCl2(C6H15P)2]·CHCl3

  • Mr = 621.66

  • Orthorhombic, P n m a

  • a = 19.0103 (9) Å

  • b = 15.7378 (7) Å

  • c = 7.6394 (4) Å

  • V = 2285.56 (19) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 6.86 mm−1

  • T = 220 K

  • 0.21 × 0.20 × 0.18 mm

Data collection
  • Bruker SMART CCD 1K area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Göttingen, Germany.]) Tmin = 0.759, Tmax = 1.0

  • 15061 measured reflections

  • 2928 independent reflections

  • 2317 reflections with I > 2σ(I)

  • Rint = 0.053

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.105

  • S = 1.02

  • 2928 reflections

  • 103 parameters

  • H-atom parameters constrained

  • Δρmax = 2.19 e Å−3

  • Δρmin = −1.98 e Å−3

Table 2
Hydrogen-bond geometry (Å, °) for (1a)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
C21A—H21B⋯Cl1Ai 0.98 2.97 3.717 (7) 134
C31A—H31A⋯Cl2Sii 0.98 2.93 3.802 (9) 149
C1S—H1S⋯Cl1Aiii 0.99 2.70 3.505 (10) 139
C1S—H1S⋯Cl1Aiv 0.99 2.70 3.505 (10) 138
Symmetry codes: (i) x, y, z+1; (ii) -x+1, -y, -z+2; (iii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+{\script{3\over 2}}]; (iv) [x-{\script{1\over 2}}, y, -z+{\script{3\over 2}}].

Compound (1b)[link]

Crystal data
  • [PtCl2(C6H15P)2]·CHCl3

  • Mr = 621.66

  • Orthorhombic, P 21 21 21

  • a = 18.9529 (9) Å

  • b = 15.7268 (8) Å

  • c = 7.4934 (4) Å

  • V = 2233.5 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 7.02 mm−1

  • T = 120 K

  • 0.21 × 0.20 × 0.18 mm

Data collection
  • Bruker SMART CCD 1K area-detector diffractometer

  • Absorption correction: multi-scan (SADABS; Sheldrick, 2003[Sheldrick, G. M. (2003). SADABS. Version 2.10. University of Göttingen, Germany.]) Tmin = 0.757, Tmax = 1.000

  • 25676 measured reflections

  • 5546 independent reflections

  • 5240 reflections with I > 2σ(I)

  • Rint = 0.045

Refinement
  • R[F2 > 2σ(F2)] = 0.023

  • wR(F2) = 0.045

  • S = 1.04

  • 5546 reflections

  • 196 parameters

  • H-atom parameters constrained

  • Δρmax = 0.91 e Å−3

  • Δρmin = −1.02 e Å−3

Table 3
Hydrogen-bond geometry (Å, °) for (1b)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
C1S—H1S⋯Cl1A 1.00 2.67 3.482 (4) 138
C1S—H1S⋯Cl1B 1.00 2.63 3.466 (4) 141
C21A—H21B⋯Cl1Ai 0.99 2.72 3.606 (5) 149
C21A—H21A⋯Cl2Sii 0.99 2.85 3.601 (5) 133
C12A—H12A⋯Cl1S 0.98 2.97 3.727 (5) 135
C32B—H32F⋯Cl1Sii 0.98 2.93 3.797 (5) 148
C31B—H31D⋯Cl2Siii 0.99 2.97 3.817 (4) 145
Symmetry codes: (i) x, y, z+1; (ii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (iii) [-x+{\script{1\over 2}}, -y, z+{\script{1\over 2}}].

Table 1
Selected geometric parameters (Å, °) for (1a), (1b) and (2)

  (1a) (1b) (2)
Pt1—Cl1A 2.3627 (17) 2.3696 (10) 2.364 (2)
Pt1—Cl1B   2.3665 (11) 2.374 (2)
Pt1—P1A 2.2540 (16) 2.2524 (11) 2.264 (2)
Pt1—P1B   2.2550 (11) 2.2616 (18)
P1A—Pt1—P1B* 104.77 (9) 103.89 (4) 98.39 (7)
P1A—Pt1—Cl1A 84.71 (6) 85.18 (4) 84.63 (9)
P1A—Pt1—Cl1B   85.06 (4) 91.33 (7)
Cl1A—Pt1—Cl1B* 85.80 (10) 85.94 (4) 85.66 (9)
Note: (*) symmetry equivalent for (1a) using symmetry operation (x, −y + [{1\over 2}], z).

Table 4
Selected geometric parameters (Å, °) for cis-[PtCl2(PR3)2] complexes

Compound Pt—P Pt—Cl P—Pt—P Cl—P—Cl Reference
PMe3 2.256 (8) 2.364 (8) 96.2 (4) 87.47 (3) a
  2.239 (6) 2.388 (8)      
PtBu3 2.321 (5) 2.367 (6) 107.3 (4) 84.2 (3) b
  2.344 (5) 2.349 (6)      
PMe2Ph 2.242 (1) 2.359 (1) 94.80 (4) 86.55 (5) c
  2.245 (1) 2.355 (1)      
PCy3 2.299 (4) * 107.6 82.1 d
  2.289 (3) *      
PEtPh2 2.2633 (9) 2.3458 (9) 100.23 (3) 85.30 (3) e
  2.2517 (9) 2.3618 (9)      
PEt2Ph 2.2515 (12) 2.3505 (12) 94.43 (4) 85.77 (5) f
  2.2544 (13) 2.3619 (12)      
Note: (*) no three-dimensional coordinates available. References: (a) Messmer et al. (1967[Messmer, G. G., Amma, E. L. & Ibers, J. A. (1967). Inorg. Chem. 6, 725-730.]); (b) Porzio et al. (1980[Porzio, W., Musco, A. & Immirzi, A. (1980). Inorg. Chem. 19, 2537-2540.]); (c) Attia et al. (1987[Attia, W. M., Balducci, G. & Calligaris, M. (1987). Acta Cryst. C43, 1053-1055.]); (d) Cameron et al. (1989[Cameron, T. S., Clark, H. C., Linden, A. & Nicholaas, A. M. (1989). Inorg. Chim. Acta, 162, 9-10.]); (e) Domanska-Babul, Chojnacki et al. (2007[Domanska-Babul, W., Chojnacki, J. & Pikies, J. (2007). Acta Cryst. E63, m1956.]); (f) Domańska-Babul, Pikies et al. (2007[Domańska-Babul, W., Pikies, J. & Chojnacki, J. (2007). Acta Cryst. E63, m2583.]).

H atoms were constrained to idealized geometries, riding on their associated C atoms, with fixed C—H distances (0.97–1.00 Å) and with Uiso(H) = 1.2Ueq(C) [or 1.5Ueq(C) for methyl H atoms]. On transforming to the low-temperature phase, the structure refinement indicated the presence of an inversion twin. The major twin fraction refined to 0.486 (5) and was subsequently fixed at 0.5. There are high values of the maximum and minimum residual electron density in (1a). These peaks (2.19 and −1.98 e A−3, respectively) are located between the Cl atoms of the chloro­form solvent mol­ecule and reflect the distribution of electron density shown in Fig. 4[link] (left) caused by the dynamic disorder of this fragment. These residual peaks serve to reinforce the conclusions drawn regarding the disorder and the phase transition.

For both compounds, data collection: SMART (Bruker, 1999[Bruker (1999). SMART. Version 5.049. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2003[Bruker (2003). SAINT. Version 6.45A. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: OLEX2 (Dolomanov et al., 2009[Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339-341.]); software used to prepare material for publication: OLEX2.

Supporting information


Comment top

As part of our studies on hydrolysis/hydroxylation of chlorophosphane ligands in situ on platinum(II) centres (Cornet et al., 2011), we have prepared in solution the complex cis-[PtCl2(Cyp2PCl)(PEt3)] (Cyp is cyclopentyl) and allowed it to hydrolyse slowly by exposure to air. During the hydrolysis process, however, the 31P NMR solution-state spectra of the reaction mixture demonstrated that ligand scrambling was occurring. Crystals suitable for single-crystal X-ray diffraction were isolated from the reaction mixture which proved to be a new 1:1 solvate of cis-[PtCl2(PEt3)2] with CHCl3, (1).

Analysis of the evolution of the length of the crystallographic c axis of (1) with temperature (Fig. 1) clearly demonstrates the onset of a phase transition at ~149 K. Data for the calculation of these unit-cell parameters were collected during continuous, very slow cooling (2 K h-1); the data collections were such that equal amounts of reciprocal space were sampled for each data point, with the temperature of the data point being assigned to that at the mid-point of the scan. Each point on the graph therefore represents data recorded over ~1 K. Full data collections and structural determinations were then carried out above and below the phase-transition temperature at 220 K, (1a), and 120 K, (1b), respectively.

At 220 K, the space group of this solvated complex (1a) is Pnma, with a mirror plane bisecting both the Pt complex and the solvent molecule, resulting in a structure with Z' = 0.5. The CHCl3 molecule shows dynamic disorder, rotating about the C—H bond axis in a symmetrical fashion with respect to the mirror plane.

Upon cooling below the phase transition the rotation of the solvent molecule ceases, with respect to the time scale of the diffraction experiment, and appears to `lock' into place. The CHCl3 molecule is subsequently no longer symmetrical about a mirror plane, causing a reduction in the symmetry of the system. The structure of (1b) thus adopts the space group P212121 with Z' = 1 at 120 K. This transition is illustrated in Figs. 2 and 3. A whole-molecule twist, of both the complex and solvent molecules, with respect to the unit cell appears to be driven by a decrease in intermolecular distances, causing stronger Cl···H interactions. This results in movements of the ethyl `arms', further breaking the higher-temperature symmetry, as seen from the positions of atoms C32A/B in Fig. 2. The system reverts to the Pnma setting on returning to higher temperatures, demonstrating that the transition is fully reversible within the constraint that the temperature ramping rates are 120 K h-1.

Electron-density maps (Fobs) through the mean plane defined by the Cl atoms of the chloroform molecule at the two temperatures are shown in Fig. 4, highlighting the decrease in dynamic disorder across the phase transition.

Selected bond distances and angles for (1a) and (1b) are listed in Table 1, together with data for one of the previously identified unsolvated monoclinic polymorphs, (2) (space group Cc), at 293 K (Otto & Muller, 2001) for which atomic coordinates are available. The second reported unsolvated polymorph (Caldwell et al., 1977) is not included in Table 1 as no three-dimensional coordinates are available, although Otto & Muller describe it as being isostructural with their cis-[PtCl2(AsEt3)2] complex. These unsolvated polymorphs differ in the alignment of the PEt3 groups to that found in both solvated polymorphs of (1).

The difference in orientation of the PEt3 ligands around the Pt—P bonds may be better understood by considering the ethyl moiety that lies close to the coordination plane of the platinum atom. As in the case of the previously reported structures, there is one substituent on each phosphorus atom in (1) that lies very near this plane. However, unlike in the previously reported structures, these in-plane substituents point towards one another, as shown in the scheme. It may be expected that this arrangement of the ethyl groups will be somewhat sterically unfavourable, although it does give rise to an increased number of C—H···Cl interactions, mediated by the presence of the CHCl3 solvent.

The packing motifs of the solvated and unsolvated structures are dominated by C—H···Cl interactions. In the case of (2) the only short intermolecular interaction is between C121—H12B···Cl1i [H···Cl = 2.905 Å; symmetry code: (i) x + 1/2, -y + 1/2, z + 1/2], which form one-dimensional chains along the [101] direction. In contrast, (1a) and (1b) form extended hydrogen-bonding networks (Tables 2 and 3); (1a) forms two-dimensional sheets which, upon cooling, interlink to give rise to the three-dimensional hydrogen-bonding network found in (1b), shown in Fig. 5.

The Pt—Cl distances (Table 1) are almost identical in all forms of the structure (1a), (1b) and (2), although the Pt—P bond lengths show some variation and are shorter in both forms of (1). The most instructive differences between (1) and (2) lie in the bond angles in the approximately squareplanar coordination geometry. While the Cl—Pt—Cl angles are very similar, the P—Pt—P angle is over 5° larger in the new polymorphs, reflecting the increased steric repulsion between the PEt3 groups. There is far less variance in the Cl—Pt—P angles found in the polymorphs of (1) (all within 1°) compared with the monoclinic form, where they differ by > 6°, a result explained by the differing steric demands on the positions of the two Cl atoms in these structures. These effects may arise from the difference in alignment of the ethyl substituents on the PEt3 ligands, compared with that in (2) described by Otto & Muller (2001). The geometrical parameters for (1a) and (1b) are similar to the literature data for other cis-[PtCl2(PR3)2] complexes (Table 4).

Related literature top

For related literature, see: Caldwell et al. (1977); Cosier & Glazer (1986); Dillon et al. (2010); Otto & Muller (2001).

Experimental top

During the synthesis of cis-[PtCl2(PCyp2Cl)(PEt3)], all manipulations, including NMR sample preparation, were carried out either under an inert atmosphere of dry nitrogen or in vacuo, using standard Schlenk line or glove-box techniques. Chemicals of the best available commercial grade were used, in general without further purification. The 31P NMR spectra of all phosphorus-containing starting materials were recorded, to verify that no major impurities were present. The synthesis of trans-[PtCl(µ-Cl)(PEt3)]2 was carried out according to the literature procedure (Dillon et al., 2010). 31P NMR spectra were obtained on a Varian Mercury 400 Fourier-transform spectrometer at 161.91 MHz; chemical shifts are referenced to 85% H3PO4, with the high-frequency direction taken as positive.

Cyp2PCl (0.042 ml, 0.22 mmol) was added via syringe to a solution of trans-[PtCl(µ-Cl)(PEt3)]2 (0.0840 g, 0.11 mmol) in CDCl3 (1 ml). Formation of cis-[PtCl2(PBCyp2Cl)(PAEt3)] was confirmed using 31P NMR spectroscopy: δPA 13.6 p.p.m. (singlet + satellites, 1JPt—P = 3506 Hz, 2JP—P = 13 Hz), δPB 113.0 p.p.m. (singlet + satellites, 1JPt—P = 4024 Hz, 2JP—P= 13 Hz). Attempted hydrolysis of this complex resulted in ligand scrambling to afford compound (1), cis-[PtCl2(PEt3)2] (31P NMR: δ10.2 p.p.m. (singlet + satellites, 1JPt—P = 3514 Hz)), and also cis-[PtCl2(PCyp2Cl)2] (31P NMR: δ108.1ppm (singlet + satellites, 1JPt—P = 4037 Hz)). Colourless crystals of (1) were obtained by slow evaporation of solvent from the reaction mixture. Crystals of (1) were also isolated from hydrolysis reactions of cis-[PtCl2(PCy2Cl)(PEt3)] and cis-[PtCl2(PCyCl2)(PEt3)] (Cy = cyclo-hexyl).

A crystal of (1) was mounted in inert oil and placed into the cold gas stream of a N2 cryostream device (Cosier & Glazer, 1986) at 220 K. Data were collected at this temperature before ramping at a rate of 120 K h-1 to 120 K, where the diffraction experiment was repeated. The temperature was again ramped at 120 K h-1 to 220 K where a short data collection was performed to assess the reversibility of the transition.

Refinement top

H atoms were constrained to idealized geometries, riding on their associated C atoms, with fixed C—H distances (0.97–1.00 Å) and with Uiso(H) = 1.2Ueq(C) [or 1.5Ueq(C) for methyl H atoms]. On transforming to the low-temperature phase, the structure refinement indicated the presence of an inversion twin. The major twin fraction refined to 0.486 (5) and was subsequently fixed at 0.5. There are high values of the maximum and minimum residual electron density in (1a). These peaks (2.19 and -1.98 e A-3, respectively) are located between the Cl atoms of the chloroform solvent molecule, and reflect the distribution of electron density shown in Fig. 4 (left), caused by the dynamic disorder of this fragment. These residual peaks serve to reinforce the conclusions drawn regarding the disorder and the phase transition.

Computing details top

For both compounds, data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: OLEX2 (Dolomanov et al., 2009). Software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009) for (1a); OLEX2 (Dolomanov et al. 2009) for (1b).

Figures top
[Figure 1] Fig. 1. Graph showing evolution of the c-axis length of (1) with temperature.
[Figure 2] Fig. 2. The molecular structure of (1a) at 220 K (left, the mirror plane runs through atoms Pt1, Cl1S and C1S) and (1b) at 120 K (right). Atomic displacement parameters are shown at 50% probability in all crystallographic figures.
[Figure 3] Fig. 3. Projection of the crystal packing along the [100] direction of (1a) and (1b) (left and right, respectively), showing the shift in relative molecular orientations as well as the layered motif exhibited in both structures. H atoms have been omitted for clarity.
[Figure 4] Fig. 4. Electron-density maps (Fobs) through the mean plane defined by the Cl atoms of the chloroform solvent molecule in the structures at 220 K (left) and 120 K (right). Contour lines are displayed at 0.5 e Å-3 intervals (higher contour levels have been omitted for clarity for the 120 K data).
[Figure 5] Fig. 5. Hydrogen-bonding networks of (1a) at 220 K (left) and (1b) at 120 K (right). The displayed intermolecular interactions were identified using the same threshold delta function in OLEX2 (Dolomanov et al., 2009) of 1.68 Å to highlight the difference between the structures either side of the phase transition. H atoms not involved in intermolecular contacts have been omitted for clarity.
(1a) cis-dichloridobis(triethylphosphine)platinum(II) chloroform monosolvate top
Crystal data top
[PtCl2(C6H15P)2]·CHCl3Dx = 1.807 Mg m3
Mr = 621.66Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, PnmaCell parameters from 5535 reflections
a = 19.0103 (9) Åθ = 2.5–27.8°
b = 15.7378 (7) ŵ = 6.86 mm1
c = 7.6394 (4) ÅT = 220 K
V = 2285.56 (19) Å3Block, colourless
Z = 40.21 × 0.20 × 0.18 mm
F(000) = 1208
Data collection top
Bruker SMART CCD 1K area-detector
diffractometer
2928 independent reflections
Radiation source: fine-focus sealed tube2317 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.053
Detector resolution: 7.9 pixels mm-1θmax = 28.3°, θmin = 2.1°
ω scansh = 2524
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 2019
Tmin = 0.759, Tmax = 1.0l = 810
15061 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.105H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0491P)2 + 14.4642P]
where P = (Fo2 + 2Fc2)/3
2928 reflections(Δ/σ)max = 0.001
103 parametersΔρmax = 2.19 e Å3
0 restraintsΔρmin = 1.98 e Å3
Crystal data top
[PtCl2(C6H15P)2]·CHCl3V = 2285.56 (19) Å3
Mr = 621.66Z = 4
Orthorhombic, PnmaMo Kα radiation
a = 19.0103 (9) ŵ = 6.86 mm1
b = 15.7378 (7) ÅT = 220 K
c = 7.6394 (4) Å0.21 × 0.20 × 0.18 mm
Data collection top
Bruker SMART CCD 1K area-detector
diffractometer
2928 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
2317 reflections with I > 2σ(I)
Tmin = 0.759, Tmax = 1.0Rint = 0.053
15061 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.105H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0491P)2 + 14.4642P]
where P = (Fo2 + 2Fc2)/3
2928 reflectionsΔρmax = 2.19 e Å3
103 parametersΔρmin = 1.98 e Å3
Special details top

Experimental. The data collection nominally covered a full sphere of reciprocal space by a combination of 4 sets of ω scans each set at different ϕ and/or 2θ angles and each scan (10.00 s exposure) covering -0.300\ degrees in ω. The crystal to detector distance was 4.424 cm.

R(int) was 0.0791 before and 0.0427 after absorption correction. The Ratio of minimum to maximum transmission is 0.759252. The λ/2 correction factor is 0.0000

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

The large WGHT parameter and the low bond precision alerts are generated because the solvent molecule disorder was deliberately not refined as this study was designed to highlight the phase transition occurring.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pt10.675107 (17)0.25000.62106 (4)0.02504 (11)
P1A0.64589 (9)0.13655 (10)0.7858 (2)0.0298 (3)
Cl1A0.71140 (11)0.14781 (12)0.4133 (2)0.0468 (4)
C21A0.6063 (4)0.1469 (4)1.0030 (9)0.0375 (15)
H21B0.63790.18081.07650.045*
H21A0.56210.17850.99150.045*
C31A0.5837 (4)0.0699 (4)0.6672 (10)0.0422 (17)
H31B0.60590.05060.55840.051*
H31A0.57350.01950.73800.051*
C22A0.5909 (5)0.0626 (5)1.0976 (11)0.060 (2)
H22B0.56640.07411.20650.090*
H22C0.63480.03361.12240.090*
H22A0.56180.02701.02370.090*
C11A0.7221 (4)0.0685 (5)0.8193 (11)0.0476 (18)
H11A0.70700.01650.87920.057*
H11B0.74120.05220.70510.057*
C32A0.5155 (5)0.1136 (6)0.6231 (13)0.070 (3)
H32B0.49300.13270.73000.105*
H32A0.48470.07410.56280.105*
H32C0.52480.16200.54810.105*
C12A0.7799 (4)0.1105 (6)0.9261 (12)0.059 (2)
H12A0.76150.12681.03970.089*
H12B0.79670.16060.86510.089*
H12C0.81850.07090.94160.089*
C1S0.3745 (6)0.25001.1242 (16)0.048 (3)
H1S0.32310.25001.14510.058*
Cl1S0.3914 (4)0.25000.9134 (10)0.341 (11)
Cl2S0.4105 (3)0.1635 (4)1.2048 (14)0.292 (5)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pt10.02761 (18)0.02415 (17)0.02334 (17)0.0000.00139 (13)0.000
P1A0.0343 (8)0.0232 (7)0.0320 (8)0.0015 (7)0.0013 (7)0.0014 (6)
Cl1A0.0544 (11)0.0448 (10)0.0411 (9)0.0038 (8)0.0103 (8)0.0162 (8)
C21A0.041 (4)0.041 (4)0.031 (3)0.005 (3)0.003 (3)0.005 (3)
C31A0.049 (4)0.034 (3)0.045 (4)0.012 (3)0.003 (3)0.005 (3)
C22A0.079 (6)0.051 (5)0.049 (5)0.020 (5)0.001 (4)0.015 (4)
C11A0.045 (4)0.038 (4)0.059 (5)0.012 (3)0.001 (4)0.009 (4)
C32A0.057 (5)0.063 (6)0.091 (7)0.003 (5)0.026 (5)0.018 (5)
C12A0.045 (4)0.074 (6)0.060 (5)0.014 (4)0.012 (4)0.014 (5)
C1S0.036 (5)0.042 (6)0.066 (7)0.0000.001 (5)0.000
Cl1S0.077 (4)0.85 (3)0.099 (5)0.0000.013 (4)0.000
Cl2S0.090 (3)0.203 (6)0.582 (15)0.030 (3)0.018 (6)0.242 (8)
Geometric parameters (Å, º) top
Pt1—P1Ai2.2540 (16)C31A—H31B0.9800
Pt1—P1A2.2540 (16)C31A—H31A0.9800
Pt1—Cl1A2.3627 (17)C22A—H22B0.9700
Pt1—Cl1Ai2.3627 (17)C22A—H22C0.9700
P1A—C21A1.829 (7)C22A—H22A0.9700
P1A—C31A1.821 (7)C11A—H11A0.9800
P1A—C11A1.819 (7)C11A—H11B0.9800
C21A—C22A1.538 (10)C32A—H32B0.9700
C31A—C32A1.507 (12)C32A—H32A0.9700
C11A—C12A1.520 (12)C32A—H32C0.9700
C1S—Cl1S1.642 (14)C12A—H12A0.9700
C1S—Cl2Si1.643 (8)C12A—H12B0.9700
C1S—Cl2S1.643 (8)C12A—H12C0.9700
C21A—H21B0.9800C1S—H1S0.9900
C21A—H21A0.9800
P1A—Pt1—P1Ai104.77 (9)H31B—C31A—H31A107.6
P1Ai—Pt1—Cl1A170.51 (7)C21A—C22A—H22B109.5
P1A—Pt1—Cl1A84.71 (6)C21A—C22A—H22C109.5
P1A—Pt1—Cl1Ai170.51 (7)H22B—C22A—H22C109.5
P1Ai—Pt1—Cl1Ai84.72 (6)C21A—C22A—H22A109.5
Cl1Ai—Pt1—Cl1A85.80 (10)H22B—C22A—H22A109.5
C21A—P1A—Pt1122.5 (2)H22C—C22A—H22A109.5
C31A—P1A—Pt1109.8 (3)C12A—C11A—H11A108.9
C31A—P1A—C21A103.6 (3)P1A—C11A—H11A108.9
C22A—C21A—P1A115.3 (5)C12A—C11A—H11B108.9
C11A—P1A—Pt1110.4 (3)P1A—C11A—H11B108.9
C11A—P1A—C21A104.6 (4)H11A—C11A—H11B107.7
C11A—P1A—C31A104.3 (4)C31A—C32A—H32B109.5
C32A—C31A—P1A114.0 (6)C31A—C32A—H32A109.5
C12A—C11A—P1A113.3 (6)H32B—C32A—H32A109.5
Cl1S—C1S—Cl2S106.6 (6)C31A—C32A—H32C109.5
Cl1S—C1S—Cl2Si106.6 (6)H32B—C32A—H32C109.5
Cl2Si—C1S—Cl2S111.9 (10)H32A—C32A—H32C109.5
C22A—C21A—H21B108.4C11A—C12A—H12A109.5
P1A—C21A—H21B108.4C11A—C12A—H12B109.5
C22A—C21A—H21A108.4H12A—C12A—H12B109.5
P1A—C21A—H21A108.4C11A—C12A—H12C109.5
H21B—C21A—H21A107.5H12A—C12A—H12C109.5
C32A—C31A—H31B108.7H12B—C12A—H12C109.5
P1A—C31A—H31B108.7Cl1S—C1S—H1S110.5
C32A—C31A—H31A108.7Cl2S—C1S—H1S110.5
P1A—C31A—H31A108.7Cl2Si—C1S—H1S110.5
Symmetry code: (i) x, y+1/2, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C21A—H21B···Cl1Aii0.982.973.717 (7)134
C31A—H31A···Cl2Siii0.982.933.802 (9)149
C1S—H1S···Cl1Aiv0.992.703.505 (10)139
C1S—H1S···Cl1Av0.992.703.505 (10)138
Symmetry codes: (ii) x, y, z+1; (iii) x+1, y, z+2; (iv) x1/2, y+1/2, z+3/2; (v) x1/2, y, z+3/2.
(1b) cis-dichloridobis(triethylphosphine)platinum(II) chloroform monosolvate top
Crystal data top
[PtCl2(C6H15P)2]·CHCl3Dx = 1.849 Mg m3
Mr = 621.66Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121Cell parameters from 6948 reflections
a = 18.9529 (9) Åθ = 2.5–28.3°
b = 15.7268 (8) ŵ = 7.02 mm1
c = 7.4934 (4) ÅT = 120 K
V = 2233.5 (2) Å3Block, colourless
Z = 40.21 × 0.20 × 0.18 mm
F(000) = 1208
Data collection top
Bruker SMART CCD 1K area-detector
diffractometer
5546 independent reflections
Radiation source: fine-focus sealed tube5240 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.045
Detector resolution: 7.9 pixels mm-1θmax = 28.3°, θmin = 1.7°
ω scansh = 2523
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 2020
Tmin = 0.757, Tmax = 1.000l = 99
25676 measured reflections
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.045 w = 1/[σ2(Fo2) + (0.0142P)2 + 0.9726P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
5546 reflectionsΔρmax = 0.91 e Å3
196 parametersΔρmin = 1.02 e Å3
0 restraintsAbsolute structure: fixed due to inversion twin
Primary atom site location: structure-invariant direct methodsAbsolute structure parameter: 0.5
Crystal data top
[PtCl2(C6H15P)2]·CHCl3V = 2233.5 (2) Å3
Mr = 621.66Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 18.9529 (9) ŵ = 7.02 mm1
b = 15.7268 (8) ÅT = 120 K
c = 7.4934 (4) Å0.21 × 0.20 × 0.18 mm
Data collection top
Bruker SMART CCD 1K area-detector
diffractometer
5546 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
5240 reflections with I > 2σ(I)
Tmin = 0.757, Tmax = 1.000Rint = 0.045
25676 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.045Δρmax = 0.91 e Å3
S = 1.04Δρmin = 1.02 e Å3
5546 reflectionsAbsolute structure: fixed due to inversion twin
196 parametersAbsolute structure parameter: 0.5
0 restraints
Special details top

Experimental. The data collection nominally covered a full sphere of reciprocal space by a combination of 6 sets of ω scans each set at different ϕ and/or 2θ angles and each scan (10.00 s exposure) covering -0.300\ degrees in ω. The crystal to detector distance was 4.424 cm.

R(int) was 0.0786 before and 0.0443 after absorption correction. The Ratio of minimum to maximum transmission is 0.757430. The λ/2 correction factor is 0.0000

A non standard unit cell setting was used to maintain consistency with the higher temperature phase in space group Pnma.

The Pt1 – P1b inconsistency with the Hirshfeld test is believed to be due to Fourier termination errors.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Pt10.193474 (8)0.243929 (8)0.364760 (17)0.01508 (4)
Cl1A0.22137 (6)0.33608 (6)0.12473 (15)0.0246 (2)
P1A0.15305 (6)0.36208 (6)0.50042 (14)0.0152 (2)
P1B0.17255 (6)0.13972 (6)0.56457 (15)0.0173 (2)
Cl1B0.24816 (7)0.13603 (7)0.19350 (16)0.0307 (3)
Cl2S0.44128 (7)0.16527 (8)0.10031 (19)0.0404 (3)
Cl3S0.42004 (8)0.32998 (9)0.06034 (18)0.0450 (3)
Cl1S0.41143 (8)0.30983 (8)0.32183 (17)0.0419 (3)
C1S0.3946 (2)0.2625 (3)0.1141 (6)0.0256 (9)
H1S0.34290.25070.10390.031*
C21A0.1171 (2)0.3608 (3)0.7257 (6)0.0209 (10)
H21A0.07480.32380.72690.025*
H21B0.15240.33510.80650.025*
C31A0.0835 (2)0.4122 (2)0.3678 (6)0.0221 (8)
H31B0.07320.46920.41750.027*
H31A0.10050.41990.24390.027*
C21B0.1225 (2)0.1563 (3)0.7703 (6)0.0202 (9)
H21D0.15010.19400.84960.024*
H21C0.07810.18610.74030.024*
C12A0.2840 (2)0.4104 (2)0.6365 (7)0.0232 (9)
H12A0.30380.35690.59150.035*
H12B0.26570.40160.75740.035*
H12C0.32100.45400.63900.035*
C11A0.2242 (2)0.4394 (2)0.5141 (6)0.0211 (9)
H11A0.24320.44950.39300.025*
H11B0.20500.49390.55900.025*
C11B0.2552 (2)0.0947 (3)0.6392 (8)0.0299 (10)
H11D0.24550.05230.73360.036*
H11C0.27770.06450.53800.036*
C12B0.3067 (3)0.1606 (3)0.7116 (6)0.0322 (10)
H12D0.32220.19780.61430.048*
H12F0.34780.13160.76310.048*
H12E0.28340.19460.80390.048*
C32A0.0158 (2)0.3599 (3)0.3650 (8)0.0415 (13)
H32B0.01940.38840.29010.062*
H32C0.00250.35440.48680.062*
H32A0.02570.30330.31640.062*
C22B0.1042 (3)0.0748 (3)0.8734 (7)0.0352 (12)
H22A0.07080.04070.80360.053*
H22C0.08280.08990.98820.053*
H22B0.14730.04180.89420.053*
C22A0.0965 (3)0.4476 (3)0.7995 (6)0.0290 (11)
H22D0.06180.47420.72020.043*
H22F0.13850.48380.80730.043*
H22E0.07600.44070.91870.043*
C32B0.0507 (3)0.0763 (3)0.4035 (7)0.0346 (12)
H32E0.05150.12590.32440.052*
H32F0.02360.08980.51120.052*
H32D0.02870.02830.34160.052*
C31B0.1256 (3)0.0530 (3)0.4551 (6)0.0271 (11)
H31C0.15180.03610.34650.033*
H31D0.12430.00330.53630.033*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Pt10.01713 (7)0.01275 (6)0.01536 (6)0.00163 (6)0.00011 (6)0.00073 (6)
Cl1A0.0281 (5)0.0272 (5)0.0186 (5)0.0016 (4)0.0021 (5)0.0063 (5)
P1A0.0174 (6)0.0128 (5)0.0155 (5)0.0002 (4)0.0032 (4)0.0004 (4)
P1B0.0157 (6)0.0132 (5)0.0231 (5)0.0003 (4)0.0003 (4)0.0007 (4)
Cl1B0.0353 (7)0.0209 (5)0.0357 (6)0.0029 (5)0.0147 (5)0.0077 (4)
Cl2S0.0394 (7)0.0317 (6)0.0502 (8)0.0083 (5)0.0126 (6)0.0068 (6)
Cl3S0.0451 (8)0.0457 (8)0.0441 (7)0.0061 (6)0.0030 (7)0.0158 (6)
Cl1S0.0454 (8)0.0432 (7)0.0371 (7)0.0049 (6)0.0011 (6)0.0123 (5)
C1S0.022 (2)0.023 (2)0.032 (2)0.0020 (17)0.0046 (17)0.000 (2)
C21A0.022 (2)0.018 (2)0.023 (2)0.0018 (18)0.0036 (19)0.0009 (18)
C31A0.023 (2)0.0213 (18)0.023 (2)0.0025 (16)0.000 (2)0.001 (2)
C21B0.024 (3)0.017 (2)0.020 (2)0.0038 (17)0.0003 (18)0.0039 (17)
C12A0.017 (2)0.0242 (19)0.028 (2)0.0037 (15)0.005 (2)0.005 (2)
C11A0.025 (2)0.015 (2)0.023 (2)0.0027 (17)0.0041 (19)0.0006 (16)
C11B0.023 (2)0.022 (2)0.045 (3)0.0055 (17)0.001 (3)0.014 (2)
C12B0.025 (2)0.035 (2)0.037 (2)0.006 (2)0.005 (2)0.009 (2)
C32A0.028 (3)0.042 (3)0.054 (3)0.009 (2)0.022 (3)0.014 (3)
C22B0.042 (3)0.035 (2)0.028 (3)0.006 (2)0.005 (3)0.011 (2)
C22A0.027 (3)0.029 (2)0.031 (3)0.002 (2)0.001 (2)0.008 (2)
C32B0.030 (3)0.035 (3)0.038 (3)0.011 (2)0.003 (2)0.011 (2)
C31B0.035 (3)0.015 (2)0.031 (3)0.0074 (19)0.009 (2)0.0058 (18)
Geometric parameters (Å, º) top
Pt1—Cl1A2.3696 (10)C21B—H21C0.9900
Pt1—P1A2.2524 (11)C12A—H12A0.9800
Pt1—P1B2.2550 (11)C12A—H12B0.9800
Pt1—Cl1B2.3665 (11)C12A—H12C0.9800
P1A—C21A1.821 (5)C11A—H11A0.9900
P1A—C31A1.830 (4)C11A—H11B0.9900
P1A—C11A1.818 (4)C11B—H11D0.9900
P1B—C21B1.828 (4)C11B—H11C0.9900
P1B—C11B1.808 (4)C12B—H12D0.9800
P1B—C31B1.824 (4)C12B—H12F0.9800
Cl2S—C1S1.770 (4)C12B—H12E0.9800
Cl3S—C1S1.752 (4)C32A—H32B0.9800
Cl1S—C1S1.755 (4)C32A—H32C0.9800
C21A—C22A1.524 (6)C32A—H32A0.9800
C31A—C32A1.524 (6)C22B—H22A0.9800
C21B—C22B1.536 (6)C22B—H22C0.9800
C12A—C11A1.529 (6)C22B—H22B0.9800
C11B—C12B1.523 (6)C22A—H22D0.9800
C32B—C31B1.516 (6)C22A—H22F0.9800
C1S—H1S1.0000C22A—H22E0.9800
C21A—H21A0.9900C32B—H32E0.9800
C21A—H21B0.9900C32B—H32F0.9800
C31A—H31B0.9900C32B—H32D0.9800
C31A—H31A0.9900C31B—H31C0.9900
C21B—H21D0.9900C31B—H31D0.9900
P1A—Pt1—Cl1A85.06 (4)H12A—C12A—H12B109.5
P1A—Pt1—P1B103.89 (4)C11A—C12A—H12C109.5
P1A—Pt1—Cl1B170.15 (4)H12A—C12A—H12C109.5
P1B—Pt1—Cl1A171.01 (4)H12B—C12A—H12C109.5
P1B—Pt1—Cl1B85.18 (4)C12A—C11A—H11A109.1
Cl1B—Pt1—Cl1A85.94 (4)P1A—C11A—H11A109.1
Cl3S—C1S—Cl2S110.0 (2)C12A—C11A—H11B109.1
Cl3S—C1S—Cl1S110.8 (2)P1A—C11A—H11B109.1
Cl1S—C1S—Cl2S109.1 (2)H11A—C11A—H11B107.8
C21A—P1A—Pt1122.47 (14)C12B—C11B—H11D108.9
C21A—P1A—C31A103.8 (2)P1B—C11B—H11D108.9
C31A—P1A—Pt1110.81 (14)C12B—C11B—H11C108.9
C21B—P1B—Pt1123.20 (14)P1B—C11B—H11C108.9
C12A—C11A—P1A112.6 (3)H11D—C11B—H11C107.7
C11A—P1A—Pt1108.96 (15)C11B—C12B—H12D109.5
C11A—P1A—C21A103.5 (2)C11B—C12B—H12F109.5
C11A—P1A—C31A106.10 (18)H12D—C12B—H12F109.5
C11B—P1B—Pt1109.72 (16)C11B—C12B—H12E109.5
C11B—P1B—C21B104.2 (2)H12D—C12B—H12E109.5
C11B—P1B—C31B105.6 (2)H12F—C12B—H12E109.5
C12B—C11B—P1B113.5 (3)C31A—C32A—H32B109.5
C32A—C31A—P1A112.5 (3)C31A—C32A—H32C109.5
C22B—C21B—P1B115.0 (3)H32B—C32A—H32C109.5
C22A—C21A—P1A115.0 (3)C31A—C32A—H32A109.5
C32B—C31B—P1B113.0 (3)H32B—C32A—H32A109.5
C31B—P1B—Pt1109.33 (16)H32C—C32A—H32A109.5
C31B—P1B—C21B103.4 (2)C21B—C22B—H22A109.5
Cl3S—C1S—H1S109.0C21B—C22B—H22C109.5
Cl1S—C1S—H1S109.0H22A—C22B—H22C109.5
Cl2S—C1S—H1S109.0C21B—C22B—H22B109.5
C22A—C21A—H21A108.5H22A—C22B—H22B109.5
P1A—C21A—H21A108.5H22C—C22B—H22B109.5
C22A—C21A—H21B108.5C21A—C22A—H22D109.5
P1A—C21A—H21B108.5C21A—C22A—H22F109.5
H21A—C21A—H21B107.5H22D—C22A—H22F109.5
C32A—C31A—P1A112.5 (3)C21A—C22A—H22E109.5
C32A—C31A—H31B109.1H22D—C22A—H22E109.5
P1A—C31A—H31B109.1H22F—C22A—H22E109.5
C32A—C31A—H31A109.1C31B—C32B—H32E109.5
P1A—C31A—H31A109.1C31B—C32B—H32F109.5
H31B—C31A—H31A107.8H32E—C32B—H32F109.5
C22B—C21B—P1B115.0 (3)C31B—C32B—H32D109.5
C22B—C21B—H21D108.5H32E—C32B—H32D109.5
P1B—C21B—H21D108.5H32F—C32B—H32D109.5
C22B—C21B—H21C108.5C32B—C31B—H31C109.0
P1B—C21B—H21C108.5P1B—C31B—H31C109.0
H21D—C21B—H21C107.5C32B—C31B—H31D109.0
C11A—C12A—H12A109.5P1B—C31B—H31D109.0
C11A—C12A—H12B109.5H31C—C31B—H31D107.8
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C1S—H1S···Cl1A1.002.673.482 (4)138
C1S—H1S···Cl1B1.002.633.466 (4)141
C21A—H21B···Cl1Ai0.992.723.606 (5)149
C21A—H21A···Cl2Sii0.992.853.601 (5)133
C12A—H12A···Cl1S0.982.973.727 (5)135
C32B—H32F···Cl1Sii0.982.933.797 (5)148
C31B—H31D···Cl2Siii0.992.973.817 (4)145
Symmetry codes: (i) x, y, z+1; (ii) x1/2, y+1/2, z+1; (iii) x+1/2, y, z+1/2.

Experimental details

(1a)(1b)
Crystal data
Chemical formula[PtCl2(C6H15P)2]·CHCl3[PtCl2(C6H15P)2]·CHCl3
Mr621.66621.66
Crystal system, space groupOrthorhombic, PnmaOrthorhombic, P212121
Temperature (K)220120
a, b, c (Å)19.0103 (9), 15.7378 (7), 7.6394 (4)18.9529 (9), 15.7268 (8), 7.4934 (4)
V3)2285.56 (19)2233.5 (2)
Z44
Radiation typeMo KαMo Kα
µ (mm1)6.867.02
Crystal size (mm)0.21 × 0.20 × 0.180.21 × 0.20 × 0.18
Data collection
DiffractometerBruker SMART CCD 1K area-detector
diffractometer
Bruker SMART CCD 1K area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Multi-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.759, 1.00.757, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
15061, 2928, 2317 25676, 5546, 5240
Rint0.0530.045
(sin θ/λ)max1)0.6660.667
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.105, 1.02 0.023, 0.045, 1.04
No. of reflections29285546
No. of parameters103196
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
w = 1/[σ2(Fo2) + (0.0491P)2 + 14.4642P]
where P = (Fo2 + 2Fc2)/3
w = 1/[σ2(Fo2) + (0.0142P)2 + 0.9726P]
where P = (Fo2 + 2Fc2)/3
Δρmax, Δρmin (e Å3)2.19, 1.980.91, 1.02
Absolute structure?Fixed due to inversion twin
Absolute structure parameter?0.5

Computer programs: SMART (Bruker, 1999), SAINT (Bruker, 2003), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), OLEX2 (Dolomanov et al., 2009), OLEX2 (Dolomanov et al. 2009).

Hydrogen-bond geometry (Å, º) for (1a) top
D—H···AD—HH···AD···AD—H···A
C21A—H21B···Cl1Ai0.982.973.717 (7)134
C31A—H31A···Cl2Sii0.982.933.802 (9)149
C1S—H1S···Cl1Aiii0.992.703.505 (10)139
C1S—H1S···Cl1Aiv0.992.703.505 (10)138
Symmetry codes: (i) x, y, z+1; (ii) x+1, y, z+2; (iii) x1/2, y+1/2, z+3/2; (iv) x1/2, y, z+3/2.
Hydrogen-bond geometry (Å, º) for (1b) top
D—H···AD—HH···AD···AD—H···A
C1S—H1S···Cl1A1.002.673.482 (4)138
C1S—H1S···Cl1B1.002.633.466 (4)141
C21A—H21B···Cl1Ai0.992.723.606 (5)149
C21A—H21A···Cl2Sii0.992.853.601 (5)133
C12A—H12A···Cl1S0.982.973.727 (5)135
C32B—H32F···Cl1Sii0.982.933.797 (5)148
C31B—H31D···Cl2Siii0.992.973.817 (4)145
Symmetry codes: (i) x, y, z+1; (ii) x1/2, y+1/2, z+1; (iii) x+1/2, y, z+1/2.
Table 1. Selected geometric parameters (Å, °) for (1a), (1b) and (2). top
(1a)(1b)(2)
Pt1—Cl1A2.3627 (17)2.3696 (10)2.364 (2)
Pt1—Cl1B2.3665 (11)2.374 (2)
Pt1—P1A2.2540 (16)2.2524 (11)2.264 (2)
Pt1—P1B2.2550 (11)2.2616 (18)
P1A—Pt1—P1B*104.77 (9)103.89 (4)98.39 (7)
P1A—Pt1—Cl1A84.71 (6)85.18 (4)84.63 (9)
P1A—Pt1—Cl1B85.06 (4)91.33 (7)
Cl1A—Pt1—Cl1B*85.80 (10)85.94 (4)85.66 (9)
Note: (*) symmetry equivalent for (1a) using symmetry operation (x, -y+1/2, z).
Table 4. Selected geometric parameters (Å, °) for cis-[PtCl2(PR3)2] complexes. top
CompoundPt—PPt—ClP—Pt—PCl—P—ClReference
PMe32.256 (8)2.364 (8)96.2 (4)87.47 (3)Messmer et al. (1967)
2.239 (6)2.388 (8)
PtBu32.321 (5)2.367 (6)107.3 (4)84.2 (3)Porzio et al. (1980)
2.344 (5)2.349 (6)
PMe2Ph2.242 (1)2.359 (1)94.80 (4)86.55 (5)Attia et al. (1987)
2.245 (1)2.355 (1)
PCy32.299 (4)*107.682.1Cameron et al. (1989)
2.289 (3)*
PEtPh22.2633 (9)2.3458 (9)100.23 (3)85.30 (3)Domanska-Babul, Chojnacki & Pikies (2007)
2.2517 (9)2.3618 (9)
PEt2Ph2.2515 (12)2.3505 (12)94.43 (4)85.77 (5)Domańska-Babul, Pikies & Chojnacki (2007)
2.2544 (13)2.3619 (12)
Note: (*) no three-dimensional coordinates available.
 

Acknowledgements

We thank the EPSRC (UK) for research grant No. EP/C536436/1 (MRP) and for a research studentship (HJS), the Maria da Graça Memorial Fund/Chemistry Department, Durham University (PKM), for financial support, and Johnson Matthey plc for the loan of precious metal compounds.

References

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