research communications
cis-diamminebis(nitrito-κN)platinum(II)
ofaUniversity of Innsbruck, Institute of Mineralogy & Petrography, Innrain 52, A-6020 Innsbruck, Austria, bUniversity of Innsbruck, Institute of Pharmacy, Innrain 80, 6020 Innsbruck, Austria, and cMED-EL Medical Electronics, Fürstenweg 77a, A-6020 Innsbruck, Austria
*Correspondence e-mail: volker.kahlenberg@uibk.ac.at
Single crystals of cis-[Pt(NO2)2(NH3)2], were obtained by means of hypersaturation directly out of a plating electrolyte. The square-planar coordination environment of the divalent PtII atom is formed by four N atoms belonging to two ammine and two monodentate nitrite ligands. The ligands adopt a cis configuration. The contains stacks of close-packed molecules which run parallel to [001]. There are nine crystallographically independent intermolecular N—H⋯O hydrogen bonds, resulting in a hydrogen-bonded hxl-type framework in which each molecule serves as an eight-connected node. Four of the nine distinct hydrogen bonds connect complexes which belong to the same close-packed column parallel to [001]. In contrast to the previously reported of the trans isomer, the title structure does not display intramolecular hydrogen bonding.
Keywords: crystal structure; hydrogen bonding; topology; platinum(II); cis-isomer.
CCDC reference: 1053034
1. Chemical context
Several platinum salt systems have been studied intensively for the ). One of the materials that has frequently been used as a platinum source in electrochemical deposition processes is diamminebis(nitrito)platinum(II), better known as platinum p-salt. Aqueous slurries of this compound are especially suited for the production of dense and homogeneous coatings. Indeed, this material was used for electroplating by Keitel & Zschiegner as early as 1931. The ligands stabilize the platinum ion in solution and prevent the oxidation of PtII to PtIV. However, to enable electrochemical platinum deposition out of this stable complex, temperatures of approximately 363 K are required.
of platinum and platinum alloys with regard to their economic availability and their hydrolysis behaviour in solution. An excellent summary of the different systems can be found in the review paper of Baumgärtner & Raub (19882. Structural commentary
The 3)2(NO2)2] complex whose ammine and nitrito ligands adopt a cis configuration (Fig. 1). The PtII atom is coordinated by one nitrogen atom from each of the four ligands in a square-planar fashion. The distances between the positions of Pt, N1, N2, N3 and N4 and the corresponding least-squares plane are −0.0018 (13), −0.0191 (15), 0.0202 (16), −0.0192 (15) and 0.0199 (15) Å, respectively. As expected, the Pt—N bonds to the ammine ligands, 2.039 (3) and 2.052 (3) Å, are somewhat longer than the Pt—N bonds to each of the monodentate nitrite groups, 1.995 (3) and 2.001 (4) Å. The largest deviation of any N—Pt—N bond angle from its ideal value is observed in the angle between the two nitrite groups [N1—Pt—N2 = 93.06 (13)°]. The bond-valence sum for the four cation–anion interactions around the PtII atom is 2.256 valence units according to a calculation using the parameter set for the Pt—N bond given by Brown (2002). The NO2 planes defined by the two nitrite groups form angles of 38.6 (2) and 61.6 (2)°, respectively, with the least-squares plane of the central PtN4 unit. Moreover, these NO2 planes are twisted against one another by 62.4 (4)°.
of the title structure contains a neutral [Pt(NH3. Supramolecular features
Molecules are arranged into columns propagating parallel to [001] in such a way that neighbouring cis-[Pt(NH3)2(NO2)2] units are related by glide mirror symmetry, and their central PtN4 planes form an angle of approximately 85° with the stacking vector (Fig. 2). The metal coordination centres of neighbouring molecules in the resulting stack are separated by 3.5486 (2) Å and the corresponding intermolecular Pt⋯Pt⋯Pt angle is 176.1°. By comparison, the double value of the default Pt contact radius (Bondi, 1964) is 3.44 Å. The distances between platinum ions belonging to neighbouring columns are considerably longer and correspond to the length of the a axis [6.8656 (5) Å].
All six available hydrogen-bonding donor sites of the ammine groups and each of the four nitrite O atoms are engaged in nine intermolecular N—H⋯O bonds (Table 1; Fig. 3), whose H⋯O distances lie between 2.14 and 2.57 Å. Four of these interactions are formed within the same supramolecular stack parallel to [001], i.e., neighbouring molecules within this one-periodic structure are connected to one another by four-point N—H⋯O connections.
In total, each molecule is engaged in 18 hydrogen-bonding interactions which link it to eight neighbours via two four-point, four two-point and two one-point connections. The resulting N—H⋯O-bonded framework structure has the topology of the hexagonal lattice (hxl) (O'Keeffe et al., 2008). Fig. 4 gives a graphical representation of this hydrogen-bonding structure (HBS) in the style proposed by Hursthouse et al. (2015). It shows that 14 out of the 18 hydrogen-bonding interactions of an individual molecule lie within the (010) planes, and eight of these within the same column parallel to [001] (all interactions involving the central molecule and either molecule of A and A′). The descriptor of this HBS is F188[36.418.53.6-hxl] according to the methodology proposed by Hursthouse et al. (2015). Additionally, the sequence [gIV.t.gII.gIV.t.gII.21II.21II] describes the symmetry operations and numbers of hydrogen bonds involved in the eight distinct connections between two molecules which define this HBS.
4. Database survey
Various platinum(II) complexes, including diamminebis(nitrito)platinum(II), have been studied intensively as precious metal sources in electrochemical deposition processes (Keitel & Zschiegner, 1931; Baumgärtner & Raub, 1988). Previous reports by Khranenko et al. (2007), Laligant et al. (1991) and Madarász et al. (2009) contain crystal structures with a close relationship to cis-[Pt(NH3)2(NO2)2,] and of these the trans isomer and its Pd analogue (Madarász et al., 2009) are of particular interest.
In the trans-[Pt(NH3)2(NO2)2], the PtII atom is coordinated in a square-planar fashion by N atoms of the four ligands. The shortest Pt⋯Pt distance is much longer (4.84 Å) than in the title structure as there are no close-packed columnar units similar to those found in the cis analogue (Fig. 2). In addition to intramolecular N—H⋯O interactions, each of the six ammine hydrogen atoms of the trans-Pt(NH3)2(NO2)2 molecule is employed in just one intermolecular N—H⋯O interaction in such a way that each molecule is hydrogen-bonded to eight neighbouring molecules. Altogether, an individual trans-[Pt(NH3)2(NO2)2] molecule is engaged in twelve hydrogen-bonding interactions which are grouped into four two-point and four one-point connections (Fig. 5a). The underlying net of the resulting HBS has the body-centered cubic (bcu) topology (O'Keeffe et al., 2008) and the descriptor according to Hursthouse et al. (2015) for this HBS is F128[424.64-bcu].
ofThe structure of the palladium analogue, trans-[Pd(NH3)2(NO2)2], also displays a square-planar metal coordination by four N atoms of the ammine and nitrite ligands, and the shortest intermolecular Pd⋯Pd distance is 5.42 Å. As in the trans-Pt analogue, each H atom is employed in just one intermolecular N—H⋯O bond so that each molecule is engaged in twelve individual hydrogen-bonding interactions. In contrast to the trans-PtII analogue, these are exclusively two-point antiparallel contacts to just six neighbours (Fig. 5b). The underlying net of the 3-periodic HBS formed as a result of these interactions, has the primitive cubic (pcu) topology (O'Keeffe et al., 2008) and its descriptor is F126[412.63-pcu].
The HBSs formed by three structural analogues (Figs. 4 and 5) are each based on intermolecular N—H⋯O interactions involving the same set of six hydrogen-bonding donor and four hydrogen-bonding acceptor sites per molecule. However, the ensuing extensive hydrogen bonding results in three different framework structures, each of which was found to possess the topology of a particular Bravais lattice.
5. Synthesis and crystallization
Single crystals of cis-Pt(NH3)2(NO2)2 were obtained by means of hypersaturation directly out of a plating electrolyte. In order to grow larger single crystals, the water from the solution was partly evaporated at ambient temperature over a time span of two months. For structure analysis, a single crystal of good optical quality showing sharp extinction when imaged between crossed polarizers was selected and mounted on the tip of a 0.025 mm thick Mylar cryoloop (LithoLoops, Molecular Dimensions Inc.) using a perfluoropolyether inert oil (Hampton Research). Subsequently, the crystal was flash-cooled in a 173 (2) K dried air stream generated by an Oxford Cryosystems Desktop Cooler. A preliminary determination using on Oxford Diffraction Gemini Ultra single crystal diffractometer resulted in a set of lattice parameters that could not be found in the recent WEB based version of the Inorganic Database (ICSD, 2014). Therefore, we decided to perform a full data collection for structure solution.
6. Refinement
Crystal data, data collection and structure . A data set corresponding to a hemisphere of was collected. Structure solution by revealed the positions of all non-hydrogen atoms. All missing hydrogen atoms were identified from difference Fourier calculations. The H atoms of NH3 groups were idealized and included as rigid groups allowed to rotate but not tip (N—H = 0.91 Å), with their displacement parameters set to Uiso(H) = 1.5Ueq(N) of the parent N atom. The largest peaks of the final difference were close to the position of the metal atom.
details are summarized in Table 2
|
7. Analysis of hydrogen-bonded structures
The topologies of HBSs were determined and classified with the programs ADS and IsoTest of the TOPOS package (Blatov, 2006) in the manner described by Baburin & Blatov (2007). The topology graphs for HBSs (Figs. 4 and 5) are based on nets drawn with the IsoCryst program of the TOPOS package. The HBS of the title structure was defined from nine N—H⋯O interactions, which are listed in Table 1. Not included in this analysis was the interaction N4—H4C⋯O3(x, −y + , z − ) (H⋯A = 2.63 Å), interpreted as an additional opportunistic contact between the central molecule and molecule A. The definition of the HBSs of trans-[Pt(NH3)2(NO2)2] and trans-[Pd(NH3)2(NO2)2] were based on the intermolecular N—H⋯O interactions listed in Tables S1 and S2, respectively, of the Supporting information.
Supporting information
CCDC reference: 1053034
10.1107/S2056989015004879/wm5133sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S2056989015004879/wm5133Isup2.hkl
Supporting information file. DOI: 10.1107/S2056989015004879/wm5133Isup3.pdf
Data collection: CrysAlis PRO (Agilent, 2014); cell
CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ATOMS for Windows (Dowty, 2011), ORTEP-3 for Windows (Farrugia, 2012), Mercury (Macrae et al., 2006) and TOPOS (Blatov, 2006); software used to prepare material for publication: PLATON (Spek, 2009), publCIF (Westrip, 2010) and WinGX (Farrugia, 2012).[Pt(NO2)2(NH3)2] | F(000) = 576 |
Mr = 321.18 | Dx = 3.701 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 6.8656 (5) Å | Cell parameters from 2142 reflections |
b = 12.6428 (8) Å | θ = 3.5–28.5° |
c = 7.0931 (5) Å | µ = 24.30 mm−1 |
β = 110.579 (8)° | T = 173 K |
V = 576.40 (7) Å3 | Thin plate, yellow |
Z = 4 | 0.20 × 0.12 × 0.02 mm |
Agilent Xcalibur (Ruby, Gemini ultra) diffractometer | 1061 independent reflections |
Radiation source: sealed tube | 972 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
Detector resolution: 10.3575 pixels mm-1 | θmax = 25.4°, θmin = 3.5° |
ω scans | h = −8→7 |
Absorption correction: analytical [CrysAlis PRO (Agilent, 2014), based on expressions derived by Clark & Reid (1995)] | k = −11→15 |
Tmin = 0.036, Tmax = 0.609 | l = −6→8 |
3435 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.018 | H-atom parameters constrained |
wR(F2) = 0.044 | w = 1/[σ2(Fo2) + (0.0222P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max = 0.002 |
1061 reflections | Δρmax = 1.02 e Å−3 |
85 parameters | Δρmin = −0.92 e Å−3 |
0 restraints | Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0024 (2) |
Experimental. Absorption correction: CrysAlis PRO (Agilent, 2014) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by Clark & Reid (1995) |
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. |
x | y | z | Uiso*/Ueq | ||
Pt | 0.64201 (3) | 0.24522 (2) | 0.18480 (2) | 0.00838 (12) | |
O2 | 0.9425 (5) | 0.0838 (2) | 0.3550 (5) | 0.0214 (7) | |
O1 | 1.0428 (4) | 0.1964 (3) | 0.1858 (4) | 0.0234 (7) | |
O3 | 0.4941 (4) | 0.0546 (2) | 0.2976 (4) | 0.0182 (7) | |
O4 | 0.3278 (4) | 0.0944 (3) | −0.0112 (4) | 0.0217 (7) | |
N1 | 0.9066 (5) | 0.1640 (3) | 0.2494 (5) | 0.0111 (8) | |
N2 | 0.4699 (5) | 0.1141 (3) | 0.1524 (5) | 0.0135 (8) | |
N3 | 0.3735 (5) | 0.3303 (3) | 0.1142 (5) | 0.0128 (8) | |
H3A | 0.3409 | 0.3580 | −0.0116 | 0.019* | |
H3B | 0.3911 | 0.3837 | 0.2048 | 0.019* | |
H3C | 0.2686 | 0.2873 | 0.1178 | 0.019* | |
N4 | 0.8117 (5) | 0.3823 (3) | 0.2226 (5) | 0.0138 (8) | |
H4A | 0.9371 | 0.3732 | 0.3225 | 0.021* | |
H4B | 0.7415 | 0.4358 | 0.2562 | 0.021* | |
H4C | 0.8318 | 0.3986 | 0.1058 | 0.021* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pt | 0.00787 (17) | 0.00841 (16) | 0.00881 (15) | 0.00001 (5) | 0.00287 (9) | 0.00083 (5) |
O2 | 0.0189 (17) | 0.018 (2) | 0.0267 (18) | 0.0068 (13) | 0.0069 (13) | 0.0098 (14) |
O1 | 0.0141 (16) | 0.030 (2) | 0.0294 (18) | 0.0024 (14) | 0.0119 (13) | 0.0097 (16) |
O3 | 0.0252 (17) | 0.0128 (18) | 0.0188 (16) | −0.0033 (13) | 0.0105 (13) | 0.0029 (14) |
O4 | 0.0184 (17) | 0.030 (2) | 0.0145 (16) | −0.0099 (13) | 0.0028 (13) | −0.0059 (14) |
N1 | 0.0095 (18) | 0.011 (2) | 0.0132 (18) | −0.0016 (14) | 0.0047 (14) | −0.0013 (15) |
N2 | 0.0148 (19) | 0.013 (2) | 0.015 (2) | −0.0016 (15) | 0.0078 (15) | −0.0025 (16) |
N3 | 0.0111 (18) | 0.014 (2) | 0.0137 (18) | 0.0006 (14) | 0.0042 (13) | 0.0020 (16) |
N4 | 0.0110 (19) | 0.016 (2) | 0.0150 (19) | −0.0017 (15) | 0.0047 (15) | 0.0004 (16) |
Pt—N1 | 1.995 (3) | O4—N2 | 1.251 (4) |
Pt—N2 | 2.001 (4) | N3—H3A | 0.9100 |
Pt—N3 | 2.039 (3) | N3—H3B | 0.9100 |
Pt—N4 | 2.052 (3) | N3—H3C | 0.9100 |
O2—N1 | 1.233 (4) | N4—H4A | 0.9100 |
O1—N1 | 1.242 (4) | N4—H4B | 0.9100 |
O3—N2 | 1.239 (4) | N4—H4C | 0.9100 |
N1—Pt—N2 | 93.06 (13) | Pt—N3—H3A | 109.5 |
N1—Pt—N3 | 178.67 (13) | Pt—N3—H3B | 109.5 |
N2—Pt—N3 | 87.85 (13) | H3A—N3—H3B | 109.5 |
N1—Pt—N4 | 88.58 (13) | Pt—N3—H3C | 109.5 |
N2—Pt—N4 | 177.96 (13) | H3A—N3—H3C | 109.5 |
N3—Pt—N4 | 90.53 (14) | H3B—N3—H3C | 109.5 |
O2—N1—O1 | 118.5 (3) | Pt—N4—H4A | 109.5 |
O2—N1—Pt | 122.3 (2) | Pt—N4—H4B | 109.5 |
O1—N1—Pt | 119.2 (3) | H4A—N4—H4B | 109.5 |
O3—N2—O4 | 118.9 (3) | Pt—N4—H4C | 109.5 |
O3—N2—Pt | 120.4 (3) | H4A—N4—H4C | 109.5 |
O4—N2—Pt | 120.5 (3) | H4B—N4—H4C | 109.5 |
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3A···O3i | 0.91 | 2.27 | 3.026 (5) | 140 |
N3—H3A···O1ii | 0.91 | 2.49 | 3.107 (5) | 126 |
N3—H3B···O4iii | 0.91 | 2.22 | 2.941 (5) | 136 |
N3—H3C···O1iv | 0.91 | 2.12 | 3.015 (5) | 169 |
N3—H3B···O3v | 0.91 | 2.30 | 2.976 (5) | 131 |
N4—H4A···O4vi | 0.91 | 2.56 | 3.392 (4) | 153 |
N4—H4A···O1iii | 0.91 | 2.57 | 3.261 (5) | 133 |
N4—H4B···O3v | 0.91 | 2.14 | 2.994 (4) | 156 |
N4—H4C···O2i | 0.91 | 2.18 | 3.072 (5) | 167 |
Symmetry codes: (i) x, −y+1/2, z−1/2; (ii) x−1, −y+1/2, z−1/2; (iii) x, −y+1/2, z+1/2; (iv) x−1, y, z; (v) −x+1, y+1/2, −z+1/2; (vi) x+1, −y+1/2, z+1/2. |
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