trans-Di­chloro­bis­(tri­phenyl­phosphine)­nickel(II) bis­(di­chloro­methane) solvate: redetermination at 120 K

Re-investigation of [NiCl₂(PPh₃)₂]·2CH₂Cl₂ at 120 K yielded much more accurate geometric parameters than the earlier room temperature study and confirmed the main conclusion of the latter: the Ni-P and Ni-Cl bonds in this centrosymmetric square-planar complex [2.2439 (5) and 2.1672 (5) Å] are significantly shorter than in the tetrahedral solvent-free [NiCl₂(PPh₃)₂].

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.029
• wR factor = 0.074
• Data-to-parameter ratio = 17.3

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

In a solvent-free crystal, [NiCl₂(PPh₃)₂], (I), adopts a tetrahedral coordination of the Ni atom (Garton et al., 1963; Bruins Slot et al., 1984; Corain et al., 1985; Brammer & Stevens, 1989) and a green–blue colour. However, the [NiCl₂(PPh₃)₂]^.2ClCH₂CH₂Cl solvate, (II), is deep-red and shows a trans square-planar coordination (Corain et al., 1985) with both Ni—P and Ni—Cl bonds significantly shorter than in (I). The same coordination was found in the [NiCl₂(PPh₃)₂]^.2CH₂Cl₂ solvate, (III), the pseudo-polymorph of (II), but the precision of the room-temperature crystallographic study of (III) (Sletten & Kovacs, 1993) was not very high (R = 0.107).

Presently, we redetermined the structure of (III) at 120 K, which appeared essentially the same as at room temperature. The unit cell and the arrangement of the complex molecules bear a close semblance to those of (II). The Ni atom is located at an inversion centre and hence has a rigorously planar trans-coordination (Fig. 1). Thus, (II) and (III) can be described as allogons of (I). The Ni—P and Ni—Cl bond distances we found in (III), 2.2439 (4) and 2.1672 (4) Å, practically coincide with those reported by Sletten & Kovacs (1993) (2.241 and 2.164 Å), as well as with the corresponding distances in (II), viz. 2.242 (3) and 2.155 (3) Å (Corain et al., 1985). The most accurate study (at 94 K) of the tetrahedral allogon (Brammer & Stevens, 1989) gave the distances Ni—P = 2.3180 (2) and Ni—Cl = 2.2075 (2) Å, longer than in (III) by 0.07 and 0.04 Å, respectively. The P—C bond lengths change contrary to the Ni—P, averaging 1.827 (4) Å in (III) against 1.816 (4) Å in the tetrahedral allogon, in accordance with the view that nickel d-electrons are back-donated into the σ*(P—C) orbitals rather than into the pure d-orbitals of the phosphorus atoms (Xiao et al., 1983; Marynick, 1984). Shorter P—C distances in (III) at room temperature, averaging 1.815 (9) Å, are obviously a spurious effect of thermal motion.

S2. Experimental

Green–mauve (I) was dissolved in CH₂Cl₂. After 48 h at 253 K, an orange–red precipitate of (III) formed, including crystals of X-ray quality. On drying in vacuo, (III) recovered the green colour of the starting (I).

S3. Refinement

Csp³—H bond distances vary from 0.92 (3) to 0.98 (4) Å and Csp²—H distances from 0.90 (2) to 0.99 (2) Å.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SMART; data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXTL (Bruker, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures

Fig. 1. The molecules of [NiCl2(PPh3)2] and CH2Cl2 in (III). Displacement ellipsoids are drawn at the 50% probability level.

trans-Dichloro-bis(triphenylphosphine)nickel(II) bis(dichloromethane) solvate

Crystal data

[NiCl2(C18H15P)2]·2CH2Cl2	Dx = 1.480 Mg m^−3
Mr = 824.00	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 879 reflections
a = 22.970 (6) Å	θ = 12.0–23.4°
b = 20.005 (4) Å	µ = 1.07 mm^−1
c = 8.048 (2) Å	T = 120 K
V = 3698.2 (15) Å^3	Prism, red
Z = 4	0.7 × 0.25 × 0.2 mm
F(000) = 1688

Data collection

SMART 1K CCD area-detector diffractometer	4885 independent reflections
Radiation source: fine-focus sealed tube	4081 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
Detector resolution: 8 pixels mm^-1	θmax = 29.0°, θmin = 1.8°
ω scans	h = −31→24
Absorption correction: integration (XPREP SHELXTL; Bruker, 1998), Rint = 0.049 before correction	k = −25→26
Tmin = 0.659, Tmax = 0.821	l = −10→7
26505 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.029	Hydrogen site location: difference Fourier map
wR(F^2) = 0.074	All H-atom parameters refined
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0309P)^2 + 2.4862P] where P = (Fo^2 + 2Fc^2)/3
4885 reflections	(Δ/σ)max = 0.001
282 parameters	Δρmax = 0.44 e Å^−3
0 restraints	Δρmin = −0.30 e Å^−3

Special details

Experimental. The data collection nominally covered over a hemisphere 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 sec exposure) covering 0.3° in ω. Crystal to detector distance 4.51 cm.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Ni	0.5000	0.5000	0.5000	0.01498 (7)
P	0.564300 (16)	0.437742 (19)	0.35820 (5)	0.01467 (8)
Cl1	0.548257 (17)	0.591541 (18)	0.45793 (5)	0.02135 (9)
Cl2	0.71862 (2)	0.63825 (3)	0.63057 (7)	0.03979 (12)
Cl3	0.66591 (2)	0.76007 (3)	0.76531 (8)	0.04354 (13)
C10	0.65491 (10)	0.67585 (13)	0.7102 (4)	0.0477 (6)
H101	0.6262 (14)	0.6727 (15)	0.631 (4)	0.063 (9)*
H102	0.6413 (16)	0.6511 (18)	0.807 (5)	0.091 (12)*
C11	0.52750 (7)	0.38249 (7)	0.21219 (19)	0.0165 (3)
C12	0.53980 (7)	0.31465 (8)	0.1976 (2)	0.0197 (3)
H12	0.5664 (9)	0.2953 (10)	0.266 (3)	0.021 (5)*
C13	0.51017 (8)	0.27589 (9)	0.0801 (2)	0.0243 (3)
H13	0.5176 (10)	0.2300 (11)	0.076 (3)	0.030 (6)*
C14	0.46947 (8)	0.30499 (9)	−0.0247 (2)	0.0249 (3)
H14	0.4499 (10)	0.2796 (11)	−0.108 (3)	0.032 (6)*
C15	0.45682 (8)	0.37287 (9)	−0.0106 (2)	0.0242 (3)
H15	0.4304 (10)	0.3922 (11)	−0.079 (3)	0.034 (6)*
C16	0.48517 (7)	0.41118 (8)	0.1086 (2)	0.0209 (3)
H16	0.4766 (9)	0.4551 (10)	0.116 (3)	0.022 (5)*
C21	0.61974 (7)	0.47845 (7)	0.2296 (2)	0.0167 (3)
C22	0.66208 (7)	0.51838 (8)	0.3063 (2)	0.0209 (3)
H22	0.6627 (10)	0.5244 (11)	0.429 (3)	0.030 (6)*
C23	0.70479 (8)	0.54994 (9)	0.2119 (2)	0.0253 (4)
H23	0.7328 (10)	0.5756 (11)	0.263 (3)	0.032 (6)*
C24	0.70590 (8)	0.54185 (9)	0.0402 (2)	0.0273 (4)
H24	0.7351 (9)	0.5645 (10)	−0.025 (3)	0.026 (5)*
C25	0.66425 (8)	0.50231 (9)	−0.0371 (2)	0.0272 (4)
H25	0.6655 (11)	0.4968 (12)	−0.154 (3)	0.044 (7)*
C26	0.62124 (7)	0.47080 (8)	0.0569 (2)	0.0212 (3)
H26	0.5951 (9)	0.4454 (11)	0.003 (3)	0.026 (5)*
C31	0.60851 (7)	0.38543 (7)	0.49536 (19)	0.0164 (3)
C32	0.59301 (7)	0.37657 (8)	0.6622 (2)	0.0203 (3)
H32	0.5592 (10)	0.3958 (11)	0.699 (3)	0.029 (6)*
C33	0.62776 (8)	0.33755 (9)	0.7664 (2)	0.0235 (3)
H33	0.6152 (10)	0.3315 (11)	0.879 (3)	0.031 (6)*
C34	0.67835 (8)	0.30822 (8)	0.7057 (2)	0.0237 (3)
H34	0.7012 (10)	0.2827 (11)	0.777 (3)	0.036 (6)*
C35	0.69411 (7)	0.31688 (8)	0.5407 (2)	0.0230 (3)
H35	0.7284 (10)	0.2983 (11)	0.502 (3)	0.031 (6)*
C36	0.65944 (7)	0.35517 (8)	0.4355 (2)	0.0204 (3)
H36	0.6704 (10)	0.3618 (11)	0.327 (3)	0.030 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni	0.01408 (13)	0.01319 (12)	0.01767 (13)	−0.00012 (9)	0.00158 (10)	−0.00086 (10)
P	0.01393 (17)	0.01419 (17)	0.01588 (17)	0.00000 (13)	0.00085 (14)	−0.00050 (14)
Cl1	0.02029 (18)	0.01647 (17)	0.02729 (19)	−0.00295 (13)	0.00544 (15)	−0.00209 (14)
Cl2	0.0369 (3)	0.0470 (3)	0.0354 (3)	0.0013 (2)	−0.0066 (2)	−0.0022 (2)
Cl3	0.0318 (2)	0.0474 (3)	0.0514 (3)	−0.0068 (2)	−0.0037 (2)	−0.0128 (2)
C10	0.0285 (11)	0.0454 (13)	0.0693 (17)	−0.0101 (9)	0.0025 (11)	−0.0083 (12)
C11	0.0164 (7)	0.0167 (7)	0.0164 (7)	−0.0022 (5)	0.0009 (6)	−0.0007 (5)
C12	0.0202 (7)	0.0189 (7)	0.0199 (7)	0.0014 (6)	0.0002 (6)	0.0004 (6)
C13	0.0297 (9)	0.0177 (7)	0.0256 (8)	−0.0012 (6)	0.0007 (7)	−0.0044 (6)
C14	0.0234 (8)	0.0296 (9)	0.0217 (8)	−0.0045 (7)	−0.0012 (6)	−0.0074 (7)
C15	0.0207 (8)	0.0308 (9)	0.0211 (8)	0.0011 (7)	−0.0025 (6)	0.0014 (7)
C16	0.0209 (8)	0.0188 (7)	0.0231 (8)	0.0013 (6)	−0.0022 (6)	0.0013 (6)
C21	0.0144 (7)	0.0151 (7)	0.0204 (7)	0.0019 (5)	0.0022 (6)	0.0016 (6)
C22	0.0182 (7)	0.0212 (7)	0.0233 (8)	−0.0007 (6)	0.0004 (6)	−0.0001 (6)
C23	0.0181 (8)	0.0246 (8)	0.0333 (9)	−0.0043 (6)	0.0017 (7)	0.0003 (7)
C24	0.0217 (8)	0.0267 (8)	0.0335 (9)	−0.0024 (7)	0.0091 (7)	0.0062 (7)
C25	0.0292 (9)	0.0299 (9)	0.0225 (8)	−0.0016 (7)	0.0068 (7)	0.0020 (7)
C26	0.0213 (8)	0.0206 (7)	0.0216 (8)	−0.0007 (6)	0.0020 (6)	−0.0007 (6)
C31	0.0168 (7)	0.0143 (6)	0.0181 (7)	−0.0015 (5)	−0.0020 (6)	−0.0007 (5)
C32	0.0201 (8)	0.0210 (7)	0.0199 (8)	0.0000 (6)	0.0012 (6)	−0.0003 (6)
C33	0.0282 (9)	0.0241 (8)	0.0183 (8)	−0.0033 (6)	−0.0006 (7)	0.0030 (6)
C34	0.0237 (8)	0.0196 (7)	0.0279 (8)	−0.0008 (6)	−0.0072 (7)	0.0035 (6)
C35	0.0192 (8)	0.0212 (8)	0.0286 (9)	0.0034 (6)	−0.0020 (7)	−0.0006 (6)
C36	0.0207 (8)	0.0209 (7)	0.0197 (8)	0.0006 (6)	0.0010 (6)	0.0002 (6)

Geometric parameters (Å, º)

Ni—Cl1	2.1672 (5)	C21—C26	1.399 (2)
Ni—Cl1^i	2.1672 (5)	C21—C22	1.402 (2)
Ni—P^i	2.2439 (5)	C22—C23	1.392 (2)
Ni—P	2.2439 (5)	C22—H22	0.99 (2)
P—C11	1.8212 (16)	C23—C24	1.391 (3)
P—C31	1.8289 (16)	C23—H23	0.92 (2)
P—C21	1.8318 (16)	C24—C25	1.388 (3)
Cl2—C10	1.766 (3)	C24—H24	0.96 (2)
Cl3—C10	1.760 (3)	C25—C26	1.395 (2)
C10—H101	0.92 (3)	C25—H25	0.95 (3)
C10—H102	0.98 (4)	C26—H26	0.90 (2)
C11—C12	1.391 (2)	C31—C32	1.400 (2)
C11—C16	1.404 (2)	C31—C36	1.402 (2)
C12—C13	1.400 (2)	C32—C33	1.396 (2)
C12—H12	0.91 (2)	C32—H32	0.92 (2)
C13—C14	1.387 (3)	C33—C34	1.390 (3)
C13—H13	0.93 (2)	C33—H33	0.96 (2)
C14—C15	1.393 (3)	C34—C35	1.387 (3)
C14—H14	0.95 (2)	C34—H34	0.93 (2)
C15—C16	1.390 (2)	C35—C36	1.392 (2)
C15—H15	0.91 (2)	C35—H35	0.93 (2)
C16—H16	0.90 (2)	C36—H36	0.92 (2)
Cl1—Ni—Cl1^i	180.0	C26—C21—C22	118.86 (15)
Cl1—Ni—P^i	86.97 (2)	C26—C21—P	122.01 (12)
Cl1^i—Ni—P^i	93.03 (2)	C22—C21—P	119.13 (12)
Cl1—Ni—P	93.03 (2)	C23—C22—C21	120.46 (16)
Cl1^i—Ni—P	86.97 (2)	C23—C22—H22	118.5 (13)
P^i—Ni—P	180.0	C21—C22—H22	121.1 (13)
C11—P—C31	107.45 (7)	C24—C23—C22	120.14 (17)
C11—P—C21	103.17 (7)	C24—C23—H23	119.6 (15)
C31—P—C21	102.09 (7)	C22—C23—H23	120.3 (15)
C11—P—Ni	111.07 (5)	C25—C24—C23	119.89 (16)
C31—P—Ni	112.09 (5)	C25—C24—H24	120.1 (13)
C21—P—Ni	119.88 (5)	C23—C24—H24	120.0 (13)
Cl3—C10—Cl2	112.34 (12)	C24—C25—C26	120.19 (17)
Cl3—C10—H101	110.0 (19)	C24—C25—H25	119.3 (15)
Cl2—C10—H101	108.3 (19)	C26—C25—H25	120.5 (15)
Cl3—C10—H102	109 (2)	C25—C26—C21	120.46 (16)
Cl2—C10—H102	110 (2)	C25—C26—H26	117.8 (14)
H101—C10—H102	107 (3)	C21—C26—H26	121.7 (14)
C12—C11—C16	119.30 (14)	C32—C31—C36	119.12 (15)
C12—C11—P	123.52 (12)	C32—C31—P	120.66 (12)
C16—C11—P	117.17 (12)	C36—C31—P	120.20 (12)
C11—C12—C13	119.92 (15)	C33—C32—C31	120.09 (15)
C11—C12—H12	120.0 (12)	C33—C32—H32	121.5 (14)
C13—C12—H12	120.0 (12)	C31—C32—H32	118.4 (14)
C14—C13—C12	120.40 (16)	C34—C33—C32	120.19 (16)
C14—C13—H13	120.8 (14)	C34—C33—H33	122.0 (14)
C12—C13—H13	118.8 (14)	C32—C33—H33	117.8 (14)
C13—C14—C15	120.02 (16)	C35—C34—C33	120.09 (16)
C13—C14—H14	121.4 (14)	C35—C34—H34	120.7 (15)
C15—C14—H14	118.6 (14)	C33—C34—H34	119.2 (15)
C16—C15—C14	119.72 (16)	C34—C35—C36	120.11 (16)
C16—C15—H15	119.9 (15)	C34—C35—H35	119.8 (14)
C14—C15—H15	120.3 (15)	C36—C35—H35	120.0 (14)
C15—C16—C11	120.61 (15)	C35—C36—C31	120.40 (16)
C15—C16—H16	118.6 (13)	C35—C36—H36	120.1 (14)
C11—C16—H16	120.7 (13)	C31—C36—H36	119.5 (14)

Symmetry code: (i) −x+1, −y+1, −z+1.