trans-Tetra­chloro­bis(4-methyl­pyridine)­germanium(IV)

The structure of the title compound, [GeCl₄(C₆H₇N)₂], (I), is the first example of an addition compound of GeCl₄ with two aromatic nitro­gen bases. The mol­ecule, with essential D_2h symmetry, has crystallographic C_2h symmetry. The environment around the Ge atom can be described as a slightly distorted octahedron with the 4-methyl­pyridine ligands occupying axial positions and the four chloro ligands in the equatorial plane. The structure of (I) is isomorphous with the corresponding silicon halides.

Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SMART; data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97.

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Crystal data

[GeCl4(C6H7N)2]	Dx = 1.707 Mg m^−3
Mr = 400.64	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pmna	Cell parameters from 2407 reflections
a = 7.154 (2) Å	θ = 1–25°
b = 7.933 (2) Å	µ = 2.64 mm^−1
c = 13.731 (3) Å	T = 173 K
V = 779.3 (3) Å^3	Block, colourless
Z = 2	0.60 × 0.20 × 0.20 mm
F(000) = 400

Data collection

Siemens CCD three-circle diffractometer	1036 independent reflections
Radiation source: fine-focus sealed tube	895 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
ω scans	θmax = 28.3°, θmin = 2.6°
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	h = −9→5
Tmin = 0.301, Tmax = 0.621	k = −10→8
3722 measured reflections	l = −17→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.026	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.062	w = 1/[σ^2(Fo^2) + (0.0334P)^2 + 0.1042P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
1036 reflections	Δρmax = 0.41 e Å^−3
57 parameters	Δρmin = −0.51 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0063 (14)

Special details

Experimental. ;

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cl1	0.72510 (7)	0.16635 (6)	0.43468 (3)	0.02974 (16)
Ge1	0.5000	0.0000	0.5000	0.01699 (14)
N1	0.5000	0.1450 (3)	0.62414 (15)	0.0186 (4)
C2	0.5000	0.3149 (3)	0.6175 (2)	0.0230 (6)
H2	0.5000	0.3659	0.5549	0.028*
C3	0.5000	0.4162 (3)	0.6989 (2)	0.0240 (6)
H3	0.5000	0.5354	0.6919	0.029*
C4	0.5000	0.3445 (3)	0.79128 (19)	0.0205 (5)
C41	0.5000	0.4504 (4)	0.8814 (2)	0.0285 (6)
H41A	0.5000	0.5623	0.8628	0.043*	0.50
H41B	0.3975	0.4180	0.9215	0.043*	0.50
H41C	0.5000	0.3836	0.9399	0.043*	0.50
H41D	0.3929	0.5179	0.8789	0.043*	0.50
C5	0.5000	0.1696 (3)	0.79704 (19)	0.0230 (5)
H5	0.5000	0.1156	0.8588	0.028*
C6	0.5000	0.0748 (3)	0.71332 (19)	0.0220 (5)
H6	0.5000	−0.0446	0.7186	0.026*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cl1	0.0322 (3)	0.0279 (3)	0.0291 (3)	−0.01187 (19)	0.0090 (2)	−0.00667 (19)
Ge1	0.0192 (2)	0.01502 (19)	0.0167 (2)	0.000	0.000	−0.00263 (14)
N1	0.0210 (11)	0.0165 (9)	0.0183 (11)	0.000	0.000	−0.0028 (8)
C2	0.0272 (14)	0.0195 (12)	0.0224 (14)	0.000	0.000	0.0010 (10)
C3	0.0272 (14)	0.0158 (12)	0.0288 (14)	0.000	0.000	−0.0032 (10)
C4	0.0155 (12)	0.0234 (12)	0.0226 (13)	0.000	0.000	−0.0064 (11)
C41	0.0313 (15)	0.0290 (13)	0.0251 (15)	0.000	0.000	−0.0112 (11)
C5	0.0252 (14)	0.0258 (13)	0.0181 (13)	0.000	0.000	−0.0006 (11)
C6	0.0261 (13)	0.0178 (12)	0.0221 (13)	0.000	0.000	0.0018 (10)

Geometric parameters (Å, º)

Cl1—Ge1	2.2670 (6)	C3—H3	0.9500
Ge1—N1	2.057 (2)	C4—C5	1.390 (4)
Ge1—N1^i	2.057 (2)	C4—C41	1.495 (4)
Ge1—Cl1^ii	2.2670 (6)	C41—H41A	0.9240
Ge1—Cl1^i	2.2670 (6)	C41—H41B	0.9530
Ge1—Cl1^iii	2.2670 (6)	C41—H41C	0.9620
N1—C6	1.345 (3)	C41—H41D	0.9355
N1—C2	1.350 (3)	C5—C6	1.373 (4)
C2—C3	1.377 (4)	C5—H5	0.9500
C2—H2	0.9500	C6—H6	0.9500
C3—C4	1.390 (4)
N1—Ge1—N1^i	180.0	C2—C3—H3	119.9
N1—Ge1—Cl1	90.13 (4)	C4—C3—H3	119.9
N1^i—Ge1—Cl1	89.87 (4)	C3—C4—C5	117.4 (2)
N1—Ge1—Cl1^ii	90.13 (4)	C3—C4—C41	121.7 (2)
N1^i—Ge1—Cl1^ii	89.87 (4)	C5—C4—C41	120.9 (2)
Cl1—Ge1—Cl1^ii	90.53 (3)	C4—C41—H41A	108.2
N1—Ge1—Cl1^i	89.87 (4)	C4—C41—H41B	109.1
N1^i—Ge1—Cl1^i	90.13 (4)	H41A—C41—H41B	114.8
Cl1—Ge1—Cl1^i	180.0	C4—C41—H41C	112.4
Cl1^ii—Ge1—Cl1^i	89.47 (3)	H41A—C41—H41C	139.4
N1—Ge1—Cl1^iii	89.87 (4)	H41B—C41—H41C	50.8
N1^i—Ge1—Cl1^iii	90.13 (4)	C4—C41—H41D	107.0
Cl1—Ge1—Cl1^iii	89.47 (3)	H41A—C41—H41D	55.9
Cl1^ii—Ge1—Cl1^iii	180.0	H41B—C41—H41D	62.9
Cl1^i—Ge1—Cl1^iii	90.53 (3)	H41C—C41—H41D	110.2
C6—N1—C2	118.3 (2)	C6—C5—C4	119.9 (2)
C6—N1—Ge1	121.53 (17)	C6—C5—H5	120.0
C2—N1—Ge1	120.14 (17)	C4—C5—H5	120.0
N1—C2—C3	121.9 (2)	N1—C6—C5	122.4 (2)
N1—C2—H2	119.1	N1—C6—H6	118.8
C3—C2—H2	119.1	C5—C6—H6	118.8
C2—C3—C4	120.1 (2)
N1^i—Ge1—N1—C6	0.0 (3)	C6—N1—C2—C3	0.0
Cl1—Ge1—N1—C6	−134.736 (16)	Ge1—N1—C2—C3	180.0
Cl1^ii—Ge1—N1—C6	134.736 (16)	N1—C2—C3—C4	0.0
Cl1^i—Ge1—N1—C6	45.264 (17)	C2—C3—C4—C5	0.0
Cl1^iii—Ge1—N1—C6	−45.264 (16)	C2—C3—C4—C41	180.0
N1^i—Ge1—N1—C2	180.0 (3)	C3—C4—C5—C6	0.0
Cl1—Ge1—N1—C2	45.264 (17)	C41—C4—C5—C6	180.0
Cl1^ii—Ge1—N1—C2	−45.264 (16)	C2—N1—C6—C5	0.0
Cl1^i—Ge1—N1—C2	−134.736 (17)	Ge1—N1—C6—C5	180.0
Cl1^iii—Ge1—N1—C2	134.736 (17)	C4—C5—C6—N1	0.0

Symmetry codes: (i) −x+1, −y, −z+1; (ii) −x+1, y, z; (iii) x, −y, −z+1.