p-Diiso­cyano­tetra­methyl­benzene

p-Diiso­cyano­tetra­methyl­benzene, p-C₆(CH₃)₄(NC)₂, crystallizes in the monoclinic space group C2/c. One-half of the mol­ecule is crystallographically independent, with the other half being generated by an inversion centre located at the centre of the mol­ecule.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.046
• wR factor = 0.131
• Data-to-parameter ratio = 18.2

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT031_ALERT_4_C Refined Extinction Parameter within Range ......       2.75 Sigma
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT230_ALERT_2_C Hirshfeld Test Diff for    N1     -   C2       =       5.53 su
PLAT320_ALERT_2_C Check Hybridisation of  C1     in Main Residue .          ?

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: SMART (Bruker 1997-2000); cell refinement: SAINT-Plus (Bruker 1997-1999); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXL97.

1,4-bisisocyano-2,3,5,6-tetramethyl benzene

Crystal data

C12H12N2	F(000) = 392
Mr = 184.24	Dx = 1.221 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 17.1518 (17) Å	Cell parameters from 4202 reflections
b = 5.1324 (5) Å	θ = 2.6–28.3°
c = 12.3670 (12) Å	µ = 0.07 mm^−1
β = 112.010 (2)°	T = 100 K
V = 1009.32 (17) Å^3	Block, colourless
Z = 4	0.5 × 0.35 × 0.35 mm

Data collection

Bruker AXS SMART APEX CCD diffractometer	1181 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.080
Graphite monochromator	θmax = 28.3°, θmin = 3.5°
ω scans	h = −22→21
4935 measured reflections	k = −6→6
1257 independent reflections	l = −16→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)] = 0.046	H-atom parameters constrained
wR(F^2) = 0.131	w = 1/[σ^2(Fo^2) + (0.0698P)^2 + 0.6662P] where P = (Fo^2 + 2Fc^2)/3
S = 1.05	(Δ/σ)max = 0.016
1257 reflections	Δρmax = 0.32 e Å^−3
69 parameters	Δρmin = −0.27 e Å^−3
0 restraints	Extinction correction: SHELXL, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.011 (4)

Special details

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)
N1	0.35731 (5)	1.04662 (17)	0.68084 (7)	0.0217 (3)
C3	0.33877 (6)	0.71435 (19)	0.53560 (8)	0.0190 (3)
C4	0.28404 (6)	0.56146 (19)	0.44509 (8)	0.0189 (3)
C1	0.40179 (7)	1.1675 (2)	0.75919 (9)	0.0288 (3)
C2	0.30288 (6)	0.89616 (19)	0.58851 (8)	0.0188 (3)
C5	0.43300 (6)	0.6884 (2)	0.57347 (9)	0.0245 (3)
H5A	0.4605	0.8340	0.6249	0.037*	0.899 (16)
H5B	0.4483	0.6906	0.5047	0.037*	0.899 (16)
H5C	0.4513	0.5237	0.6155	0.037*	0.899 (16)
H5D	0.4462	0.5315	0.5385	0.037*	0.101 (16)
H5E	0.4585	0.6749	0.6587	0.037*	0.101 (16)
H5F	0.4555	0.8418	0.5479	0.037*	0.101 (16)
C6	0.31677 (6)	0.3562 (2)	0.38534 (9)	0.0242 (3)
H6A	0.2740	0.2207	0.3533	0.036*	0.721 (16)
H6B	0.3680	0.2782	0.4419	0.036*	0.721 (16)
H6C	0.3296	0.4365	0.3220	0.036*	0.721 (16)
H6D	0.3737	0.4029	0.3915	0.036*	0.279 (16)
H6E	0.2797	0.3454	0.3029	0.036*	0.279 (16)
H6F	0.3181	0.1872	0.4228	0.036*	0.279 (16)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0224 (4)	0.0249 (5)	0.0205 (4)	−0.0007 (3)	0.0111 (3)	−0.0005 (3)
C3	0.0198 (5)	0.0224 (5)	0.0175 (4)	0.0016 (3)	0.0100 (4)	0.0030 (3)
C4	0.0220 (5)	0.0204 (5)	0.0179 (5)	0.0014 (3)	0.0114 (4)	0.0018 (3)
C1	0.0261 (5)	0.0349 (6)	0.0265 (5)	−0.0015 (4)	0.0110 (4)	−0.0056 (4)
C2	0.0211 (5)	0.0212 (5)	0.0160 (4)	−0.0010 (3)	0.0091 (3)	0.0006 (3)
C5	0.0193 (5)	0.0319 (6)	0.0237 (5)	0.0022 (4)	0.0096 (4)	−0.0003 (4)
C6	0.0277 (5)	0.0248 (5)	0.0257 (5)	0.0021 (4)	0.0163 (4)	−0.0022 (4)

Geometric parameters (Å, º)

N1—C1	1.1628 (14)	C5—H5D	0.9800
N1—C2	1.4045 (12)	C5—H5E	0.9800
C3—C4	1.4008 (13)	C5—H5F	0.9800
C3—C2	1.4070 (13)	C6—H6A	0.9800
C3—C5	1.5106 (13)	C6—H6B	0.9800
C4—C6	1.5105 (13)	C6—H6C	0.9800
C2—C4^i	1.4065 (13)	C6—H6D	0.9800
C5—H5A	0.9800	C6—H6E	0.9800
C5—H5B	0.9800	C6—H6F	0.9800
C5—H5C	0.9800
C1—N1—C2	178.30 (10)	H5A—C5—H5F	56.3
C4—C3—C2	117.65 (9)	H5B—C5—H5F	56.3
C4—C3—C5	121.14 (8)	H5C—C5—H5F	141.1
C2—C3—C5	121.20 (9)	H5D—C5—H5F	109.5
C3—C4—C2^i	117.92 (9)	H5E—C5—H5F	109.5
C3—C4—C6	121.39 (8)	C4—C6—H6A	109.5
C2^i—C4—C6	120.69 (9)	C4—C6—H6B	109.5
N1—C2—C4^i	117.59 (8)	H6A—C6—H6B	109.5
N1—C2—C3	117.99 (8)	C4—C6—H6C	109.5
C4^i—C2—C3	124.42 (9)	H6A—C6—H6C	109.5
C3—C5—H5A	109.5	H6B—C6—H6C	109.5
C3—C5—H5B	109.5	C4—C6—H6D	109.5
H5A—C5—H5B	109.5	H6A—C6—H6D	141.1
C3—C5—H5C	109.5	H6B—C6—H6D	56.3
H5A—C5—H5C	109.5	H6C—C6—H6D	56.3
H5B—C5—H5C	109.5	C4—C6—H6E	109.5
C3—C5—H5D	109.5	H6A—C6—H6E	56.3
H5A—C5—H5D	141.1	H6B—C6—H6E	141.1
H5B—C5—H5D	56.3	H6C—C6—H6E	56.3
H5C—C5—H5D	56.3	H6D—C6—H6E	109.5
C3—C5—H5E	109.5	C4—C6—H6F	109.5
H5A—C5—H5E	56.3	H6A—C6—H6F	56.3
H5B—C5—H5E	141.1	H6B—C6—H6F	56.3
H5C—C5—H5E	56.3	H6C—C6—H6F	141.1
H5D—C5—H5E	109.5	H6D—C6—H6F	109.5
C3—C5—H5F	109.5	H6E—C6—H6F	109.5
C2—C3—C4—C2^i	1.38 (15)	C4—C3—C2—N1	178.78 (8)
C5—C3—C4—C2^i	−177.49 (8)	C5—C3—C2—N1	−2.35 (14)
C2—C3—C4—C6	−178.34 (8)	C4—C3—C2—C4^i	−1.48 (16)
C5—C3—C4—C6	2.79 (14)	C5—C3—C2—C4^i	177.39 (9)

Symmetry code: (i) −x+1/2, −y+3/2, −z+1.