4,4'-[2,2-Dimethyl-propane-1,3-diyl-bis(nitrilo-methyl-idyne)]dibenzonitrile.

The title compound, C(21)H(20)N(4), is a bidentate Schiff base ligand. An intra-molecular C-H⋯N hydrogen bond forms a five-membered ring, producing an S(5) ring motif. The cyano and imino [-C(H(2))-N=C-] functional groups are coplanar with the benzene ring in each half of the mol-ecule. The packing of the mol-ecules is controlled by C-H⋯π and π-π inter-actions [centroid-to-centroid distance = 3.6944 (8) Å].

Related literature

For related literature on hydrogen-bond motifs, see Bernstein et al. (1995 ▶). For values of bond lengths, see Allen et al. (1987 ▶). For related structures, see, for example: Li et al. (2005 ▶); Bomfim et al. (2005 ▶); Glidewell et al. (2005 ▶, 2006 ▶); Sun et al. (2004 ▶); Habibi et al. (2007 ▶); Fun et al. (2008 ▶).

Experimental

Crystal data

C21H20N4

M = 328.41

Monoclinic,

a = 6.3833 (2) Å

b = 34.0679 (8) Å

c = 8.5190 (2) Å

β = 100.654 (2)°

V = 1820.65 (8) Å3

Z = 4

Mo Kα radiation

μ = 0.07 mm−1

T = 100.0 (1) K

0.42 × 0.20 × 0.19 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker 2005 ▶) T min = 0.970, T max = 0.986

21813 measured reflections

5329 independent reflections

3711 reflections with I > 2σ(I)

R int = 0.046

Refinement

R[F 2 > 2σ(F 2)] = 0.056

wR(F 2) = 0.139

S = 1.04

5329 reflections

228 parameters

H-atom parameters constrained

Δρmax = 0.24 e Å−3

Δρmin = −0.20 e Å−3

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2003 ▶).

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808018345/at2578sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808018345/at2578Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C21H20N4	F000 = 696
Mr = 328.41	Dx = 1.198 Mg m−3
Monoclinic, P21/c	Mo Kα radiation λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3870 reflections
a = 6.3833 (2) Å	θ = 2.4–29.3º
b = 34.0679 (8) Å	µ = 0.07 mm−1
c = 8.5190 (2) Å	T = 100.0 (1) K
β = 100.654 (2)º	Block, colourless
V = 1820.65 (8) Å3	0.42 × 0.20 × 0.19 mm
Z = 4

Bruker SMART APEXII CCD area-detector diffractometer	5329 independent reflections
Radiation source: fine-focus sealed tube	3711 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.046
T = 100.0(1) K	θmax = 30.2º
φ and ω scans	θmin = 1.2º
Absorption correction: multi-scan(SADABS; Bruker 2005)	h = −9→7
Tmin = 0.970, Tmax = 0.986	k = −48→48
21813 measured reflections	l = −12→12

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)] = 0.056	H-atom parameters constrained
wR(F2) = 0.139	w = 1/[σ2(Fo2) + (0.0568P)2 + 0.5007P] where P = (Fo2 + 2Fc2)/3
S = 1.04	(Δ/σ)max < 0.001
5329 reflections	Δρmax = 0.24 e Å−3
228 parameters	Δρmin = −0.19 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction correction: none

Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment.

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.

	x	y	z	Uiso*/Ueq
N1	0.8180 (2)	0.14310 (4)	1.22220 (14)	0.0240 (3)
N2	0.7297 (2)	0.07939 (4)	0.76666 (14)	0.0243 (3)
N3	0.1075 (3)	0.23585 (4)	1.75196 (17)	0.0346 (4)
N4	0.2208 (2)	0.01242 (4)	−0.06341 (15)	0.0278 (3)
C1	0.4959 (3)	0.16261 (4)	1.41380 (17)	0.0234 (3)
H1A	0.4844	0.1376	1.3689	0.028*
C2	0.3530 (3)	0.17457 (4)	1.50763 (17)	0.0243 (3)
H2A	0.2462	0.1576	1.5267	0.029*
C3	0.3698 (3)	0.21224 (4)	1.57374 (16)	0.0226 (3)
C4	0.5288 (3)	0.23767 (4)	1.54525 (17)	0.0254 (3)
H4A	0.5386	0.2628	1.5886	0.031*
C5	0.6719 (3)	0.22545 (4)	1.45229 (17)	0.0237 (3)
H5A	0.7789	0.2424	1.4335	0.028*
C6	0.6573 (3)	0.18785 (4)	1.38618 (16)	0.0211 (3)
C7	0.8171 (3)	0.17624 (4)	1.29000 (16)	0.0224 (3)
H7A	0.9230	0.1942	1.2785	0.027*
C8	0.9911 (3)	0.13680 (4)	1.13468 (17)	0.0245 (3)
H8A	1.0761	0.1147	1.1816	0.029*
H8B	1.0823	0.1598	1.1469	0.029*
C9	0.9149 (3)	0.12886 (4)	0.95573 (16)	0.0215 (3)
C10	0.7881 (3)	0.09017 (4)	0.93463 (16)	0.0232 (3)
H10A	0.8736	0.0694	0.9923	0.028*
H10B	0.6600	0.0930	0.9796	0.028*
C11	0.5405 (3)	0.06825 (4)	0.71580 (16)	0.0226 (3)
H11A	0.4445	0.0675	0.7857	0.027*
C12	0.4686 (3)	0.05644 (4)	0.54744 (16)	0.0212 (3)
C13	0.6067 (3)	0.05915 (4)	0.43861 (17)	0.0231 (3)
H13A	0.7442	0.0687	0.4719	0.028*
C14	0.5402 (3)	0.04776 (4)	0.28203 (17)	0.0233 (3)
H14A	0.6322	0.0497	0.2096	0.028*
C15	0.3345 (3)	0.03329 (4)	0.23295 (16)	0.0212 (3)
C16	0.1937 (3)	0.03068 (4)	0.33940 (17)	0.0256 (3)
H16A	0.0561	0.0212	0.3058	0.031*
C17	0.2624 (3)	0.04247 (4)	0.49654 (17)	0.0255 (3)
H17A	0.1694	0.0410	0.5685	0.031*
C18	0.2220 (3)	0.22512 (4)	1.67256 (18)	0.0270 (3)
C19	0.2687 (3)	0.02115 (4)	0.06860 (17)	0.0227 (3)
C20	1.1140 (3)	0.12547 (5)	0.88075 (19)	0.0287 (4)
H20A	1.1895	0.1500	0.8920	0.043*
H20B	1.0729	0.1192	0.7695	0.043*
H20C	1.2046	0.1051	0.9337	0.043*
C21	0.7745 (3)	0.16266 (4)	0.87814 (18)	0.0274 (4)
H21A	0.8507	0.1870	0.8986	0.041*
H21B	0.6466	0.1638	0.9222	0.041*
H21C	0.7381	0.1584	0.7650	0.041*

	U11	U22	U33	U12	U13	U23
N1	0.0265 (8)	0.0254 (6)	0.0199 (6)	−0.0005 (5)	0.0037 (5)	−0.0025 (5)
N2	0.0282 (8)	0.0233 (6)	0.0222 (6)	−0.0009 (5)	0.0070 (5)	−0.0030 (5)
N3	0.0335 (10)	0.0336 (8)	0.0379 (8)	0.0006 (6)	0.0099 (7)	−0.0063 (6)
N4	0.0268 (8)	0.0305 (7)	0.0270 (6)	−0.0013 (6)	0.0071 (6)	−0.0028 (5)
C1	0.0282 (9)	0.0186 (7)	0.0219 (7)	−0.0002 (6)	0.0011 (6)	−0.0015 (5)
C2	0.0257 (9)	0.0222 (7)	0.0244 (7)	−0.0010 (6)	0.0028 (6)	0.0011 (5)
C3	0.0230 (9)	0.0247 (7)	0.0193 (6)	0.0030 (6)	0.0015 (6)	−0.0003 (5)
C4	0.0319 (10)	0.0203 (7)	0.0234 (7)	0.0002 (6)	0.0034 (6)	−0.0040 (5)
C5	0.0275 (9)	0.0212 (7)	0.0222 (7)	−0.0033 (6)	0.0037 (6)	−0.0006 (5)
C6	0.0236 (9)	0.0214 (7)	0.0168 (6)	0.0013 (6)	0.0002 (6)	0.0006 (5)
C7	0.0232 (9)	0.0225 (7)	0.0206 (6)	−0.0012 (6)	0.0019 (6)	0.0007 (5)
C8	0.0250 (9)	0.0235 (7)	0.0244 (7)	0.0015 (6)	0.0029 (6)	−0.0025 (5)
C9	0.0232 (9)	0.0200 (7)	0.0220 (6)	0.0002 (6)	0.0059 (6)	−0.0009 (5)
C10	0.0275 (9)	0.0234 (7)	0.0191 (6)	0.0005 (6)	0.0056 (6)	−0.0007 (5)
C11	0.0286 (10)	0.0193 (7)	0.0218 (7)	0.0010 (6)	0.0095 (6)	0.0000 (5)
C12	0.0277 (9)	0.0152 (6)	0.0214 (6)	0.0012 (6)	0.0063 (6)	0.0000 (5)
C13	0.0234 (9)	0.0226 (7)	0.0240 (7)	−0.0016 (6)	0.0058 (6)	−0.0023 (5)
C14	0.0269 (9)	0.0225 (7)	0.0226 (7)	−0.0003 (6)	0.0101 (6)	−0.0013 (5)
C15	0.0266 (9)	0.0161 (6)	0.0211 (6)	0.0020 (6)	0.0051 (6)	−0.0004 (5)
C16	0.0256 (9)	0.0258 (7)	0.0257 (7)	−0.0031 (6)	0.0054 (6)	−0.0004 (6)
C17	0.0274 (10)	0.0289 (8)	0.0227 (7)	−0.0025 (7)	0.0107 (6)	0.0002 (6)
C18	0.0300 (10)	0.0236 (7)	0.0268 (7)	0.0002 (7)	0.0037 (7)	−0.0020 (6)
C19	0.0240 (9)	0.0199 (7)	0.0253 (7)	0.0007 (6)	0.0075 (6)	0.0000 (5)
C20	0.0284 (10)	0.0290 (8)	0.0309 (8)	−0.0013 (7)	0.0112 (7)	−0.0014 (6)
C21	0.0306 (10)	0.0242 (7)	0.0274 (7)	0.0020 (7)	0.0053 (7)	0.0009 (6)

N1—C7	1.2687 (18)	C9—C21	1.532 (2)
N1—C8	1.459 (2)	C9—C10	1.539 (2)
N2—C11	1.264 (2)	C10—H10A	0.9700
N2—C10	1.4576 (17)	C10—H10B	0.9700
N3—C18	1.143 (2)	C11—C12	1.4786 (19)
N4—C19	1.1486 (19)	C11—H11A	0.9300
C1—C2	1.380 (2)	C12—C17	1.391 (2)
C1—C6	1.395 (2)	C12—C13	1.396 (2)
C1—H1A	0.9300	C13—C14	1.379 (2)
C2—C3	1.398 (2)	C13—H13A	0.9300
C2—H2A	0.9300	C14—C15	1.392 (2)
C3—C4	1.389 (2)	C14—H14A	0.9300
C3—C18	1.444 (2)	C15—C16	1.392 (2)
C4—C5	1.379 (2)	C15—C19	1.446 (2)
C4—H4A	0.9300	C16—C17	1.389 (2)
C5—C6	1.396 (2)	C16—H16A	0.9300
C5—H5A	0.9300	C17—H17A	0.9300
C6—C7	1.476 (2)	C20—H20A	0.9600
C7—H7A	0.9300	C20—H20B	0.9600
C8—C9	1.536 (2)	C20—H20C	0.9600
C8—H8A	0.9700	C21—H21A	0.9600
C8—H8B	0.9700	C21—H21B	0.9600
C9—C20	1.529 (2)	C21—H21C	0.9600
C7—N1—C8	115.55 (14)	N2—C10—H10B	109.4
C11—N2—C10	117.85 (13)	C9—C10—H10B	109.4
C2—C1—C6	120.21 (13)	H10A—C10—H10B	108.0
C2—C1—H1A	119.9	N2—C11—C12	121.33 (14)
C6—C1—H1A	119.9	N2—C11—H11A	119.3
C1—C2—C3	119.66 (15)	C12—C11—H11A	119.3
C1—C2—H2A	120.2	C17—C12—C13	119.54 (13)
C3—C2—H2A	120.2	C17—C12—C11	120.10 (14)
C4—C3—C2	120.41 (14)	C13—C12—C11	120.36 (15)
C4—C3—C18	119.30 (14)	C14—C13—C12	120.32 (15)
C2—C3—C18	120.29 (15)	C14—C13—H13A	119.8
C5—C4—C3	119.66 (14)	C12—C13—H13A	119.8
C5—C4—H4A	120.2	C13—C14—C15	119.65 (14)
C3—C4—H4A	120.2	C13—C14—H14A	120.2
C4—C5—C6	120.45 (15)	C15—C14—H14A	120.2
C4—C5—H5A	119.8	C16—C15—C14	120.88 (13)
C6—C5—H5A	119.8	C16—C15—C19	120.37 (15)
C1—C6—C5	119.60 (14)	C14—C15—C19	118.75 (14)
C1—C6—C7	122.45 (13)	C17—C16—C15	118.87 (16)
C5—C6—C7	117.95 (14)	C17—C16—H16A	120.6
N1—C7—C6	123.57 (15)	C15—C16—H16A	120.6
N1—C7—H7A	118.2	C16—C17—C12	120.73 (14)
C6—C7—H7A	118.2	C16—C17—H17A	119.6
N1—C8—C9	113.72 (13)	C12—C17—H17A	119.6
N1—C8—H8A	108.8	N3—C18—C3	178.73 (19)
C9—C8—H8A	108.8	N4—C19—C15	177.74 (17)
N1—C8—H8B	108.8	C9—C20—H20A	109.5
C9—C8—H8B	108.8	C9—C20—H20B	109.5
H8A—C8—H8B	107.7	H20A—C20—H20B	109.5
C20—C9—C21	109.99 (12)	C9—C20—H20C	109.5
C20—C9—C8	107.02 (13)	H20A—C20—H20C	109.5
C21—C9—C8	110.40 (12)	H20B—C20—H20C	109.5
C20—C9—C10	110.25 (12)	C9—C21—H21A	109.5
C21—C9—C10	109.88 (13)	C9—C21—H21B	109.5
C8—C9—C10	109.26 (11)	H21A—C21—H21B	109.5
N2—C10—C9	111.35 (11)	C9—C21—H21C	109.5
N2—C10—H10A	109.4	H21A—C21—H21C	109.5
C9—C10—H10A	109.4	H21B—C21—H21C	109.5
C6—C1—C2—C3	0.6 (2)	C21—C9—C10—N2	64.21 (16)
C1—C2—C3—C4	0.2 (2)	C8—C9—C10—N2	−174.52 (13)
C1—C2—C3—C18	−179.80 (14)	C10—N2—C11—C12	−179.43 (12)
C2—C3—C4—C5	−0.6 (2)	N2—C11—C12—C17	176.85 (14)
C18—C3—C4—C5	179.36 (15)	N2—C11—C12—C13	−3.1 (2)
C3—C4—C5—C6	0.3 (2)	C17—C12—C13—C14	−0.6 (2)
C2—C1—C6—C5	−0.8 (2)	C11—C12—C13—C14	179.35 (13)
C2—C1—C6—C7	178.55 (14)	C12—C13—C14—C15	−0.4 (2)
C4—C5—C6—C1	0.4 (2)	C13—C14—C15—C16	0.9 (2)
C4—C5—C6—C7	−179.02 (14)	C13—C14—C15—C19	−179.39 (13)
C8—N1—C7—C6	−178.95 (13)	C14—C15—C16—C17	−0.5 (2)
C1—C6—C7—N1	1.7 (2)	C19—C15—C16—C17	179.79 (14)
C5—C6—C7—N1	−178.92 (14)	C15—C16—C17—C12	−0.4 (2)
C7—N1—C8—C9	−119.58 (14)	C13—C12—C17—C16	1.0 (2)
N1—C8—C9—C20	176.60 (12)	C11—C12—C17—C16	−178.95 (13)
N1—C8—C9—C21	56.91 (17)	C4—C3—C18—N3	−19 (9)
N1—C8—C9—C10	−64.04 (16)	C2—C3—C18—N3	161 (9)
C11—N2—C10—C9	−134.31 (14)	C16—C15—C19—N4	149 (5)
C20—C9—C10—N2	−57.17 (17)	C14—C15—C19—N4	−31 (5)

D—H···A	D—H	H···A	D···A	D—H···A
C20—H20B···N2	0.96	2.57	2.923 (2)	102
C21—H21C···Cg1i	0.96	2.95	3.7193 (16)	138

Table 1

Hydrogen-bond geometry (Å, °)

Cg1 is the centroid of the C12–C17 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C20—H20B⋯N2	0.96	2.57	2.923 (2)	102
C21—H21C⋯Cg1i	0.96	2.95	3.7193 (16)	138

Symmetry code: (i) .