(Z)-2,2,2-Trichloro-N-cyano-acetamidine.

The title compound, C(3)H(2)Cl(3)N(3), crystallizes as the Z isomer with respect to the C=N bond. The -C(NH(2))=NCN functional group is effectively planar (r.m.s. deviation = 0.016 Å), with only the three Cl atoms out of the mol-ecular plane. A strong network of N-H⋯N hydrogen bonds forms dimers which are associated into ribbons in the crystal structure. Hydrogen bonding is suspected to be the cause of the near-equivalence of the formal C-N and C=N bonds (Δ(CN) = 0.008 Å).

Related literature

For literature related to characterization, see: Huffman & Schaefer (1963 ▶). For comparable structures of N′-cyano­amidines; see Allen (2002 ▶). For the crystal structures of N 2-cyano-3-[2-diamino­methyl­eneamino)-4-thia­zolylmethyl­thio]propionn class="Chemical">amidine­monohydrate, (II) and 3-{2-[amino­(methyl­amino)methyl­eneamino]-4-thia­zolylmethyl­thio}-N 2-cyano­propionamidine, (III), see Ishida et al. (1989 ▶). For the crystal structure of (E)-1,2-bis­(1-amino-1-(cyano­imino)-2-methyl­prop-2-yl)diazene-1,2- dioxide, (IV), see: Tretyakov et al. (2006 ▶). For the sole other acyclic trichloro­methyl amidine with a reported crystal structure, N-(4-amino-3-furan­zanyl)-2,2,2-trichloro-N-methoxy­acetamidine, (V), see: George & Gilardi (1986 ▶). For background to the ΔCN parameter, see: Boeré, et al. (1998 ▶).

Experimental

Crystal data

C3H2Cl3N3

M = 186.43

Monoclinic,

a = 5.5388 (4) Å

b = 6.6127 (4) Å

c = 18.4727 (12) Å

β = 95.122 (1)°

V = 673.89 (8) Å3

Z = 4

Mo Kα radiation

μ = 1.26 mm−1

T = 173 K

0.41 × 0.27 × 0.21 mm

Data collection

Bruker APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2006 ▶) T min = 0.616, T max = 0.770

7459 measured reflections

1552 independent reflections

1479 reflections with I > 2σ(I)

R int = 0.017

Refinement

R[F 2 > 2σ(F 2)] = 0.019

wR(F 2) = 0.050

S = 1.06

1552 reflections

83 parameters

H-atom parameters constrained

Δρmax = 0.41 e Å−3

Δρmin = −0.27 e Å−3

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT-Plus (Bruker, 2006 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL (Sheldrick, 2008 ▶); molecular graphics: Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: publCIF (Westrip, 2009 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809031079/wn2341sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809031079/wn2341Isup2.hkl

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

C3H2Cl3N3	F(000) = 368
Mr = 186.43	Dx = 1.838 Mg m−3
Monoclinic, P21/n	Melting point: 441 K
Hall symbol: -P 2yn	Mo Kα radiation, λ = 0.71073 Å
a = 5.5388 (4) Å	Cell parameters from 4497 reflections
b = 6.6127 (4) Å	θ = 2.2–27.6°
c = 18.4727 (12) Å	µ = 1.26 mm−1
β = 95.122 (1)°	T = 173 K
V = 673.89 (8) Å3	Block, colourless
Z = 4	0.41 × 0.27 × 0.21 mm

Bruker APEXII CCD area-detector diffractometer	1552 independent reflections
Radiation source: Molybdenum	1479 reflections with I > 2σ(I)
graphite	Rint = 0.017
φ and ω scans	θmax = 27.5°, θmin = 2.2°
Absorption correction: multi-scan (SADABS; Bruker, 2006)	h = −7→7
Tmin = 0.616, Tmax = 0.770	k = −8→8
7459 measured reflections	l = −24→23

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.019	H-atom parameters constrained
wR(F2) = 0.050	w = 1/[σ2(Fo2) + (0.0247P)2 + 0.2765P] where P = (Fo2 + 2Fc2)/3
S = 1.06	(Δ/σ)max = 0.001
1552 reflections	Δρmax = 0.41 e Å−3
83 parameters	Δρmin = −0.27 e Å−3
0 restraints	Extinction correction: SHELXTL (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0231 (18)

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
Cl1	0.23790 (5)	0.15285 (5)	0.181208 (18)	0.02983 (10)
Cl2	0.66794 (6)	0.37010 (5)	0.233709 (17)	0.02976 (10)
Cl3	0.33903 (6)	0.53919 (5)	0.119806 (17)	0.02989 (10)
C2	0.62444 (19)	0.20753 (17)	0.10178 (6)	0.0179 (2)
C3	0.7632 (2)	−0.09854 (17)	0.06561 (7)	0.0224 (2)
C1	0.4692 (2)	0.31232 (17)	0.15584 (6)	0.0196 (2)
N2	0.62859 (18)	0.01089 (15)	0.10646 (5)	0.0229 (2)
N1	0.74493 (18)	0.32334 (15)	0.05999 (6)	0.0230 (2)
H1A	0.8430	0.2689	0.0305	0.028*
H1B	0.7277	0.4555	0.0614	0.028*
N3	0.8680 (2)	−0.21297 (17)	0.03320 (6)	0.0298 (2)

	U11	U22	U33	U12	U13	U23
Cl1	0.02508 (16)	0.02924 (17)	0.03733 (18)	−0.00196 (11)	0.01472 (13)	0.00338 (12)
Cl2	0.03001 (17)	0.03173 (17)	0.02701 (16)	0.00592 (12)	−0.00034 (12)	−0.01080 (12)
Cl3	0.03524 (18)	0.02289 (16)	0.03307 (17)	0.01263 (12)	0.01157 (13)	0.00600 (11)
C2	0.0173 (5)	0.0184 (5)	0.0181 (5)	0.0013 (4)	0.0022 (4)	−0.0011 (4)
C3	0.0260 (6)	0.0158 (5)	0.0259 (6)	−0.0021 (4)	0.0060 (5)	0.0019 (4)
C1	0.0199 (5)	0.0175 (5)	0.0221 (5)	0.0025 (4)	0.0054 (4)	0.0012 (4)
N2	0.0269 (5)	0.0166 (5)	0.0264 (5)	0.0015 (4)	0.0096 (4)	0.0000 (4)
N1	0.0270 (5)	0.0168 (5)	0.0270 (5)	0.0010 (4)	0.0121 (4)	0.0001 (4)
N3	0.0364 (6)	0.0194 (5)	0.0355 (6)	0.0012 (4)	0.0136 (5)	−0.0025 (4)

Cl1—C1	1.7549 (12)	C2—C1	1.5396 (15)
Cl2—C1	1.7733 (12)	C3—N3	1.1533 (17)
Cl3—C1	1.7686 (12)	C3—N2	1.3226 (16)
C2—N2	1.3032 (15)	N1—H1A	0.8800
C2—N1	1.3115 (15)	N1—H1B	0.8800
N2—C2—N1	127.94 (11)	C2—C1—Cl2	106.31 (7)
N2—C2—C1	114.43 (10)	Cl1—C1—Cl2	109.15 (6)
N1—C2—C1	117.52 (10)	Cl3—C1—Cl2	108.98 (6)
N3—C3—N2	172.16 (13)	C2—N2—C3	121.04 (10)
C2—C1—Cl1	111.47 (8)	C2—N1—H1A	120.0
C2—C1—Cl3	111.73 (8)	C2—N1—H1B	120.0
Cl1—C1—Cl3	109.12 (6)	H1A—N1—H1B	120.0
N2—C2—C1—Cl1	−26.28 (12)	N2—C2—C1—Cl2	92.56 (10)
N1—C2—C1—Cl1	157.21 (9)	N1—C2—C1—Cl2	−83.95 (11)
N2—C2—C1—Cl3	−148.66 (9)	N1—C2—N2—C3	−0.9 (2)
N1—C2—C1—Cl3	34.83 (12)	C1—C2—N2—C3	−176.95 (10)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···N3i	0.88	2.10	2.9583 (15)	164
N1—H1B···N3ii	0.88	2.40	3.1893 (15)	150

Value	(I)	(II)	(III)	(IV)	(V)
C2-N1	1.3115 (15)	1.308 (4)	1.308 (3)	1.307 (2)	1.387 (4)
C2-N2	1.3032 (15)	1.320 (4)	1.317 (3)	1.306 (2)	1.2737 (4)
ΔCN	0.008	-0.012	-0.009	0.001	0.114
C2-C1	1.5396 (15)	1.520 (4)	1.513 (3)	1.522 (3)	1.525 (5)
C3-N3	1.1533 (17)	1.164 (4)	1.1567 (3)	1.153 (3)
C3-N2	1.3226 (16)	1.320 (4)	1.333 (3)	1.322 (3)
N2-C2-N1	127.94 (11)	118.0 (2)	125.9 (2)	126.0 (2)	127.7 (3)
N2-C2-C1	114.43 (10)	124.1 (2)	116.8 (2)	114.9 (1)	117.2 (3)
N1-C2-C1	117.52 (10)	117.9 (2)	117.3 (2)	118.7 (1)	115.0 (3)
C2-N2-C3	121.04 (10)	119.1 (2)	118.7 (1)
N3-C3-N2	172.16 (13)	173.2 (2)	173.9 (3)	173.2 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯N3i	0.88	2.10	2.9583 (15)	164
N1—H1B⋯N3ii	0.88	2.40	3.1893 (15)	150

Symmetry codes: (i) ; (ii) .

Table 2

Comparative distances (Å) and angles (°) in amidines (I)–(V)

Value	(I)	(II)	(III)	(IV)	(V)
C2—N1	1.3115 (15)	1.308 (4)	1.308 (3)	1.307 (2)	1.387 (4)
C2—N2	1.3032 (15)	1.320 (4)	1.317 (3)	1.306 (2)	1.2737 (4)
ΔCN	0.008	−0.012	−0.009	0.001	0.114
C2—C1	1.5396 (15)	1.520 (4)	1.513 (3)	1.522 (3)	1.525 (5)
C3—N3	1.1533 (17)	1.164 (4)	1.1567 (3)	1.153 (3)
C3—N2	1.3226 (16)	1.320 (4)	1.333 (3)	1.322 (3)
N2—C2—N1	127.94 (11)	118.0 (2)	125.9 (2)	126.0 (2)	127.7 (3)
N2—C2—C1	114.43 (10)	124.1 (2)	116.8 (2)	114.9 (1)	117.2 (3)
N1—C2—C1	117.52 (10)	117.9 (2)	117.3 (2)	118.7 (1)	115.0 (3)
C2—N2—C3	121.04 (10)	119.1 (2)	118.7 (1)
N3—C3—N2	172.16 (13)	173.2 (2)	173.9 (3)	173.2 (2)

Compound (I) corresponds to the title compound and (II)–(V) are defined in the Related Literature section. Atom numbering corresponds to that in Fig. 1 (in Supplementary materials).