A novel triple-stranded cadmium(II) polymer chain: catena-poly[cadmium(II)-μ-1,2-bis­(imidazol-1-yl)­ethane-κ²N³:N^3′-di-μ-1,5-dicyanamido-κ⁴N¹:N⁵]

In the crystal structure of the title complex, [Cd(C₂N₃)₂(C₈H₁₀N₄)]_n or [Cd(dca)₂(bim)]_n, where dca is dicyanamide and bim is 1,2-bis­(imidazol-1-yl)ethane, each Cd^II atom is in a distorted octa­hedral environment. Four N atoms from four dca ligands occupy the equatorial positions, and two N atoms from two bim ligands occupy the axial positions. Each Cd^II atom is situated at a center of symmetry, and a twofold axis runs through the mid-points of the bim exocyclic C—C bond and the Cd...Cd vector. The structure consists of chains in which neighboring Cd^II atoms are connected through one bim and two end-to-end dca bridges.

Key indicators

• Single-crystal X-ray study
• T = 193 K
• Mean [sigma](C-C) = 0.004 Å
• Disorder in main residue
• R factor = 0.020
• wR factor = 0.054
• Data-to-parameter ratio = 12.3

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT301_ALERT_3_C Main Residue  Disorder .........................       8.00 Perc.

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 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
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL.

catena-poly[cadmium(II)-µ-1,2-bis(imidazol-1-yl)ethane-κ²N³:N^3'– di-µ-1,5-dicyanamido-κ⁴N¹:N⁵]

Crystal data

[Cd(C2N3)2(C8H10N4)]	F(000) = 800
Mr = 406.71	Dx = 1.736 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3014 reflections
a = 12.770 (3) Å	θ = 3.1–25.4°
b = 8.4986 (17) Å	µ = 1.42 mm^−1
c = 14.568 (3) Å	T = 193 K
β = 100.162 (6)°	Block, colorless
V = 1556.2 (6) Å^3	0.40 × 0.30 × 0.11 mm
Z = 4

Data collection

Rigaku Mercury CCD diffractometer	1424 independent reflections
Radiation source: fine-focus sealed tube	1339 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.019
ω scans	θmax = 25.3°, θmin = 3.1°
Absorption correction: multi-scan (North et al., 1968)	h = −15→15
Tmin = 0.601, Tmax = 0.860	k = −9→10
7367 measured reflections	l = −17→17

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)] = 0.020	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.054	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0312P)^2 + 1.619P] where P = (Fo^2 + 2Fc^2)/3
1424 reflections	(Δ/σ)max < 0.001
116 parameters	Δρmax = 0.37 e Å^−3
0 restraints	Δρmin = −0.36 e Å^−3

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 > 2σ(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)
Cd1	0.5000	0.5000	0.5000	0.02520 (10)
N1	0.48122 (13)	0.0401 (2)	0.63851 (12)	0.0248 (3)
N2	0.46656 (13)	0.2588 (2)	0.55640 (12)	0.0295 (4)
N3	0.62292 (16)	0.5463 (3)	0.63574 (14)	0.0392 (4)
N4A	0.7229 (8)	0.5469 (13)	0.7973 (7)	0.053 (3)	0.50
N4B	0.7206 (8)	0.6142 (11)	0.7873 (8)	0.045 (2)	0.50
N5	0.64184 (15)	0.6042 (2)	0.93115 (13)	0.0386 (4)
C1	0.52394 (16)	0.1813 (2)	0.62616 (14)	0.0280 (4)
H1A	0.5875	0.2204	0.6630	0.034*
C2	0.38269 (16)	0.1612 (3)	0.52245 (15)	0.0339 (5)
H2A	0.3275	0.1852	0.4716	0.041*
C3	0.39044 (19)	0.0258 (3)	0.57227 (18)	0.0326 (5)
H3A	0.3430	−0.0611	0.5633	0.039*
C4	0.52426 (16)	−0.0809 (2)	0.70589 (14)	0.0272 (4)
H4A	0.6021	−0.0654	0.7234	0.033*
H4B	0.5123	−0.1852	0.6757	0.033*
C5	0.66585 (16)	0.5622 (3)	0.71016 (16)	0.0348 (5)
C6	0.67607 (16)	0.5910 (3)	0.86445 (15)	0.0341 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.03254 (15)	0.02412 (15)	0.01858 (14)	−0.00034 (7)	0.00357 (9)	0.00068 (7)
N1	0.0253 (8)	0.0255 (8)	0.0234 (9)	0.0006 (7)	0.0032 (7)	−0.0005 (7)
N2	0.0314 (8)	0.0272 (9)	0.0299 (9)	−0.0002 (7)	0.0049 (7)	0.0018 (7)
N3	0.0431 (11)	0.0460 (11)	0.0259 (11)	−0.0018 (10)	−0.0011 (9)	−0.0028 (9)
N4A	0.027 (3)	0.112 (7)	0.019 (3)	0.028 (5)	0.001 (2)	0.003 (5)
N4B	0.025 (3)	0.083 (6)	0.025 (3)	−0.012 (4)	−0.003 (2)	0.004 (4)
N5	0.0410 (10)	0.0431 (11)	0.0336 (10)	−0.0043 (8)	0.0115 (9)	−0.0005 (8)
C1	0.0274 (10)	0.0250 (10)	0.0304 (10)	−0.0016 (8)	0.0018 (8)	−0.0003 (8)
C2	0.0283 (10)	0.0377 (12)	0.0333 (12)	−0.0025 (9)	−0.0012 (9)	0.0036 (9)
C3	0.0289 (11)	0.0352 (11)	0.0318 (12)	−0.0065 (9)	−0.0002 (9)	0.0008 (9)
C4	0.0288 (10)	0.0212 (9)	0.0308 (11)	0.0026 (8)	0.0025 (8)	−0.0002 (8)
C5	0.0257 (10)	0.0469 (14)	0.0325 (13)	0.0032 (10)	0.0072 (10)	−0.0030 (11)
C6	0.0231 (10)	0.0471 (14)	0.0297 (12)	0.0008 (9)	−0.0020 (9)	−0.0017 (10)

Geometric parameters (Å, º)

Cd1—N2^i	2.2769 (17)	N4A—C5	1.353 (10)
Cd1—N2	2.2769 (17)	N4B—C5	1.292 (11)
Cd1—N3	2.331 (2)	N4B—C6	1.360 (11)
Cd1—N3^i	2.331 (2)	N5—C6	1.139 (3)
Cd1—N5^ii	2.3900 (19)	N5—Cd1^iii	2.3900 (19)
Cd1—N5^iii	2.3900 (19)	C1—H1A	0.9500
N1—C1	1.343 (3)	C2—C3	1.355 (3)
N1—C3	1.377 (3)	C2—H2A	0.9500
N1—C4	1.460 (3)	C3—H3A	0.9500
N2—C1	1.319 (3)	C4—C4^iii	1.522 (4)
N2—C2	1.375 (3)	C4—H4A	0.9900
N3—C5	1.133 (3)	C4—H4B	0.9900
N4A—C6	1.290 (11)
N2^i—Cd1—N2	180.0	C6—N4A—C5	116.0 (7)
N2^i—Cd1—N3	90.74 (7)	C5—N4B—C6	115.3 (7)
N2—Cd1—N3	89.26 (7)	C6—N5—Cd1^iii	139.01 (18)
N2^i—Cd1—N3^i	89.26 (7)	N2—C1—N1	111.44 (18)
N2—Cd1—N3^i	90.74 (7)	N2—C1—H1A	124.3
N3—Cd1—N3^i	180.0	N1—C1—H1A	124.3
N2^i—Cd1—N5^ii	88.74 (6)	C3—C2—N2	109.92 (19)
N2—Cd1—N5^ii	91.26 (6)	C3—C2—H2A	125.0
N3—Cd1—N5^ii	88.39 (7)	N2—C2—H2A	125.0
N3^i—Cd1—N5^ii	91.61 (7)	C2—C3—N1	105.86 (19)
N2^i—Cd1—N5^iii	91.26 (6)	C2—C3—H3A	127.1
N2—Cd1—N5^iii	88.74 (6)	N1—C3—H3A	127.1
N3—Cd1—N5^iii	91.61 (7)	N1—C4—C4^iii	113.99 (15)
N3^i—Cd1—N5^iii	88.39 (7)	N1—C4—H4A	108.8
N5^ii—Cd1—N5^iii	180.0	C4^iii—C4—H4A	108.8
C1—N1—C3	107.27 (18)	N1—C4—H4B	108.8
C1—N1—C4	127.25 (17)	C4^iii—C4—H4B	108.8
C3—N1—C4	125.41 (18)	H4A—C4—H4B	107.6
C1—N2—C2	105.51 (17)	N3—C5—N4B	165.7 (4)
C1—N2—Cd1	127.83 (14)	N3—C5—N4A	167.1 (5)
C2—N2—Cd1	126.64 (14)	N5—C6—N4A	167.2 (5)
C5—N3—Cd1	166.24 (19)	N5—C6—N4B	165.8 (5)
N3—Cd1—N2—C1	−15.63 (18)	C1—N1—C3—C2	0.0 (3)
N3^i—Cd1—N2—C1	164.37 (18)	C4—N1—C3—C2	−177.24 (19)
N5^ii—Cd1—N2—C1	72.74 (18)	C1—N1—C4—C4^iii	98.1 (2)
N5^iii—Cd1—N2—C1	−107.26 (18)	C3—N1—C4—C4^iii	−85.3 (3)
N3—Cd1—N2—C2	166.29 (18)	Cd1—N3—C5—N4B	−126 (2)
N3^i—Cd1—N2—C2	−13.71 (18)	Cd1—N3—C5—N4A	93 (2)
N5^ii—Cd1—N2—C2	−105.34 (18)	N4A—N4B—C5—N3	−161.2 (11)
N5^iii—Cd1—N2—C2	74.66 (18)	C6—N4B—C5—N3	134.3 (18)
N2^i—Cd1—N3—C5	124.7 (9)	C6—N4B—C5—N4A	−64.5 (17)
N2—Cd1—N3—C5	−55.3 (9)	N4B—N4A—C5—N3	159.0 (14)
N5^ii—Cd1—N3—C5	−146.6 (9)	C6—N4A—C5—N3	−127.7 (19)
N5^iii—Cd1—N3—C5	33.4 (9)	C6—N4A—C5—N4B	73 (2)
C6—N4A—N4B—C5	−120.1 (4)	Cd1^iii—N5—C6—N4A	−75 (3)
C5—N4A—N4B—C6	120.1 (4)	Cd1^iii—N5—C6—N4B	142.2 (19)
C2—N2—C1—N1	−0.1 (2)	N4B—N4A—C6—N5	−160.0 (13)
Cd1—N2—C1—N1	−178.47 (13)	C5—N4A—C6—N5	134 (2)
C3—N1—C1—N2	0.1 (2)	C5—N4A—C6—N4B	−65.9 (16)
C4—N1—C1—N2	177.20 (18)	N4A—N4B—C6—N5	162.0 (12)
C1—N2—C2—C3	0.0 (3)	C5—N4B—C6—N5	−126.1 (16)
Cd1—N2—C2—C3	178.47 (15)	C5—N4B—C6—N4A	71.9 (19)
N2—C2—C3—N1	0.0 (3)

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x, −y+1, z−1/2; (iii) −x+1, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C4—H4A···N4A^iv	0.99	2.50	3.414 (10)	154

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