A two-dimensional anionic Cd^II polymer constructed through dicyanamide coordination bridges

In the search for potential ferroelectric materials, mol­ecular-based one-, two- and three-dimensional cadmium(II) organic-inorganic compounds have been of inter­est as they often display solid-solid phase transitions induced by a variation in temperature. A new cadmium dicyanamide complex, poly[4-di­methyl­amino-1-ethyl­pyridin-1-ium [tri-[mu]-dicyanamido-[kappa]⁶N¹:N⁵-cadmium(II)]], {(C₉H₁₅N₂)[Cd(C₂N₃)₃]}_n, was synthesized by the reaction of 4-di­methyl­amino-1-ethyl­pyridin-1-ium bromide, cadmium nitrate tetra­hydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each Cd^II cation is octa­hedrally coordinated by six terminal N atoms from six anionic dicyanamide (dca) ligands. Neighbouring Cd^II cations are linked together by dicyanamide bridges to form a two-dimensional coordination polymer. The organic cations are not involved in the formation of the supra­molecular network.

Computing details

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Poly[4-dimethylamino-1-ethylpyridin-1-ium [tri-µ-dicyanamido-κ⁶N¹:N⁵-cadmium(II)]]

Crystal data

(C9H15N2)[Cd(C2N3)3]	F(000) = 920
Mr = 461.78	Dx = 1.569 Mg m^−3
Orthorhombic, Pbcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2c 2b	Cell parameters from 2313 reflections
a = 7.7042 (15) Å	θ = 3.0–30.5°
b = 14.457 (3) Å	µ = 1.14 mm^−1
c = 17.549 (4) Å	T = 293 K
V = 1954.5 (7) Å^3	Block, colourless
Z = 4	0.30 × 0.26 × 0.25 mm

Data collection

Rigaku SCXmini diffractometer	1674 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.028
Graphite monochromator	θmax = 27.5°, θmin = 3.0°
ω scans	h = −10→6
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −18→18
Tmin = 0.726, Tmax = 0.763	l = −22→22
12742 measured reflections	3 standard reflections every 180 reflections
2313 independent reflections	intensity decay: none

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)] = 0.045	H-atom parameters constrained
wR(F^2) = 0.098	w = 1/[σ^2(Fo^2) + (0.0288P)^2 + 3.5336P] where P = (Fo^2 + 2Fc^2)/3
S = 1.19	(Δ/σ)max < 0.001
2313 reflections	Δρmax = 0.71 e Å^−3
135 parameters	Δρmin = −0.68 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008)
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0819 (12)

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)
N4	0.4868 (6)	0.1538 (5)	0.5628 (4)	0.147 (3)
Cd1	1.0000	0.0000	0.5000	0.03462 (13)
C8	0.8972 (5)	0.0452 (3)	0.3147 (2)	0.0455 (10)
N6	0.8310 (8)	0.0675 (7)	0.2500	0.103 (3)
C7	0.6357 (6)	0.1231 (3)	0.5438 (3)	0.0554 (12)
N7	1.2099 (5)	0.1165 (3)	0.5082 (2)	0.0505 (9)
N3	0.7743 (5)	0.1009 (3)	0.5357 (2)	0.0561 (10)
N5	0.9464 (5)	0.0313 (3)	0.37423 (19)	0.0535 (9)
C9	1.3433 (5)	0.1308 (3)	0.5305 (3)	0.0511 (11)
N1	−0.0430 (6)	0.1777 (3)	0.7500	0.0427 (11)
N2	0.3536 (6)	0.3695 (3)	0.7500	0.0426 (11)
C5	−0.2009 (8)	0.1208 (4)	0.7500	0.0510 (15)
H5A	−0.2011	0.0813	0.7947	0.061*	0.50
H5B	−0.2011	0.0813	0.7053	0.061*	0.50
C3	0.2322 (7)	0.3040 (4)	0.7500	0.0367 (12)
C2	0.1607 (6)	0.2682 (3)	0.6814 (2)	0.0430 (10)
H2	0.2064	0.2865	0.6348	0.052*
C1	0.0266 (5)	0.2076 (3)	0.6834 (2)	0.0459 (10)
H1	−0.0190	0.1858	0.6377	0.055*
C4	0.4247 (6)	0.4055 (3)	0.8219 (2)	0.0540 (11)
H4A	0.3315	0.4269	0.8537	0.081*
H4B	0.5023	0.4558	0.8114	0.081*
H4C	0.4867	0.3571	0.8478	0.081*
C6	−0.3625 (10)	0.1798 (5)	0.7500	0.074 (2)
H6A	−0.4632	0.1407	0.7500	0.111*
H6B	−0.3635	0.2182	0.7053	0.111*	0.50
H6C	−0.3635	0.2182	0.7947	0.111*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N4	0.036 (3)	0.227 (7)	0.178 (7)	0.039 (3)	−0.032 (3)	−0.141 (6)
Cd1	0.02607 (19)	0.0542 (2)	0.02363 (18)	0.00032 (17)	−0.00107 (15)	−0.00130 (16)
C8	0.030 (2)	0.077 (3)	0.029 (2)	0.006 (2)	0.0046 (16)	−0.001 (2)
N6	0.053 (4)	0.231 (9)	0.024 (3)	0.057 (5)	0.000	0.000
C7	0.034 (2)	0.073 (3)	0.059 (3)	0.006 (2)	−0.006 (2)	−0.024 (2)
N7	0.0354 (19)	0.065 (2)	0.051 (2)	−0.0069 (16)	−0.0029 (17)	−0.0034 (18)
N3	0.036 (2)	0.073 (2)	0.059 (2)	0.0111 (18)	−0.0014 (18)	−0.014 (2)
N5	0.056 (2)	0.075 (2)	0.0294 (18)	0.000 (2)	−0.0025 (16)	0.0042 (17)
C9	0.032 (2)	0.067 (3)	0.054 (3)	0.011 (2)	−0.0070 (19)	−0.020 (2)
N1	0.046 (3)	0.039 (2)	0.043 (3)	0.004 (2)	0.000	0.000
N2	0.036 (3)	0.057 (3)	0.035 (2)	0.001 (2)	0.000	0.000
C5	0.047 (4)	0.046 (3)	0.060 (4)	−0.001 (3)	0.000	0.000
C3	0.036 (3)	0.043 (3)	0.032 (3)	0.007 (2)	0.000	0.000
C2	0.053 (2)	0.046 (2)	0.030 (2)	0.0033 (18)	0.0053 (18)	−0.0016 (16)
C1	0.054 (3)	0.047 (2)	0.036 (2)	0.003 (2)	−0.0003 (19)	−0.0071 (18)
C4	0.047 (2)	0.072 (3)	0.043 (2)	−0.004 (2)	0.000 (2)	−0.008 (2)
C6	0.056 (5)	0.073 (5)	0.094 (6)	0.013 (4)	0.000	0.000

Geometric parameters (Å, º)

Cd1—N5^i	2.291 (3)	N2—C3	1.332 (7)
Cd1—N5	2.291 (3)	N2—C4	1.471 (5)
Cd1—N7	2.339 (4)	N2—C4^v	1.471 (5)
Cd1—N7^i	2.339 (4)	C5—C6	1.509 (9)
Cd1—N3	2.355 (4)	C5—H5A	0.9700
Cd1—N3^i	2.355 (4)	C5—H5B	0.9700
C7—N3	1.124 (5)	C3—C2	1.421 (5)
N4—C7	1.275 (6)	C3—C2^v	1.421 (5)
N4—C9^ii	1.286 (6)	C2—C1	1.355 (6)
C8—N5	1.130 (5)	C2—H2	0.9300
C8—N6	1.285 (5)	C1—H1	0.9300
N6—C8^iii	1.285 (5)	C4—H4A	0.9600
N7—C9	1.119 (5)	C4—H4B	0.9600
C9—N4^iv	1.286 (6)	C4—H4C	0.9600
N1—C1^v	1.357 (5)	C6—H6A	0.9600
N1—C1	1.357 (5)	C6—H6B	0.9600
N1—C5	1.469 (7)	C6—H6C	0.9600
C7—N4—C9^ii	124.6 (5)	C4—N2—C4^v	118.3 (5)
N5^i—Cd1—N5	180.00 (5)	N1—C5—C6	111.5 (5)
N5^i—Cd1—N7	87.62 (13)	N1—C5—H5A	109.3
N5—Cd1—N7	92.38 (13)	C6—C5—H5A	109.3
N5^i—Cd1—N7^i	92.38 (13)	N1—C5—H5B	109.3
N5—Cd1—N7^i	87.62 (13)	C6—C5—H5B	109.3
N7—Cd1—N7^i	180.00 (13)	H5A—C5—H5B	108.0
N5^i—Cd1—N3	89.98 (14)	N2—C3—C2	122.1 (3)
N5—Cd1—N3	90.02 (14)	N2—C3—C2^v	122.1 (3)
N7—Cd1—N3	92.78 (14)	C2—C3—C2^v	115.8 (5)
N7^i—Cd1—N3	87.22 (14)	C1—C2—C3	120.6 (4)
N5^i—Cd1—N3^i	90.02 (14)	C1—C2—H2	119.7
N5—Cd1—N3^i	89.98 (14)	C3—C2—H2	119.7
N7—Cd1—N3^i	87.22 (14)	C2—C1—N1	122.0 (4)
N7^i—Cd1—N3^i	92.78 (14)	C2—C1—H1	119.0
N3—Cd1—N3^i	180.00 (18)	N1—C1—H1	119.0
N5—C8—N6	174.1 (6)	N2—C4—H4A	109.5
C8^iii—N6—C8	124.1 (6)	N2—C4—H4B	109.5
N3—C7—N4	171.0 (5)	H4A—C4—H4B	109.5
C9—N7—Cd1	142.2 (4)	N2—C4—H4C	109.5
C7—N3—Cd1	155.8 (4)	H4A—C4—H4C	109.5
C8—N5—Cd1	170.8 (4)	H4B—C4—H4C	109.5
N7—C9—N4^iv	172.6 (5)	C5—C6—H6A	109.5
C1^v—N1—C1	119.0 (5)	C5—C6—H6B	109.5
C1^v—N1—C5	120.4 (3)	H6A—C6—H6B	109.5
C1—N1—C5	120.4 (3)	C5—C6—H6C	109.5
C3—N2—C4	120.8 (2)	H6A—C6—H6C	109.5
C3—N2—C4^v	120.8 (2)	H6B—C6—H6C	109.5
N5—C8—N6—C8^iii	164 (6)	N7^i—Cd1—N5—C8	42 (3)
C9^ii—N4—C7—N3	−167 (4)	N3—Cd1—N5—C8	−46 (3)
N5^i—Cd1—N7—C9	44.9 (6)	N3^i—Cd1—N5—C8	134 (3)
N5—Cd1—N7—C9	−135.1 (6)	Cd1—N7—C9—N4^iv	−108 (5)
N7^i—Cd1—N7—C9	147 (16)	C1^v—N1—C5—C6	87.3 (4)
N3—Cd1—N7—C9	134.8 (6)	C1—N1—C5—C6	−87.3 (4)
N3^i—Cd1—N7—C9	−45.2 (6)	C4—N2—C3—C2	179.8 (4)
N4—C7—N3—Cd1	140 (4)	C4^v—N2—C3—C2	−2.5 (8)
N5^i—Cd1—N3—C7	−105.0 (10)	C4—N2—C3—C2^v	2.5 (8)
N5—Cd1—N3—C7	75.0 (10)	C4^v—N2—C3—C2^v	−179.8 (4)
N7—Cd1—N3—C7	167.4 (10)	N2—C3—C2—C1	−174.1 (4)
N7^i—Cd1—N3—C7	−12.6 (10)	C2^v—C3—C2—C1	3.4 (7)
N3^i—Cd1—N3—C7	12 (100)	C3—C2—C1—N1	−0.9 (7)
N6—C8—N5—Cd1	54 (8)	C1^v—N1—C1—C2	−1.8 (8)
N5^i—Cd1—N5—C8	−14 (100)	C5—N1—C1—C2	172.8 (4)
N7—Cd1—N5—C8	−138 (3)

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