(C₄H₁₂N₂)[CoCl₄]: tetrahedrally coordinated Co²⁺ without the orbital degeneracy

We report on the synthesis, crystal structure and magnetic properties of a previously unreported Co²⁺ compound, (C₄H₁₂N₂)[CoCl₄], based upon a tetrahedral crystalline environment. The magnetic ground state of Co²⁺, measured with magnetization, implies an absence of spin-orbit coupling and orbital degeneracy. This contrasts with compounds based upon an octahedral and even known tetrahedral Co²⁺ [Cotton et al. (1961). J. Am. Chem. Soc. 83, 4690] systems where a sizable spin-orbit coupling is measured. The compound is characterized with single-crystal X-ray diffraction, magnetic susceptibility, IR and UV–vis spectroscopy. Magnetic susceptibility measurements find no magnetic ordering above 2 K. The results are also compared with the previously known monoclinic hydrated analogue.

Computing details

Program(s) used to solve structure: olex2.solve (Bourhis et al., 2013); program(s) used to refine structure: SHELXL (Sheldrick, 2008); molecular graphics: Olex2 (Dolomanov et al., 2009); software used to prepare material for publication: Olex2 (Dolomanov et al., 2009).

Figures

(I)

Crystal data

Cl4Co·C4H12N2	Dx = 1.746 Mg m^−3
Mr = 288.89	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 8051 reflections
a = 8.2876 (6) Å	θ = 2.5–30.4°
b = 11.1324 (9) Å	µ = 2.48 mm^−1
c = 11.9121 (9) Å	T = 293 K
V = 1099.02 (15) Å^3	Prism, blue
Z = 4	0.2 × 0.2 × 0.2 mm
F(000) = 580

Data collection

Bruker APEX-II CCD diffractometer	4190 independent reflections
Radiation source: sealed tube	3465 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
Detector resolution: 8 pixels mm^-1	θmax = 33.2°, θmin = 2.5°
ϕ and ω scans	h = −12→12
Absorption correction: multi-scan SADABS2008/1 (Bruker,2008) was used for absorption correction. wR2(int) was 0.0830 before and 0.0581 after correction. The Ratio of minimum to maximum transmission is 0.8516. The λ/2 correction factor is 0.0015.	k = −17→17
Tmin = 0.636, Tmax = 0.747	l = −18→18
40260 measured reflections

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)] = 0.032	H-atom parameters constrained
wR(F^2) = 0.074	w = 1/[σ^2(Fo^2) + (0.036P)^2 + 0.062P] where P = (Fo^2 + 2Fc^2)/3
S = 1.07	(Δ/σ)max = 0.001
4190 reflections	Δρmax = 0.33 e Å^−3
100 parameters	Δρmin = −0.77 e Å^−3
0 restraints	Absolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
Primary atom site location: iterative	Absolute structure parameter: 0.004 (13)

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
Co1	0.22854 (3)	0.03580 (2)	0.59184 (2)	0.03279 (7)
Cl1	0.43625 (6)	−0.09778 (5)	0.59417 (5)	0.03906 (11)
Cl2	0.23787 (6)	0.14196 (4)	0.75416 (4)	0.03625 (11)
Cl3	0.25139 (7)	0.15017 (5)	0.43604 (4)	0.04321 (13)
Cl4	−0.01362 (6)	−0.06584 (5)	0.59817 (5)	0.03867 (11)
N1	0.4274 (2)	0.52476 (17)	0.66435 (15)	0.0341 (4)
H1A	0.5188	0.5127	0.7036	0.041*
H1B	0.4549	0.5499	0.5951	0.041*
N2	0.0846 (2)	0.52426 (18)	0.64591 (15)	0.0356 (4)
H2A	0.0529	0.5000	0.7145	0.043*
H2B	−0.0045	0.5369	0.6044	0.043*
C1	0.3296 (3)	0.6189 (2)	0.72043 (18)	0.0374 (4)
H1C	0.3905	0.6932	0.7239	0.045*
H1D	0.3048	0.5942	0.7966	0.045*
C2	0.1757 (3)	0.6388 (2)	0.6564 (2)	0.0433 (5)
H2C	0.1099	0.6978	0.6951	0.052*
H2D	0.2004	0.6697	0.5823	0.052*
C3	0.1824 (2)	0.42830 (19)	0.59315 (18)	0.0348 (4)
H3A	0.2059	0.4499	0.5160	0.042*
H3B	0.1214	0.3539	0.5926	0.042*
C4	0.3374 (3)	0.4099 (2)	0.6556 (2)	0.0391 (5)
H4A	0.3145	0.3794	0.7302	0.047*
H4B	0.4029	0.3509	0.6167	0.047*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.02726 (13)	0.03873 (13)	0.03238 (12)	−0.00125 (10)	−0.00037 (12)	0.00253 (11)
Cl1	0.0350 (2)	0.0445 (3)	0.0377 (2)	0.00632 (19)	0.0022 (2)	0.0049 (2)
Cl2	0.0319 (2)	0.0375 (2)	0.0393 (2)	−0.0031 (2)	0.0008 (2)	−0.00246 (18)
Cl3	0.0444 (3)	0.0469 (3)	0.0384 (2)	0.0014 (3)	0.0020 (2)	0.0102 (2)
Cl4	0.0319 (2)	0.0502 (3)	0.0339 (2)	−0.00842 (19)	−0.0015 (2)	0.0005 (2)
N1	0.0239 (8)	0.0445 (9)	0.0339 (8)	−0.0040 (8)	−0.0024 (7)	−0.0008 (7)
N2	0.0239 (8)	0.0462 (10)	0.0367 (9)	0.0033 (8)	0.0007 (7)	−0.0002 (8)
C1	0.0393 (11)	0.0346 (10)	0.0384 (10)	−0.0053 (8)	−0.0008 (9)	−0.0044 (9)
C2	0.0389 (12)	0.0336 (11)	0.0574 (14)	0.0069 (9)	−0.0028 (11)	0.0003 (10)
C3	0.0279 (9)	0.0397 (9)	0.0366 (9)	−0.0013 (7)	−0.0024 (9)	−0.0076 (9)
C4	0.0313 (11)	0.0345 (10)	0.0517 (13)	0.0031 (9)	−0.0034 (10)	−0.0047 (10)

Geometric parameters (Å, º)

Co1—Cl1	2.2749 (6)	N2—C3	1.481 (3)
Co1—Cl2	2.2674 (6)	C1—H1C	0.9700
Co1—Cl3	2.2586 (6)	C1—H1D	0.9700
Co1—Cl4	2.3052 (6)	C1—C2	1.503 (3)
N1—H1A	0.9000	C2—H2C	0.9700
N1—H1B	0.9000	C2—H2D	0.9700
N1—C1	1.484 (3)	C3—H3A	0.9700
N1—C4	1.485 (3)	C3—H3B	0.9700
N2—H2A	0.9000	C3—C4	1.499 (3)
N2—H2B	0.9000	C4—H4A	0.9700
N2—C2	1.487 (3)	C4—H4B	0.9700
Cl1—Co1—Cl4	109.73 (2)	H1C—C1—H1D	108.2
Cl2—Co1—Cl1	107.73 (2)	C2—C1—H1C	109.7
Cl2—Co1—Cl4	104.93 (2)	C2—C1—H1D	109.7
Cl3—Co1—Cl1	108.36 (2)	N2—C2—C1	110.31 (18)
Cl3—Co1—Cl2	113.83 (2)	N2—C2—H2C	109.6
Cl3—Co1—Cl4	112.12 (2)	N2—C2—H2D	109.6
H1A—N1—H1B	108.0	C1—C2—H2C	109.6
C1—N1—H1A	109.3	C1—C2—H2D	109.6
C1—N1—H1B	109.3	H2C—C2—H2D	108.1
C1—N1—C4	111.42 (17)	N2—C3—H3A	109.5
C4—N1—H1A	109.3	N2—C3—H3B	109.5
C4—N1—H1B	109.3	N2—C3—C4	110.93 (17)
H2A—N2—H2B	107.9	H3A—C3—H3B	108.0
C2—N2—H2A	109.2	C4—C3—H3A	109.5
C2—N2—H2B	109.2	C4—C3—H3B	109.5
C3—N2—H2A	109.2	N1—C4—C3	110.34 (18)
C3—N2—H2B	109.2	N1—C4—H4A	109.6
C3—N2—C2	112.11 (17)	N1—C4—H4B	109.6
N1—C1—H1C	109.7	C3—C4—H4A	109.6
N1—C1—H1D	109.7	C3—C4—H4B	109.6
N1—C1—C2	109.85 (18)	H4A—C4—H4B	108.1
N1—C1—C2—N2	56.7 (2)	C2—N2—C3—C4	55.2 (2)
N2—C3—C4—N1	−55.2 (2)	C3—N2—C2—C1	−56.0 (2)
C1—N1—C4—C3	57.5 (2)	C4—N1—C1—C2	−58.4 (2)