4-[(4′-Chloro­methyl-[1,1′-biphen­yl]-4-yl)meth­yl]bis­(dimethyl­glyoximato-κ2 N,N′)(pyridine-κN)cobalt(III)

Sarvendra Kumar; Suresh Thapa

doi:10.1107/S1600536812001092

. 2012 Jan 14;68(Pt 2):m160–m161. doi: 10.1107/S1600536812001092

4-[(4′-Chloromethyl-[1,1′-biphenyl]-4-yl)methyl]bis(dimethylglyoximato-κ² N,N′)(pyridine-κN)cobalt(III)¹

Sarvendra Kumar ^a, Suresh Thapa ^b,^*

PMCID: PMC3274891 PMID: 22346838

Abstract

The title compound, [Co(C₁₄H₁₄Cl)(C₄H₆N₂O₂)₂(C₅H₅N)], is a model compound for the more complex cobalamines like vitamins B₁₂. The Co^III atom is coordinated by a (4′-chloromethyl-[1,1′-biphenyl]-4-yl)methyl group, an N-bonded pyridine and two N,N′-bidentate dimethylglyoximate ligands in a distorted octahedral geometry. The glyoximate ligands exhibit intramolecular O—H⋯O hydrogen bonds, which is very common in cobaloxime derivatives.

Related literature

For general background, see: Bresciani-Pahor et al. (1985 ▶); Revathi et al. (2009 ▶); Brown (2006 ▶); Randaccio (1999 ▶); For structure–property relationships, see: Gupta et al. (2004 ▶); Dutta et al. (2009 ▶). For a related structure, see: Kumar & Gupta (2011 ▶).

Experimental

Crystal data

[Co(C₁₄H₁₄Cl)(C₄H₆N₂O₂)₂(C₅H₅N)]
M _r = 583.95
Triclinic,
a = 9.1208 (15) Å
b = 11.3999 (19) Å
c = 13.661 (2) Å
α = 72.869 (3)°
β = 77.504 (3)°
γ = 87.276 (3)°
V = 1325.1 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.79 mm⁻¹
T = 100 K
0.32 × 0.28 × 0.26 mm

Data collection

Bruker SMART CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2004 ▶) T _min = 0.786, T _max = 0.821
7047 measured reflections
4789 independent reflections
3996 reflections with I > 2σ(I)
R _int = 0.022

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.125
S = 1.04
4789 reflections
349 parameters
H-atom parameters constrained
Δρ_max = 0.65 e Å⁻³
Δρ_min = −0.43 e Å⁻³

Data collection: SMART (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: DIAMOND (Brandenburg, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812001092/fk2049sup1.cif

e-68-0m160-sup1.cif^{(27.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812001092/fk2049Isup2.hkl

e-68-0m160-Isup2.hkl^{(229.8KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Co1—N1	1.875 (2)
Co1—N2	1.877 (2)
Co1—N3	1.879 (2)
Co1—N4	1.875 (2)
Co1—N5	2.055 (2)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O2—H2⋯O4	0.84	1.67	2.479 (3)	161
O3—H3⋯O1	0.84	1.67	2.478 (3)	160

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Acknowledgments

The authors are thankful to the IIT Kanpur, India, for the data collection. SK is thankful to TWAS and CONICET, Argentina.

supplementary crystallographic information

Comment

The chemistry and molecular structure of bis(dimethylglyoximato)cobalt(III) complexes, trivially known as cobaloximes (Bresciani-Pahor et al., 1985), have been of great interest to chemists for the past four decades for two reasons. First, the coordination chemistry of these complexes is far-reaching, with almost unlimited possibilities for substituents in the axial position and variation in the equatorial ligands (Brown, 2006; Randaccio 1999). Second, many organometallic cobaloxime derivatives have been used as model compounds for the study of vitamin B₁₂ coenzyme. Cobaloximes have played its role in helping to understand the reactivity of the cobalt-carbon bond (Gupta et al.,2004; Dutta et al., 2009). The inherently weak Co—C bond in the organocobaloximes undergoes homolytic cleavage with visible light, similar to the activation of vitamin B₁₂ by apoenzyme and have been utilized in organic synthesis, catalysis and in polymer chemistry. Most of the recent studies on cobaloximes have been focused on their structure-property relationships (Gupta et al., 2004). Herein, we have reported the synthesis and structure of a new cobaloxime.

The crystal structure of the title compound is shown in Figure 1. The coordination of cobalt(III) ion is slightly distorted octahedral (Revathi et al., 2009) with the aryl group, the 4-((4'-(chloromethyl)-[1,1'-biphenyl]-4-yl)methyl group, a pyridine ligand and two N,N-bidentate dimethylglyoximate ligands. The Co—N(dmg) bond lengths range from 1.873 (2) to 1.880 (2) Å. The bite angles N3—Co1—N4 and N1—Co1—N2 of the ligand are 81.45 (11)° and 81.44 (11)°, respectively. The coordinated 4-((4'-(chloromethyl)-[1,1'-biphenyl]-4-yl)methyl group and the pyridine ring nitrogen are coordinated axially in trans position with the angle C14—Co1—N5 = 177.88 (9)°. The important bond lengths and bond angles are given in Table 1, and intramolecular hydrogen bonding parameters are given in Table 2. The two glyoximate moieties are linked together by strong intramolecular O–H···O hydrogen bonding (Fig. 2). Additionally, the packing (Fig. 2) shows molecules bonded through C-H···π interactions within 3.4824 (4) - 3.5907 (5) Å.

Experimental

A solution of ClCo(dmgH)₂py (1 mmol) in 10 ml of methanol was purged thoroughly with N₂ for 20 min and was cooled to 0°C with stirring. The solution turned deep blue after the addition of a few drops of aqueous NaOH followed by sodium borohydride (1.5 mmol in 0.5 ml of water). The colour of the solution turned orange-red on addition of 4,4'-bis(chloromethyl)-1,1'-biphenyl (1 mmol). The reaction was stirred 1 h at 0°C then poured into 20 ml chilled water. The resulting orange-red precipitate was filtered, washed with water, and dried. The obtained orange coloured compound was recrystallized from dichloromethane and methanol. After five days, orange coloured crystals were obtained, suitable for single-crystal data collection.