Syntheses and coordination isomerism of heteroleptic divalent-metal (M = Co, Zn) carbazate complexes

• Published in: Journal of coordination chemistry 2014-10, Vol.67 (20), p.3324-3334
• Main Authors: Srinivasan, Krishnan, Kathiresan, Ayyasamy, Harrison, William T.A., Govindarajan, Subbaiah
• Format: Article
• Language: English
• Subjects: Bidentate ligand; Coordination isomerism; Crystal structure; Crystals; Decomposition; Distortion; Ligands; Thermal analysis; Thiocyanate anion; Thiocyanates; Zinc
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2014.965697

Three heteroleptic divalent-metal alkyl-carbazate-thiocyanate complexes, [M(NCS) 2 (NH 2 NHCOOR) 2 ] [M = Co and R = CH 2 CH 3 (1); M = Co and R = CH 3 (2); M = Zn and R = CH 3 (3)], have been prepared and characterized, and their crystal structures determined. In 1, Co(II) adopts a fairly regular centrosymmetric trans-CoO 2 N 4 octahedral geometry arising from its coordination by two N,O-bidentate ethylcarbazate ligands and two trans N-bonded thiocyanates. In isostructural 2 and 3, the metals adopt distorted cis-MO 2 N 4 octahedral geometries arising from two N,O-bidentate methylcarbazate ligands with cis N-bonded thiocyanates. The crystal structures feature N-H⋯O and N-H⋯S interactions. Thermal analysis data show that these compounds begin to decompose at temperatures between 130 and 160 °C. Crystal data: 1, CoC 8 H 16 N 6 O 4 S 2 , M r  = 383.32, P2 1 /n (No. 14), a = 5.2599(3) Å, b = 7.4209(4) Å, c = 20.1948(12) Å, β = 94.070(1)°, V = 786.28(8) Å 3 , Z = 2, R(F) = 0.028, wR(F 2 ) = 0.073; 2, CoC 6 H 12 N 6 O 4 S 2 , M r  = 355.27, P2 1 /n (No. 14), a = 7.8663(3) Å, b = 10.5804(3) Å, c = 17.6313(5) Å, β = 102.019(10)°, V = 1435.26(8) Å 3 , Z = 4, R(F) = 0.036, wR(F 2 ) = 0.097; 3, ZnC 6 H 12 N 6 O 4 S 2 , M r  = 361.71, P2 1 /n (No. 14), a = 7.8883(2) Å, b = 10.5756(3) Å, c = 17.5827(5) Å, β = 101.676(1)°, V = 1436.46(7) Å 3 , Z = 4, R(F) = 0.031, wR(F 2 ) = 0.084.