名称:
Nickel thioether chemistry: syntheses and crystal structures of [Ni2L2(µ-Cl)2][BF4]2(l = 1,4,7,10-tetrathiacyclododecane, 1,4,8,11-tetrathiacyclotetradecane or 1,5,9,13-tetrathiacyclohexadecane)
摘要:
Reaction of NiCl2 with 1 molar equivalent of the macrocycles (L) 1,4,7,10-tetrathiacyclododecane ([12]aneS4), 1,4,8,11-tetrathiacyclotetradecane ([14]aneS4) or 1,5,9,13-tetrathiacyclohexadecane ([16]aneS4) and NaBF4 in MeNO2 for 30 min afforded green or blue solutions, from which the complexes [Ni2L2Cl2][BF4]2 can be isolated. The complex [Ni2([12]aneS4)2Cl2][BF4]2.2MeNO2 crystallises in the monoclinic space group C2/m with a = 11.0651(20), b = 13.4977(24), c = 12,7222(21) angstrom, beta = 104.824(21)-degrees and Z = 2. The complex [Ni2([14]aneS4)2Cl2] [BF4]2.6MeNO2 crystallises in the triclinic space group P1BAR with a = 10.6341(18), b = 11.6481(22), c = 12.2457(25) angstrom, alpha = 88.547(7), beta = 67.288(12), gamma = 68.647(6)-degrees and Z = 1. The complex [Ni2([16]aneS4)2Cl2][BF4]2.2MeNO2 crystallises in the monoclinic space group Cc with a = 16.024(4), b = 13.6862(17), c = 19.7329(24) angstrom, beta = 92.042(19)-degrees and Z = 4. Single-crystal structure determinations on each of these products showed the presence of dichloro-bridged dimeric cations exhibiting edge-sharing bioctahedral structures, with the macrocyclic ligands co-ordinated in a cis fashion about the Ni. The Ni-S bond lengths and internal crystallographic symmetry vary significantly between the structures, the shortest distances being observed for [Ni2([14]aneS4)2Cl2]2+ [Ni-S 2.3694(22), 2.3765(21), 2.3756(21), 2.3798(21) angstrom, Ni-Cl 2.4416(20), 2.4252(20) angstrom]; for [Ni2([12]aneS4)2Cl2]2+, Ni-S 2.412(3), 2.4144(25), 2.373(3), Ni-Cl 2.411(3), 2.382(3) angstrom and for [Ni2([16]aneS4)2Cl2]2+, Ni-S 2.4098(22)-2.4421(22), Ni-Cl 2.3860(21)-2.4205(20) angstrom. These variations are related to the differing hole sizes of the three tetrathia macrocyles. The Ni ... Ni distances are similar in all three structures, 3.5534(12)-3.5692(12) angstrom. The complexes [Ni2L2Cl2] [BF4]2 exhibit only irreversible electrochemical oxidation and reduction processes according to cyclic voltammetry in MeCN-0.1 mol dm-3 NBu(n)4PF6 at 293 K. Reaction of NiCl2 with 1,4,7-trithiacyclononane ([9]aneS3) and NaBF4 affords the triply bridged dimeric complex [Ni2([9]aneS3)2Cl3]BF4.