Nickel(II) compounds of some nitro-substituted imine–triamine macrocycles; the structure of (5,7,7,13 tetramethyl-13-nitro-1,4,8,11-tetraazacyclotetradec-4-ene κ 4N1,4,8,11)nickel(II) tetrachlorozincate(II)

Abstract

Reaction of (4,6,6-trimethyl-3,7-diazanon-3-ene-1,9-diamine)nickel(II) cations with methanal and nitroethane in water or methanol plus base yields the nitro-substituted imine–triamine azamacrocyclic cation (5,7,7,13-tetramethyl-13-nitro-1,4,8,11-tetraazacyclotetradec-4-ene)nickel(II). Similar reaction with nitropropane yields the (13-ethyl-5,7,7-trimethyl-13-nitro-1,4,8,11-tetraazacyclotetradec-4-ene)nickel(II) cation. Singlet ground state salts [Ni(L)]–(ClO 4) 2 and –ZnCl 4 and triplet ground state compounds [Ni(L)(NCS) 2], Ni(L)(NO 2)]ClO 4, [Ni(L)(C 5H 7O 2)]ClO 4 (pentan-2,4-dionato) and [{Ni(L)} 2(C 2O 4)](ClO 4) 2 were prepared. (5,7,7,13-Tetramethyl-13-nitro-1,4,8,11-tetraazacyclotetradec-4-ene)nickel(II) tetrachlorozincate has the nickel(II) ion in tetrahedrally twisted {±0.045(2) Å} square-planar coordination with the Ni displaced by 0.143(1) Å from the N 4 mean plane, with distances Ni–N1 = 1.934(3), Ni–N4 = 1.909(3), Ni–N8 = 1.932(3) and Ni–N11 = 1.927(3) Å. The cation shows disorder in the location of the axial component of the gem-dimethyl group that was modeled with superposition of the 5,7,7,13-tetramethyl-4-ene and 5,5,7,13-tetramethyl-7-ene arrangements, with site occupation factors of 0.80(1) and 0.20(1), respectively. The nitro group is axially oriented, on the same side of the plane as the axial methyl substituent. The tetrachlorozincate ion is sited on the less crowded side of the cation plane, with one chloride ion axially located with Ni–Cl = 2.921(1) Å.