Synthesis and crystal structure of complexes of manganese(II), cobalt(II), and nickel(II) isothiocyanates with ɛ-caprolactam

The possibility of ɛ-caprolactam (CPL) to coordinate to manganese(II), cobalt(II), and nickel(II) rhodanides has been investigated. New complexes trans-[M(CPL)4(NCS)2], where M = Mn (I), Co (II), and Ni (III), have been synthesized. The complexes have been studied by chemical analysis and IR spectroscopy. According to X-ray diffraction, complexes are isostructural to each other and crystallize in monoclinic space group P21/c, Z = 2. For I: a = 6.9457(2) Å, b = 17.7751(6) 0A, c = 12.8999(4) 0A, β = 104.2670(10)°, V = 1543.51(8) Å3, ρcalc = 1.342 g/cm3, R1 = 0.0426. For II: a = 6.8925(2) Å, b = 17.8189(8) Å, c = 12.7278(6) Å, β = 104.421(2)°, V = 1513.93(11) Å3, ρcalc = 1.377 g/cm3, R1 = 0.0280. For III: a = 6.7804(2) Å, b = 18.4631(4) Å, c = 12.4841(3) Å, β = 105.2950(10)°, V = 1507.49(7) Å3, ρcalc = 1.382 g/cm3, R1 = 0.0273. Structures I–III are molecular; the metal atom in each of them coordinates four CPL molecules and two NCS groups via oxygen and nitrogen atoms, respectively.