Trinuclear thiocyanate-bridged compounds of the type [ML]2[Mn(NCS)4](ClO4)2 (where M = Cu(ii), Ni(ii); L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)

Abstract

The complexes of general formula [ML]₂[Mn(NCS)₄](ClO₄)₂ (where M = Cu(II), Ni(II); L = N-dl-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) were obtained and the crystal structures of both heteronuclear compounds were determined at 173 K. Complex [CuL]₂[Mn(NCS)₄](ClO₄)₂ (1) crystallizes in a monoclinic space group, C2/c, with a = 41.297(9) Å, b = 7.571(2) Å, c = 16.417(4) Å, β = 96.97(15)°, Z = 8, whereas complex [NiL]₂[Mn(NCS)₄](ClO₄)₂·H₂O (2) crystallizes in a monoclinic space group, P2/c, with a = 21.018(5) Å, b = 7.627(2) Å, c = 16.295(4) Å, β = 104.47(1)°, Z = 4. The magnetic behaviour of (1) and (2) has been investigated over the temperature range 1.8–300 K. Complex (1) displays ferromagnetic coupling inside the trinuclear core of CuMnCu and compound (2) behaves like a mononuclear Mn(II) system. The magnetic properties of the second compound (2) with a similar trinuclear structure shows that Ni(II) ions have a diamagnetic character and a rather weak zero-field splitting at the central Mn(II) ion occurs. Finally, the magnitudes of the Cu(II)–M(II) interactions with M = Ni and Mn have been compared and qualitatively justified.