Solvent control in the synthesis of [Mn(NCS)2(bpe)2(H2O)2] and [Mn(NCS)2(bpe)1.5(CH3OH)]n (bpe = 1,2-bis(4-pyridyl)ethene): structural analysis and magnetic properties

Abstract

The combined use of pseudohalides and N,N′-type flexible organic spacers represents an excellent strategy for the preparation of extended systems in co-ordination chemistry. In this context, the formation of two Mn^II–NCS–bpe systems (bpe = 1,2-bis(4-pyridyl)ethene) of formula [Mn(NCS)₂(bpe)₂(H₂O)₂] 1 and [Mn(NCS)₂(bpe)_1.5(CH₃OH)]_n2 has been observed to be solvent-dependent. Both compounds were structurally characterised by means of X-ray single crystal diffraction and IR spectroscopy. Compound 1 consists of monomeric units where the manganese(II) ions are octahedrally co-ordinated. Compound 2 exhibits zigzag chains where the octahedral manganese(II) ions are alternatively bridged through N,N′-bpe and di-μ-(1,3)-NCS groups. Magnetic susceptibility measurements for 2 were consistent with the occurrence of weak antiferromagnetic coupling (J = −1.6 cm⁻¹) through the thiocyanate bridges.