Probing the effect of substituents and solvent on [Mn(R-sal-N-1,5,8,12)]BPh: a systematic investigation of SCO properties

In manganese( iii ) complexes with BPh 4 − as the counter anion, the ligand field strength and non-covalent interactions between cations and anions of the flexible Schiff-base ligands (R-sal-N-1,5,8,12) 2− are tuned by modifying the different substituents at the 5-position or 3,5-positions on the phenyl rings of the salicylaldehyde, and the magneto-structural properties of complexes 5-I-BPh 4 ( 1 ), 5- t Bu-BPh 4 ( 2 ), 5-OCH 3 -BPh 4 ( 3 ), naphth-BPh 4 ( 4 ) and 5-Br-3-OCH 3 -BPh 4 ( 5 ) are investigated. Complex 1 undergoes an incomplete SCO with two different Mn( iii ) sites, while complexes 2 and 3 remain in the HS state throughout the entire temperature range, suggesting the absence of magnetic state conversion. Under the effect of solvent, complex 4 shows different magnetic properties. Upon solvent loss, 4 displays a more complete SCO with a T 1/2 of 140 K. In contrast to the complexes described above, complex 5 possesses two substituents, namely 5-Br and 3-OCH 3 . As a result, it exhibits an abrupt SCO effect due to the significantly stronger intermolecular cooperativity. The non-covalent interactions and magneto-structural properties of complexes 1 - 5 are tuned by modifying the solvents and different substituents at the 5-position or 3,5-positions on the phenyl rings of the salicylaldehyde.