Abstract

The reaction of NiCl<inf>2</inf> with two equivalents of Hqsal-X (Hqsal-X = 5-X-N-(8-quinolyl)salicylaldimine) yields the octahedral complexes, [Ni(qsal)<inf>2</inf>]·MeOH 1 and [Ni(qsal-X)<inf>2</inf>] (X = OMe 2, Cl 3, Br 4, Me 5, t-Bu 6). UV-Vis spectroscopic studies show that the LMCT band is sensitive to the substituent, ranging from 465 to 520 nm. Crystal structures of [Ni(qsal)<inf>2</inf>]·MeOH 1 and [Ni(qsal-X)<inf>2</inf>] (X = OMe 2, Cl 3, Br 4) reveal that the Ni centres are octahedral, the qsal-X ligands coordinated with a meridional geometry. The packing in the structures is found to be strongly dependent on the substituent with 1D π-π chains in 3 and 4, π-π dimers in 2 and a 1D hydrogen bonded chain in 1. DFT calculations indicate almost identical electronic structures in 1-6 suggesting the difference in packing is due to the different supramolecular preferences of the substituent.