The near infra red (NIR) chiroptical properties of nickel dithiolene complexes

Abstract

Enantiomerically pure dianionic, monoanionic and neutral dithiolene complexes formulated as [Ni((R,R)-CHMePh-thiazdt)₂]^−2,−1,0 and [Ni((S,S)-CHMePh-thiazdt)₂]^−2,−1,0 (CHMePh-thiazdt: N-(1-phenylethyl)-1,3-thiazoline-2-thione-4,5-dithiolate) have been synthesized from the enantiopure N-(1-phenylethyl)-1,3-thiazoline-2-thione precursors. The electrochemical and spectro-electrochemical investigations carried out on these complexes show that the CHMePh-thiazdt ligands act as electron rich ligands and that the complexes are strong near infrared (NIR) absorbers in the range of 800–1100 nm for the neutral species and 1050–1500 nm for the reduced radical anion species. Circular dichroism (CD) thin layer spectro-electrochemical experiments carried out on the neutral (R,R) enantiomer, [Ni((R,R)-CHMePh-thiazdt)₂], revealed a redox switching of CD-active bands, not only in the UV-vis but also in the NIR region.