Experimental and Theoretical Evaluation of Four NLO?Active Divalent Transition?Metal Complexes Supported by an Enantiomerically Pure Tetradentate Schiff Base Ligand

This paper reports on a series of five chiral Schiff base push-pull compounds derived from enantiomerically pure (1R,2R)-(?)-1,2-diaminocyclohexane. The NiII, CuII, ZnII and PdII complexes supported by ferrocene-containing unsymmetrically-substituted N2O2 quadridentate ligand were prepared via template reactions isolated in 74–87 % yields. A combination EA, IR, UV/vis 1H/13C{1H} NMR spectroscopy, HRMS spectrometry, cyclic voltammetry single-crystal X-ray analysis (for the proligand 2 its NiII derivative 3), together with computational methods (DFT TD-DFT) was used to fully characterize study properties all products. Both 3 crystallize orthorhombic non-centrosymmetric space group P212121, two (R,R)-(?)-chiral carbon atoms their structure. Second-order nonlinear polarizabilities ? have been measured using Harmonic Light Scattering at 1.91 ?m, Pd(II) species showing higher NLO response 460×10?30 esu.