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Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Electrochromic second-order NLO chromophores based on M(II) (M = Ni, Pd, Pt) complexes with diselenolato-dithione
Davide Espa1, Luca Pilia, Luciano Marchiò
1Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Unità di Ricerca dell'INSTM, S.S. 554-Bivio per Sestu, I09042 Monserrato-Cagliari, Italy.
Abstract:
The donor-acceptor type mixed-ligand complexes [M(Bz(2)pipdt)(dsit)]; dsit = 2-thioxo-1,3-dithiole-4,5-diselenolato (donor); Bz(2)pipdt = 1,4-dibenzyl-piperazine-2,3-dithione (acceptor); M(II) = Ni (1), Pd (2), and Pt (3) were prepared and characterized to investigate the variation of the properties by substituting selenium for sulfur in the donor ligand dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato of the corresponding known complexes. Both these classes of complexes exhibit large negative second-order polarizabilities, amongst the highest values determined so far for metal-complexes, and are potential candidates for redox switchability of the molecular first hyperpolarizability due to the bleaching/restoring of the solvatochromic peak for mono-reduction/oxidation. DFT and TD-DFT calculations on 1-3 allow one to correlate geometries and electronic structures and are in agreement with the observed minor changes following the substitution of selenium for sulfur atoms in the dichalcogenolato ligand. The observed differences can be ascribed to the increased size of the selenium atom leading to increased M-X distances and dipolar moments of the ground state, which are highest for the Pd-derivative in the triad.
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