Cis and trans-bis(tetrathiafulvalene-acetylide) platinum(II) complexes: syntheses, crystal structures, and influence of the ancillary ligands on their electronic properties

• Published in: Dalton transactions : an international journal of inorganic chemistry 2013-01, Vol.42 (2), p.383-394
• Main Authors: Vacher, Antoine, Barrière, Frédéric, Camerel, Franck, Bergamini, Jean-François, Roisnel, Thierry, Lorcy, Dominique
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Crystal structure; Density functional theory; Diffraction; Electronics; Ligands; Mathematical analysis; Organic chemistry; Oxidation; Voltammetry
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c2dt31686b

A series of four platinum(II) complexes bearing two tetrathiafulvalene acetylide ligands coordinated either cis or trans to the metal center are reported: cis-Pt(bipy)(C≡CMe(3)TTF)(2), cis-Pt(tBu(2)bipy)(C≡CMe(3)TTF)(2), cis-Pt(dppe)(C≡CMe(3)TTF)(2) and trans-Pt(PPh(3))(2)(C≡CMe(3)TTF)(2). The X-ray diffraction studies of the four complexes are reported and discussed. The electrochemical investigations carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) evidenced different redox behavior as a function of the ancillary ligand. Only for the cis-Pt(dppe)(C≡CMe(3)TTF)(2) complex is the first oxidation wave resolved (ΔE = 70 mV) into two one-electron processes. Spectroelectrochemical investigations performed on the four complexes did not evidence any electronic interactions between the two organic electrophores. The splitting of the first oxidation wave observed in cis-Pt(dppe)(C≡CMe(3)TTF)(2) is mainly explained by the non-equivalence of the two TTF moieties induced by the geometrical constraint imposed by the ancillary dppe ligand as found by density functional theory calculations.