Monoarylplatinum(II) Complexes with a 2-Phenylpyridyl Ligand and Coordinated Solvent, [Pt(Ar)(Phpy)(solv)] (Phpy = 2-phenylpyridyl; solv = NCCH3, dmso). Preparation from [Pt(Ar)2(solv)2], Structures, and Chemical Properties

• Published in: Organometallics 2007-04, Vol.26 (9), p.2383-2391
• Main Authors: Yagyu, Takeyoshi, Ohashi, Jun-ichi, Maeda, Masunobu
• Format: Article
• Language: English
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om061137m

Diarylplatinum(II) complexes, [Pt(Ar)2(dmso)2] (Ar = C6H3Me2-3,5 (1a), C6H3(CF3)2-3,5 (1b), Ph (1c); dmso = dimethyl sulfoxide) and [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b), were prepared and fully characterized. Heating mixtures of 2-phenylpyridine (PhpyH) with the complexes in solution at 50 °C caused coordination of PhpyH and its cyclometalation accompanied by elimination of arene to produce monoarylplatinum(II) complexes with a solvent ligand, [Pt(Ar)(Phpy)(dmso)] (Ar = C6H3Me2-3,5 (3a), C6H3(CF3)2-3,5 (3b), Ph (3c)) and [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)] (4b). The rate of the reactions decreased in the order 1a > 1c > 2b > 1b. Crystal structures of 3a,c and 1H NMR spectra of the complexes showed that the aryl ligand and phenyl group of the Phpy ligand occupied cis positions. A diarylplatinum complex with a monodentate phenylpyridyl ligand, [Pt(C6H3Me2-3,5)2(CF3PhpyH)(dmso)] (5), was isolated and characterized using X-ray crystallography. The neutral arylplatinum(II) complex 4b underwent exchange of the acetonitrile ligand more easily than the cationic complex, [Pt{C6H3(CF3)2-3,5}(bpy)(NCCH3)]+, because of the C-bonded phenyl group of the Phpy ligand had a greater trans effect than the N-bonded pyridyl group of bpy. Oxidative addition of I2 to 3a,b and 4b readily gave Pt(IV) dimeric complexes with bridging iodo ligands, [(Pt(Ar)(Phpy)I)2(μ-I)2] (Ar = C6H3Me2-3,5 (7a), C6H3(CF3)2-3,5 (7b)). The dimeric structure of 7b was confirmed using X-ray crystallography.