Synthesis. solid state structure and spectro-electrochemistry of ferrocene-ethynyl phosphine and phosphine oxide transition metal complexes

The synthesis of ferroeene-ethynyl phosphine platinum dichloride complexes based on (FeC=C)"Ph3 _ nP (ta, 11 = 1; tb, 11 = 2; te, 11 = 3; Fe = ferroeenyl, (.,s-CsHs)(.,s-CsH4 )Fe) is deseribed. Air-oxidation of te afforded (FeC= ChP=O (6). Treatment of ta-tc with [(PhC= NJ,PtClz] (2) or [(tht)AuCI] (tht = tetrahydrothiophene) (7), respeetively, gave the heterometallie transition complexes cis-[((FeC= C)n Ph3 _ nPJ,PtCb] (3a, 11 = 1; 3b, 11 = 2; 3e, 11 = 3) or [((FeC= C)"PPh3_,,)AuCI] (Sa, 11 = 1; Sb, 11 = 2). Further treatment of these molecules with HC= CMe (4a, Me = Fe; 4b, Me = Re = (.., s-CsHs)(.., s-CsH4 )Ru) in the presenee of [Cul] produeed tralls-[((FeC=C)PhzPJ,Pt(C==CFeh] (5) (reaetion of 3a with 4a) and [(FeC=C)"Ph3_"PAuC= CMe] (11 = 1: 9a, Me = Fe; 9b, Me = Re; 11 = 2: l1a, Me = Fe; l1b. Me = Re) (reaetion of 4a, 4b with Sa, Sb), respeetively. The struetures of 3a, 5, 6, S, 9a, and 9b in the solid state were established by single-erystal X-ray strueture analysis. The main eharaeteristie features of these molecules are the linear phosphorus-gold-aeetylide arrangements, the tetra-eoordination at phosphorus and the square-planar surrounding at platinum. The eleetroehemieal and speetro-eleetroehemical behavior of eomplexes 5, 8a, 9a, 9b and [(Ph3P)AuC= CFe] was investigated in the UV/Vis/NIR. Near IR bands that are Iikely associated with charge transfer from the ((FeC= C)PhzPJ,Pt or the ((FeC= C)"Ph3 _"P)Au (/1 = 0, 1) moieties appear upon oxidation of the cr-bonded ferroeene-ethynyl groups. These bands undergo a (stepwise) blue shift as ferroeene-ethynyl substituents on the phosphine coligands are oxidized.