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The synthesis, structure and photophysical properties of the complexes [Ru[(CO)(TFA) (PPh 3 ) 2 (L)][(L = ppy = 2-phenylpyridine, ( 1a ); L = 2–(p–tolyl)pyridine] ( 1b ), are reported. The complexes were characterized by UV-VIS, IR and NMR and by single-crystal X-ray diffraction techniques. We also report the synthesis, structure and photophysical properties of [Ru(CO)(L)(PPhMe 2 ) 2 (L′)] + [PF 6 ] − [L′ = bipyridine, L = TFA, ( 3a ); L = H, ( 3b ) and L = H, L′ = 4,4′-dimethlyl bipyridine ( 3c )]. These compounds were characterized by UV-VIS, IR and NMR techniques and by a single crystal X-ray diffraction in the case of 3a. The solid state structure of [Ru(Me 2 PhP) 2 (CO) 2 (TFA) 2 (2) which is the starting material for the synthesis 3a - 3c is also reported to verify the trans relationship of the less bulky PPhMe 2 and for comparison with the previously reported PPh 3 analogs. The purpose of this study was to determine the impact, if any, of replacing bpy with ppy in the case of 1a and alkylation of the benzene ring in the case of 1b on the photophysical and electrochemical properties compared to related Ru(bpy) complexes. In contrast to the bpy analogs 1a and 1b showed reversible 1e − oxidations and blue-shifted MLCT absorptions. In the case of 3a - 3c we were interested in the effect on the photophysical properties of substituting PPh 3 with the less bulky but more electron donating PPhMe 2 . There were only minor changes in the photophysical and electrochemical properties relative to the previously reported PPh 3 analogs. [ABSTRACT FROM AUTHOR]

Reactions of Ru3(CO)10(µ-dppf) (1) (dppf = 1,1'-bis(diphenylphosphino)ferrocene), Ru3(CO)10(µ-dppm) (2) (dppm = bis(diphenylphosphino)methane), and the orthometalated derivative Ru3(CO)9{µ3- PPhCH2PPh(C6H4)} (3) with silanes (Ph3SiH, Et3SiH, Ph2SiH2) are reported. Treatment of 1 with Ph3SiH and Ph2SiH2 at room temperature leads to facile Si--H bond activation to afford Ru3(CO)9(µ-dppf)(SiPh3)(µ-H) (4) (60% yield) and Ru3(CO)9(µ-dppf)(SiPh2H)(µ-H) (6) (53% yield), respectively. The reaction of 1 with Ph3SiH has been investigated by electronic structure calculations, and these data have facilitated the analysis of the potential energy surface leading to 4. Compound 1 does not react with Et3SiH at room temperature but reacts at 68 °C to give Ru3(CO)9(µ-dppf)(SiEt3)(µ-H) (5) in 45% yield. Reaction of 2 with Ph3SiH at room temperature yields two new products: Ru3(CO)9(µ-dppm)(SiPh3)(µ-H) (7) in 40% yield and Ru3(CO)6(µ3-O)(µ-dppm)(SiPh3)(µ- H)3 (8) in 15% yield. Interestingly, at room temperature compound 7 slowly reverts back to 2 in solution with decomposition and liberation of Ph3SiH. Complex 8 can also be prepared from the direct reaction between 7 and H2O. Similar reactions of 2 with Et3SiH and Ph2SiH2 give only intractable materials. The orthometalated compound 3 does not react with Ph3SiH, Et3SiH and Ph2SiH2 at room temperature but does react at 66 °C to give Ru3(µ-CO)(CO)7{µ3- PPhCH2PPh(C6H4)}(SiR2R¹)(µ- H)](9, R = R' = Ph, 71% yield; 10, R = R' = Et, 60% yield; 11, R = Ph, R' = H, 66% yield) by activation of the Si--H bond. Compounds 4 and 8--11 have been structurally characterized. In 4, both the dppf and the hydride bridge a common Ru--Ru vector, whereas NMR studies on 7 indicate that two ligands span different Ru--Ru edges. Compound 8 contains a face-capping oxo moiety, a terminally coordinated SiPh3 ligand, and three bridging hydride ligands, whereas 9--11 represent simple oxidative addition products. In all of the compounds examined, the triruthenium framework retains its integrity and the silyl groups occupy equatorial sites. [ABSTRACT FROM AUTHOR]

The series of complexes [XRu(CO)(L–L)(L′)2][PF6] (X = H, TFA, Cl; L–L = 2,2′-bipyridyl, 1,10-phenanthroline, 5-amino-1,10-phenanthroline and 4,4′-dicarboxylic-2,2′-bipyridyl; L′2 = 2PPh3, Ph2PC2H4PPh2, Ph2PCH＝CHPPh2) have been synthesized from the starting complex K[Ru(CO)3(TFA)3] (TFA = CF3CO2) by first reacting with the phosphine ligand, followed by reaction with the L–L and anion exchange with NaPF6. In the case of L–L = phenanthroline and L′2 = 2PPh3, the neutral complex Ru(Ph3P)(CO)(1,10-phenanthroline)(TFA)2 is also obtained and its solid state structure is reported. Solid state structures are also reported for the cationic complexes where L–L = phenanthroline, L2 = 2PPh3 and X = Cl and for L–L = 2,2′-bipyridyl, L2 = 2PPh3 and X = H. All the complexes were characterized in solution by a combination of 1H and 31P NMR, IR, mass spectrometry and elemental analyses. The purpose of the project was to synthesize a series of complexes that exhibit a range of excited-state lifetimes and that have large Stokes shifts, high quantum yields and high intrinsic polarizations associated with their metal-to-ligand charge-transfer (MLCT) emissions. To a large degree these goals have been realized in that excited-state lifetimes in the range of 100 ns to over 1 μs are observed. The lifetimes are sensitive to both solvent and the presence of oxygen. The measured quantum yields and intrinsic anisotropies are higher than for previously reported Ru(II) complexes. Interestingly, the neutral complex with one phosphine ligand shows no MLCT emission. Under the conditions of synthesis some of the initially formed complexes with X = TFA are converted to the corresponding hydrides or in the presence of chlorinated solvents to the corresponding chlorides, testifying to the lability of the TFA Ligand. The compounds show multiple reduction potentials which are chemically and electrochemically reversible in a few cases as examined by cyclic voltammetry. The relationships between the observed photophysical properties of the complexes and the nature of the ligands on the Ru(II) is discussed. [Copyright &y& Elsevier]