Photoinduced reductive elimination of cyanoalkanes from hydridocyanoalkyl complexes of platinum(II)

The photoinduced reductive elimination of cyanoalkanes (CH3CN, CH3CH2CN and CH3(CH2)2CN) from trans-hydridocyanoalkyl complexes of platinum(II), [PtH(R)(PPh3)2] (R = CH2CN, (CH2)2CN, (CH2)3CN) has been studied. The three trans complexes undergo isomerization to cis forms in the initial step before the reductive elimination. The elimination from the cis isomers is intramolecular as shown by the absence of crossover with the [PtH(CH2CN)(Ph2PCH=CHPPh2)] analogue and of the failure to detect the presence of free radicals during the reaction. The monomeric [Pt(PPh3)2] complex has been identified as the initial product of reductive elimination. Several reactions of this mechanistically important compound are also described

Spin trapping and some reactions of ruthenium-centred radicals

The generation of ruthenium-centred radicals by photolysis of dimeric ruthenium complex [Ru(CO)2Cp]2 (Cp=η5-C5H5) has been studied by EPR and spin trapping. Mechanistic studies reveal that in toluene homolytic cleavage of both the RuRu and RuCO bonds takes place yielding ·Ru(CO)2Cp radicals and an intermediate dinuclear ruthenium complex which is CO-bridged. This reacts with P[OCH(CH3)2]3 yielding the monosubstituted dinuclear compound {Cp2Ru2(CO)3P[COH(CH3)2]3}. The ruthenium-centred radicals react with dioxygen to form peroxyl radicals which may abstract hydrogen from CH bonds. The reactivity of the photogenerated ruthenium species with various substrates is reported

Investigation of the copper-magnesium-alkaline phosphate system.

--

Equilibrium between CO-bridged and non-bridged forms of [(η5-C5H5]Ru(CO)2]2 and selective photoreactivity of the non-bridged form

The reaction volumes, ΔV for the equilibrium between CO-bridged and non-bridged forms of the [(η5-C5H5)Ru(CO)2]2 complex in isooctane, isopropanol and acetonitrile were determined spectrophotometrically. The values of ΔV show that an increase in pressure facilitates formation of the CO-bridged form. The effect of pressure is discussed and compared to that of temperature and solvent polarity. Selective photolysis of the non-bridged form in toluene induces the symmetrical cleavage of the Ru--Ru bond to give two [(η5-C5H5)Ru(CO)2]. radicals. EPR experiments with nitrosodurene spin trap indicate that the ruthenium organometallic radicals activate the C--H bond and abstract an H atom from toluene

Ligand and medium controlled photochemistry of iron and ruthenium mixed-ligand complexes : prospecting for versatile systems

Selected Fe and Ru systems, whose photochemical behaviour is sensitive to numerous parameters, are presented. These systems, containing multiple species in equilibrium, are versatile enough to be adapted to special tasks and may also be used to model the phenomena and mechanisms occurring in nature. The role of various parameters is analysed and principal emphasis is given to the ligand sphere influence on the nature of the excited state and thereby on the photochemical mode. This is crucial in the case of Fe(II) complexes of the type [Fe(CN) 5 L] n , whereas in the carbolyl – cyclopentadienyl complexes, represented by [cpRu(CO) 2 ] 2 , the nature of the excited state is of less importance than for pentacyanofer- rates(II). The photochemistry of the carbonyl – cyclopentadienyl complexes is more suscepti- ble to the impact of the medium and the role of the secondary processes is more significant

Unsymmetrical bridging of an acetylide ligand in the cation [Pt2(CCBut)3(µ-dppm)2]+ (dppm = Ph2PCH2PPh2): x ray structure determination of the tetraphenylborate salt.

--

CCDC 147086: Experimental Crystal Structure Determination

Related Article: B.Vendemiati, G.Prini, A.Meetsma, B.Hessen, J.H.Teuben, O.Traverso|2001|Eur.J.Inorg.Chem.||707|doi:10.1002/1099-0682(200103)2001:3<707::AID-EJIC707>3.3.CO;2-Q,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 147087: Experimental Crystal Structure Determination

Related Article: B.Vendemiati, G.Prini, A.Meetsma, B.Hessen, J.H.Teuben, O.Traverso|2001|Eur.J.Inorg.Chem.||707|doi:10.1002/1099-0682(200103)2001:3<707::AID-EJIC707>3.3.CO;2-Q,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.