336142-03-1Relevant academic research and scientific papers
Alkyne insertion into the Ru-C bond of a four-membered metallacycle. Insertion rate and reaction pathway
Ghosh, Kaushik,Chattopadhyay, Swarup,Pattanayak, Sujay,Chakravorty, Animesh
, p. 1419 - 1423 (2008/10/08)
The insertion of HOCH2C≡CH(ha) into the Ru-C bond of RuII(RL1)(PPh3)2(CO)Cl, 1, has afforded RuII(RL3)(PPh3)2(CO)Cl, 3, which has been structurally characterized. Insertion rates in CH2Cl2-MeOH for ha as well as for PhC≡CH (pa), which inserts similarly into 1 affording RuII(RL2)(PPh3)2(CO)Cl, 2, are proportional to the product of the concentrations of alkyne and methanol. The insertion rate of ha is nearly 5 times faster than that of pa, and for a given alkyne the rate increases as R becomes more electron-withdrawing (OMe A reaction model implicating the adduct 1·MeOH, which binds and activates the alkyne via displacement of MeOH, is proposed.
Metallacycle expansion by alkyne insertion. Chemistry of a new family of ruthenium organometallics
Ghosh, Kaushik,Pattanayak, Sujay,Chakravorty, Animesh
, p. 1956 - 1960 (2008/10/08)
Acetylene and phenylacetylene reacts with carbonylchloro[4-methyl-6-((R-imino)methyl)-phenolato-C,O] bis(triphenylphosphine)ruthenium(II), Ru(RL1)(PPh3)2(CO)Cl (3), affording the inserted product carbonylchloro[2-vinyl-4-methyl-6-((R-imino)methyl)phenolato-C,O]bis- (triphenylphosphine)ruthenium(II), Ru(RL2,X)(PPh3)2(CO)Cl (4), in virtually quantitative yield. The X-ray structures of 4b (R = X = Ph) and 4g (R = Et, X = H) have revealed the presence of distorted-octahedral RuC2P2ClO coordination spheres. In the conversion 3 → 4, the Ru(C,O) chelate ring expands from four-membered to six-membered. The insertion of phenylacetylene is regiospecific, and a reaction model implicating initial Ru-O cleavage and steric control is proposed. The Ru-O bond in 4 is significantly shorter (by ～0.14 ?) and stronger than that in 3. This is reflected in the lowering of the ruthenium(III)-ruthenium(II) reduction potential by ～200 mV. The uncoordinated Schiff base moiety in 4 is present in the hydrogen-bonded iminium-phenolato zwitterionic form, as revealed by the N?O distance as well as by IR and NMR data.
