173437-70-2Relevant academic research and scientific papers
Synthesis and structural characterization of (carbene)ruthenium complexes binding nucleobases
Fillaut, Jean-Luc,De Los Rios, Isaac,Masi, Dante,Romerosa, Antonio,Zanobini, Fabrizio,Peruzzini, Maurizio
, p. 935 - 942 (2002)
The new (carbene)ruthenium(II) nucleobase derivatives fac,cis-[(PNP)RuCl{C(NHC4 H3N2O2)(CH2Ph)}]Cl (5) and fac,cis-[(PNP)RuCl{C(NHC5H3N4) (CH2Ph)}]Cl (6) [PNP = CH3CH2CH2N (CH2CH2PPh2)2] were synthesised by treating (vinylidene)ruthenium(II) complex fac,cis-[(PNP)RuCl2{C= C(H)Ph}] (1) with 5-aminouracil or adenine, respectively. Both complexes were characterized by spectroscopic techniques (IR and NMR) and elemental analyses, which confirmed the formation of the aminocarbene moieties incorporating 1 equiv. of the nucleobase in the complex framework. Crystal and molecular structure determination by X-ray diffraction analysis of the uracil derivative 5 revealed a very unusual O-coordination of the exocyclic C=O group on the C(4) atom of the uracil ring to the ruthenium atom leading to an unprecedented six-membered aminocarbene metallacycle. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Ruthenium-assisted synthesis of gem-deuterated alkenes from monosubstituted propargyl alcohols and D2O
Bianchini, Claudio,De los Rios, Isaac,Lopez, Carlos,Peruzzini, Maurizio,Romerosa, Antonio
, p. 485 - 488 (2007/10/03)
The cyclohexenylvinylidene complex fac,cis-[(PNP)RuCl2{C=CH(C=CHCH2CH2CH2CH2)}] (2) is synthesized by reaction of mer,trans-[(PNP)RuCl2(PPh3)] (1) with 1-ethynylcyclohexanol [PNP
C-C bond formation between vinylidene and alkynyl ligands at ruthenium(II) leading to either enynyl or dienynyl complexes
Bianchini, Claudio,Innocenti, Paolo,Peruzzini, Maurizio,Romerosa, Antonio,Zanobini, Fabrizio
, p. 272 - 285 (2008/10/08)
The Ru(II) complex mer,trans-(PNP)RuCl2(PPh3) (1) reacts with either phenylacetylene or p-tolylacetylene to give fac,cis-(PNP)RuCl2{C=CH(R)} (R = Ph (2), p-tolyl (3)) in refluxing tetrahydrofuran (THF) and mer,trans-(PNP)RuCl2{C=CH(R)} (R = Ph (4), p-tolyl (5)) in a refluxing THF/EtOH mixture (1:2 v:v) [PNP = CH3CH2CH2N(CH2CH2PPH 2)2]. The fac,cis vinylidene complexes 2 and 3 react with an excess of LiC≡CPh converting to the σ-alkynyl-η3-enynyl complexes anti,mer-(PNP)Ru(C≡CPh){η3-PhC3=CH(Ph)} (8) and anti,mer-(PNP)-Ru(C≡CPh){η3-ChC3=CH(p-tolyl)} (9), respectively. Conversely, treatment of the mer,trans vinylidene isomers with an excess of LiC≡CPh, followed by addition of a primary alcohol, exclusively gives the σ-alkynyl-η-dienynyl complexes mer-(PNP)Ru(C≡CPh){η-PhC=C-(C≡CPh)CH=CH(R)} (R = Ph, 12; R = p-tolyl, 13), Single-crystal X-ray analyses have been carried out on 8 and 13. In both compounds the coordination geometry around the Ru atom approximates an octahedron with three positions taken by a mer PNP ligand and one position taken by a phenylethynyl group. The coordination sphere around the metal center is completed by an η3-1,4-diphenylbut-3-en-1-ynyl ligand in 8 and by a 1-p-tolyl-3-(phsnyl-ethynyl)-4-phenylbuta-1(E),3(Z)-dien-4-yl ligand in 13. The latter ligand essentially uses the C1 carbon atom to bind the metal, although a weak bonding interaction may be envisaged also with the alkynyl substituent in the 3-position. A single-crystal X-ray analysis has also been carried out on the octahedral fac,cis-(PNP)RuCl2(CO) complex obtained by treatment of the vinylidenes 2 and 3 with molecular oxygen. The influence of the bonding mode of the PNP ligand on the different reactivity shown by the fac and mer vinylidene complexes toward LiC≡CPh is discussed in light of a multiform experimental study (X-ray structure determinations, multinuclear NMR spectroscopy, deuterium- and p-tolyl-labeling experiments, independent reactions with isolated compounds).
The mechanism of the Ru-assisted C-C bond cleavage of terminal alkynes by water
Bianchini, Claudio,Casares, Juan A.,Peruzzini, Maurizio,Romerosa, Antonio,Zanobini, Fabrizio
, p. 4585 - 4594 (2007/10/03)
The hydration of phenylacetylene in the presence of the complex mer,trans-(PNP)RuCl2(PPh3) in THF at 60°C leads to the cleavage of the C-C triple bond with formation of the carbonyl complex fac,cis-(PNP)RuCl2(CO) and toluene [PNP = CH3CH2CH2N(CH2CH2PPh2)2]. A study under different experimental conditions, the use of model and isotope labeling experiments, and the detection of several intermediates, taken altogether, show that the C-C bond cleavage reaction comprises a number of steps, among which the most relevant to the mechanism are 1-alkyne to vinylidene tautomerism, conversion of a vinylidene ligand to hydroxycarbene by intramolecular attack of water, deprotonation of hydroxycarbene to σ-acyl, deinsertion of CO from the acyl ligand, and hydrocarbon elimination by protonation of the metal-alkyl moiety. The following intermediate species have been isolated and characterized: the vinylidene fac,cis-(PNP)RuCl2{C=C(H)Ph}, the (aquo)(σ-alkynyl) complex fac-(PNP)RuCl(C≡CPh)(OH2), and the (benzyl)carbonyl mer-(PNP)RuCl(η1-CH2Ph)(CO). Other intermediates such as the σ-acyl mer-(PNP)RuCl(η1-COCH2Ph)(CO) have been intercepted by addition of appropriate reagents, while the independent synthesis of the aminocarbene complex fac,cis-(PNP)RuCl2{C(NC5H10)(CH2Ph)} and its reaction with water have provided evidence for the intermediacy of a hydroxycarbene species in the C-C bond cleavage reaction.
