228117-91-7Relevant academic research and scientific papers
Stereochemically Controlled Synthesis of Ruthenium(II) Complexes Containing Bis(oxazolin-2'-yl)pyridine Ligands. X-ray Crystal Structures of trans-[RuCl2(PPh3){κ(3)-N,N,N-(S,S)-(i)Pr-pybox}] and [RuCl(=C=C=CPh2)(PPh3){κ(3)-N,N,N-(S,S)-(i)Pr-pybox}][PF6] ((S,S)-(i)Pr-pybox ...
Cadierno, Victorio,Gamasa, M. Pilar,Gimeno, Jose,Iglesias, Luis,Garcia-Granda, Santiago
, p. 2874 - 2879 (2008/10/08)
The treatment of achiral and chiral bis(oxazolin-2'-yl)pyridine (pybox) complexes trans-[RuCl2(η(2)-H2C=CH2)(κ(3)-N,N,N-pybox)] [pybox= 2,6-bis(dihydrooxazolin-2'-yl)pyridine] (1a) and [RuCl2(η(2)-H2C= CH2)(κ(3)-N,N,N-(SS)-(i)Pr-pybox)] [(SS)-(i)Pr-pybox = 2,6-bis[4'-(S)-isopropyloxazolin-2'-yl]pyridine] (1b) with an excess of triphenylphosphine in dichloromethane at 50°C leads to the formation of the first ruthenium(II) derivatives containing both bis(oxazolin-2'-yl)pyridine and phosphine ligands trans-[RuCl2(PPh3)(κ(3)-N,N,N-pybox)] (2a) and trans-[RuCl2(PPh3){κ(3)-N,N,N-(SS)-(i)Pr-pybox}] (2b). Chiral complex 2b slowly isomerizes in acetone at 50°C to generate cis-[RuCl2(PPh3){κ(3)-N,N,N-(SS)-(i)Pr-pybox}] (3). Complex 3 can bealso obtained from the reaction of 1b with PPh3 in MeOH. The structure of 3 has been confirmed by X-ray crystallography [orthorhombic; space gr oup P212121; Z = 4; a = 12.772(6) ?, b = 15.208(5) ?, c = 19.601(7) ?; final R1 = 0.0565 and wR2 = 0.0944 (both for I > 2σ(I))]. The reaction of the achiral pybox complex 2a with 1,1-diphenyl-2-propyn-1-ol and AgBF4 in CH2Cl2 stereoselectively affords the cationic allenylidene derivative [RuCl(=C=C=CPh2)(PPh3)(κ(3)-N,N,N-pybox)][BF4] (4a), while the methoxycarbene complex [RuCl{=C(OMe)CH=CPh2}(PPh3)(κ(3)-N,N,N-pybox)][PF6] (5) is obtained when the reaction is conducted in methanol and in the presence of NaPF6, via the addition of MeOH to the initially formed allenylidene complex 4a. In contrast, the chiral pybox complex 2b reacts with 1,1-diphenyl-2-propyn-1-ol and NaPF6 in MeOH togive the stable allenylidene complex [RuCl(=C=C=CPh2)(PPh3){κ(3)- N,N,N-(SS)-(i)Pr-pybox}][PF6] (4b). The X-ray crystal structure of 4b [orthorhombic; space group P212121; Z = 4; a = 14.79(3) ?, b = 16.254(8) ?, c = 22.917(18) ?; final R1 = 0.0545 and wR2 = 0.1381 (bothfor I > 2σ(I))] shows an octahedral coordination of the ligands a round the ruthenium atom with the chloride and triphenylphosphine ligands in a trans arrangement and mutually cis with respect to the allenylidene moiety. The allenylidene complex 4b is also formed by the reaction ofthe cis dichloride complex 3 with 1,1-diphenyl-2-propyn-1-ol and NaPF6 in MeOH. IR, (1)H, (31)P{(1)H}, and (13)C{(1)H} NMR data of all novel co mpounds are also reported.
