A new family of phosphido-bridged dinuclear ruthenium carbonyl complexes: synthesis of [Ru_2(CO)_6{#mu#-P(C(CH)_3O)_2}](#mu#-#eta#~1, #eta#~2-C(CH)_3O)] and its reactivity towards terminal alkynes

摘要

Thermal reaction of [Ru_3(CO)_12] with tri(2-furyl)phosphine affords the dinuclear phosphido-bridged complex [Ru_2(CO)_6{#mu#-P(C(CH)_3O)_2}](#mu#-#eta#~1, #eta#~2-C(CH)_3O)] 1a in good yield via cleavage of Ru-Ru P-C(furyl) bonds in the starting compounds and a small amount of the disubstitution product [Ru_3(CO)_10{P(C(CH)_3O)_3}_2] 1b. The X-ray structural analysis of 1a shows that it contains a dissociated furyl fragment bonded to the Ru_2 unit in a #mu#-#eta#~1, #eta#~2 coordination mode through one #sigma# and one #pi# bond. This represents the first structurally characterised example of such a furyl-bonded dinuclear organometallic complex. Complex 1a readily reacts with two equivalents of terminal alkynes HC#XI#CR [R=Ph, p-C_6H_4Me, p-C_6H_4NO_2, (C_4H_2S)C#XI#CH or (C_4H_2S)_2C#XI#CH] by an interesting head-to-tail ynyl coupling with a furan group to form a series of phosphido-bridged diruthenium compounds containing a novel furyl-substituted C_4 hydrocarbyl chain of stoichiometry [Ru_2(CO)_4{#mu#-P(C(CH)_3O)_2}{#mu#-#eta#~1,#eta#~,#eta#~2,#eta#~3-RCC(H)C(R)C(H)C(CH)_3O}] [R=Ph 2, p-C_6H_4Me 3, p-C_6H_4NO_2, 4, (C_4H_2S)C#XI#CH 5 or (C_4H_2S)_2C#XI#CH 6] in moderate to good yields, all of which have bee characterised by spectroscopic and crystallographic methods. Assignments of the proton NMR spectra have been made with the aid of a 2-D `1H-~1H COSY technique. On reaction with the thienyl-linked diyne ligands, only one free C#XI#CH group is involved in the coupling sequence while the other terminal alkyne functionality remains intact. All these new dinuclear complexes are electron pecise with 34 cluster valence electrons,