The Thermolysis of Ru3(CO)12 with Carboxylic Acids Revisited: Stepwise Assembly of Ru2 to Ru6 Cluster Frameworks

Abstract

AbstractThermolysis of Ru3(CO)12 with carboxylic acids directly accessed a large variety of low valence ruthenium carbonyl complexs. Under the conditions of the reaction firstly reported by J. Lewis, 3 equivalents of acids were employed to assembly sawhorse‐type dirutheniumtetra carbonyl complex. Six Ru3‐Ru6 ruthenium clusters were unexpectedly isolated in the reaction of Ru3(CO)12 with 1 equivalent of carboxylic acids under thermal condition. The reaction of Ru3(CO)12 with ten kind of carboxylic acids were systematically investigated. The reactions of Ru3(CO)12 with non‐coordinative carboxylic acids afforded β‐H2Ru4(CO)13 (2), Ru6(μ6‐C)(μ‐CO)(CO)16 (3) and then to Ru6(μ6‐C)(μ‐CO)(CO)13(η6‐C6H5CH3) (4), respectively. The further experiments indicated that the formation of 3 was attributed to the assembly of tetraruthenium carbonyl dihydrid 2 with polymeric sawhorse diruthenium intermediate [Ru2(CO)4(OOR)2]n (R= alkyl, aryl). The thermolysis of phenylpropiolic acid with Ru3(CO)12 unveiled an alternative pathway to access Ru6 skeleton. The triruthenium cluster [(μ‐H)Ru3(CO)9(μ3‐η2‐(⊥)‐C≡CC6H5)] (5) and butterfly tetraruthenium compound Ru4(CO)12(HC≡CC6H5) (6) were identified as the key intermediates in the construction of compound 3.