Theoretical study on homoleptic mononuclear and binuclear ruthenium carbonyls Ru(CO)_n(n=3―5) and Ru_2(CO)_n(n=8,9)  

作　　者：PENG Bin1,GU FengLong1,ZHANG XiuHui2,LUO Qiong2 & LI QianShu1,2 1 School of Chemistry and Environment,South China Normal University,Guangzhou 510631,China 2 Beijing Institute of Technology,Beijing 100081,China 

出　　处：《Science China Chemistry》2009年第11期1938-1944,共7页中国科学（化学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 20873045 and 20973066)

摘　　要：Homoleptic mononuclear and binuclear ruthenium carbonyls Ru(CO)n(n=3―5) and Ru2(CO)n(n=8,9) have been investigated using density functional theory.Sixteen isomers are obtained.For Ru(CO)5,the lowest-energy structure is the singlet D3h trigonal bipyramid.Similar to Os(CO)5,the distorted square pyramid isomer with C2v symmetry lies ～7 kJ·mol-1 higher in energy.For the unsaturated mononuclear ruthenium carbonyls Ru(CO)4 and Ru(CO)3,a singlet structure with C2v symmetry and a Cs bent Tshaped structure are the lowest-energy structures,respectively.The global minimum for the Ru2(CO)9 is a singly bridged(CO)4Ru(μ-CO)Ru(CO)4 structure.A triply bridged Ru2(CO)6(μ-CO)3 structure analogous to the known Fe2(CO)9 structure is predicted to lie very close in energy to the global minimum.For Ru2(CO)8,the doubly bridged C2 structure is predicted to be the global minimum.For the lowest-energy structures of M2(CO)n(M=Fe,Ru,Os,n=9,8),it is found that both iron and ruthenium are favored to form structures containing more bridging carbonyl groups,while osmium prefers to have structures with less bridging carbonyl groups.The study of dissociation energy shows that the dissociation of Ru2(CO)9 into the mononuclear fragments Ru(CO)5+Ru(CO)4 is a less energetically demanding process than the dissociation of one carbonyl group from Ru2(CO)9 to give Ru2(CO)8.Homoleptic mononuclear and binuclear ruthenium carbonyls Ru(CO)n(n=3―5) and Ru2(CO)n(n=8,9) have been investigated using density functional theory.Sixteen isomers are obtained.For Ru(CO)5,the lowest-energy structure is the singlet D3h trigonal bipyramid.Similar to Os(CO)5,the distorted square pyramid isomer with C2v symmetry lies ～7 kJ·mol-1 higher in energy.For the unsaturated mononuclear ruthenium carbonyls Ru(CO)4 and Ru(CO)3,a singlet structure with C2v symmetry and a Cs bent Tshaped structure are the lowest-energy structures,respectively.The global minimum for the Ru2(CO)9 is a singly bridged(CO)4Ru(μ-CO)Ru(CO)4 structure.A triply bridged Ru2(CO)6(μ-CO)3 structure analogous to the known Fe2(CO)9 structure is predicted to lie very close in energy to the global minimum.For Ru2(CO)8,the doubly bridged C2 structure is predicted to be the global minimum.For the lowest-energy structures of M2(CO)n(M=Fe,Ru,Os,n=9,8),it is found that both iron and ruthenium are favored to form structures containing more bridging carbonyl groups,while osmium prefers to have structures with less bridging carbonyl groups.The study of dissociation energy shows that the dissociation of Ru2(CO)9 into the mononuclear fragments Ru(CO)5+Ru(CO)4 is a less energetically demanding process than the dissociation of one carbonyl group from Ru2(CO)9 to give Ru2(CO)8.

关 键 词：dinuclear ruthenium CARBONYLS DFT theoretical study 

分 类 号：O641.12[理学—物理化学]