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...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.展开更多
Mbius container molecules C64H8,C60N4H4,and C58N6H2 with topological one-sided characteristics were constructed at the first time by imitating natural trumpet shells.The structure is an open cage with an inner hexagon...Mbius container molecules C64H8,C60N4H4,and C58N6H2 with topological one-sided characteristics were constructed at the first time by imitating natural trumpet shells.The structure is an open cage with an inner hexagonal bridge.The bridge joints the outer and inner surfaces of the cage to form a new one-sided Mbius structure.The optimized structures of the three molecules in the singlet(the ground state),triplet and quintet states are obtained using the density functional theory(B3LYP).For the ground state structures of the three Mbius molecules,their oxidizabilities are weaker than that of the C60 and reducibilities are close to that of the stable C80 cage and slightly stronger than that of the C60.These may show that the unusual Mbius structures have some stability.Their potential properties were predicted,for example,the special aromaticity of the bridge ring due to the unique interaction between the bridge and the cage wall.These findings enlarge the knowledge of Mbius molecules. The idea of bionic and topological imitating in chemistry may promote the design of new complex-shaped nano-molecules and molecular devices.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.20873045 and 20973066)
文摘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.
基金supported by the National Natural Science Foundation of China (20773046)
文摘Mbius container molecules C64H8,C60N4H4,and C58N6H2 with topological one-sided characteristics were constructed at the first time by imitating natural trumpet shells.The structure is an open cage with an inner hexagonal bridge.The bridge joints the outer and inner surfaces of the cage to form a new one-sided Mbius structure.The optimized structures of the three molecules in the singlet(the ground state),triplet and quintet states are obtained using the density functional theory(B3LYP).For the ground state structures of the three Mbius molecules,their oxidizabilities are weaker than that of the C60 and reducibilities are close to that of the stable C80 cage and slightly stronger than that of the C60.These may show that the unusual Mbius structures have some stability.Their potential properties were predicted,for example,the special aromaticity of the bridge ring due to the unique interaction between the bridge and the cage wall.These findings enlarge the knowledge of Mbius molecules. The idea of bionic and topological imitating in chemistry may promote the design of new complex-shaped nano-molecules and molecular devices.
