title: Sequential bonding of CO molecules to a titanium dimer: A photoelectron velocity-map imaging spectroscopic and theoretical study of Ti2(CO)n-(n = 1-9).
abstract: Binuclear titanium carbonyl cluster anions, Ti2(CO)n-(n = 4-6), are produced via a laser vaporization supersonic cluster source and characterized by mass-selected photoelectron velocity-map imaging spectroscopy. Quantum chemical calculations are carried out for Ti2(CO)n-(n = 1-9) to explore the trend of sequential bonding of CO molecules to a titanium dimer. It has been found that the CO molecules bind to Ti2in a side-on fashion and form a stable Ti2[η2(μ2-C, O)]3structure at n = 3, the motif of which retains up to n = 5. Starting at n = 6, a new building block of two CO groups side-on-bonded to Ti2is favored, the structure of which persists up to n = 9. In the larger clusters (n = 6-9), the side-on-bonded CO molecule can be stabilized via the removal of two electrons from an anionic titanium carbonyl, which is different from the effect of charge on CO binding in rhodium carbonyls where bridge-bonded CO molecules are selectively destabilized by the removal of an electron from a neutral rhodium carbonyl. The present study provides a stepwise picture for molecular-level understanding of CO bonding on transition-metal clusters, which is directly relevant to the elementary processes of CO at metal catalysts.
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation Center of Chemistry for Energy and Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, People's Republic of China.
authors.forename: Jinghan
authors.initials: J
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation Center of Chemistry for Energy and Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xie
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation Center of Chemistry for Energy and Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, People's Republic of China.
authors.forename: Dongxu
authors.initials: D
authors.lastname: Dai
authors.affiliation: State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China.
authors.forename: Zichao
authors.initials: Z
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation Center of Chemistry for Energy and Materials (iChEM), Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, Liaoning, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang