The Spectroscopic Study Of Heteronuclear 14 Group Elementsiron Carbonyl Anions And Scandium-Nickel Carbonyl Anions

Infrared photo-dissociation spectroscopy?IRPD?is a wildly used method to study the cluster ions in the gas phase.It has high sensitivity and can give the vibrational information of mass selected ions.In this dissertation,the A₂Fe?CO?₃^-?A=Ge,Sn,Pb?and ScNi?CO?_n^-?n=2-6?cluster anions were produced by the laser vaporization supersonic cluster ion source and characterized by the mass spectrometry and infrared photo-dissociation spectroscopy.In comination with theoretical calculations,their structures were determined,and their bonding characters were discussed.This study will improve our understanding of the main-group-metal-transition-metal carbonyls anions and scandium-transition-metal carbonyl anions.It also provide new insight into the chemical properties of the heteronuclear metal clusters and their important roles in the surface catalysis.The main work is as follows:?1?The experimentally observed A₂Fe?CO?₃^-?A=Ge,Sn,Pb?anions were characterized to have Cs symmetry involving all the four CO ligands coordinated on the Fe center.The extra negative charge of the A₂Fe?CO?₃^-?A=Ge,Sn,Pb?anions is mainly located on the Fe?CO?₃ group.The iron center had 15-electron configuration and the Fe?CO?₃^-group is analogy to a group-15 element atom with big size,which binds to two carbon atoms.The A₂Fe?CO?₃^-?A=Ge,Sn,Pb?anions can be regard as been formed between Fe?CO?₃^-group and the A₂ dimmer with three metal-metal single bonds and with the iron center having 17-electron configuration.?2?The experimentally observed ScNi?CO?_n^-?n=3-6?cluster anions were been regared to formed between Ni?CO?3 groups and Sc?CO?n groups with different combinations.Natural charge population analysis showed that the positive charge of the ScNi?CO?_n^-?n=3-6?cluster anions,mainly located on the Sc atom and Sc?CO?_n group,and the Sc atoms transfer electron densities to the CO ligands.The frontier molecular orbitals of the isomers with side-on-bonded,or bridging carbonyls,are delocalized?orbitals mainly involving the metal–carbon unit,which stabilize the whole isomers.For the isomer with only terminal carbonyls,the Sc-Ni is a?type single bond,which is formed between a Sc 4s,3d hybrid orbital and a Cr 4s,4p,3d hybrid orbital.The Sc-Ni bonding strength decreased as more CO terminal bonded to the Sc atom,which is consistent with the evolution of the predicted Sc-Ni distances.