The Research Of Infrared Photodissociation Spectroscopy Of Mass-Selected Heteronuclear Iron-Copper Carbonyl Cluster Anions In The Gas Phase

Infrared photodissociation spectroscopy(IRPD) is a powerful method to study the ions in the gas phase. It can provide the vibrational information of mass selected ions in the gas phase with high sensitivity. In this paper, we explicated the home-made apparatus based on collinear tandem time-of-flight mass spectrometer, which is designed and installed for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase. In combination with quantum chemical calculation, the copper-iron carbonyl complexes have been studied in the gas phase both experimentally and theoretically. The main work is as follows:(1) The design and construction of the home-made apparatus for the measurement of infrared photodissociation spectroscopy of mass-selected ions in the gas phase. This apparatus have three main parts, including the laser vaporization cluster sources, linear time-of-flight mass spectrometer andtamdem infrared photodissociation mass spectrometer.The ions from a pulsed laser vaporization supersonicion source are skimmed and mass separated by the linear time-of-flight mass spectrometer. The ion of interest is mass selected, decelerated and dissociated by a tunable IR laser. The fragment and parent ions are reaccelerated and mass analyzed by tamdem infrared photodissociation mass spectrometer. The infrared photodissociation spectrum is obtained by monitoring the yield of the fragment ion as a function of the dissociation IR laser wavelength and normalizing to parent ion signal.(2) Experimental and theoretical studies on the CuFe(CO)n-(n=4-7) anion clusters in the gas phase. Mass-selected heteronuclear iron-copper carbonyl cluster anions CuFe(CO)n-(n=4-7) are studied by infrared photodissociation spectroscopy in the carbonyl stretching frequency region in the gas phase. The cluster anions are produced via a laser vaporization supersonic cluster ion source. Their geometric structures are determined by comparison of the experimental spectra with those calculated by density functional theory.The experimentally observed CuFe(CO)n-(n=4-7) cluster anions are characterized to have(OC)4Fe-Cu(CO)n-4 structures, each involving a C3 v symmetry Fe(CO)4-building block.Bonding analysis indicates that the Fe-Cu bond in the CuFe(CO)n-(n=4-7) cluster anions is an ? type single bond with the iron center possessing the most favored 18-electron configuration. The CO-tagged structure was also observed for the n=6 species. The n=6species has enhanced intensity in the mass spectroscopy with the strongest Fe-Cu bonding energy. The interactions between Fe(CO)4 and Cu(CO)n-4(n=6,7) moieties were rather weak due to the steric crowding. The Fe(CO)4 is keep C3 v or slighted distorted C3 v structure and act as a stabilizing group in these gas phase ions. The results provide important new insight into the structure and bonding of hetronuclear transition metal carbonyl cluster anions.