Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai 200433, China.
J Phys Chem A. 2012 Dec 20;116(50):12349-56. doi: 10.1021/jp3108123. Epub 2012 Dec 10.
Infrared spectra of mass-selected homoleptic dinuclear chromium carbonyl cluster cations Cr(2)(CO)(n)(+) with n = 7-9 are measured via infrared photodissociation spectroscopy in the carbonyl stretching frequency region in the gas phase. The structures are established by comparison of the experimental spectra with the simulated spectra derived from density functional calculations. The Cr(2)(CO)(n)(+) cluster cations are characterized to have the (OC)(5)Cr-C-O-Cr(CO)(n-6)(+) structures with a linear bridging carbonyl group bonded to one chromium atom through its carbon atom and to the other chromium atom through its oxygen atom. The cluster cations all have a sextet ground state with the positive charge and the unpaired electrons located on the Cr(CO)(n-6) moiety. The formation of the linear bridging structures without Cr-Cr bonding can be rationalized that chromium forms strong Cr-CO bonds but weak Cr-Cr bonds.
采用气相红外光解离光谱法，在羰基伸缩振动频率区域内，测量了质量选择的同核双核铬羰基簇阳离子 Cr(2)(CO)(n)(+)（n=7-9）的红外光谱。通过将实验光谱与密度泛函计算得到的模拟光谱进行比较，确定了结构。Cr(2)(CO)(n)(+) 簇阳离子的特征为具有（OC）（5）Cr-C-O-Cr(CO)(n-6)(+)结构，其中线性桥接羰基通过其碳原子与一个铬原子键合，通过其氧原子与另一个铬原子键合。所有簇阳离子均具有六重态基态，正电荷和不成对电子位于 Cr(CO)(n-6)部分上。形成无 Cr-Cr 键的线性桥接结构可以解释为铬形成强 Cr-CO 键但弱 Cr-Cr 键。
