Infrared-Driven Charge-Transfer in Transition Metal-Containing B12X122– (X = H, F) Clusters

Density functional theory (DFT) calculations and infrared multiple photon dissociation (IRMPD) spectroscopy are employed to probe [TM·(B12H12)]− and [TM·(B12H12)2]2– clusters [TM = Ag(I), Cu(I), Co(II), Ni(II), Zn(II), Cd(II)]. A comparison is made between the charge-transfer properties of the clusters containing the hydrogenated dodecaborate dianions, B12H122–, and the fluorinated analogues, B12F122–, for clusters containing Cd(II), Co(II), Ni(II), and Zn(II). IRMPD of the [TM·(B12H12)]− and [TM·(B12H12)2]2– species yields B12H11– via hydride abstraction and B12H12– in all cases. To further explore the IR-induced charge-transfer properties of the B12X122– (X = H, F) cages, mixed-cage [TM(B12H12)(B12F12)]2– [TM = Co(II), Ni(II), Zn(II), Cd(II)] clusters were investigated. IRMPD of the mixed-cage species yielded appreciable amounts of B12F12– and B12H12– in most cases, indicating that charge-transfer to the central TM cation is a favorable process; formation of B12F12– is the dominant process for the Co(II...