145333-68-2Relevant academic research and scientific papers
Communication between metal centers in tungsten(0)-tungsten(II) complexes bridged by 1,4-diisocyanobenzene: Is the ligand π system involved?
Grubisha, Desiree S.,Rommel, Jeffrey S.,Lane, Thomas M.,Tysoe, Wilfred T.,Bennett, Dennis W.
, p. 5022 - 5027 (2008/10/08)
The ability of the aromatic diisocyanide ligand 1,4-diisocyanobenzene to act as a mediator for charge polarization between W(O) and W(II) centers was investigated. A series of bridged complexes were synthesized which contained W(0)-W(0), W(0)-W(II), and W(II)-W(II) metal centers, coupled by CNC6H4NC. C-N stretching vibrations for the W(0) ends of the molecules were actually at higher energies than those for the W(II) ends. Infrared and multinuclear NMR studies indicated that the W(0)-W(II) molecules were effectively unperturbed hybrids of the W(0)-W(0) and W(II)-W(II) molecules. In contrast, the MLCT band of the binuclear complexes is red-shifted 1221 cm-1 compared to that of the mononuclear complexes, indicating that the π system is involved in M-L-M bonding and should telegraph differences in charge from one metal center to the other through charge polarization across the ring. The apparent contradiction is resolved in the X-ray photoelectron spectra of the W(0)-W(II) complexes, which exhibit nearly identical W(4f) chemical shifts for the two tungsten centers, indicating that the metals are in very similar electronic environments.
