TY - JOUR AU - Choua, S. AU - Sidorenkova, H. AU - Berclaz, T. AU - Geoffroy, M. AU - Rosa, P. AU - Mézailles, N. AU - Ricard, L. AU - Mathey, F. AU - Le Floch, P. TI - One-electron reduction product of biphosphinine derivative and of its Ni(0) complex: crystal structure, EPR/ENDOR and DFT investigations on (tmbp).- and [Ni(tmbp)2].- PY - 2000 JF - Journal of the American Chemical Society JA - J. Am. Chem. Soc. SN - 0002-7863 VL - 122 IS - 49 SP - 12227 EP - 12234 L1 - http://pubs.acs.org/doi/pdf/10.1021/ja002125%2B L2 - http://pubs.acs.org/doi/full/10.1021/ja002125%2B L3 - http://pubs.acs.org/doi/abs/10.1021/ja002125%2B L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00050.png M3 - 10.1021/ja002125+ UR - http://dx.doi.org/10.1021/ja002125+ N2 - The radical anion (tmbp)•-, where tmbp = 4,4‘,5,5‘-tetramethyl-2,2‘-biphosphinine, was generated by reduction of tmbp on a potassium mirror. EPR/ENDOR spectra and DFT calculations show that, in contrast to the neutral species, this anion is planar and that the unpaired electron is mainly delocalized on the PCCP fragment with a large participation of the phosphorus pπ orbitals. This planar structure was confirmed by the first crystal structure of an anionic biphosphinine:  [tmbp][Li(2.2.1)]. Reduction of [Ni(tmbp)2] led to the 19-electron complex whose g and 31P hyperfine tensors were obtained from EPR in liquid and frozen solutions. These results, together with DFT calculations on [Ni(bp)2] and [Ni(bp)2]•-, indicate that, by accepting an extra electron, the neutral nickel complex distorts toward a more planar geometry and that the dihedral angle between the two phosphinine rings of each ligand slightly increases. In the reduced Ni complex, the unpaired electron is mainly delocalized on the ligands, in a molecular orbital which retains the characteristics of the SOMO found for the reduced isolated ligand. A charge decomposition analysis (CDA) shows that, in [Ni(bp)2], metal−ligand back-donation strongly contributes to the metal−ligand bonding. ID - 50 ER -