Weakly Bonded Lewis Base Adducts of Plumbocene and Stannocene:  A Synthetic and Calculational Study

• Published in: Organometallics Vol. 17; no. 15; pp. 3176 - 3181
• Main Authors: Armstrong, David R, Beswick, Michael A, Cromhout, Natalie L, Harmer, Christopher N, Moncrieff, David, Russell, Christopher A, Raithby, Paul R, Steiner, Alexander, Wheatley, Andrew E. H, Wright, Dominic S
• Format: Journal Article
• Language: English
• Published: American Chemical Society 20.07.1998
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om980077k

The coordination of [(η-Cp)2Pb] and [(η-Cp)2Sn] by bidentate Lewis-base ligands gives the first examples of adducts of neutral p-block metallocenes. Ab initio MO calculations of [(η-Cp)2Pb·TMEDA] (1) (TMEDA = (Me2NCH2)2), [Cp2Pb·4,4‘-Me2bipy] (2) (4,4‘-Me2bipy = 4,4‘-dimethylbipyridine), and the new complex [(η-Cp)2Sn·TMEDA] (3) confirm that despite the presence of longer Pb−N and Sn−N bonds in the solid-state structures of the TMEDA adducts, the association of TMEDA with the metallocenes is more favorable than with 4,4‘-Me2bipy. This finding is a consequence of the greater reorganization energy of 4,4‘-Me2bipy compared to TMEDA. The low association energies of these species can be rationalized in terms of metal lone pair/ligand lone pair repulsion.