Lithium Oligophosphanediides in the Li/PhPCl 2 System

Optimized conditions for the selective synthesis of [Li 2 (P n Ph n )(tmeda) x ] ( n = 2, 3, 4) have been developed. X‐ray diffraction with single crystals show [Li 2 (P 2 Ph 2 )(tmeda) 2 ] and [Li 2 (P 4 Ph 4 )(tmeda) 2 ] to be ion triples, while for n = 3 the ion pair [Li(tmeda) 2 ] + [Li(P 3 Ph 3 )(tmeda)] – is observed. NMR experiments support the assumption that these structures are retained in solution. Structural differences between the lithium and the corresponding sodium compounds, [Na 2 (P n Ph n )(tmeda) x ], can be partially rationalized using the electrostatic stabilization parameters, ESP = Σ(1/ r   M   + ,M   +) + Σ(1/ r   P   – ,P   –) – Σ(1/ r   M   + ,P   –); M = Li, Na. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)