Synthesis and structural studies of dimeric sodium compounds having pentametallacyclooctane and hexametallacyclo undecane structure using different phosphinamine derivatives

The treatment of two bulky phosphinamines [Ph2PNH(CHPh2)] (1) and [Ph2PNH(CPh3)] (2) with 30% hydrogen peroxide afforded phosphinicamides [Ph2P(O)NH(CHPh2)] (3) and [Ph2P(O)NHCPh3] (4) in good yield. When the same phosphinamines are reacted with elemental sulfur, corresponding sulfur compounds [Ph2P(S)NH(CHPh2)] (5) and [Ph2P(S)NHCPh3] (6) are obtained. Further reactions of 4–6 with sodium bis(trimethylsilyl)amide in THF solution afforded corresponding sodium salts of molecular formula [{(THF)2Na(Ph2P(O)NCPh3)}2] (8), [{(THF)2Na(Ph2P(S)NCHPh2)}2] (7) and [{(THF)2Na(Ph2P(S)NCPh3)}{(THF)Na(Ph2P(S)NCPh3)}] (9) and all the sodium complexes 7–9 are dimeric and form highly strained polymetallacyclic motif in solid state structures. Molecular structure of all the complexes are established by single crystal X-ray diffraction analysis.

► Various bulky phosphinamines and derivatives have been synthesized. ► Very straight forward synthesis, i.e. easily accessible of the compounds. ► Novel structural motifs in sodium complexes using heteroatoms are observed. ► Three hetero atoms (N, P, S or O) are making the poly metallacycles.