Solid state transitions in zinc(II) di-n-alkylphosphinate polymers

A study has been made of the reversible solid state transitions in a series of eleven zinc(II) di-n-alkylphosphinate polymers, [Zn(R2PO2)2]n, with R from C4 to C18, by means of differential scanning calorimetry and x-ray analysis. Wide line n.m.r. measurements have been also made for some compounds. The existence of two crystal forms, denoted α and β, has been established for the compounds examined. The results indicate that the α→β polymorphic transition is associated with disordering of the hydrocatbon side chains.