TRANSFORMATIONS OF 1D NI(II) DIPHOSPHINATE COORDINATION POLYMERS

We have reported several 1D, 2D and 3D coordination polymers based on diphosphinic acid (pcp= P,P'-diphenylmethylenediphosphate or pc2p= P,P'-diphenylethylenediphosphate) and in some cases we have described crystal-crystal transformation induced by temperature and by water. In this work, we report the different behaviour, under heating, of three 1D coordination polymers, namely [Ni(H2O)4(bipy)·pc2p]n, 1, [Ni(H2O)4(bpye)·pc2p]n, 2, and [Ni(H2O)4(bpe)·pc2p]n, 3 (bpe = 1,2-bis(4-pyridyl)ethene)). For 1, only an amorphous phase was obtained, while in case of 2 an anhydrous crystalline 3D coordination polymer was detected. Finally for 3, we have obtained a monohydrated [Ni(H2O)(bpe)pc2p]n and an anhydrous [Ni(bpe)pc2p]n phase. An interpretation based on the length of the bipyridine as well as on the role of supramolecular interactions will be given.