A cyclic hydrogen-bonded system with collective proton motion in bis(2,2'-dihydroxy-3-biphenylyl)methane

Bis [3,3'-(2,2'-dihydroxybiphenyl)] methane (BBPM) was synthesized. It was studied by osmometry and by 1 H NMR and FTIR spectroscopies. Furthermore, the monotetrachloroaurate of BBPM was also investigated. BBPM is a monomer in acetonitrile solution. Within this molecule the four OH groups form a cyclic hydrogen-bonded structure in which a collective proton fluctuation occurs. In the case of the monotetrachloroaurate the cyclic structure is more stable, the additional OH group is also hydrogen-bonded, and its proton is involved in the collective proton fluctuation, as in the case of crown ethers