Formation and polymorphic phase transitions of crystalline inclusion compounds between 2,2 '-bis(9-hydroxy-9-fluorenyl)biphenyl host and acetone guest

The 2,2'-bis(9-hydroxy-9-fluorenyl)biphenyl host compound (1) was found to form various crystalline inclusion compounds with acetone depending on the crystallization conditions or on the method of preparation (inclusion of ac etone vapour, co-crystallization from solution). In order to understand and control the formation of these pseudopolymorphic phases regarding potentia l uses, single crystals of the existing phases (two 1:2 and one 1: 1 compou nd) were prepared, their structures were solved by single-crystal x-ray dif fraction (XRD) analysis and the desolvation and phase transformations were studied using simultaneous thermogravimetry-differential scanning calorimet ry (TG-DSC) and variable-temperature powder XRD. The results explain the in clusion and desolvation behaviour and also clarify the observed, apparently accidental formation of a 1:1 or 1:2 inclusion compound at ambient tempera ture. Copyright (C) 2001 John Wiley & Sons, Ltd.