TRINUCLEAR GOLD(I) PYRAZOLATE COMPLEXES EXHIBITING HEXAGONAL COLUMNARMESOPHASES WITH ONLY 3 SIDE-CHAINS

Reaction of long-chain alkyl-substituted pyrazoles with AuCl(SMe2) yie lds trinuclear gold(I) pyrazolate complexes, two of which exhibit mono tropic mesophases. Optical microscopy and/or X-ray diffraction studies show that these compounds form hexagonal columnar mesophases. They ar e only the third examples of discotic mesogens possessing only three a liphatic side chains. The X-ray crystal structure of one compound reve als that two molecules form a ''dimer'' mainly through intermolecular Au-Au interactions. The ''dimers'' are stacked in a tilted fashion to form columns along the b axis in the crystal phase, which are presumab ly rearranged to the hexagonal columnar structure in the mesophase.