CROWN COMPOUNDS FOR ANIONS - A POLYMERIC COMPLEX OF CYCLIC TRIMERIC PERFLUORO-O-PHENYLENEMERCURY WITH THIOCYANATE ANION CONTAINING AN INFINITE HELICAL CHAIN OF ALTERNATING MOLECULES OF MERCURY-CONTAINING MACROCYCLE AND SCN- IONS

It has been shown by IR spectroscopy that cyclic trimeric perfluoro-o- phenylenemercury (o-C6F4Hg)(3) is capable of binding thiocyanate anion s in acetone solution, forming complexes whose composition is dependen t on the ratio of reagents. In the interaction of (o-C6F4Hg)(3) with a n equimolar amount of [(n)Bu(4)N](SCN-)-S-+ in ethanol the complex for mulated as [(o-C6F4Hg)(3)(SCN)](-)[(n)Bu(4)N](+) has been isolated. An X-ray diffraction study of the complex has revealed that in the solid state it is polymeric and contains an infinite helical chain of alter nating (o-C6F4Hg)(3) molecules and thiocyanate anions. Every SCN- ion in the complex is bonded to the mercury atoms of two neighbouring mole cules of the macrocycle through the sulphur atom and forms with each o f these molecules two relatively short Hg...S bonds and one considerab ly longer Hg...S bond.