A computational approach to seeking methylmercury(II) thiolate calix(4)arene hosts for both octasulfur and organosulfur compounds as guests

Calculations have been carried out on the conformational preferences of calix[4]arene thiols and their methylmercury(II) derivatives. Calculations have also been carried out on host–guest combinations of methylmercury(II) ethanethiolate calix[4]arenes and 1,4-dithiacyclohexane, octasulfur, thiacyclopropane, and thiophene. For the 1,4-dithiacyclohexane, thiacyclopropane, and thiophene guests, calculations have been carried out for both 1:1 and 1:4 ratios of the methylmercury(II) ethanethiolate calix[4]arene to the sulfur containing guests. For octasulfur only the 1:1 host–guest ratio has been considered because it has four sulfurs that are conformationally arranged to bind to the four mercury(II) centers. The computational results generally show that host–guest formation is enthalpically favored over the separated molecules in cases where adducts with mercury-sulfur donor atom interactions are allowed to reach energy minima.Key words: calixarene, methylmercury, octasulfur, organosulfur compounds.