Engineering solid-state photoreactivity within silver(I) organosulfonate complexes containing an ester-functionalized reactant molecule

The formation, structure, and photoreactivity of a pair of silver(I) complexes based upon either trifluoromethanesulfonate [Ag(CF3SO3)] or p-toluenesulfonate [Ag(C7H7SO3)] anions along with the ester-based reactant molecule trans-1-(4-methylbenzoate)-2-(4-pyridyl)ethylene (1) are reported. In both complexes, silver(I) ions form coordinated covalent bonds to the 4-pyridyl group on the olefin containing reactant molecule and due to either argentophilic interactions or close packing of a pair of silver(I) ions ultimately places a pair of carbon-carbon bonds (C = C) on neighboring molecules of 1 in a suitable position to undergo a solid-state [2 + 2] cycloaddition reaction. In particular, the complexes [Ag(CF3SO3)(1)2]·CH3CN and [Ag2(C7H7SO3)2(1)4] both undergo a quantitative photoreaction to yield the head-to-head photoproduct rctt-1,2-bis(4-methylbenzoate)-3,4-bis(4-pyridyl)cyclobutane (2) upon exposure to ultraviolet light.