Organoplatinum crystals for gas-triggered switches

Abstract

Considerable effort is being devoted to the fabrication of nanoscale devices¹. Molecular machines, motors and switches have been made, generally operating in solution^2,3,4,5,6,7, but for most device applications (such as electronics and opto-electronics), a maximal degree of order and regularity is required⁸. Crystalline materials would be excellent systems for these purposes, as crystals comprise a vast number of self-assembled molecules, with a perfectly ordered three-dimensional structure⁹. In non-porous crystals, however, the molecules are densely packed and any change in them (due, for example, to a reaction) is likely to destroy the crystal and its properties. Here we report the controlled and fully reversible crystalline-state reaction of gaseous SO₂ with non-porous crystalline materials consisting of organoplatinum molecules. This process, including repetitive expansion–reduction sequences (on gas uptake and release) of the crystal lattice, modifies the structures of these molecules without affecting their crystallinity. The process is based on the incorporation of SO₂ into the colourless crystals and its subsequent liberation from the orange adducts by reversible bond formation and cleavage¹⁰. We therefore expect that these crystalline materials will find applications for gas storage devices and as opto-electronic switches^11,12.