ИСТИНА

Recently some of us demonstrated that a number of zinc(II) malonates containing 1,2-bis(pyridin-4-yl)ethylene undergo a photoinitiated [2+2] cycloaddition reaction in a single-crystal-to-single-crystal manner. Here, we present the results of our study of a novel photo-sensitive zinc(II) coordination complex containing two unsaturated fragments, namely, 1,2-bis(pyridin-4-yl)ethylene (bpe) and 2-allylmalonate (2-Amal). This complex was obtained from aqueous solution of zinc(II) acetate, 2-allylmalonic acid (H2Amal) and 1,2-bis(pyridin-4-yl)ethylene (bpe). Ethylene fragments of 2-allylmalonate and bpe are in the reactive positions (Figure, top). At irradiation for 8 hours the complex underwent [2+2] cycloaddition in a single-crystal-to-single-crystal manner to form a 2-((2,3-di(pyridin-4-yl)cyclobutyl)methyl)malonate (Figure, bottom). As both compounds are 3D coordination polymers, the process is the 3D → 3D reaction. The conversion rate was 50% in respect to 2-Amal. Further irradiation was accompanied by destruction of the single crystal and formation of an insoluble reaction product.