Alfuth Jan, Jeannin Olivier, Fourmigué Marc
Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes), 35000, Rennes, France.
Department of Organic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, 80-233, Gdańsk, Poland.
Angew Chem Int Ed Engl. 2022 Sep 5;61(36):e202206249. doi: 10.1002/anie.202206249. Epub 2022 Jul 27.
The face-to-face association of (E)-1,2-di(4-pyridyl)ethylene (bpen) molecules into rectangular motifs stabilized for the first time by chalcogen bonding (ChB) interactions is shown to provide photoreactive systems leading to cyclobutane formation through single-crystal-to-single-crystal [2+2] photodimerizations. The chelating chalcogen bond donors are based on original aromatic, ortho-substituted bis(selenocyanato)benzene derivatives 1-3, prepared from ortho-diboronic acid bis(pinacol) ester precursors and SeO and malononitrile in 75-90 % yield. The very short intramolecular Se⋅⋅⋅Se distance in 1-3 (3.22-3.24 Å), a consequence of a strong intramolecular ChB interaction, expands to 3.52-3.54 Å in the chalcogen-bonded adducts with bpen, a distance (<4 Å) well adapted to the face-to-face association of the bpen molecules into the reactive position toward photochemical dimerization.
（E）-1,2-二（4-吡啶基）乙烯（bpen）分子通过硫族元素键（ChB）相互作用首次稳定形成矩形基序的面对面缔合，被证明可提供光反应体系，通过单晶到单晶的[2+2]光二聚反应导致环丁烷形成。螯合硫族元素键供体基于原始的芳香族邻位取代双（硒氰酸酯）苯衍生物1-3，由邻二硼酸双（频哪醇）酯前体与SeO和丙二腈制备，产率为75-90%。1-3中非常短的分子内Se⋅⋅⋅Se距离（3.22-3.24 Å）是强烈分子内ChB相互作用的结果，在与bpen形成的硫族元素键加合物中扩展到3.52-3.54 Å，该距离（<4 Å）非常适合bpen分子面对面缔合到光化学二聚反应的反应位置。
