Crystalline Divinyldiarsenes and Cleavage of the As=As Bond |
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| Authors: | Dr Mahendra K Sharma Dr Sebastian Blomeyer Beate Neumann Dr Hans-Georg Stammler Priv-Doz?Dr Rajendra S Ghadwal |
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| Institution: | Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany |
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| Abstract: | The first divinyldiarsenes {(NHC)C(Ph)}As]2 (NHC=IPr 3 a , SIPr 3 b ; IPr=C{(NAr)CH}2; SIPr=C{(NAr)CH2}2; Ar=2,6-iPr2C6H3) are reported. Compounds 3 a and 3 b were prepared by the reduction of corresponding chlorides {(NHC)C(Ph)}AsCl2 (NHC=IPr 2 a , SIPr 2 b ) with Mg. Calculations revealed a small HOMO–LUMO energy gap of 3.86 ( 3 a ) and 4.24 eV ( 3 b ). Treatment of 3 a with (Me2S)AuCl led to the cleavage of the As=As bond to restore 2 a , which is expected to proceed via the diarsane {(IPr)C(Ph)}AsCl]2 ( 4 ). Remarkably, 4 as well as 2 a can be selectively accessed on treatment of 3 a with an appropriate amount of C2Cl6. Moreover, 3 a readily reacts with PhEEPh (E=Se or Te) at room temperature to give {(IPr)C(Ph)}As(EPh)2 (E=Se 5 a ; Te 5 b ), revealing the cleavage of As=As and E?E bonds and the formation of As?E bonds. Such highly selective stepwise oxidation ( 3 a → 4 → 2 a ) and bond metathesis ( 3 a → 5 a , b ) reactions are unprecedented in main-group chemistry. |
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| Keywords: | arsenic double bond main-group elements pi conjugation vinyl |
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