Abstract
In contrast to the extensively studied carboranes with even skeletal electron counts ([2n+2], [2n+4]), systems with odd electron counts ([2n+3]) are rare (n = number of skeletal atoms). With the assistance of a diphosphene-bridge, dicarborane dianions {[(Ar)NC((t)Bu)C(2)B(10)H(10)]P}(2)(2-) [Ar = Dipp (2) or Dmp (4); Dipp = 2,6-(i)Pr(2)C(6)H(3), Dmp = 2,6-Me(2)C(6)H(3)] with formal [2n+3] skeletal electrons in each carborane cage were obtained via single electron reduction of imine-stabilized carboranyl-phosphinidene or -diphosphene with potassium graphite (KC(8)) or cobaltocene (CoCp(2)), respectively. The delocalization of the two unpaired electrons across the carborane cages and diphosphene-bridge was evidenced by experimental and theoretical results.