The homoleptic sandwich anion [Co(P2C2tBu2)2]-: a versatile building block for phosphaorganometallic chemistry

Phosphaalkynes (RC=P) are valuable starting materials for a wide range of low-coordinate phosphorus compounds.[1] Similar to alkynes,[2] these reactive, triply-bonded molecules oligomerize in the coordination sphere of transition metals to give diphosphacyclobutadienes, triphosphabenzenes, or higher oligomers.[1, 3] The reactions of phosphaalkynes with “vaporized” metal atoms are particularly intriguing, as illustrated by the reaction of cobalt atoms with tBuC=P which affords a mixture of three complexes (A–C) that are difficult to prepare by conventional synthetic methods.[4] Although fascinating compounds can be obtained by metal vapor (MV) synthesis,[5, 6] its applicability is limited due to the low product yields and the need for a special experimental setup.