Synthesis and crystal structure of [Cs([2.2.2]crypt)]2[Mo(CO)5]

Abstract

Reduction of the heteroleptic metal carbonyl complex Mo(CO)3(η5-Cp)H with the metallic salt Cs5Bi4 in the presence of [2.2.2]crypt (= 4,7,13,16,21,24-hexa\xadoxa-1,10-di\xadaza\xadbicyclo\xad[8.8.8]hexa\xadcosa\xadne) in liquid ammonia led to single crystals of bis\xad[(4,7,13,16,21,24-hexa\xadoxa-1,10-di\xadaza\xadbicyclo\xad[8.8.8]hexa\xadcosa\xadne)caesium] penta\xadcarbonyl\xadmolybdate, [Cs(C18H36N2O6)]2[Mo(CO)5] or [Cs([2.2.2]crypt)]2[Mo(CO)5]. The twofold negatively charged anionic complex corresponds to the 18 valence electron rule. It consists of an Mo atom coordinated by five carbonyl ligands in a shape inter\xadmediate between trigonal–bipyramidal and square-pyramidal. The Mo—C distances range from 1.961\u2005(3) to 2.017\u2005(3)\u2005A, and the C≡O distances from 1.164\u2005(3) to 1.180\u2005(4)\u2005A.