Two-electron reductive reactivity of trivalent uranium tetraphenylborate complexes of (C 5Me 5) 1− and (C 5Me 4H) 1−

Abstract

The reductive reactivity of the (BPh 4) 1− ligand in pentamethylcyclopentadienyl [(C 5Me 5) 2U][(μ-η 2:η 1-Ph) 2BPh 2] ( 1) was compared with that of the tetramethyl analog, [(C 5Me 4H) 2U][(μ-η 6:η 1-Ph)(μ-η 1:η 1-Ph)BPh 2] ( 2) using PhSSPh as a probe to determine if the mode of (BPh 4) 1− bonding affected the reduction. Both complexes act as two-electron reductants to form (C 5Me 4R) 2U(SPh) 2 [R = Me, 3; H, 4], but only in the R = H case could the product be crystallographically characterized. An improved synthesis of 1 from [(C 5Me 5) 2UH] 2 ( 5) and [Et 3NH][BPh 4] is also reported as well as its reaction with MeCN that provides another route to the unusual, parallel-ring, uranium metallocene [(C 5Me 5) 2U(NCMe) 5][BPh 4] 2 ( 6).