Linear uranium metallocenes with polydentate aromatic nitrogen ligands

Abstract

Treatment of [Cp*₂U(NCMe)₅]X₂ [Cp* = C₅Me₅, X = BPh₄ (1) or I (1′)] or Cp*₂UI₂ in acetonitrile with the polydentate aromatic nitrogen bases phen, terpy and R₄btbp led to the formation of the linear uranium metallocenes [Cp*₂U(NCMe)₃(phen)]X₂ [X = BPh₄ (2), I (2′)], [Cp*₂U(NCMe)₂(terpy)][BPh₄]₂ (4), [Cp*₂U(NCMe)(Me₄btbp)][BPh₄]₂ (5) and [Cp*₂U(NCMe)(CyMe₄btbp)][X]₂, [X = BPh₄ (6), I (6′)], [phen = 1,10-phenanthroline, terpy = 2,2′:6,2′′-terpyridine, Me₄btbp = 6,6′-bis-(3,3,6,6-tetramethyl-1,2,4-triazin-3-yl)-2,2′-bipyridine, CyMe₄btbp = 6,6′-bis-(3,3,6,6-tetramethyl-cyclohexane-1,2,4-triazin-3-yl)-2,2′-bipyridine]. The bent metallocene [Cp*₂U(phen)₂][BPh₄]₂ (3) was isolated from the reaction of 1 and two molar equivalents of phen in THF. The X-ray crystal structures of 2·2MeCN, 3·2THF, 4 and 6′·2MeCN were determined.