Macrocyclic Complexes of Niobium(III): Synthesis, Structure, and Magnetic Behavior of Mononuclear and Dinuclear Species That Incorporate the [P2N2] System

详细信息    查看全文

• 作者：Michael D. Fryzuk ; Christopher M. Kozak ; Michael R. Bowdridge ; Weichang Jin ; Dean Tung ; Brian O. Patrick ; and Steven J. Rettig
• 刊名：Organometallics
• 出版年：2001
• 出版时间：August 20, 2001
• 年：2001
• 卷：20
• 期：17
• 页码：3752 - 3761
• 全文大小：141K
• 年卷期：v.20,no.17(August 20, 2001)
• ISSN：1520-6041

文摘

The coordination chemistry of the two mixed donor macrocyclic ligands ^R[P₂N₂] (where^R[P₂N₂] = RP(CH₂SiMe₂NSiMe₂CH₂)₂PR, R = cyclohexyl (Cy) or phenyl (Ph)) with niobium(III) is presented. The reaction of the dilithio precursors ^R[P₂N₂]Li₂(S) (R = Cy, S = THF; R= Ph, S = 1,4-dioxane) with NbCl₃(DME) (DME = 1,2-dimethoxyethane) generates thecomplexes ^R[P₂N₂]NbCl (R = Cy, 1; R = Ph, 2). For R = Cy, single-crystal X-ray diffractionstudies and variable-temperature magnetic susceptibility measurements indicate that 1 ismononuclear in the solid state; however, analogous variable-temperature magnetic datasuggest that 2 is dinuclear in the solid state due to the observation of antiferromagneticexchange. In solution, 2 is apparently monomeric similar to 1. Adduct formation betweenthese mononuclear complexes is also evident; reaction of 2 with neutral donors andcoordinating solvents produces the mononuclear derivatives ^Ph[P₂N₂]NbCl(L) (L = py, CO,PMe₃, THF, MeCN), of which the pyridine adduct, 3e, has been characterized crystallographically. Subsequent replacement of the chlorides can be achieved to generate theparamagnetic alkyl complexes ^R[P₂N₂]NbR' (R = Cy, Ph; R' = CH₂SiMe₃, CH(SiMe₃)₂). Therepresentative compounds ^Cy[P₂N₂]NbCH₂SiMe₃ (4a) and ^Ph[P₂N₂]NbCH(SiMe₃)₂ (5b) havebeen characterized by X-ray crystallography.