An entry to half-sandwich complexes of first row transition metals (Ni, Co, Mn) containing the Kläui tripodal ligand, LOMe: synthesis and crystal structures of oligomeric, [LOMeM(μ-X)(L)]n (n = 2, 4), and monomeric complexes, LOMeM(L2)(X)

Abstract

A series of half-sandwich complexes of Ni, Co and Mn containing the Kläui tripodal ligand L_OMe [κ³-(η⁵-C₅H₅)Co{P(O)(OCH₃)₂}₃] are prepared by reaction of the labile precursors, L_OMeM(L)(κⁿ-NO₃) [M = Ni, Co; L = acetone (1, n = 2), PPh₃ (2, n = 2), κ²-bipy (8, n = 1), κ²-tmeda (9, n = 1)] and [L_OMeMn(py)(μ-NO₃)]₂ (15), with anionic N- and O-nucleophiles. Oligomeric complexes are formed from complexes 1, 2, and 15via elimination of the κ¹-ligands (L). Reactions with NaN₃ and sodium aryloxide (NaOAr) afford the tetrameric μ₃-azido complexes, [L_OMeM(μ₃-N₃)]₄ (3), and the dimeric μ-aryloxo complexes, [L_OMeM(μ-OAr)(X)]₂ (5, 6: Ar = 2,6-Me₂-C₆H₃, 2,4,6-Me₃-C₆H₂, 2- and 4-NO₂-C₆H₄, C₆F₅; X = none, ROH), respectively, but the sandwich complexes (L_OMe)₂M result from reactions with other O-nucleophiles such as NaOH, NaOR, and NaOAr [Ar = C₆H₅, 4-MeC₆H₄, 2,6-X₂-C₆H₃ (X = F, Cl)]. Mononuclear complexes L_OMeM(κ²-L)(κ¹-NO₃) 8 and 9 are obtained by treatment of 1 or 2 with bidentate ligands and further converted to L_OMeM(κ²-L)-X-type azido (10, 11), halo (12), aryloxo (13) and MeCN-coordinated cationic complexes (14).