6-Aminofulvene-2-aldimine, a novel class of ambidentate cyclopentadienyl/diimine ligand: synthesis and characterisation of magnesium complexes

Abstract

Two magnesium complexes of the 6-aminofulvene-2-aldimine (AFA) system bearing cyclohexyl groups on the donor nitrogen atoms have been synthesised; in the first the ligand is coordinated via the two nitrogen donors while in the second it is found to ligate magnesium via the cyclopentadienyl and the imine donors.

Unexpected Formation and Structural Characterization of a Dinuclear Sodium Half-Sandwich Complex

“…The same coordination mode was established for some 6-aminofulvene-2-aldiminate complexes of palladium [27,28], copper [29,30] and zinc [27], while the η 5 -coordination mode as a cyclopentadienyldiimine has been found in some AFA complexes of ruthenium [27,31]. Notably, two magnesium complexes of the AFA ligand system bearing cyclohexyl groups at the nitrogen atoms have been reported, in which both coordination modes have been realized [32]. Deprotonation of N,N′-dicyclohexyl-6-aminofulvene-2-aldimine (HCy2AFA) with MeLi followed by reaction with MeMgBr afforded the N,N′-coordinated complex [ [1,2C5H3-N,N′]MgMe(THF)] with an uncoordinated cyclopentadienyl ring.…”

“…In all these compounds, the 6-aminofulvene-2-aldiminate anion acts as a As a consequence of this resonance, a 6-aminofulvene-2-aldiminate ligand can coordinate to a metal atom in a chelating mode through the two imine nitrogen donors as a fulvenealdiminate (A) or in an η 5 -mode as a cyclopentadienyldiimine. Complexes of this ligand system have been reported for some main group metals, as well as first and second row transition metals [25][26][27][28][29][30][31][32]. Closer investigation of the coordination chemistry of 6-aminofulvene-2-aldiminate ligands began in 1998 with the discovery of a straightforward synthesis of the C-phenyl-substituted precursor C 5 H 3 [1,2-C(Ph)NH] 2 H based on the reaction of magnesocene with benzonitrile.…”

Bis(tert-butyl isocyanide-κC)[4-fluoro-N-({2-[N-(4-fluorophenyl)carboximidoyl]cyclopenta-2,4-dien-1-ylidene}methyl)anilinido-κ2N,N′]copper(I)

“…The diimine-substituted cyclopentadienyl 6-aminofulvene-2aldimines (AFAs) have recently attracted attention as ligands for a variety of metals because of both their similarity to well established ligand systems, such as -diketiminate, aminotroponiminate or anilidoiminate ligands (Willcocks et al, 2011;Bailey et al, 2003Bailey et al, , 2007Bailey et al, , 2010, and their ability to bind to metal centres via the diimine donor groups or via the cyclopentadienyl unit (Bailey et al, 2003(Bailey et al, , 2007.…”

Unprecedented double migratory insertion of phenyl isocyanide into cyclopentadienyl C–H bonds

“…The molecular structure of 2 (Fig. 1) shows a three coordinate (the two arms of the AFA ligand and the carbon atom of a phenylisocyanide ligand) trigonal planar coordination geometry about 21 which is presumably a reflection of both the trigonal coordination geometry in 2 and larger ionic radii of Cu(I). Complex, 2 represents a rare example of a metal complex of the AFA ligand system, 21,22 despite the fact that AFA derivatives have been know since 1963 [23][24][25] and are related to both the N,N¢-disubstituted amino-troponimate 26,27 and b-diketiminate ligand systems.…”