Azomethine derivatives. Part X. 1,1,3,3-Tetramethylguanidine adducts of trimethylaluminium, triethylaluminium, and aluminium trichloride: dimethyl-, diethyl-, and dichloro-bis(dimethylamino)methyleneamino-aluminium

Abstract

The adducts (Me,N),C:NH,AIX, (X = Me or Et), from (Me,N),C:NH + 3 (or more) AI,X6 in hexane, are monomeric in dilute benzene solution and are believed to have a structure co-ordinated through the imino-nitrogen. They lose XH when heated, forming [(Me,N),C:NAIX,J,. for which four-membered ring structures are suggested. Although the adduct (Me,N),C:NH,AICI, does not similarly afford [(Me2N),C:NAICI,], when heated, the latter can be prepared from (Me,N),C:NLi and AICI,.1.r. spectroscopic details are given for all these new compounds.Also discussed are the l H n.m.r. spectra of the alkylaluminium compounds and the mass spectra of (Me,N),C:NH,-AICI, and [(Me,N),C:NAlEt,],.1,1,3,3-TETRAMETHYLGUANIDINE (Me,N),C:NH (I) has three potential donor sites of two distinct types, vix., the two dimethylamino-nitrogens and one imino-nitrogen.The object of this study of its interaction with some aluminium compounds was to investigate whether incorporating other potential donor sites in a molecule containing the imino-group )C=NH affected the manner of its interaction with aluminium Lewis acids. In an earlier study using diphenylketimine Ph2C:NH, ad-

Application of neutral amidines and guanidines in coordination chemistry

“…and trivalent Cr. Until the late 1990s further work was sporadic, with reports of TMG adducts of AlX 3 (X = Me, Et, Cl) 54 and an example of a technetium nitride complex referred to at the time as a "rare example of TMG coordination". 55 In response to the need for better control over metal mediated chemical processes, further developments in the design of guanidines as ligands have been implemented.…”

Three asymmetric guanidinato metal complexes: Synthesis, crystal structures and their use as pre-catalysts in the Meerwein–Ponndorf–Verley reduction

“…Guanidinato [(NR) 2 C(NR 0 2 ) À ] (R, R 0 = alkyl, aryl, silyl, etc) ligands are related to amidinates by substitution of the central C-R substituent by an amino group [1]. Since the appearance of the first transition metal guanidinate prepared by Lappert's group in 1970 [2], the monoanionic ligands have been attracted considerable attention as their excellent steric and electronic tunability by changing various groups.…”

Guanidinate anions and dianions. Reactions involving alkylguanidines, (RNH)2CNR (R = i-Pr or Cy), and metal amido complexes M(NMe2)5 (M = Ta or Nb)

“…1 This interest has been partly motivated by the rather limited application of guanidinates in transition metal chemistry. 2, 3 We are particularly interested in the application of N,NЈ,NЉ-trialkylguanidines as ligands due to their ability to yield dianionic species by deprotonation of a second N-H function (Scheme 2). The resultant species could function as a diamido ligand and may exhibit π delocalization (Y conjugation) of the lone pairs on the sp 2 hybridized nitrogen centers (I) making it an analogue of the trimethylenemethane dianion.…”