Titanium complexes with imidazolin-2-iminato ligands

Abstract

The reaction of 1,3-di-tert-butylimidazolin-2-ylidene with trimethylsilyl azide furnishes the corresponding N-silylated 2-iminoimidazoline which reacts with titanium(IV) chlorides to yield imidazolin-2-iminato titanium complexes.

Novel N-heterocyclic ylideneamine gold(i) complexes: synthesis, characterisation and screening for antitumour and antimalarial activity

“…Alkylation of the resulting neutral product with CF 3 SO 3 Me and subsequent deprotonation with KH (as for II and III) gave the neutral ligand I in good yield. Strict temperature control during the execution of the final deprotonation step proved crucial in all instances.…”

“…X-ray structure elucidation of a single crystal isolated from a crystallisation mixture of II aided in identifying the byproduct as 3-methyl-2-(3-methyl-3H-benzothiazol-2-ylideneamino)benzothiazol-3-ium trifluoromethanesulfonate (IV †), the result of a condensation reaction which entails the loss of ammonia. Compounds similar to this dimeric byproduct have been prepared by Deligeorgiev and Gadjev 14 by treating 3-methyl-3H-benzothiazol-2-ylideneamine derivatives with HX, where X = CH 3 SO 3 -, ClO 4 -, Br -or I -. The highly hygroscopic ligands I-III are soluble in water and organic solvents such as alcohols, dichloromethane, DMSO, THF, acetone or diethyl ether, but insoluble in alkanes such as n-pentane and n-hexane.…”

“…This arises from the reactivity of such complexes towards thiols, enabling the formation of strong protein bonds to AuPR 3 , which in turn prevents gold(I) phosphines from reaching their intracellular targets.…”

“…Replacement of the PR 3 moiety in phosphazenes with an N-heterocyclic carbene (NHC) was an initiative that exploited the striking electronic similarities between the electron rich trialkylphosphines and NHC's. 3 In contrast to the phosphazenes, their ylideneamine counterparts are less susceptible to oxidation and may be regarded as superior in terms of stability.…”

“…Neutral phosphazene ligands, R 3 P NH, can be readily prepared by the acid catalysed reactions of N-silylized phosphazenes R 3 P NSiMe 3 , with i-propanol or methanol, or by deprotonation of the corresponding aminophosphonium salts, [R 3 P NH 2 ]Cl using sodium amide. These ligands are, however, thermally sensitive and prone to oxidation in the presence of water affording related phosphorane oxides.…”