1,3,4,5-Tetramethyl-2-methyleneimidazoline—an ylidic olefin

Abstract

The ylidic properties of 1,3,4,5-tetramethyl-2-methyleneimidazoline 4, obtained by deprotonation of the pentamethylimidazolium ion 3, are revealed both by its physical and chemical properties; the X-ray structure of 4 is reported.

Syntheses and Structures of Molybdenum, Tungsten, and Manganese Complexes of a Cyclic Thiourea, [M(CO)5(SC3N2Me4)] (M = Mo, W) and [{CpMn(CO)2}2(μ‐SC3N2Me4)]

“…Thione, selone, and tellone, E=C(NiPr) 2 (CMe) 2 (E = S, Se, Te), react with [M(CO) 6 ] or [M(CO) 5 (thf)] to produce the corresponding mononuclear chalcogenoimidazoline complexes. [8] Chromium derivatives [Cr(CO) 5 {E=C(NiPr) 2 (CMe) 2 }] (11, E = S, Se, Scheme 4) were crystallographically characterized.…”

“…[1][2][3][4] NHCs also form various adducts with p-block element fragments to give compounds with a formula of E-C(NR) 2 (CRЈ) 2 , where E = BX 3 , AlX 3 , GeI 2 , SnCl 2 , CH 2 , S, Se, and so forth. [4,5] The sulfur adducts, imidazolinethiones (cyclic thioureas), are employed as precursors of NHCs. [6] They are also components of tris(mercaptoimidazolyl)hydroborate ligands, which attract considerable attention because of their facecapping character and strong electron-donating ability, and are applied to enzyme models.…”

Coordination Chemistry of Ene‐1,1‐diamines and a Prototype “Carbodicarbene”

“…[17] The C1À C6 and the C6ÀC7 bond lengths fall within the range for normal single bonds between sp 2 -and sp 3 -hybridized carbon atoms (1.478(3) and 1.495(3) , respectively), whereas the C7 À O1 bond (1.232(2) ) corresponds to a normal carbonyl group (Figure 3). [16] Notably, the aurated carbon atom in 8 is tetrahedrally coordinated, and hence represents a chiral center.…”

Ring Expansion of 2-Alkylidenedihydroquinolines to 2-Iminodihydro-1-benzazepines by Phenyl, Methanesulphonyl, and Trifluoromethanesulphonyl Azide[1]

“…[14] The reactivity of 2-alkylidene-N-heterocycles in 1,3-dipolar cycloaddition reactions with organic azides may be estimated on the basis of 13 C chemical shifts. [13] With this view, we have recorded the NMR spectra of a number of 2-alkylidenedihydroquinolines 2.…”