1 -Methylimidazole, complexes with

Jay. J.L Padgett. C.W. Walsh, R.D.B. Hanks, T.W. Pennington, W.T. Noncovalent interactions in 2-mercapto-1-methylimidazole complexes with organic iodides. Cryst. 

In the complex with two methylimidazol units one of them is N-coordinated and the other a C-coordinating carbene ligand. It seems that in the synthesis of this complex a homoleptic rearrangement of the QFs precursor complex is accompanied by a rapid migration of the proton nitrogen to the initially coordinated carbon. 

Varying ratios of the ligands 7V-(2-thiophenyl)-2,5-dimethylpyrrole and V-methylimidazole were used to form tetrahedral zinc complexes with S4, S3N, and S2N2 coordination spheres. X-ray structural analyses and IR spectra were recorded for all compounds and the relevance to zinc finger proteins was discussed. The comparison to cobalt and cadmium structures showed only minor differences, supporting the theory that changes on substituting these metals into zinc proteins would be minor.538... 

The metal ion, e.g. Fe or Co, when in its lower oxidation state can share electron charge with the oxygen molecule adduct. Several iron and cobalt prophyrin derivatives and cobalt-Schiff bases show the necessary reversibility and rates for successful application [e.g. 23]. a, a, a", a" -weso-tetrakis[(o-piralamidophenyl)-po phinato] Co (II) has been complexed with 1-methylimidazole to make a complex (CoPIm) which, when mixed with polybutyl methacrylate gave oxygen permeabilities on the order of 10-9 sec-cm/(cm2-s-cmHg) with a selectivity of about 5 over nitrogen [23]. 

Correlations between pK,d values and the equilibrium constants for the formation of iodine complexes with imidazoles suggest that the charge transfer complexes are of the /j-type involving donation of the unshared electron pair at N-3. For examples of K and pK3 values are imidazole, 202, 6.95 1-methylimidazole, 333, 7.33 4-phenylimidazole, 152, 6.10 4,5-diphenylimidazole, 141, 5.90 (83BSB923). 

An 15NNMR study of the complexation of l-methylimidazole-15N2 with Zn(N03)2 and Cd(N03)2 has been made.438... 

A second important breakthrough was in the acetylation step. With 1 -methylimidazole as the catalyst, complete acetylation can be achieved without removing the borate formed from sodium borohydride in the prior reduction step (Blakeney et al., 1983 Harris et al., 1988). Borate complexes with ds-diol groups in the monosaccharides. In earlier methods (Albersheim et al., 1967 Selvendran etal., 1979), the borate had to be removed or acetylation would not go to completion (Wolfram and Thompson, 1963). The reduction and acetylation reactions are summarized in Figure E3.2.2. 

The tautomer 82c of 3-methylimidazole, however, was found in the 1 1 complex with rac-17. X-ray structure analysis of the above inclusion complex showed that molecules of 82c act as hydrogen-bond donors and acceptors between two dimeric assemblies of binaphthyl molecules (Scheme 2). Methyl groups are located in the vicinity of the dimeric host. However, steric hindrance of this methyl group is less important for the energetics of crystal construction than formation of two hydrogen bonds. 

---