Benzimidazole complexes

One of the limitations of Co(II) benzimidazole complexes is their limited availability related to a multistep synthetic procedure for the ligand. Almost... 

In extended X-ray absorption fine structure (EXAFS) studies of urease, Hasnain, Piggott, and co-workers (33, 34) demonstrated that spectra were similar to those of benzimidazole complexes, consistent... 

Benzimidazole and 2-substituted benzimidazoles form 4 1 complexes with NbCl5 which precipitate from THF solution and behave as 1 1 electrolytes in DMF.585 A band at 1639 cm-1 in the i.r. spectra of the benzimidazole complex is assigned to v(C=N) it is 26 cm -1 higher than in free benzimidazole, in accord with co-ordination of the ligand through its azomethine nitrogens only this is supported by the retention... 

EXAFS studies (Hasnain and Piggott, 1983 Alagna et al., 1984) have shown that the spectrum of urease is similar to those of benzimidazole complexes (Fig. 5-2) suggesting that the nickel is coordinated by histidine nitrogen and oxygen ligands. 

The deoxo reaction, performing the reduction of dioxygen with hydrogen, usually catalysed by a noble metal catalyst, was also reported to occur with NaY encapsulated complexes of Cu(embelin) (18) and 2-aminobenzimidazole (19).[134] The Cu(embelin) complex entrapped in NaY is a stable catalyst, that showing enhanced activity compared with the homogeneous case and may be reused many times, the corresponding benzimidazole complex is deactivated rapidly. 

Support for the above conclusions was also obtained from an analysis of the Cd NMR and solid state MAS spectra of the five, six, and seven coordinate cadmium texaphyrin complexes 116, 156, and 157, respectively [70]. From the solid-state MAS results, a single tensor was observed for the five-coordinate complex 116 with a corresponding isotropic chemical shift of 194 ppm. The MAS spectrum of a complex prepared in the presence of pyridine, however, revealed two tensors, presumed to be due to a mixture of six and seven coordinate species. Based upon the isotropic chemical shifts and the symmetry of the tensors the six coordinate species was assigned to the isotropic shift at 188 ppm and the seven coordinate species assigned to the isotropic shift at 221 ppm. The MAS spectrum of the benzimidazole complex of cadmium texaphyrin consists of only a single... 

Benzimidazole was iodinated at the 2-position to form a copper-benzimidazole complex 246 by treatment with Cul and KI in aqueous ammonium hydroxide (Scheme 59) <2005CE0514>. 

M. Kawahara, J. Morita, M. Rikukawa, K. Sanui, and N. Ogata. Synthesis and proton conductivity of thermally stable polymer electrolyte Poly(benzimidazole) complexes with strong acid molecules. Electrochimica Acta 45, 1395-1398 2000. 

Group 11. Paramagnetic (1H, 15N) NMR spectra were used to study a Cu -IDA (=iminodiacetic acid) complex localised on a protein surface. H and 13C NMR spectra were reported for copper(II) bis-benzimidazole complexes.1225 Variable temperature H NMR spectra of copper complexes of p-octafluorinated triarylcorroles reveal a thermally-accessible paramagnetic excited state, i.e. a Cu11 corrole 7i-cation radical.1226 Copper(II) forms of stellacyanin from Rhus vernicifera were characterised by H NMR.1227... 

As briefly described in O Sect. 18.2.3.2, soft-donor extractants have potential for selective separation of trivalent actinide ions. To understand the difference in extraction between Am " and trivalent lanthanide elements, Yaita et al. (2001) studied Am and Nd complexes with N-donor ligand benzimidazole by EXAFS. Although they found slight difference in the coordination number of water molecules and in the distance, Yaita et al. concluded that the coordination structure of Am - benzimidazole complexes is almost similar to that of Nd " complexes. 

D. Zhang, L. Yan, Probing the acid-base equilibrium in acid-benzimidazole complexes by H NMR spectra and density functional theory calculations, J. Phys. Chem. B 114 (2010) 12234-12241. 

Xu, L. Huang, Z.-H. Sandoval, C. A. Gu, L.-Q- Huang, Z.-S. Asymmetric hydrogenation of 3,5-bistrifluoromethyl acetophenone in pilot scale with industrially viable Ru/diphosphine-benzimidazole complexes. Org. Process Res. Dev. 2014,18,1137-1141. 

Fig. 3.3 NMR spectra of the acid-benzimidazole complexes in DMSO-de. The numbers 3, 4, and 5 highlight the shifts for H of the same numbers in...

The same type of rearrangement has been observed for the square-planar benzimidazole complex, [Ni(Bimd)4][N03]2-2.5C2H50H. Upon heating, the ethanol of crystallization is lost and coordination of the nitrate counterions occurs to yield the octahedral complex, [Ni(N03)2(Bimd)4]. 

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