Cyclometallation of bis-benzimidazole derivatives with rhodium(III) halides

Gayathri, V.; Leelamani, E.G.; Gowda, N. M. Nanje; Reddy, G.K.N.

doi:10.1016/s0277-5387(99)00129-1

Cited by 18 publications

(11 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As part of our continuing research in the field of syntheses of nitrogencontaining heterocyclic ligands and their metal complexes with palladium and rhodium, 3 we are reporting here the synthesis and crystal structure of 6-pyridyl-5,6-dihydrobenzo [4,5]…”

mentioning

confidence: 99%

See 1 more Smart Citation

Crystal Structure of 6-Pridyl-5,6-dihydrobenzo[4,5]-imidazo[1,2-c]quinazoline

et al. 2004

View full text Add to dashboard Cite

The N-heterocycles are of considerable importance in view of their presence in several biological systems. Benzimidazole derivatives and their metal complexes exhibit anti-bacterial, veterinary, anti-helmintic, insecticidal and virucidal activities. 1 Multidentate N-heterocycles produce organized supramolecules on coordination to metal ions and they appear quite promising for the design of stable light conversion devices. 2In this direction, some of the multidentate N-heterocycles and their complexes have been prepared and characterized. As part of our continuing research in the field of syntheses of nitrogencontaining heterocyclic ligands and their metal complexes with palladium and rhodium, 3 we are reporting here the synthesis and crystal structure of 6-pyridyl-5,6-dihydrobenzo [4,5]The synthesised ligand was characterized by physical, spectral and single crystal X-ray structural analyses.o-Aminophenylbenzimidazole (0.05 mol: 10.45 g) was dissolved in 200 ml of alcohol. To this, 2-pyridylinaldehyde (0.05 mol; 4.75 g) was added, and the mixture was refluxed for 4 -5 hours. The chemical structure is as shown in Fig. 1. A yellow compound was obtained. It was concentrated under reduced pressure. The solid was recrystallized from methanol to get a pure compound. A suitable crystal for X-ray analysis was grown by the slow evaporation method using methanol as solvent.A single crystal of the title ligand of dimensions 0.2 × 0.4 × 0.5 mm was chosen for X-ray diffraction studies. The measurements were made on a Rigaku AFC7S diffractometer with graphite-monochromated radiation (Mo Kα). The data were collected using the ω-2θ scan technique and reduced using the teXsan data reduction program. 4 Lorentz and polarization corrections were applied. The structure was solved by direct methods and refined by a full-matrix least squares method with anisotropic temperature factors for the non-H atoms. All the H atoms were placed at chemically acceptable positions and were refined with isotropic temperature factors. The experimental crystallographic details are given in Table 1.The final coordinates and equivalent thermal parameters of non-H atoms are listed in Table 2. Table 3 gives the bond distances and angles of non-hydrogen atoms. The bond distances and bond angles are in good agreement with the standard values. The title compound C19H12N4 was synthesised and the structure was investigated by X-ray crystallography. It crystallizes in the monoclinic space group P21/c with cell parameters a = 8.697(9)Å, b = 13.045(10)Å, c = 13.271(4)Å, β = 97.38(4)å nd Z = 4. The final residual factor is 0.0628.

show abstract

mentioning

confidence: 99%

“…The data were collected using the ω-2θ scan technique and reduced using the teXsan data reduction program. 4 Lorentz and polarization corrections were applied. The structure was solved by direct methods and refined by a full-matrix least squares method with anisotropic temperature factors for the non-H atoms.…”

mentioning

confidence: 99%

Crystal Structure of 6-Pridyl-5,6-dihydrobenzo[4,5]-imidazo[1,2-c]quinazoline

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Transition metal complexes based on nitrogen heterocycles with benzimidazole rings have been studied extensively [1][2][3][4][5]. Some of the Cu(II) complexes show good catalytic activity, particularly toward the synthetically important oxidation of substituted phenols [6].…”

Section: Introductionmentioning

confidence: 99%

Liquid-phase catalytic oxidation of organic substrates by a recyclable polymer-supported copper(II) complex

Shilpa

Gayathri

2013

Transition Met Chem

View full text Add to dashboard Cite

Chloromethylated polystyrene beads crosslinked with 6.5 % divinylbenzene were functionalized with 2-(2 0 -pyridyl) benzimidazole (PBIMH) and on subsequent treatment with Cu(OAc) 2 in methanol gave a polymersupported diacetatobis(2-pyridylbenzimidazole)copper(II) complex [PS-(PBIM) 2 Cu(II)], which was characterized by physicochemical techniques. The supported complex showed excellent catalytic activity toward the oxidation of industrially important organic compounds such as phenol, benzyl alcohol, cyclohexanol, styrene, and ethylbenzene. An effective catalytic protocol was developed by varying reaction parameters such as the catalyst and substrate concentrations, reaction time, temperature, and substrateto-oxidant ratio to obtain maximum selectivity with high yields of products. Possible reaction mechanisms were worked out. The catalyst could be recycled five times without any metal leaching or much loss in activity. This catalyst is truly heterogeneous and allows for easy work up, as well as recyclability and excellent product yields under mild conditions.

show abstract

“…Other studies have illustrated how tripodal (N-heterocyclic alkyl)amine ligand design influences the geometry of the complexes and the internal exchange processes between isomers. [3,4] Gayathri et al [5,6] prepared a series of cyclometallated rhodium complexes with 1,3-bis(benzimidazolyl)benzene. The conventional 13 C NMR experiment takes longer time to detect the cyclometallated carbon because of sensitivity problem and also due to poor solubility of metal complexes in the desired solvents.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of rhodium(III) complexes with tris/tetrakis‐benzimidazoles and benzothiazoles—quick identification of cyclometallation by nuclear magnetic resonance spectroscopy

Chandrashekhar

Gayathri

Gowda

2009

Magnetic Reson in Chemistry

View full text Add to dashboard Cite

] (X = Cl, Br, I). Elemental analysis, IR and 1 H nuclear magnetic resonance (NMR) chemical shifts supported the binuclear nature of the complexes. Cyclometallation was detected by conventional 13 C NMR spectra that showed a doublet around ∼190 ppm. Cyclometallation was also detected by gradient-enhanced heteronuclear multiple bond correlation (g-HMBC) experiment that showed cross-peaks between the cyclometallated carbon and the central benzene ring protons of 1-3. Cyclometallation was substantiated by two-dimensional 1 H-1 H correlated experiments (gradiant-correlation spectroscopy and rotating frame Overhauser effect spectroscopy) and 1 H-13 C single bond correlated two-dimensional NMR experiments (gradient-enhanced heteronuclear single quantum coherence). The 1 H-15 N g-HMBC experiment suggested the coordination of the heterocycles to the metal ion via tertiary nitrogen.

show abstract

Cyclometallation of bis-benzimidazole derivatives with rhodium(III) halides

Cited by 18 publications

References 25 publications

Crystal Structure of 6-Pridyl-5,6-dihydrobenzo[4,5]-imidazo[1,2-c]quinazoline

Crystal Structure of 6-Pridyl-5,6-dihydrobenzo[4,5]-imidazo[1,2-c]quinazoline

Liquid-phase catalytic oxidation of organic substrates by a recyclable polymer-supported copper(II) complex

Synthesis of rhodium(III) complexes with tris/tetrakis‐benzimidazoles and benzothiazoles—quick identification of cyclometallation by nuclear magnetic resonance spectroscopy

Contact Info

Product

Resources

About