Infrared and Raman studies of heterocyclic compounds—II Infrared spectra and normal vibrations of benzimidazole and bis-(benzimidazolato)-metal complexes

Cordes, Marcia; Walter, J. L.

doi:10.1016/0584-8539(68)80165-5

Cited by 107 publications

(43 citation statements)

References 24 publications

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“…A broad band at ca 176 cm 1 is tentatively attributed to the N-Fe-N bending mode. 10,19 In addition, the broad band of H 2 O in the region of 3000-3400 cm 1 in spectrum (c) is clearly weaker than that in spectrum (f), indicating that the competitive adsorption of imidazole molecules results in a small number of water molecules adsorbed on the Fe electrode. Figure 3 illustrates the SERS spectra of imidazole in a basic solution of pH 11.…”

Section: In the Sers Spectrum (C) This Indicates Neutral Molecumentioning

confidence: 97%

Surface‐enhanced Raman scattering of imidazole adsorbed on an iron surface

Wang

Shi

Yang

et al. 2002

J Raman Spectroscopy

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The adsorption of imidazole on a roughened polycrystalline iron electrode was investigated by the SERS technique at pH values of neutral, 11 and 14 and compared with those from each solution. The results indicated that imidazole was adsorbed as mainly the neutral form and/or a certain amount of ylide form on the Fe surface in a neutral solution. The molecules have maximum adsorption at −0.9 V potential with tilted or perpendicular orientation with respect to the Fe surface, whereas a face-on orientation of imidazole was favored at both more cathodic and anodic potentials. In a weaker basic solution imidazole was also adsorbed on the Fe surface as the neutral form, and took a face-on orientation with respect to the Fe surface at all measured potentials because of its weaker adsorption than that in a neutral solution. Neutral and anionic forms of imidazole on the Fe surface were indicated by SERS at pH 14.

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Section: In the Sers Spectrum (C) This Indicates Neutral Molecumentioning

confidence: 97%

Surface‐enhanced Raman scattering of imidazole adsorbed on an iron surface

Wang

Shi

Yang

et al. 2002

J Raman Spectroscopy

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“…It is pertinent that square nickel complexes of the imidazoles (1, 16) also have bands in the 400 cmregion which may be vNi-N in origin. A normal coordinate analysis of the square planar bis-(imidazolinato)nickel(II) has been reported (17) and a band at 445 cm-I assigned to the nickel nitrogen stretching mode. Our own work (18) with an extensive series of metal ethylenediamine complexes, also suggests that this mode should be sought near 400 cm-'.…”

Section: Square Planar Nickel(i1) Complexesmentioning

confidence: 99%

Cobalt(II) and nickel(II) complexes of some bidentate imidazoline ligands. Stereochemically dependent derealization in the imidazoline rings

Lever¹,

Ramaswamy²,

Simonsen³

et al. 1970

Can. J. Chem.

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Tetrahedral and octahedral cobalt(II), and square and octahedral nickel(I1) complexes of 1,2-bis(2'-imidazolin-2'-yl)benzene, 1,2-bis(2'-imidazolin-2'-yl)ethane, and some imidazoline ring methyl substituted ligands are reported. The structures are confirmed by three X-ray structural analyses, magnetism, and electronic and vibrational (conventional and far i.r.) spectroscopy. Both cis and trans octahedral complexes of the type M(ligand)z(NCS)z [M = Co(II), Ni(II)] have been characterized, and none of these exhibit splitting of the v(CN)(NCS) absorption in the i.r. spectrum at room temperature. Low temperature studies reveal splitting of the v(CN) band in the cis isomers. Both 13C and I5N satellite absorption is identified. The delocalization of the double bond in the imidazoline rings in these complexes is discussed in terms of the i.r. and X-ray data.Canadian Journal of Chemistry, 48, 3076 (1970) We report here the metal complexing ability calibrant. The U.V. spectra were recorded with a Cary 14 of some novel bidentate ligands containing spectrometer and molecular weight data with a modified Gallenkamp Model 7665K semi-micro ebulliometer, imidazoline rings.the coordination calibrated with azobenzene and with benzoic acid. Infrachemistry of imidazole and its derivatives has red and far i.r. data were obtained with a Beckman IR 12 been extensively investigated (1, 2), studies of its spectrometer, and magnetic susceptibilities, via the Gouy dihydro derivative are restricted to the chemistry method with an Alpha 4 in. magnet calibrated with of 2,2,-bi-2-imidazoline (3). since the dihydro mercury cobalt tetrathiocyanate. Low temperature electronic and vibrational data were obtained with a Beckman ligand is somewhat simpler than imidazole, being V L T -~ Variable Temperature Cell, with quartz (elecnon-aromatic, it was thought that a study of its tronic), o r NaCl (i.r.) windows. Microanalyses were metal complexing ability might prove rewarding. substituted derivative (4, LME) were synthesized TO 1,3-diiminoisoindoline (6) (7.25 g, 0.05 mole) disby the phosphorus pentasulfide catalyzed reaction solved in boiling absolute ethanol, was added ethyleneof ethylenediamine (or 1,2-propanediamine) with diamine (6.2 g, 0.1 mole) and the mixture refluxed until phthalodinitrile or succinonitrile, a standard evolution of ammonia had ceased. The bulk of the solvent was removed by distillation at reduced pressure until route for the preparation Of imidazolines (4). crystallization occurred. The white crystalline product The ethane derivative LE has been reported (5) (6.1 g, 60% yield) was recrystallized from benzene. T h e but the other ligands were previously unknown. pure product melted at 174-175". Reaction of the parent ligands with cobalt and Method B (Based on (7)) nickel salts in alcohol led to the isolation of a 0-Dicyan~benzene (6.4 g, 0.05 mole), ethylenediamine series of square, tetrahedral, and octahedral (6.2 g, 0.1 mole), and a catalytic amount of phosphorus pentasulfide (20 mg) were mixed together. Upon applicacomp...

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“…All would be infrared active. It is difficult to identify the in- plane bending modes in either benzimidazole of its simple salts; probably NH bending is mixed into several modes (4). The bands at 1232 and 1383 cm-l of the simple cation, which appear to shift to 1245 cm-I and 1410 cm-I in the complex, and which are much weaker in the Raman than the infrared spectrum, are possible candidates.…”

Section: Resultsmentioning

confidence: 99%

Complex hydrogen bonded cations. The benzimidazole benzimidazolium cation

Borah¹,

Wood²

1976

Can. J. Chem.

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B. BORAH and J. L. WOOD. Can. J. Chem. 54, 2470 (1976). The complex salts (Bz2H)+Y-, BZ = benzimidazole, Y = PFs-or BF4-have been identified in solution. and the molecularitv of the fluoroborate. which has been crvstallised. confirmed gravimetrically. Infrared and ~i m a n spectra, together with those of thideuterated systems, indicate a similar structure in solution and the crystal, viz., an asymmetric single minimum bridging proton potential, in conformity with the X-ray structure, proving that the pronounced doublet observed in the V, band of the H bridged system is not due to proton tunnelling. The origin of the asymmetric structure is discussed.On a identifiC en solution les sels complexes (Bz2H)+Y-, Bz = benzimidazole, Y = PF6-.ou BF4-et on a confirm6 gravimktriquement la mol6cularit6 du fluoroborate qui a kt6 cristallisC. Les spectres infrarouges et Raman de ces complexes de mCme que ceux des systkmes deutCrCs correspondants indiquent que la structure est similaire en solution et a l'Ctat cristallin savoir la prCsence d'un potentiel asymktrique, comportant un pont de proton et un seul minimum; ceci est en accord avec la structure dCduite de rayon-X; ces rksultats prouvent que le doublet prononce observe dans la bande v, du systkme hydrogkne pontC n'est pas due h un effet tunnel du proton. On discute de I'origine de la structure asymktrique.[Traduit par le journal] Introduction tained. The spectra of the crystalline complex The vibrational spectra of solutions containing and of the complex in solution are discussed in both benzimidazole and its cation show many this report, and the crystal structure reported in indications of complexing between these species. the accompanying paper. A preliminary account In particular the V, (NH stretching) infrared of the present results has been given (3). band has a notable doublet contour, which is replaced by a single band in the D bridged species, a behaviour similar to that in many other (BHB)+ complexes involving heterocyclic bases. However, although this has often been taken as a characteristic consequence of proton tunnelling in a double minimum potential (1), such a cause of the v, band doubling in the complexes previously examined was rejected, since several other spectroscopic features do not tally with this model. Instead, an asymmetric single minimum potential for the hydrogen bond (on the vibrational time scale) was proposed (2). Previous attempts to obtain a direct check on this inference by crystallisation of the complexes and consequent structure determination have met the difficulty that solutions containing the complex yielded crystals of either the base or the free salt. However, crystals of the complex benzimidazole salt suitable for X-ray analysis have been ob-

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Infrared and Raman studies of heterocyclic compounds—II Infrared spectra and normal vibrations of benzimidazole and bis-(benzimidazolato)-metal complexes

Cited by 107 publications

References 24 publications

Surface‐enhanced Raman scattering of imidazole adsorbed on an iron surface

Surface‐enhanced Raman scattering of imidazole adsorbed on an iron surface

Cobalt(II) and nickel(II) complexes of some bidentate imidazoline ligands. Stereochemically dependent derealization in the imidazoline rings

Complex hydrogen bonded cations. The benzimidazole benzimidazolium cation

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