Boron and transition metal compounds derived from 2-uroylbenzimidazole

Fialon, Marie‐Pierre; Garcı́a-Báez, Efrén V.; Andrade‐López, Noemí; Osorio‐Monreal, Guadalupe; Canseco-Melchor, Graciela; Velázquez‐Montes, Imelda; Barba-Behrens, Noráh; Contreras, Rosalinda

doi:10.1002/(sici)1098-1071(1999)10:7<577::aid-hc11>3.0.co;2-s

Cited by 14 publications

(2 citation statements)

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“…In all cobalt coordination compounds v(C=N) shifts to higher frequencies (1514-1600 Cobalt(Ill)Coordination Compound of Ethyl 4-Methyl-5-Imidazolecarboxylate cm), due to the coordination of the imidazole nitrogen atom N3 to the metal ion. In the spectra of [Co(emizco)2C12] and [Co(emizco)2Br2].H20 the v(C=O) band is splitted and shifted to higher energy (1730 and 1690 cm) indicating that the ligands are not coordinated to Co 2+ by the ester oxygen atoms, only by the heterocyclic nitrogen, as has been previously observed for analogous cobalt(II) imidazolic compounds, [24,25]. On the other hand, for [Co(emizco)2(H20)](NO3)2.2H20, the ester bands were shifted to ca.…”

Section: Resultsmentioning

confidence: 51%

Cobalt(II) Coordination Compounds of Ethyl 4‐Methyl‐5‐Imidazolecarboxylate: Chemical and Biochemical Characterization on Photosynthesis and Seed Germination

King-Dı́az

Montes-Ayala

Escartín-Guzmán

et al. 2005

Bioinorganic Chemistry and Applications

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In this work we present the synthesis, structural and spectroscopic characterization of Co2+ coordination compounds with ethyl 4-methyl-5-imidazolecarboxylate (emizco). The effects of emizco, the metal salts CoCl2.6H2O, CoBr2, Co(NO3)2.6H2O and their metal coordination compounds [Co(emizco)2Cl2], [Co(emizco)2 Br2].H2O, [Co(emizco)2 (H2O)2(NO2)2.2H2O were evaluated on photosynthesis in spinach chloroplasts. Seed germination and seedling growth of the monocotyledonous species Lolium multiflorum and Triticum aestivum and the dicotyledonous species Trifolium alexandrinum and Physalis ixocarpa were also assayed under the effect of the compounds and salts. The results showed that cobalt(II) salts and their emizco coordination compounds inhibit photosynthetic electron flow and ATP-synthesis, behaving as Hill reaction inhibitors. Coordination compounds are more potent inhibitors than the salts. It was found that the salts target is at the b6f level while the complexes targets are at QB(D1)-protein and b6f level. The QB inhibition site was confirmed by variable chlorophyll a fluorescence yield. On the other hand, emizco inhibits seed germination, root and shoot development, in both weed and crop species. Cobalt(II) coordination compounds are the most effective photosynthesis inhibitors, but they are less potent than emizco in germination and seedling growth, while the metal salts are the least active of all.

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Section: Resultsmentioning

confidence: 51%

Cobalt(II) Coordination Compounds of Ethyl 4‐Methyl‐5‐Imidazolecarboxylate: Chemical and Biochemical Characterization on Photosynthesis and Seed Germination

King-Dı́az

Montes-Ayala

Escartín-Guzmán

et al. 2005

Bioinorganic Chemistry and Applications

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“…Our research has been focused on polyfunctional aromatic molecules bearing labile protons and nitrogen or oxygen atoms as basic sites, which can be used as ligands for transition metal atoms and as starting materials for polycyclic molecules. [8][9][10][11][12][13][14][15][16] The reaction of dimethyl-N-(5-chloro-2-benzoxazolyl)dithiocarbonimidate (2) with sodium o-aminophenolate in DMF afforded compound 1. The bis-heterocycle 1 is an aromatic nitrogenated heterocycle with lone pairs, one acidic proton and a planar delocalized system.…”

Section: Introductionmentioning

confidence: 99%

Structural Analysis and Coordination Compounds of [(1,3‐Benzoxazol‐2‐yl)‐(5‐chloro‐1,3‐benzoxazol‐2‐yl)]amine

Téllez¹,

Ramírez-Trejo²,

Vieto-Peña³

et al. 2013

Zeitschrift anorg allge chemie

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A novel [(1,3-benzoxazol-2-yl)-(5-chloro-1,3-benzoxazol-2yl)]amine (L) (1) compound was synthesized. The molecule has a nitrogen atom between 1,3-benzoxazol-2-yl and 5-chloro-1,3-benzoxazol-2-yl groups. For compound 1 there are twelve possible conformers and tautomers. Ab initio calculations were performed in order to investigate the more stable structures. Three crystals of compound Materials and Methods: All chemicals were reagent grade: methanol (J. T. Baker), 2-amino-5-chloro-benzoxazole (Aldrich); NaOH, CS 2 , CH 3 I, DMF, THF, Co(CH 3 CO 2 ) 2 ·4H 2 O, and Ni(CH 3 CO 2 ) 2 ·4H 2 O. They were used without further purification. Melting points were determined with an Electrothermal 9100 apparatus. FAB mass spectra were obtained with a Jeol model SX-102 spectrometer. Elemental analyses were carried out with a Fisions Instruments EA-1108. An FT IR spectrometer (Perkin-Elmer Model 1605) was used for obtaining IR spectra of solid samples in KBr pellets (4000-400 cm -1 ). The UV/ Vis/NIR spectra (diffuse reflectance) were recorded with a Varian Cary 5E spectrophotometer. NMR spectra were recorded with a VARIAN model Unity Inova (300 and 400 MHz) or a Bruker-Avance-DPX 300 by using [D 6 ]DMSO or CDCl 3 as solvent. Magnetic susceptibility measurements were performed on pulverized samples at room temperature with a Johnson Matthey DG8 5HJ balance. X-ray single crystal data for 1a, 1b, and1c were collected with a KAPPA-CCD area detector diffractometer. The crystal structures were determined and refined with the SHELXS97 and Crystals programs. [18,19] Ab initio cal-[(1,3-Benzoxazol-2-yl)-(5-chloro-1,3-benzoxazol-2-yl)]amine culations were performed in order to obtain the minimum energy structure for the twelve tautomers and conformers of compound 1 using the Gaussian 98 package. [20] Geometries were checked to be the minimal by means of the frequency analysis.

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