Spectral and XRD studies on perchlorate salts of several Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes from 1-methyllumazine and 1,6,7-trimethyllumazine

Acuña-Cueva, Esther R.; Faure, R.; Illán‐Cabeza, Nuria A.; Jiménez‐Pulido, Sonia B.; Moreno‐Carretero, Miguel N.

doi:10.1016/s0277-5387(02)01085-9

Cited by 14 publications

(7 citation statements)

References 27 publications

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“…The second angle corresponds to the bite angle of the rigid chelating lumazine moiety. The Cu−O(4) bond distance of 2.449 Å is much longer than the usual values in lumazine derivatives complexes, ,, which allows us to define the geometry as tetrahedral with considerable trigonal planar distortion (“3 + 1”) with N(5), N(61), and S(63) in the basal plane and O(4) weakly coordinated in the apical position; in agreement with this, the sum of the angles S(63)−Cu−N(61), N(61)−Cu−N(5), and N(5)−Cu−S(63) (357.6°) is clearly closer to the expected value for a trigonal-planar configuration (360°) than the ideal value for a tetrahedron (328.5°). The Cu···Cu distance (2.876(2) Å) is almost equal to the sum of the van der Waals radius of copper (2.8 Å), indicating a minimum interaction between two copper atoms …”

Section: Resultssupporting

confidence: 64%

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

et al. 2008

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The synthesis and characterization of the first thiosemicarbazone-lumazine (TSCLMH=the thiosemicarbazone of 6-acetyl-1,3,7-trimethyllumazine) hybrid ligand is reported. The influence of the conformation of this compound on its energy and the atomic contribution to the molecular orbitals have been theoretically investigated. Ni(II), Cu(I), Zn(II), and Cd(II) complexes of this ligand have been synthesized and characterized by elemental analysis, thermogravimetric studies, IR, 1H, 13C, and 15N NMR, and UV-vis-NIR spectroscopy, magnetic measurements, and X-ray crystallography. Four types of coordination modes for the ligand may be predicted: (a) double bidentate; (b) tetradentate; (c) tridentate; (d) bidentate. Structures of representative complexes of types a, b, and d have been determined by X-ray crystallography. In the [Cu(TSCLMH)]2(ClO4)2 complex, TSCLMH acts as a doubly bidentate bridging ligand forming a dimer with a Cu...Cu distance of 2.876 A. The geometry around the metal ion is trigonally distorted tetrahedral with a relatively long (four-atom) bridge between the metal centers instead of the shorter, mainly single atom, bridges present in other thiosemicarbazone derivatives complexes. In the [Cd(NO3)2(TSCLMH)(EtOH)] complex, the metal ion displays eight-coordinated geometry with the TSCLMH ligand acting in a tetradentate planar fashion and two nitrate anions, one monodentate and the other bidentate. The coordination polyhedron in [Cd(TSCLM)2(H2O)].MeOH.2H2O is a square pyramid with two monoanionic ligands acting as bidentate NS donors and a water molecule completing the coordination sphere. Fluorescence spectroscopic properties of TSCLMH have been studied as well as the changes in position and intensity of fluorescence bands caused by the complexation with different metal ions (Ni2+, Cu+, Zn2+, Cd2+).

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Section: Resultssupporting

confidence: 64%

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

et al. 2008

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“…On the basis of the above experimental evidence, we proposed that 2 would favorably coordinate with metal ions by the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring, and the thiazole nitrogen of benzothiazole ring in a terdentate manner leading to the formation of five-membered chelate ring . The change in the photophysical properties of 2 both in the absence or presence of metal ions and relatively strong complexation between 2 and Hg 2+ /Cu 2+ in 2:1/1:1 stoichiometry, respectively, can be easily understood by assuming 2 as a planar terdentate molecule and by assuming that the resulting 2 + Cu 2+ and 2 + Hg 2+ complexes would be able to attain either a distorted square pyramidal and/or octahedral structure, respectively, in the medium, as depicted in Scheme . The proposed mode of interaction with both the metal ions would be nearly close to that observed in the crystals of different complexes reported by Kurahashi et al…”

Section: Resultsmentioning

confidence: 99%

Chromo and Fluorogenic Properties of Some Azo-Phenol Derivatives and Recognition of Hg²⁺ Ion in Aqueous Medium by Enhanced Fluorescence

Misra

Shahid

2010

J. Phys. Chem. C

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Azo-phenol based receptors, having an azo core incorporated with naphthol and substituted (-H, -NO 2 , -CH 3 , and -OCH 3 ) benzothiazole units have been synthesized and their detailed optical properties have been investigated in different media. The nitro substituted azo derivative, 2, has shown, categorically, promising optical behavior in the absence as well as presence of different transition metal ions in aqueous-acetonitrile solution and has illustrated greater sensitivity, using the "naked-eye" for the detection of Hg 2+ ion by enhanced fluorescence. The mechanism of metal-ion interaction has been established by absorption, emission, FT-IR, and 1 HNMR spectroscopic experiments that indicated favorable coordination of Hg 2+ metal ion by the phenolic oxygen atom, the azo nitrogen atom adjacent to the naphthol ring, and the thiazole nitrogen of benzothiazole ring, obviously in a terdentate manner leading to the formation of a five-membered chelate ring. The 2:1 stoichiometry and association constants, K assoc (abs.) ) 1.04 ( 0.3 × 10 5 M -2 and K assoc (em.) ) 1.51 × 10 5 M -2 have been estimated with the help of Job's plot and the Benesi-Hildebrand method. The cis-trans isomerism and azo-hydrazone type of tautomerism by the photoinduced proton transfer reaction and also metal induced (Hg 2+ ion) proton transfer reaction from the hydrazone form in the present organic molecular systems have been confirmed by photoirradiation and fluorescence excitation experiments and by 1 H and 13 C NMR spectral analysis.

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“…Emizco cobalt(II) and nickel(II) nitrate compounds showed a similar structure [18,19]. This is a very common geometry for this kind of compounds [30][31][32][33][34] while cis-coordinated H 2 O molecules have been rarely observed [35]. The bond length Cu-O6 = 2.5198(15) Å observed in 5 indicates that this bond is weaker than in compound 2, but similar to 3 and 4.…”

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Crystal structure, solid state and solution characterisation of copper(II) coordination compounds of ethyl 5-methyl-4-imidazolecarboxylate (emizco)

Montes-Ayala

Escartín-Guzmán

Castillo‐Blum

et al. 2005

Journal of Inorganic Biochemistry

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Spectral and XRD studies on perchlorate salts of several Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes from 1-methyllumazine and 1,6,7-trimethyllumazine

Cited by 14 publications

References 27 publications

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

Chromo and Fluorogenic Properties of Some Azo-Phenol Derivatives and Recognition of Hg²⁺ Ion in Aqueous Medium by Enhanced Fluorescence

Crystal structure, solid state and solution characterisation of copper(II) coordination compounds of ethyl 5-methyl-4-imidazolecarboxylate (emizco)

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Spectral and XRD studies on perchlorate salts of several Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) complexes from 1-methyllumazine and 1,6,7-trimethyllumazine

Cited by 14 publications

References 27 publications

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

Versatile Coordinative Abilities of a New Hybrid Pteridine−Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties

Chromo and Fluorogenic Properties of Some Azo-Phenol Derivatives and Recognition of Hg2+ Ion in Aqueous Medium by Enhanced Fluorescence

Crystal structure, solid state and solution characterisation of copper(II) coordination compounds of ethyl 5-methyl-4-imidazolecarboxylate (emizco)

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Chromo and Fluorogenic Properties of Some Azo-Phenol Derivatives and Recognition of Hg²⁺ Ion in Aqueous Medium by Enhanced Fluorescence