Copper(II) complexes with 1,5-bis(2-hydroxybenzaldehyde)carbohydrazone

Dragancea, Diana; Shova, Sergiu; Enyedy, Éva A.; Breza, Martin; Rapta, Peter; Carrella, Luca M.; Rentschler, Eva; Dobrov, Anatolie; Arion, Vladimir B.

doi:10.1016/j.poly.2014.03.039

Cited by 9 publications

(3 citation statements)

References 45 publications

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“…Ditopic ligands based on the carbohydrazide fragment linked with pyridine, carboxylate, and oxime functional groups display coordination versatility and lead to various structural motifs. − The polydentate Schiff base ligand 1,5-bis(salicylidene)carbohydrazide (H 4 L) that resulted from a condensation reaction between 2-hydroxybenzaldehyde and carbohydrazide provides two different binding sites, ONN and ONO, to accommodate metal ions. Thus, dioxidomolybdenum(VI), diorganotin(IV), nickel(II), and copper(II) complexes have been reported. − In all of these compounds, the ligand acts as a trianion, in contrast to its thioanalogue, which also can be stabilized in metal complexes as a tetraanion …”

Section: Introductionmentioning

confidence: 99%

Vanadium(V) Complexes with Substituted 1,5-bis(2-hydroxybenzaldehyde)carbohydrazones and Their Use As Catalyst Precursors in Oxidation of Cyclohexane

Dragancea

Talmaci

Shova³

et al. 2016

Inorg. Chem.

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Six dinuclear vanadium(V) complexes have been synthesized: NH4[(VO2)2((H)LH)] (NH4[1]), NH4[(VO2)2((t-Bu)LH)] (NH4[2]), NH4[(VO2)2((Cl)LH)] (NH4[3]), [(VO2)(VO)((H)LH)(CH3O)] (4), [(VO2)(VO)((t-Bu)LH)(C2H5O)] (5), and [(VO2)(VO)((Cl)LH)(CH3O)(CH3OH/H2O)] (6) (where (H)LH4 = 1,5-bis(2-hydroxybenzaldehyde)carbohydrazone, (t-Bu)LH4 = 1,5-bis(3,5-di-tert-butyl-2-hydroxybenzaldehyde)carbohydrazone, and (Cl)LH4 = 1,5-bis(3,5-dichloro-2-hydroxybenzaldehyde)carbohydrazone). The structures of NH4[1] and 4-6 have been determined by X-ray diffraction (XRD) analysis. In all complexes, the triply deprotonated ligand accommodates two V ions, using two different binding sites ONN and ONO separated by a diazine unit -N-N-. In two pockets of NH4[1], two identical VO2(+) entities are present, whereas, in those of 4-6, two different VO2(+) and VO(3+) are bound. The highest oxidation state of V ions was corroborated by X-ray data, indicating the presence of alkoxido ligand bound to VO(3+) in 4-6, charge density measurements on 4, magnetic susceptibility, NMR spectroscopy, spectroelectrochemistry, and density functional theory (DFT) calculations. All four complexes characterized by XRD form dimeric associates in the solid state, which, however, do not remain intact in solution. Compounds NH4[1], NH4[2], and 4-6 were applied as alternative selective homogeneous catalysts for the industrially significant oxidation of cyclohexane to cyclohexanol and cyclohexanone. The peroxidative (with tert-butyl hydroperoxide, TBHP) oxidation of cyclohexane was performed under solvent-free and additive-free conditions and under low-power microwave (MW) irradiation. Cyclohexanol and cyclohexanone were the only products obtained (high selectivity), after 1.5 h of MW irradiation. Theoretical calculations suggest a key mechanistic role played by the carbohydrazone ligand, which can undergo reduction, instead of the metal itself, to form an active reduced form of the catalyst.

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Section: Introductionmentioning

confidence: 99%

Vanadium(V) Complexes with Substituted 1,5-bis(2-hydroxybenzaldehyde)carbohydrazones and Their Use As Catalyst Precursors in Oxidation of Cyclohexane

Dragancea

Talmaci

Shova³

et al. 2016

Inorg. Chem.

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“…When the configuration of this kind of ligand is S-trans, it acts in a hexadentate fashion. In this case, the formation of a dinuclear complex with a -N,N bridge is generally observed, for example in a dinuclear copper(II) complex (Dragancea et al, 2014). The S-cis-enol configuration leads to the formation of square-grid complexes by directed ISSN 2056-9890 self-assembly (Bikas et al, 2015;Sow et al, 2013;Li et al, 2014).…”

Section: Chemical Contextmentioning

confidence: 98%

“…The free dicarbonohydrazide exhibits biological activities (Bacchi et al, 1999;Kothari & Sharma, 2010), which are increased upon complexation with certain transition metals (Wu et al, 2009;Bikas et al, 2015). The synthesis of high nuclearity complexes of transition metals derived from these types of ligands are highly targeted because of their magnetic (Sow et al, 2013;Zhang et al, 2014a;Dragancea et al, 2014), catalytic (Bikas et al, 2015), biological (Zhang et al, 2014) and optical (Easwaran potti et al, 2007) properties. Recently, our research group synthesized a new tetranuclear grid complex [Zn 4 (HL 1 ) 4 ](NO 3 ) 4 Á2H 2 O where H 2 L 1 is 1,5-bis[1-(pyridin-2yl)ethylidene)carbonohydrazide].…”

Section: Chemical Contextmentioning

confidence: 99%

Diaquabis{μ-1,5-bis[(pyridin-2-yl)methylidene]carbonohydrazide(1–)}di-μ-chlorido-tetrachloridotetrazinc(II)

Seck¹,

Gaye²,

Ndoye³

et al. 2020

Acta Cryst E

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A tetranuclear ZnII complex, [Zn4(C13H11N6O)2Cl6(H2O)2] or {[Zn2(HL)(H2O)(Cl2)](μCl)2[Zn2(HL)(H2O)(Cl)]}2, was synthesized by mixing an equimolar amount of a methanol solution containing ZnCl2 and a methanol solution containing the ligand H2 L [1,5-bis(pyridin-2-ylmethylene)carbonohydrazide]. In the tetranuclear complex, each of the two ligand molecules forms a dinuclear unit that is connected to another dinuclear unit by two bridging chloride anions. In each dinuclear unit, one ZnII cation is pentacoordinated in a N2OCl2 in a distorted square-pyramidal geometry, while the other ZnII cation is hexacoordinated in a N3OCl2 environment with a distorted octahedral geometry. The basal plane around the pentacoordinated ZnII cation is formed by one chloride anion, one oxygen atom, one imino nitrogen atom and one pyridine nitrogen atom with the apical position occupied by a chloride anion. The basal plane of the hexacoordinated ZnII cation is formed by one chloride anion, one hydrazinyl nitrogen atom, one imino nitrogen atom and one pyridine nitrogen atom with the apical positions occupied by a water oxygen atom and a bridged chloro anion from another dinuclear unit, leading to a tetranuclear complex. A series of intramolecular C—H...Cl hydrogen bonds is observed in each tetranuclear unit. In the crystal, the tetranuclear units are connected by intermolecular C—H...Cl, C—H...O and N—H...O hydrogen bonds, forming a planar two-dimensional structure in the ac plane.

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Water-induced isomerism of salicylaldehyde and 2-acetylpyridine mono- and bis-(thiocarbohydrazones) improves the antioxidant activity: spectroscopic and DFT study

Assaleh

Božić

Bjelogrlić³

et al. 2019

Struct Chem

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Copper(II) complexes with 1,5-bis(2-hydroxybenzaldehyde)carbohydrazone

Cited by 9 publications

References 45 publications

Vanadium(V) Complexes with Substituted 1,5-bis(2-hydroxybenzaldehyde)carbohydrazones and Their Use As Catalyst Precursors in Oxidation of Cyclohexane

Vanadium(V) Complexes with Substituted 1,5-bis(2-hydroxybenzaldehyde)carbohydrazones and Their Use As Catalyst Precursors in Oxidation of Cyclohexane

Diaquabis{μ-1,5-bis[(pyridin-2-yl)methylidene]carbonohydrazide(1–)}di-μ-chlorido-tetrachloridotetrazinc(II)

Water-induced isomerism of salicylaldehyde and 2-acetylpyridine mono- and bis-(thiocarbohydrazones) improves the antioxidant activity: spectroscopic and DFT study

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