Synthesis and characterization of thiosemicarbazone derivatives of 2-chloro-4-hydroxy-benzaldehyde and their rhenium(I) complexes

Núñez-Montenegro, Ara; Carballo, Rosa; Vázquez‐López, Ezequiel M.

doi:10.1016/j.poly.2009.09.002

Cited by 19 publications

(9 citation statements)

References 32 publications

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“…Therefore, we reasoned that, to obtain the pure compounds, one should start from the previously isolated adducts [ReX(HL)(CO) 3 ] because analysis of the crystal structure of [ReBr(κ 2 - S , N3 -HL B )(CO) 3 ] (Chart ) confirmed the formation of this type of complex, in which only the conformation of the C1–N2 bond has been inverted. As observed previously, ,,, these types of structures (conformers) are far from unknown, at least in rhenium(I) complexes. Although the production methods for these types of compounds involve relatively long reaction times at room or moderate temperatures (for instance, CHCl 3 under reflux), we observed that adduct formation with the ligands HL A/B is practically complete in 1 h in low-polarity solvents (acetone or chloroform).…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Novel Dinuclear N-Substituted 4-(Dimethylamino)benzaldehyde Thiosemicarbazonates of Rhenium(I): Formation of Four- and/or Five-Membered Chelate Rings, Conformational Analysis, and Reactivity

et al. 2020

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The reaction of fac-[ReX(CH3CN)2(CO)3] (X = Cl, Br) with N-phenyl-[4-(dimethylamino)benzaldehyde] thiosemicarbazone (HL A ) or N-4-methoxybenzyl-[4-(dimethylamino)benzaldehyde] thiosemicarbazone (HL B ) under controlled synthetic conditions gave 4 mononuclear [ReX(HL)(CO)3] (X = Cl, Br) and 16 dinuclear [Re2L2(CO)6] compounds. These complexes were obtained as single crystals, and their structures were established by X-ray diffraction. The structural study of these dimers showed the formation of several solvates, the presence of linkage isomerism, and the stabilization of four- and/or five-membered chelate rings. The different ligand coordination modes (a new μ-κ2-S,N2:κ-N3 coordination mode for a thiosemicarbazone ligand was observed), the conformation of the thiosemicarbazone chain in each case, the formal symmetry of the dimers, and the role of the synthetic procedure in the stability of the different chelate rings were analyzed and are discussed. Theoretical calculations in the gas phase were performed for the dimers with the HL A ligand in order to identify the thermodynamically most stable species. The behavior and structural stability of dimers in dimethyl sulfoxide and acetone solutions was investigated by 1H NMR spectroscopy. The strength of the ReI–L bond in solution was evidenced by the formation of [Re2(LNO2 )2(CO)6] and [Re(LA)(py)(CO)3] upon reaction of the corresponding dimer with concentrated nitric acid and pyridine, respectively.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Novel Dinuclear N-Substituted 4-(Dimethylamino)benzaldehyde Thiosemicarbazonates of Rhenium(I): Formation of Four- and/or Five-Membered Chelate Rings, Conformational Analysis, and Reactivity

et al. 2020

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“…[45] This behaviour seems to be a general feature, and it has also been observed in thiosemicarbazone analogs. [46][47][48][49][50] The corresponding signals are only slightly deshielded (0.2-0.30 ppm) for the complexes of the ligands L 3 and L 4 or they are completely unaffected, as in the rhenium complexes of L 5 and L 6 . These findings strongly support the conclusion that the observed solid-state structures with non-coordinated hydrazone groups are also present in solution.…”

Section: Nmr Studiesmentioning

confidence: 99%

Tricarbonyl Rhenium(I) and Technetium(I) Complexes with Hydrazones Derived from 4,5‐Diazafluoren‐9‐one and 1,10‐Phenanthroline‐5,6‐dione

et al. 2010

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Tricarbonylrhenium(I) and ‐technetium(I) halide (halide = Cl and Br) complexes of ligands derived from 4,5‐diazafluoren‐9‐one (df) and 1,10‐phenanthroline‐5,6‐dione (phen) derivatives of benzoic and 2‐hydroxybenzoic acid hydrazides have been prepared. The complexes have been characterized by elemental analysis, MS, IR, 1H NMR and absorption and emission UV/Vis spectroscopic methods. The metal centres (ReI and TcI) are coordinated through the nitrogen imine atoms and establish five‐membered chelate rings, whereas the hydrazone groups stand uncoordinated. The 1H NMR spectra suggest the same behaviour in solution on the basis of only marginal variations in the chemical shifts of the hydrazine protons.

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“…They have been evaluated over the last 50 years as antiviral, antibacterial, and anticancer therapeutics, and biological activities of them are a function of parent aldehyde or ketone moiety [2][3][4][5][6][7]. Thiosemicarbazone is an important group of multidentate ligands and usually coordinates with the metal through the imine nitrogen and sulfur atom [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Synthesis, spectroscopic characterization, crystal structures, and theoretical studies of (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone

et al. 2010

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Two thiosemicarbazones, (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone (24-MBTSC (1)) and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone (25-MBTSC (2)), derived from 2,4-dimethoxybenzaldehyde and 2,5-dimethoxybenzaldehyde, respectively, with thiosemicarbazide have been synthesized and their structures were characterized by elemental analyses, FT-IR, 1 H NMR spectroscopy, and X-ray single-crystal diffraction analysis. Molecular orbital calculations have been carried out for 1 and 2 by using an ab initio method (HF) and also density functional method (B3LYP) at 6-31G basis set. Compound 1 crystallizes in the monoclinic system, space group P2 1 /c, with a = 8.1342(5) Å , b = 18.1406(10) Å , c = 8.2847(6) Å , b = 109.7258(17)°, V = 1150.75(12) Å 3 , and Z = 4, whereas compound 2 crystallizes in the orthorhombic system, space group Pbca, with a = 11.0868(6) Å , b = 13.1332(6) Å , c = 15.9006(8) Å , V = 2315.2(2) Å 3 , and Z = 8. The compounds 1 and 2 displays a trans-configuration about the C=N double bond.

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Synthesis and characterization of thiosemicarbazone derivatives of 2-chloro-4-hydroxy-benzaldehyde and their rhenium(I) complexes

Cited by 19 publications

References 32 publications

Synthesis of Novel Dinuclear N-Substituted 4-(Dimethylamino)benzaldehyde Thiosemicarbazonates of Rhenium(I): Formation of Four- and/or Five-Membered Chelate Rings, Conformational Analysis, and Reactivity

Synthesis of Novel Dinuclear N-Substituted 4-(Dimethylamino)benzaldehyde Thiosemicarbazonates of Rhenium(I): Formation of Four- and/or Five-Membered Chelate Rings, Conformational Analysis, and Reactivity

Tricarbonyl Rhenium(I) and Technetium(I) Complexes with Hydrazones Derived from 4,5‐Diazafluoren‐9‐one and 1,10‐Phenanthroline‐5,6‐dione

Synthesis, spectroscopic characterization, crystal structures, and theoretical studies of (E)-2-(2,4-dimethoxybenzylidene)thiosemicarbazone and (E)-2-(2,5-dimethoxybenzylidene)thiosemicarbazone

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