Thermal studies of some purine compounds and their metal complexes

Masoud, Mamdouh S.; El-Merghany, A.; Ramadan, Ahmed M.; El-Kaway, Marwa Y. Abd

doi:10.1007/s10973-010-0722-z

Cited by 28 publications

(19 citation statements)

References 28 publications

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“…While the positive values of Δ G * showed that the reaction included in the decomposition process is non‐spontaneous. Table indicates large negative values of entropy (Δ S *), suggesting that the transition states are more ordered in a less random molecular configuration than the reactants. Also, a fraction appeared in the calculated order of reactions ( n ) confirming that the reactions proceed in a complicated manner …”

Section: Resultsmentioning

confidence: 92%

Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

Emam

Abouel‐Enein

Abouzayed

2017

Applied Organom Chemis

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Z)-5-((1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)diazenyl)-6hydroxy-2-mercaptopyrimidin-4(3H)-one (H 3 L) was exploited as a ligand for the synthesis of a series of metal complexes, where the metal was Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cr(III) and Ru(III). The structural features of the ligand and the synthesized complexes were characterized using various analytical, spectral and thermal measurements. Infrared spectra showed that the ligand coordinates to all metal ions in a neutral keto-enol-thiol manner. It behaves in a tetradentate fashion in all binuclear complexes except the Cr(III) complex, where it is hexadentate, and in a tridentate fashion in mononuclear complexes. The azo group participates in chelation only in the case of binuclear complexes. All complexes exhibit octahedral geometry except Pd(II) and Cu(II) acetate which are square planar and square pyramidal, respectively. Kinetic parameters were computed from thermal decomposition data. Axial electron spin resonance spectra were obtained for Cu(II) complexes indicating (d x 2 −y 2 ) 1 as a ground state with small g || values affording strong interaction between the ligand and metal ions. The biological measurements reveal that the ligand has antioxidant activity relative to the metal complexes, while the metal complexes have cytotoxicity in comparison to the free ligand. KEYWORDSantioxidant and anticancer activity, azodye ligand, metal complexes, spectral methods, thermal studies

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Section: Resultsmentioning

confidence: 92%

Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

Emam

Abouel‐Enein

Abouzayed

2017

Applied Organom Chemis

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“…The thermogravimeteric analysis curves allowed us to establish the temperature below which the characterized compound has a constant weight and which begins to decompose and how far the decomposition reaction can proceed [18]. The observed and stoichiometric decreases in weight of the substance make it possible to estimate an intermediate product which is formed during decomposition and at what temperature occasionally the temperature rang where this intermediate has constant weight.…”

Section: Thermal Decompositionmentioning

confidence: 99%

Biological Study of Transition Metal Complexes with Adenine Ligand

Hasan

Yahiya

Hassan

et al. 2019

The 23rd International Electronic Conference on Synthetic Organic Chemistry

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Adenine complexes were prepared with some of the first series transition metals in a stoichiometric ratio of 1: 2 (M n+ : L), where M n+ = Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ , and Cd 2+ ions. The Complexes were characterized by the physicochemical and spectroscopic techniques as electric conductivity, metal contents, IR, UV-Visible, and molar conductance techniques. The stoichiometric ratios of the synthesized complexes were confirmed by using molar ratio method. The dissociation constant of adenine ligand was determined spectrophotometrically. Solvent effect on the electronic spectra of the adenine ligand was examined using solvents with different polarities. The biological activity of adenine ligand and its metal complexes were tested in vitro against some selected species of fungi and bacteria. The results showed a satisfactory spectrum against the tested organisms.

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“…3 shows plots of ln ∆T versus 1/T for the complexes, for each DTA curve, gave straight lines from which the activation energies (Eo) are calculated. The thermodynamic parameters of decomposition processes of compounds, namely enthalpy ∆H and entropy ∆S are evaluated [30][31][32][33][34][35]. The order of chemical reaction is calculated via peak symmetry method [36].…”

Section: Table-10 Fundamental Infrared Frequencies (Cm -1 ) Of the LImentioning

confidence: 99%

Spectral and Thermal Studies of Some Nucleic Acid Complexes

et al. 2019

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Barbituric acid, thiobarbituric acid and thiouracil complexes with sodium and potassium chlorides were prepared and characterized by UV in different solvents and IR experimentally and theoretically using B3LYP method and Gaussian program. The composition of the studied complexes was also confirmed by elemental and thermal analysis, TG, DTA and DSC techniques to determine thermodynamic parameters (Ea, ΔH, ΔS and ΔG). The negative value of entropy of activation indicated the fragments have ordered structures than undecomposed complexes. The positive values of enthalpy of activation of the decomposition stages indicated that the process is endothermic. The positive values of free energy of the decomposition indicated non-spontaneous process. Evaluation of kinetics parameters were done. The isokinetic temperature β is 407 K, which is lower than experimental temperature range, confirming the processes is entropy control. However, the plots of ΔH versus ΔS for the complexes under investigation gave straight line indicating a close similarity in the mechanism.

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Thermal studies of some purine compounds and their metal complexes

Cited by 28 publications

References 28 publications

Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

Synthesis, spectral characterization, thermal studies and biological activity of (Z)‐5‐((1,5‐dimethyl‐3‐oxo‐2‐phenyl‐2,3‐dihydro‐1H‐pyrazol‐4‐yl)diazenyl)‐6‐hydroxy‐2‐mercaptopyrimidin‐4(3H)‐one and its metal complexes

Biological Study of Transition Metal Complexes with Adenine Ligand

Spectral and Thermal Studies of Some Nucleic Acid Complexes

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