An EPR study of copper(II)-substituted biguanide complexes. Part III

Ray, R.K.; Kauffmann, George B.

doi:10.1016/s0020-1693(00)80306-0

Cited by 50 publications

(25 citation statements)

References 37 publications

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“…If this value is greater than 2.3, the environment is essentially ionic and the values less than this limit indicates a covalent environment, the g 11 -values reported here are 2.23 in complex (8) and 2.19 in complex (10) indicating covalent bonding character [30,64]. The complexes show a 2 values 0.8 and 0.74 respectively, suggesting considerable covalent bonding [21,72]. Also the orbital reduction of covalency [73].…”

Section: Electron Spin Resonance (Esr)mentioning

confidence: 72%

Synthesis, spectroscopic investigation and biological activity of metal complexes with ONO trifunctionalalized hydrazone ligand

El‐Tabl

El‐Saied

Al‐Hakimi

2007

Transition Met Chem

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Mn II , Fe III , Co II , Ni II , Cu II , Zn II , La III , Ru III , Hf IV , Zr IV and U VI complexes of 4-methylphenylamino acetoacetylacetone hydrazone have been synthesized and characterized by elementals analyses, i.r., u.v.-vis. spectra, magnetic moments, conductances, thermal analyses (d.t.a and t.g.a) and e.s.r measurements. The i.r. data show that, the ligand behaves as a neutral bidentate type (10), (13) and neutral tridentate type (4), (11), (12) and (21) monobasic bidentate type (7) or monobasic tridentate type (and (22) or dibasic tridentate type (5), (9) and (17) towards the metal ion. Molar conductances in DMF solution indicate that, the complexes are non-electrolytes. The e.s.r spectra of solid complexes (8) and (10) show axial type spectra with g k > g ? > 2:0023, a d (x 2 -y 2 ) ground state with significant covalent bond character. However, complex (12), shows an isotropic type, indicating a octahedral manganese(II) complex. Antibacterial and antifungal tests of the ligand and some of its metal complexes are also carried out and it has been observed that, the complexes are more potent bactericides and fungicides than the ligand.

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Section: Electron Spin Resonance (Esr)mentioning

confidence: 72%

Synthesis, spectroscopic investigation and biological activity of metal complexes with ONO trifunctionalalized hydrazone ligand

El‐Tabl

El‐Saied

Al‐Hakimi

2007

Transition Met Chem

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“…It has recently been suggested that the effects of metformin on the mitochondria depend on a third non-protein effect—direct targeting of metal ions [23]—which takes the form of an unusual electron delocalised planar ring structure, where square planar geometry replaces more conventional tetragonal geometry [24]. The compelling evidence of direct binding of metformin to metal ions, including extensive crystallographic [25] and spectroscopic analysis [24, 26–28], contrasts with the paucity of evidence regarding direct binding of the drug to recognised metformin-regulated proteins. Further work is required to establish how the metal-binding properties of metformin enable it to mediate mitochondrial inhibition.…”

Section: Molecular Action and Target Of Metformin: Lessons And Insighmentioning

confidence: 99%

Molecular mechanism of action of metformin: old or new insights?

2013

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Metformin is the first-line drug treatment for type 2 diabetes. Globally, over 100 million patients are prescribed this drug annually. Metformin was discovered before the era of target-based drug discovery and its molecular mechanism of action remains an area of vigorous diabetes research. An improvement in our understanding of metformin’s molecular targets is likely to enable target-based identification of second-generation drugs with similar properties, a development that has been impossible up to now. The notion that 5' AMP-activated protein kinase (AMPK) mediates the anti-hyperglycaemic action of metformin has recently been challenged by genetic loss-of-function studies, thrusting the AMPK-independent effects of the drug into the spotlight for the first time in more than a decade. Key AMPK-independent effects of the drug include the mitochondrial actions that have been known for many years and which are still thought to be the primary site of action of metformin. Coupled with recent evidence of AMPK-independent effects on the counter-regulatory hormone glucagon, new paradigms of AMPK-independent drug action are beginning to take shape. In this review we summarise the recent research developments on the molecular action of metformin.

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“…The g k -values for 10 and 11 are 2.27 and 2.28 indicating considerable covalent bonding character [30,54,60]. The -bonding parameter ( 2 ) for 10 is 0.8, also suggesting covalent bonding [22,[61][62][63].…”

Section: Electron Spin Resonance (Esr)mentioning

confidence: 99%

Spectroscopic characterization and biological activity of metal complexes with an ONO trifunctionalized hydrazone ligand

El‐Tabl

El‐Saied

Al‐Hakimi

2008

Journal of Coordination Chemistry

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A series of Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), La(III), Ru(III), Hf(IV), Zr(IV) and U(VI) complexes of phenylamino acetoacetylacetone hydrazone have been synthesized and characterized by elemental analyses, IR, UV-Vis, magnetic moments, conductances, thermal analyses (DTA and TGA) and ESR measurements. The IR data show that the ligand is neutral bidentate, monobasic bidentate, monobasic tridentate or dibasic tridentate towards the metal ion. Molar conductances in DMF indicate that the complexes are non-electrolytes. The ESR spectra of solid [(L)(HL)Cu 2 (NO 3 )(H 2 O)] Á 1/2H 2 O (10) and [(H 2 L)Cu(Cl) 2 (H 2 O) 2 ] (11) show axial spectra with g k 4g ? 42.0023 indicating d ðx 2 Ày 2 Þ ground state with significant covalent bond character. However, [(HL) 2 Mn 2 (Cl) 2 (H 2 O) 4 Á H 2 O (13) shows an isotropic spectrum, indicating manganese(II) to be octahedral. Antibacterial and antifungal tests of the ligand and some of its metal complexes revealed that the complexes are more potent bactericides and fungicides than the ligand.

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An EPR study of copper(II)-substituted biguanide complexes. Part III

Cited by 50 publications

References 37 publications

Synthesis, spectroscopic investigation and biological activity of metal complexes with ONO trifunctionalalized hydrazone ligand

Synthesis, spectroscopic investigation and biological activity of metal complexes with ONO trifunctionalalized hydrazone ligand

Molecular mechanism of action of metformin: old or new insights?

Spectroscopic characterization and biological activity of metal complexes with an ONO trifunctionalized hydrazone ligand

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