14363-26-9Relevant academic research and scientific papers
Paramagnetic NMR of Phenolic Oxime Copper Complexes: A Joint Experimental and Density Functional Study
Bühl, Michael,Ashbrook, Sharon E.,Dawson, Daniel M.,Doyle, Rachel A.,Hrobárik, Peter,Kaupp, Martin,Smellie, Iain A.
, p. 15328 - 15339 (2016)
1H and13C pNMR properties of bis(salicylaldoximato)copper(II) were studied in the solid state using magic-angle-spinning NMR spectroscopy and, for the isolated complex and selected oligomers, using density-functional theory at the PBE0- 1/3//PBE0-D3 level. Large paramagnetic shifts are observed, up to δ(1H)=272 ppm and δ(13C)=1006 ppm (at 298 K), which are rationalised through spin delocalisation from the metal onto the organic ligand and the resulting contact shifts arising from hyperfine coupling. The observed shift ranges are best reproduced computationally using exchange-correlation functionals with a high fraction of exact exchange (such as PBE0- 1/3). Through a combination of experimental techniques and first-principles computation, a near-complete assignment of the observed signals is possible. Intermolecular effects on the pNMR shifts, modelled computationally in the dimers and trimers through effective decoupling between the local spins via A-tensor and total spin rescaling in the pNMR expression, are indicated to be small. Addition of electron-donating substituents and benzannelation of the organic ligand is predicted computationally to induce notable changes in the NMR signal pattern, which suggests that pNMR spectroscopy can be a sensitive probe for the spin distribution in paramagnetic phenolic oxime copper complexes.
Copper(II)-mediated oxime-nitrile coupling in non-aqueous solutions: Synthetic, structural and magnetic studies of the copper(II)-salicylaldehyde oxime reaction system
Lazarou, Katerina N.,Boudalis, Athanassios K.,Psycharis, Vassilis,Raptopoulou, Catherine P.
, p. 50 - 58 (2011)
The reactions of salicylaldehyde oxime (H2salox) with Cu II precursors yielded the known complexes [Cu(Hsalox)2] (1) and [Cu(Hsalox)2]n (2), as well as complexes [Cu 3(salox)(L1)
Copper salisylaldoxime (CuSAL) imparts protective efficacy against visceral leishmaniasis by targeting Leishmania donovani topoisomerase IB
Singh, Manoj Kumar,Bhaumik, Siddhartha Kumar,Karmakar, Subir,Paul, Joydeep,Sawoo, Sudeshna,Majumder, Hemanta K.,Roy, Amit
, p. 8 - 20 (2017)
In?vitro and in?vivo anti-leishmanial efficacy of copper salisylaldoxime (CuSAL), a transition metal complex, was evaluated and the underlying mechanism was studied. In?vitro studies revealed that 30?μM of CuSAL causes 96% reduction in parasite burden in infected macrophages. CuSAL is least toxic in host cells. A dose of 5?mg/kg bodyweight per mice on alternate days (5 doses) gives ～97% protection in both liver and spleen. Moreover, CuSAL potentially inhibits the catalytic activity of LdTOPILS and causes apoptosis of Leishmania parasites through induction of intracellular ROS generation and activation of caspase-like proteases. Interestingly, CuSAL does not inhibit the catalytic activity of human topoisomerase I. The present study illuminated that CuSAL, has potent anti-leishmanial activity, which selectively targets LdTOPILS; and is a safe for human. Therefore, this compound might be highly promising candidate to develop the rational approaches for chemotherapy of human leishmaniasis.
Calculation and experimental measurement of paramagnetic NMR parameters of phenolic oximate Cu(II) complexes
Dawson, Daniel M.,Ke, Zhipeng,Mack, Frederick M.,Doyle, Rachel A.,Bignami, Giulia P. M.,Smellie, Iain A.,Bühl, Michael,Ashbrook, Sharon E.
supporting information, p. 10512 - 10515 (2017/09/29)
We present a strategy for predicting the unusual 1H and 13C shifts in NMR spectra of paramagnetic bisoximato copper(ii) complexes using DFT. We demonstrate good agreement with experimental measurements, although 1H-13C correlation spectra show that a combined experimental and theoretical approach remains necessary for full assignment.
Nanocrystalline mixed ligand complexes of Cu (II), Ni (II), Co(II) with N, O donor ligands: Synthesis, characterization, and antimicrobial activity
Kolhe Nitin,Jadhav Shridhar,Shaikh Sajid,Takate Sushama,Aware Dinkar
, p. 2999 - 3013 (2017/01/09)
In present investigation nanocrystalline mixed ligand complexes were synthesized using 8-hydroxyquinoline, salicylaldoxime with metals like Cu (II), Ni (II) and Co (II). The metal: ligand ratio was found to be 1:1:1. These complexes were characterized usi
Study of bonding characteristics of some new metal complexes of salicylaldoxime (SALO) and its derivatives by far infrared and UV spectroscopy
Ramesh,Umasundari,Das, Kalyan K.
, p. 285 - 297 (2007/10/03)
New metal chelates of copper, lead and zinc with salicylaldoxime (SALO) and its derivatives have been prepared. The chelates have been characterized by elemental analysis, atomic absorption, infrared and UV spectroscopy. SALO behaves as a bidentate ligand forming neutral metal chelates through the phenolic oxygen and the oxime nitrogen. The M-O stretching frequencies for the transition metals show good agreement with the Irving-William's stability order Cu > Zn > Pb. Similar trend is seen for the M-N stretching frequencies in IR and the shift in transitions from UV spectral data for the metal chelates.
Effect of the coordination geometry and of substituent shielding on the kinetics of ligand substitution in copper(II) chelates
Elias, Horst,Hasserodt-Taliaferro, Christina,Hellriegel, Ludwig,Sch?nherr, Walter,Wannowius, Klaus J.
, p. 3192 - 3198 (2008/10/08)
Stopped-flow spectrophotometry has been used to study the kinetics of ligand substitution in bis(N-R-salicylaldiminato)copper(II) complexes CuA2 (R = H, OH, Me, Et, i-Pr, t-Bu, neo-Pe, phenyl) by bidentate ligands HB (N-ethylsalicylaldimine, acetylacetone) in methanol and ethylene glycol monomethyl ether at 298 K. A two-term rate law, rate = (kS + kHB[HB])[complex], has been found. The substitution of the first ligand in CuA2 is rate determining. The relative contributions of the terms kS and kHB[HB] to the overall rate are controlled by the N-alkyl group R in the following sense: (i) small groups R (such as R = Me) favor a planar trans- N2O2 coordination geometry of the complex, whereas bulky groups (such as R = t-Bu) force the complex to become strongly tetrahedrally distorted, and (ii) with increasing extent of tetrahedral distortion (due to the effect of R) the size of kS increases, whereby the contribution of the term kHB[HB] can become negligibly small. A systematic study of the kinetic effect of substituents X3 and X5 (introduced in the 3- and 5-positions of the salicylaldehyde ring) and substituents Y2, Y4, and Y6 (introduced in the 2-, 4-, and 6-positions of the N-phenyl ring) reveals that substituents X3 = CH3, Cl, Br, I, NO2, which are neighboring to the oxygen donor atom, reduce the size of kS according to their steric substituent constant Es. Substituents Y2 = CH3, F, Cl, Br, I and Y2 = Y6 = CH3, Cl (neighboring the nitrogen donor atom in the N-phenyl complexes) reduce both kS and kHB, which can be correlated with the electronic and steric properties of these substituents. The sum of the experimental results supports consistently the following mechanistic interpretation of the observed rate law, namely: (i) the second-order rate constant kHB describes the nucleophilic attack of the entering ligand HB at the copper; (ii) the first-order rate constant kS describes the attack of a protic solvent molecule, surprisingly not at the copper but at the oxygen donor atom instead.
