scholarly journals Charge-Density Induced Discrimination of Halides with a Rigid Dinuclear Copper(II) Complex

Author(s):  
Md Mhahabubur Rhaman ◽  
Mohammad Hasan ◽  
Zulfikhar A. Ali ◽  
Douglas Powell ◽  
Ritesh Tandon ◽  
...  

<p>A rigid dinuclear copper(II) complex <b>L</b> based on furan spacers has been synthesized and studied for its binding interactions with halides by colorimetric studies, UV-Vis titrations, and density functional theory (DFT) calculations. Our results from the titration studies demonstrate that <b>L</b> binds each of the halides in the order of fluoride > chloride > bromide > iodide, correlating directly with the charge density of the respective halide. Fully unconstrained DFT geometry optimizations have been carried out on both the isolated <b>L</b> as well as the anion-bound motifs. Binding energies (DE) were calculated for each of the optimized geometries, yielding an attractive DE of -92.39, -27.14, -23.16, and -13.37 kcal/mol for fluoride, chloride, bromide, and iodide, respectively, which is in accord with our experimental results. The compound has been further investigated for its biocompatibility on HeLa cells, demonstrating an excellent cell viability up to 500 µM concentration.</p>

2020 ◽  
Author(s):  
Md Mhahabubur Rhaman ◽  
Mohammad Hasan ◽  
Zulfikhar A. Ali ◽  
Douglas Powell ◽  
Ritesh Tandon ◽  
...  

<p>A rigid dinuclear copper(II) complex <b>L</b> based on furan spacers has been synthesized and studied for its binding interactions with halides by colorimetric studies, UV-Vis titrations, and density functional theory (DFT) calculations. Our results from the titration studies demonstrate that <b>L</b> binds each of the halides in the order of fluoride > chloride > bromide > iodide, correlating directly with the charge density of the respective halide. Fully unconstrained DFT geometry optimizations have been carried out on both the isolated <b>L</b> as well as the anion-bound motifs. Binding energies (DE) were calculated for each of the optimized geometries, yielding an attractive DE of -92.39, -27.14, -23.16, and -13.37 kcal/mol for fluoride, chloride, bromide, and iodide, respectively, which is in accord with our experimental results. The compound has been further investigated for its biocompatibility on HeLa cells, demonstrating an excellent cell viability up to 500 µM concentration.</p>


2020 ◽  
Vol 5 (5) ◽  
pp. 996-1002
Author(s):  
Md Mhahabubur Rhaman ◽  
Mohammad H. Hasan ◽  
Zulfikhar A. Ali ◽  
Douglas R. Powell ◽  
Ritesh Tandon ◽  
...  

A rigid dinuclear copper(ii) complex L based on furan spacers has been synthesized and studied for its binding interactions with halides by colorimetric studies, UV-vis titration, and density functional theory (DFT) calculations.


2005 ◽  
Vol 494 ◽  
pp. 79-82 ◽  
Author(s):  
V. Koteski ◽  
Bozidar Cekić ◽  
N. Novaković ◽  
J. Belošević-Čavor

The structural and geometric properties of small Mo clusters are studied by means of first principles density functional theory (DFT) calculations with planewaves and pseudopotentials. The lowest energy structures of Mon (n=2-6) clusters are determined. The evolution of electronic properties with increasing cluster size is discussed. The geometric structure, average bond lengths, and binding energies of the lowest energy isomers are reported and the results are compared with the available experimental and theoretical data.


2008 ◽  
Vol 63 (1-2) ◽  
pp. 42-48 ◽  
Author(s):  
Salim M. Khalil

Density functional theory (DFT) calculations have been performed to calculate the optimized geometries of stepwise fluorinated methylenecyclopropanes and 1-methylcyclopropenes. Increasing the number of fluorine atoms caused a destabilization of methylenecycopropane. Perfluorinated 1-methylcyclopropene was found to be present in substantial concentration. This is supported by calculations of the Gibbs free energy, isodesmic reactions and orbital energies (HOMO-LUMO). These results are compared with the fluorinated cyclopropanes keto-enol system. Enthalpies, entropies and dipole moments are reported.


2021 ◽  
Author(s):  
Xinpeng Zhao ◽  
Zhimin Zhou ◽  
hu luo ◽  
Yanfei Zhang ◽  
Wang Liu ◽  
...  

Combined experiments and density functional theory (DFT) calculations provided insights into the role of the environment-friendly γ-valerolactone (GVL) as a solvent in the hydrothermal conversion of glucose into lactic acid...


Author(s):  
Hanlin Gan ◽  
Liang Peng ◽  
Feng Long Gu

The mechanism of the Cu(i)-catalyzed domino reaction furnishing 1-aryl-1,2,3-triazole assisted by CuI and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is explored with density functional theory (DFT) calculations.


2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.


2019 ◽  
Vol 21 (6) ◽  
pp. 3227-3241 ◽  
Author(s):  
Krishnamoorthy Arumugam ◽  
Neil A. Burton

Of particular interest within the +6 uranium complexes is the linear uranyl(vi) cation and it forms numerous coordination complexes in solution and exhibits incongruent redox behavior depending on coordinating ligands. This DFT study predicts VI/V reduction potentials of a range of uranyl(vi) complexes in non-aqueous solutions within ∼0.10−0.20 eV of experiment.


2018 ◽  
Vol 74 (12) ◽  
pp. 1641-1649
Author(s):  
Wei-Tsung Lee ◽  
Matthias Zeller ◽  
David Upp ◽  
Yuliya Politanska ◽  
Doug Steinman ◽  
...  

Treatment of the ortho-triazacyclophane 1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-triene [(C6H5)3(NH)(NCH3)2, L1] with Fe[N(SiMe3)2]2 yields the dimeric iron(II) complex bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)bis[(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido)iron(II)], [Fe(C20H18N3)4] or Fe2(L1)4 (9). Dissolution of 9 in tetrahydrofuran (THF) results in solvation by two THF ligands and the formation of a simpler monoiron complex, namely bis(μ-1,4-dimethyltribenzo[b,e,h][1,4,7]triazacyclonona-2,5,8-trien-7-ido-κN 7)bis(tetrahydrofuran-κO)iron(II), [Fe(C20H18N3)2(C4H8O)2] or (L1)2Fe(THF)2 (10). The reaction is reversible and 10 reverts in vacuo to diiron complex 9. In the structures of both 9 and 10, the monoanionic triazacyclophane ligand L1− is observed in only the less-symmetric saddle conformation. No bowl-shaped crown conformers are observed in the solid state, thus preventing chelating κ3-coordination to the metal as had been proposed earlier based on density functional theory (DFT) calculations. Instead, the L1− ligands are bound in either a η2-chelating fashion through the amide and one amine donor (for one of the four ligands of 9), or solely through their amide N atoms in an even simpler monodentate η1-coordination mode. Density functional calculations on dimer 9 revealed nearly full cationic charges on each Fe atom and no bonding interaction between the two metal centers, consistent with the relatively long Fe...Fe distance of 2.912 (1) Å observed in the solid state.


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