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Structural and Spectroscopic Study of New Copper(II) and Zinc(II) Complexes of Coumarin Oxyacetate Ligands and Determination of Their Antimicrobial Activity. Molecules 2023; 28:molecules28114560. [PMID: 37299035 DOI: 10.3390/molecules28114560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/19/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Tackling antimicrobial resistance is of increasing concern in a post-pandemic world where overuse of antibiotics has increased the threat of another pandemic caused by antimicrobial-resistant pathogens. Derivatives of coumarins, a naturally occurring bioactive compound, and its metal complexes have proven therapeutic potential as antimicrobial agents and in this study a series of copper(II) and zinc(II) complexes of coumarin oxyacetate ligands were synthesised and characterised by spectroscopic techniques (IR, 1H, 13C NMR, UV-Vis) and by X-ray crystallography for two of the zinc complexes. The experimental spectroscopic data were then interpreted on the basis of molecular structure modelling and subsequent spectra simulation using the density functional theory method to identify the coordination mode in solution for the metal ions in the complexes. Interestingly, the solid-state coordination environment of the zinc complexes is in good agreement with the simulated solution state, which has not been the case in our previous studies of these ligands when coordinated to silver(I). Previous studies had indicated excellent antimicrobial activity for Ag(I) analogues of these ligands and related copper and zinc complexes of coumarin-derived ligands, but in this study none of the complexes displayed antimicrobial activity against the clinically relevant methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans.
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Energy transfer mechanism in luminescence Eu(III) and Tb(III) complexes of coumarin-3-carboxylic acid: A theoretical study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 240:118591. [PMID: 32585405 DOI: 10.1016/j.saa.2020.118591] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/03/2020] [Accepted: 06/06/2020] [Indexed: 06/11/2023]
Abstract
Excited state energy level diagrams of coumarin-3-carboxylic acid (HCCA) chromophore, Eu(CCA)Cl2(H2O)2 (1), Eu(CCA)2Cl(H2O)2 (2), Eu(CCA)3(H2O)3 (3), Tb(CCA)2Cl(H2O) (4) and Tb(CCA)2(NO3)(H2O) (5) in gas phase and polar solution have been calculated by means of DFT/TDDFT/ωB97XD methods. Based on these results, the ability of CCA to sensitize Eu(III) and Tb(III) luminescence has been examined. The competitive excited state processes in the complexes - fluorescence, intersystem crossing (ISC) and phosphorescence, were analyzed depending on the environment, number of the ligands, Ln(III) ion type (Eu and Tb) and counteranion (Cl- and NO3-). It has been found that the environment altered the S1 state energy, oscillator strength, fluorescence lifetime as well as the S1 character - polar solution stabilized the S1(ππ*) state, whereas non-polar solution (gas phase, solid state) stabilized the S1(nπ*) state. The S1(nπ*) state was decisive for the efficient energy transfer as it suppressed the S1 emission of CCA and favored ISC or direct transfer to the emitting levels of Eu(III). The HCCA triplet (T1) state minimum energy (~2.7, ~2.6ZPE eV) and (ππ*) character were retained in Eu/Tb-CCA complexes regardless of the environment. The energy gap between the higher energy T1 donor state and the acceptor levels 5D1 of Eu(III) (~0.5 eV) and 5D4 of Tb(III) (~0.1 eV) provided optimal resonance conditions for effective energy transfer for Eu(III), but less probability for Tb(III). The nonradiative energy (CCA → Eu(III)) transfer rates and quantum luminescence yield for 2 and 3 were calculated by a strategy combining DFT geometries, INDO/S excitation energies and calculated Judd-Ofelt parameters. The excitation channel T1 → 5D0 through an exchange mechanism was predicted as the most probable one to populate the main emissive Eu-centered state in complexes 2 and 3. The more efficient luminescence of 3 than that of 2 was discussed and explained.
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Synthesis, X-ray structure, and DFT modeling of a new polymeric zinc(II) complex of 2-mercaptonicotinic acid (MntH), {[Zn(Mnt–Mnt)(en)]·H2O}n. MONATSHEFTE FUR CHEMIE 2019. [DOI: 10.1007/s00706-018-2330-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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High-level Ab Initio Absorption Spectra Simulations of Neutral, Anionic and Neutral+ Chromophore of Green Fluorescence Protein Chromophore Models in Gas Phase and Solution. Photochem Photobiol 2017; 93:1356-1367. [PMID: 28436037 DOI: 10.1111/php.12778] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/29/2017] [Indexed: 12/01/2022]
Abstract
Semiclassical ab initio simulations of the absorption spectra of neutral and anionic p-hydroxybenzylidene-2,3-dimethylimidazolinone (p-HBDI), a model chromophore of green fluorescent protein (GFP) and of a positively charged neutral (N+)-HBDI chromophore model, were performed in gas phase with the resolution-of-identity algebraic diagrammatic construction through second-order (RI-ADC(2)) method. The calculated absorption spectra in gas phase are composed of one band centered at 3.51 eV (HBDI), 2.50 eV (HBDI- ) and 3.02 eV ((N+)-HBDI) owing to the absorption of the first 1 ππ* transition. Band maxima are redshifted by ~0.1 eV with respect to the corresponding vertical energies. The COSMO-RI-ADC(2) calculations of the first vertical excitation energy of HBDI, HBDI- and (N+)-HBDI forms in polar solution including microsolvation simulate the observed solvent redshift for neutral HBDI and the solvent blueshift of the HBDI- and (N+)-HBDI forms. The state-specific solvation approach applied to TDDFT calculations reproduced the experimental solvent shifts for the three HBDI forms, demonstrating a more accurate theoretical description as compared to the linear-response TDDFT approach.
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DFT study of the molecular and crystal structure and vibrational analysis of cisplatin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 176:58-66. [PMID: 28073067 DOI: 10.1016/j.saa.2017.01.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/23/2016] [Accepted: 01/02/2017] [Indexed: 05/10/2023]
Abstract
DFT and periodic-DFT (PAW-PBE method, code VASP) calculations have been performed to study the structural and vibrational characteristics of cis-diamminedichloroplatinum(II) (cisplatin) at molecular and outside molecular level. To estimate the effect of the intermolecular interactions in crystal on the structural and vibrational properties of cisplatin, three theoretical models are considered in the present study: monomer (isolated molecule), hydrogen bonded dimer and periodic solid state structures. The work focused on the role of the theoretical models for correct modeling and prediction of geometrical and vibrational parameters of cisplatin. It has been found that the elaborate three-dimensional intermolecular hydrogen bonding network in the crystalline cisplatin significantly influences the structural and vibrational pattern of cisplatin and therefore the isolated cisplatin molecule is not the correct computational model regardless of the theoretical level used. To account for the whole intermolecular hydrogen bonding network in direction of both a and c axis and for more reliable calculations of structural and vibrational parameters periodic DFT calculations were carried out in the full crystalline periodic environment with the known lattice parameters for each cisplatin polymorph phase. The model calculations performed both at molecular level and for the periodic structures of alpha and beta cisplatin polymorph forms revealed the decisive role of the extended theoretical model for reliable prediction of the structural and vibrational characteristics of cisplatin. The powder diffraction pattern and the calculated IR and Raman spectra predicted beta polymorph form of our cisplatin sample freshly synthesized for the purposes of the present study using the Dhara's method. The various rotamers realized in the polymorph forms of cisplatin were explained by the low population of the large number of rotamers in solution as well as with the high rotamer interconversion rate due to the low energy barrier.
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Synthesis, X-ray structure, spectroscopic (IR, NMR) analysis and DFT modeling of a new polymeric Zinc(II) complex of cystamine, [Zn(Cym-Cym)Cl2]. Polyhedron 2017. [DOI: 10.1016/j.poly.2016.11.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Novel silver(I) complexes of coumarin oxyacetate ligands and their phenanthroline adducts: Biological activity, structural and spectroscopic characterisation. J Inorg Biochem 2016; 163:53-67. [DOI: 10.1016/j.jinorgbio.2016.07.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 07/05/2016] [Accepted: 07/13/2016] [Indexed: 12/29/2022]
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Synthesis, spectroscopic characterization, DFT calculations and antimicrobial properties of silver(I) complexes of 2,2′-bipyridine and 1,10-phenanthroline. Polyhedron 2016. [DOI: 10.1016/j.poly.2016.04.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Spectroscopic studies, DFT calculations, and cytotoxic activity of novel silver(I) complexes of hydroxy ortho-substituted-nitro-2H-chromen-2-one ligands and a phenanthroline adduct. J Inorg Biochem 2015; 153:103-113. [DOI: 10.1016/j.jinorgbio.2015.10.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/08/2015] [Accepted: 10/05/2015] [Indexed: 11/29/2022]
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Intramolecular Charge-Transfer Excited-State Processes in 4-(N,N-Dimethylamino)benzonitrile: The Role of Twisting and the πσ* State. J Phys Chem A 2015; 119:6232-43. [PMID: 25989536 PMCID: PMC4476306 DOI: 10.1021/acs.jpca.5b03282] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
![]()
The
structural processes leading to dual fluorescence of 4-(dimethylamino)benzonitrile
in the gas phase and in acetonitrile solvent were investigated using
a combination of multireference configuration interaction (MRCI) and
the second-order algebraic diagrammatic construction (ADC(2)) methods.
Solvent effects were included on the basis of the conductor-like screening
model. The MRCI method was used for computing the nonadiabatic interaction
between the two lowest excited ππ* states (S2(La, CT) and S1(Lb, LE)) and the
corresponding minimum on the crossing seam (MXS) whereas the ADC(2)
calculations were dedicated to assessing the role of the πσ*
state. The MXS structure was found to have a twisting angle of ∼50°.
The branching space does not contain the twisting motion of the dimethylamino
group and thus is not directly involved in the deactivation process
from S2 to S1. Polar solvent effects are not
found to have a significant influence on this situation. Applying Cs symmetry restrictions, the ADC(2) calculations
show that CCN bending leads to a strong stabilization and to significant
charge transfer (CT). Nevertheless, this structure is not a minimum
but converts to the local excitation (LE) structure on releasing the
symmetry constraint. These findings suggest that the main role in
the dynamics is played by the nonadiabatic interaction of the LE and
CT states and that the main source for the dual fluorescence is the
twisted internal charge-transfer state in addition to the LE state.
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Lanthanide and transition metal complexes of bioactive coumarins: molecular modeling and spectroscopic studies. J Inorg Biochem 2014; 135:100-12. [PMID: 24680836 DOI: 10.1016/j.jinorgbio.2014.03.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 03/07/2014] [Accepted: 03/10/2014] [Indexed: 11/15/2022]
Abstract
The present paper summarizes theoretical and spectroscopic investigations on a series of active coumarins and their lanthanide and transition metal complexes with application in medicine and pharmacy. Molecular modeling as well as IR, Raman, NMR and electronic spectral simulations at different levels of theory were performed to obtain important molecular descriptors: total energy, formation energy, binding energy, stability, conformations, structural parameters, electron density distribution, molecular electrostatic potential, Fukui functions, atomic charges, and reactive indexes. The computations are performed both in gas phase and in solution with consideration of the solvent effect on the molecular structural and energetic parameters. The investigations have shown that the advanced computational methods are reliable for prediction of the metal-coumarin binding mode, electron density distribution, thermodynamic properties as well as the strength and nature of the metal-coumarin interaction (not experimentally accessible) and correctly interpret the experimental spectroscopic data. Known results from biological tests for cytotoxic, antimicrobial, anti-fungal, spasmolytic and anti-HIV activities on the studied metal complexes are reported and discussed.
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Effect of the metal⋯metal interactions on the absorption properties of Pt(II) and Pd(II) complexes of glyoxilic acid oxime in solution and solid state: Theoretical and experimental study. J Photochem Photobiol A Chem 2013. [DOI: 10.1016/j.jphotochem.2013.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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NMR, IR and DFT studies of phenylplatinum complexes with O-monodentate coordinated silsesquioxanate and auxiliary phosphine ligands. J Organomet Chem 2012. [DOI: 10.1016/j.jorganchem.2011.09.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Molecular structure and spectroscopic studies on novel complexes of coumarin-3-carboxylic acid with Ni(II), Co(II), Zn(II) and Mn(II) ions based on density functional theory. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 84:275-285. [PMID: 21996590 DOI: 10.1016/j.saa.2011.09.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 09/01/2011] [Accepted: 09/15/2011] [Indexed: 05/31/2023]
Abstract
Novel Ni(II), Co(II), Zn(II) and Mn(II) complexes of coumarin-3-carboxylic acid (HCCA) were studied at experimental and theoretical levels. The complexes were characterised by elemental analyses, FT-IR, (1)H NMR, (13)C NMR and UV-Vis spectroscopy and by magnetic susceptibility measurements. The binding modes of the ligand and the spin states of the metal complexes were established by means of molecular modelling of the complexes studied and calculation of their IR, NMR and absorption spectra at DFT(TDDFT)/B3LYP level. The experimental and calculated data verified high spin Ni(II), Co(II) and Mn(II) complexes and a bidentate binding through the carboxylic oxygen atoms (CCA2). The model calculations predicted pseudo octahedral trans-[M(CCA2)(2)(H(2)O)(2)] structures for the Zn(II), Ni(II) and Co(II) complexes and a binuclear [Mn(2)(CCA2)(4)(H(2)O)(2)] structure. Experimental and calculated (1)H, (13)C NMR, IR and UV-Vis data were used to distinguish the two possible bidentate binding modes (CCA1 and CCA2) as well as mononuclear and binuclear structures of the metal complexes.
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DFT modeling, UV-Vis and IR spectroscopic study of acetylacetone-modified zirconia sol-gel materials. J Mol Model 2011; 18:2409-22. [DOI: 10.1007/s00894-011-1257-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Accepted: 09/21/2011] [Indexed: 11/24/2022]
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DFT, IR, Raman and NMR study of the coordination ability of coumarin-3-carboxylic acid to Pr(III). J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2010.06.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Solvatochromic and Ionochromic Effects of Iron(II)bis(1,10-phenanthroline)dicyano: a Theoretical Study. Inorg Chem 2010; 49:1634-46. [DOI: 10.1021/ic9020299] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Is the CO frequency shift a reliable indicator of coumarin binding to metal ions through the carbonyl oxygen? Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.10.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Multiple adsorption of NO on cobalt-exchanged chabazite, mordenite, and ferrierite zeolites: A periodic density functional theory study. J Chem Phys 2009; 131:054101. [DOI: 10.1063/1.3182850] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Theoretical, spectral characterization and antineoplastic activity of new lanthanide complexes. J Trace Elem Med Biol 2008; 22:100-11. [PMID: 18565422 DOI: 10.1016/j.jtemb.2007.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2007] [Revised: 10/10/2007] [Accepted: 10/14/2007] [Indexed: 11/21/2022]
Abstract
The new cerium(III), lanthanum(III) and neodymium(III) complexes were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, (1)H NMR, (13)C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinates to the metal ion through both deprotonated hydroxyl groups, however participation of the carbonyl groups in the coordination to the metal ion was also suggested. Geometry optimization of 3,3'-(ortho-pyridinomethylene)di-[4-hydroxycoumarin] H(2)(o-pyhc), (H(2)L) and its dianionic forms, o-pyhc(2-), (L(2-)) were carried out at AM1 and PM3 levels as well as using density functional theory with Becke's three parameter hybrid method and correlation functional of Lee, Yang and Parr (B3LYP) with 6-31G(d) basis set. The optimized geometries of the neutral ligand isomers were stabilized by two asymmetrical intramolecular O-H...O hydrogen bonds (HBs). The conformational search showed four low-energy dianionic species (o-pyhc(2-)) on the potential energy surface. Molecular electrostatic potential calculations showed that the most preferred sites for electrophilic attack in H(2)(o-pyhc) and o-pyhc(2-) are the carbonyl oxygen atoms. The evaluation of the cytotoxic activity of the novel lantanide complexes on HL-60 myeloid cells revealed, that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum, and neodymium species, the latter being the least active. Taken together our data give us a reason to conclude that the newly synthesized lanthanide complexes should be a subset to further more detailed pharmacological and toxicological evaluation.
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Bonding Analyses, Formation Energies, and Vibrational Properties of M−R2dtc Complexes (M = Ag(I), Ni(II), Cu(II), or Zn(II)). J Phys Chem A 2007; 111:13075-87. [DOI: 10.1021/jp075008a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Theoretical study of metal-ligand interaction in Sm(III), Eu(III), and Tb(III) complexes of coumarin-3-carboxylic acid in the gas phase and solution. Inorg Chem 2007; 46:10926-36. [PMID: 17990875 DOI: 10.1021/ic7016616] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The interaction of lanthanide(III) cations (Ln(III) = Sm(III), Eu(III), and Tb(III)) with the deprotonated form of the coumarin-3-carboxylic acid (cca-) has been investigated by density functional theory (DFT/B3LYP) and confirmed by reference MP2 and CCSD(T) computations. Solvent effects on the geometries and stabilities of the Ln(III) complexes were computed using a combination of water clusters and a continuum solvation model. The following two series of systems were considered: (i) Ln(cca)2+, Ln(cca)2+, Ln(cca)3 and (ii) Ln(cca)(H2O)2Cl2, Ln(cca)2(H2O)2Cl, Ln(cca)3. The strength and character of the Ln(III)-cca- bidentate bonding were characterized by calculated Ln-O bond lengths, binding energies, ligand deformation energies, energy partitioning analysis, sigma-donation contributions, and natural population analyses. The energy decomposition calculations predicted predominant electrostatic interaction terms to the Ln-cca bonding (ionic character) and showed variations of the orbital interaction term (covalent contributions) for the Ln-cca complexes studied. Electron distribution analysis suggested that the covalent contribution comes mainly from the interaction with the carboxylate moiety of cca-.
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Excited-State Proton Transfer in 7-Hydroxy-4-methylcoumarin along a Hydrogen-Bonded Water Wire. J Phys Chem A 2006; 111:127-35. [PMID: 17201395 DOI: 10.1021/jp0662202] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
TDDFT, RI-CC2, and CIS calculations have been performed for the nondissociative excited-state proton transfer (ESPT) in the S1 state of 7-hydroxy-4-methylcoumarin (7H4MC) along a H-bonded water wire of three water molecules bridging the proton donor (OH) and the proton acceptor (C[double bond]O) groups (7H4MC.(H2O)3). The observed structural reorganization in the water-wire cluster is interpreted as a proton-transfer (PT) reaction along the H2O solvent wire. The shift of electron density within the organic chromophore 7H4MC due to the optical excitation appears to be the driving force for ESPT. All the methods used show that the reaction path occurs in the 1pipi* state, and no crossing with a Rydberg-type 1pisigma* state is found. TDDFT and RI-CC2 calculations predict an exoergic reaction of the excited-state enol-to-keto transformation. The S1 potential energy curve reveals well-defined Cs minima of enol- and keto-clusters, separated by a single barrier with a height of 17-20 kcal/mol. After surmounting this barrier, spontaneous PT along the water wire is observed, leading without any further barrier to the keto structure. The TDDFT and RI-CC2 methods appear to be reliable approaches to describe the energy surfaces of ESPT. The CIS method predicts an endoergic ESPT reaction and an energy barrier, which is too high.
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Barriers to Internal Rotation and Conformational Behaviour of the MESO and D,L Isomers of Pt(II) Complexes with Antitumour Activity. J COORD CHEM 2006. [DOI: 10.1080/00958970008055136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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DFT modeling and spectroscopic study of metal–ligand bonding in La(III) complex of coumarin-3-carboxylic acid. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.04.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Comprehensive DFT and MO studies on glyoxilic acid oxime and related ions in gas phase and solution: Conformations, basicities and acidities. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2005.08.041] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Spectroscopic and theoretical study of Cu(II), Zn(II), Ni(II), Co(II) and Cd(II) complexes of glyoxilic acid oxime. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 63:403-15. [PMID: 15982923 DOI: 10.1016/j.saa.2005.05.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 05/19/2005] [Indexed: 05/03/2023]
Abstract
The paper presents a detailed experimental and theoretical study of five metal complexes of glyoxilic acid oxime (gaoH2), Cu(gaoH)2(H2O)2 (1), Zn(gaoH)2(H2O)2 (2), Co(gaoH)2(H2O)2 (3), Ni(gaoH)2(H2O)2 (4) and [Cd(gaoH)2(H2O)2].H2O (5). The electronic and vibrational spectra were measured and discussed as to the most sensitive to the M-L binding bands. Two different types of coordination were considered for gaoH- ligand: bidentate through the carboxylic oxygen and oxime nitrogen in 1-4 and mixed bidentate and bridging through the COO group in 5. It is shown that the spectral behavior of the nu(COO) modes can be used to predict bridging ligand coordination. DFT(B3LYP/6-31++G(d,p)) calculations on model compounds: neutral, anionic and radical forms of gao and Cu(gaoH)2, have been carried out to correlate geometries, electronic and vibrational structures. The results obtained were used to assist the electronic and vibrational analysis of the complexes studied. The effect of the metal-ligand interactions (electrostatic and covalent) on the geometry structure of the ligand was investigated.
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Excited State Properties of 7-Hydroxy-4-methylcoumarin in the Gas Phase and in Solution. A Theoretical Study. J Phys Chem A 2005; 109:11860-9. [PMID: 16366637 DOI: 10.1021/jp0524025] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
TDDFT/B3LYP and RI-CC2 calculations with different basis sets have been performed for vertical and adiabatic excitations and emission properties of the lowest singlet states for the neutral (enol and keto), protonated and deprotonated forms of 7-hydroxy-4-methylcoumarin (7H4MC) in the gas phase and in solution. The effect of 7H4MC-solvent (water) interactions on the lowest excited and fluorescence states were computed using the Polarizable Continuum Method (PCM), 7H4MC-water clusters and a combination of both approaches. The calculations revealed that in aqueous solution the pi pi* energy is the lowest one for excitation and fluorescence transitions of all forms of 7H4MC studied. The calculated excitation and fluorescence energies in aqueous solution are in good agreement with experiment. It was found that, depending on the polarity of the medium, the solvent shifts vary, leading to a change in the character of the lowest excitation and fluorescence transition. The dipole-moment and electron-density changes of the excited states relative to the ground state correlate with the solvation effect on the singlet excited states and on transition energies, respectively. The calculations show that, in contrast to the ground state, the keto form has a lower energy in the pi pi* state as compared to enol, demonstrating from this point of view the energetic possibility of proton transfer from the enol to the keto form in the excited state.
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Theoretical and spectroscopic studies of pyridyl substituted bis-coumarins and their new neodymium (III) complexes. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.01.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The coordination of Cu2+ by glyoxilic acid oxime (gao)--the oxime analogue of glycine amino acid--and its deprotonated (gao- and gao2-) species has been studied with different density functional methods. Single-point calculations have also been carried out at the single- and double- (triple) excitation coupled-cluster (CCSD(T)) level of theory. The isomers studied involve coordination of Cu2+ to electron-rich sites (O,N) of neutral, anionic, and dianionic gao species in different conformations. In contrast to Cu2+-glycine, for which the ground-state structure is bidentate with the CO2(-) terminus of zwitterionic glycine, for Cu2+-gao the most stable isomer shows monodentate binding of Cu2+ with the carbonylic oxygen of the neutral form. The most stable complexes of Cu2+ interacting with deprotonated gao species (gao- and gao2-) also take place through the carboxylic oxygens but in a bidentate manner. The results with different functionals show that, for these open shell (Cu2+-L) systems, the relative stability of complexes with different coordination environments (and so, different spin distribution) can be quite sensitive to the amount of "Hartree-Fock" exchange included in the functional. Among all the functionals tested in this work, the BHandHLYP is the one that better compares to CCSD(T) results.
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Theoretical and spectroscopic evidence for coordination ability of 3,3'-benzylidenedi-4-hydroxycoumarin. New neodymium (III) complex and its cytotoxic effect. J Inorg Biochem 2005; 99:477-87. [PMID: 15621280 DOI: 10.1016/j.jinorgbio.2004.10.022] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Revised: 10/13/2004] [Accepted: 10/18/2004] [Indexed: 10/26/2022]
Abstract
Theoretical and spectroscopic studies of 3,3'-benzylidenedi-4-hydroxycoumarin (bhc) have been performed. B3LYP/6-31G* calculations reproduced the experimental molecular structure of bhc and showed two O-H...O asymmetrical intramolecular hydrogen bonds with O...O distances 2.638 and 2.696 A. The calculated Fukui functions and Molecular Electrostatic Potential for bhc and its deprotonated form, bhc(2-), predicted that the most probable reactive sites for electrophilic attack and hydrogen bonds are the carbonyl oxygens, followed by the hydroxyl oxygens. The coordination ability of 3,3'-benzylidenedi-4-hydroxycoumarin has been proved in a complexation reaction with neodymium (III) ion. The new neodymium (III) complex of bhc was studied by elemental analyses, conductivity and other physical properties, mass spectra, (1)H, (13)C NMR, UV-Vis and IR spectroscopy. The data obtained are in agreement with the metal:ligand ratio of 1:1, and the formula Nd(bhc(2-))(OH)(H(2)O), where bhc(2-)=C(25)H(14)O(6)(2-). The vibrational analysis of the neodymium (III) complex, free bhc, and its monomeric building block, 4-hydroxycoumarin, showed that in the Nd(III) complex the ligand coordinates to the metal ion through both deprotonated hydroxyl groups. The participation of both carbonyl groups in coordination to the metal ion was confirmed by the significant shift of nu(C=O) to lower wavenumber. The evaluation of the cytotoxic activity of the new Nd(III) complex on SKW-3 and HL-60/Dox cells revealed, that it is a potent cytotoxic agent and should be subset further to more detailed pharmacological and toxicological study.
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Abstract
Cerium (III), lanthanum (III) and neodymium (III) complexes with 3,3'-benzylidenebis[4-hydroxycoumarin] were synthesized in view of their application as cytotoxic agents. The complexes were characterized by different physicochemical methods: elemental analysis, mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy. The spectra of the complexes were interpreted on the basis of comparison with the spectrum of the free ligand. The vibrational analysis showed that in the complexes the ligand coordinated to the metal ion through both deprotonated hydroxyl groups; however, participation of the carbonyl groups in the coordination to the metal ion was also suggested. The evaluation of the cytotoxic activity of the novel lanthanide complexes on HL-60 myeloid cells revealed that they are potent cytotoxic agents. The cerium complex was found to exhibit superior activity in comparison to the lanthanum and neodymium coordination compounds, the latter being the least active. Our data give us reason to conclude that the newly synthesized lanthanide complexes should be submitted to further more detailed pharmacological and toxicological evaluation.
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Synthesis and Spectroscopic Study of a New Lanthanum(III) Complex of 3,3′‐Benzylidenedi‐4‐hydroxycoumarin. ACTA ACUST UNITED AC 2004. [DOI: 10.1081/sim-200026618] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Effect of the nature of mendiaxon−–X+ interactions (X+= Na+, Cu+, H+) and the hydrogen bonding on the ν(CO) behavior: theoretical and spectroscopic study. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Vibrational study of new Pt(II) and Pd(II) complexes with functionalized nitrogen-containing tertiary phosphine oxides. Ab initio study of ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2003; 59:169-192. [PMID: 12509158 DOI: 10.1016/s1386-1425(02)00163-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Vibrational study of new Pt(II) and Pd(II) complexes of functionalized nitrogen-containing tertiary phosphine oxides, namely ortho-, meta- and para-dimethylphosphinylmethyleneoxyaniline (o-, m- and p-dpmoa), (CH3)2P(O)CH2OC6H4NH2, have been presented. Geometry optimization of the ligands was performed at HF/6-31G* and B3LYP/6-31G* levels of the theory. Harmonic frequencies were calculated at HF/6-31G* optimized geometries. Relative gas-phase and solution-phase (H2O and CH3CN) basicities of o-, m- and p-dpmoa ligands have been determined by ab initio calculations at STO-3G level with the Onsager reaction field model. On the basis of the vibrational study, physical and analytical data it was suggested that the ligands in the complexes studied coordinate through the amino group and form square-planar platinum and palladium complexes of the general formula ML2Cl2 (M = Pt, Pd, L = o-, m- and p-dpmoa).
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Conformational stability and vibrational spectrum of glyoxilic acid oxime predicted from ab initio study. J Mol Struct 2002. [DOI: 10.1016/s0022-2860(01)00652-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Molecular mechanics modelling of Pt(II) complexes with antitumor activity. Influence of the type and the positions of the ring substituents on the conformational energies and thermodynamic stabilities. MONATSHEFTE FUR CHEMIE 1997. [DOI: 10.1007/bf00807562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Molecular mechanical and quantum chemical study on the species involved in the hydrolysis of cis-diamminedichloroplatinum(II) and substituted bis(ethylenediamine)dichloroplatinum(II) complexes Part I. Reactants and products. Inorganica Chim Acta 1994. [DOI: 10.1016/0020-1693(93)03765-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Temperature-dependent vibrational spectra of zinc(II) bis-(N,N′-diethyldithiocarbamate) in solid state and solution. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0584-8539(91)80251-d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Infrared spectra of Pt(II) creatinine complexes. Normal coordinate analysis of creatinine and Pt(creat)2(NO2)2. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0584-8539(91)80074-s] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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44
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Eight coordination—I. Effect of inter-ligand repulsion on the geometry of eight-coordinate complexes. Polyhedron 1991. [DOI: 10.1016/s0277-5387(00)80202-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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45
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Manifestation of the Jahn-Teller active vibrations in the vibronic spectra of tetracoordinate Cu2+, Ni2+ and Zn2+ chlorides. Chem Phys 1990. [DOI: 10.1016/0301-0104(90)85052-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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46
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Detecting the bonding type of dithiocarbamate ligands in their complexes as inferred from the asymmetric CS mode. Inorganica Chim Acta 1984. [DOI: 10.1016/s0020-1693(00)82413-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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