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1.
Dalton Trans ; 50(18): 6245-6255, 2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-33876177

RESUMO

Reaction of (2,3,9,10,16,17,23,24-octabutylphthalocyaninato)lanthanide(iii) acetylacetonates (BuPcLn(acac), 1a-c, Ln = Lu (a), Eu (b), La (c)) with a tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazine ligand (tBuPhDzPzH2, 2) produced sandwich compounds (tBuPhDzPz)Ln(BuPc) (3a-c), which represent the first heteroleptic double-deckers incorporating both Pc and DzPz decks. A combination of high-resolution mass spectrometry, UV-Vis/NIR, MCD, and 1H NMR spectroscopy, and square-wave voltammetry provided unambiguous characterization of target complexes 3 indicating that their spectral and electrochemical properties are generally intermediate with respect to their homoleptic relatives. Based on the data of solution-state 1H-1H NMR (COSY, NOESY) correlation spectroscopy supported by DFT calculations, a dimerization tendency of compounds 3 proportional to the Ln(iii) ion size was found. The spectroelectrochemical study of 3 and the corresponding homoleptic double-deckers revealed a pronounced tendency to aggregation of the one-electron oxidized forms of DzPz-containing double-decker complexes compared to homoleptic Pc2Ln compounds.

2.
Dalton Trans ; 45(30): 12041-52, 2016 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-27396712

RESUMO

A series of homoleptic bis{tetrakis(5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepino)[2,3-b,g,l,q]porphyrazinato}lanthanide sandwich complexes [(tBuPh)DzPz]2Ln (Ln = Lu, Er, Dy, Eu, Nd, Ce, La) were prepared and their physicochemical properties were studied to gain insight into the nature of specific interactions in diazepinoporphyrazines. The effect of annulated diazepine moieties and the Ln ionic radius on the properties of the complexes was investigated in comparison with double-decker phthalocyanines. A combination of experimental and theoretical studies revealed the presence of two types of hydrogen bonding interactions in the metal-free porphyrazine and the corresponding sandwich complexes, namely, interligand C-H(ax)N(meso) hydrogen bonding and O-HN(Dz) ligand-water interaction. The interligand hydrogen bonding imparts high stability of the ligand dimer and the double-decker compounds in a reduced state. This work is the first comprehensive investigation into the fundamental understanding of the unusual properties of diazepine-containing macroheterocycles.

3.
Org Biomol Chem ; 14(3): 1138-46, 2016 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-26646741

RESUMO

A series of novel 5,7-bis(2'-arylethenyl)-6H-1,4-diazepine-2,3-dicarbonitriles was synthesized through sequential aldol condensation reactions of 1,3-diketones with diaminomaleonitrile, and the resulting 5,7-dimethyl-6H-1,4-diazepines were condensed with aromatic aldehydes. The substituents' effects on the spectral properties and conformational states of the molecules in solution were studied using 2D NMR techniques and DFT calculations. Specific intramolecular steric interactions in derivatives substituted at the C6 position were discovered and investigated in detail. Differential scanning calorimetry and thermogravimetric analyses revealed the strong dependence of the thermal stability of the newly prepared diazepinodicarbonitriles on the nature of the substituents. This offers new insight into the structure-property relationships of arylethenyl-substituted diazepine derivatives.

4.
Spectrochim Acta A Mol Biomol Spectrosc ; 139: 464-70, 2015 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-25576944

RESUMO

Novel A3B-type 8(9),13(14),18(19)-tri-tert-butyl-2(5),4(7)-bis(4-tert-butylphenyl)tribenzo[g,l,q]-6H-1,4-diazepino[2,3-b]porphyrazine, which has high solubility in organic solvents, was obtained by template co-condensation of 2,3-dicyano-5,7-bis(4-tert-butylphenyl)-6H-1,4-diazepine and 4-tert-butylphthalonitrile. It was characterized by UV/Vis, (1)H, (13)C NMR spectroscopy, and MALDI-TOF/TOF mass spectrometry. We have demonstrated for the first time using fluorescence spectroscopy measurements and quantum-chemical calculations that the complicated UV/Vis spectrum of A3B-type tribenzodiazepinoporphyrazine is due to the formation of stable H-type aggregates.


Assuntos
Benzodiazepinas/química , Benzodiazepinas/síntese química , Modelos Moleculares , Porfirinas/química , Porfirinas/síntese química , Teoria Quântica , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Termodinâmica
5.
J Comput Chem ; 34(7): 533-44, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23108605

RESUMO

Large-scale on-the-fly Born-Oppenheimer molecular dynamics simulations using recent advances in linear scaling electronic structure theory and trajectory integration techniques have been performed for protonated water clusters around the magic number (H(2)O)(n)H(+) , for n = 20 and 21. Besides demonstrating the feasibility and efficiency of the computational approach, the calculations reveal interesting dynamical details. Elimination of water molecules is found to be fast for both cluster sizes but rather insensitive to the initial geometry. The water molecules released acquire velocities compatible with thermal energies. The proton solvation shell changes between the well-known Eigen and Zundel motifs and is characterized by specific low-frequency vibrational modes, which have been quantified. The proton transfer mechanism largely resembles that of bulk water but one interesting variation was observed.

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