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1.
J Phys Chem Lett ; 11(3): 877-884, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31931562

RESUMO

BODIPY chromophores can serve as organic-based triplet photosensitizers for a wide range of applications. To perform this function, the formation of the triplet state is critical, and a better understanding of how to modulate the formation of the triplet state could lead to further advances in BODIPY-based sensitizers for solar energy conversion and photodynamic therapy. In this work we investigate the ability of halogen bonding, a noncovalent solvent interaction, to facilitate intersystem crossing in a diiodo-BODIPY. Ultrafast transient absorption spectroscopy is applied to diiodo-BODIPY in the presence of pyridine-based halogen bonding solvent molecules to determine the rate constants for intersystem crossing. We find that halogen bonding facilitates the formation of the triplet state by increasing the intersystem crossing rate constant of diiodo-BODIPY. The results are interpreted in terms of the Marcus expression for intersystem crossing. Quantum chemical calculations show that halogen bonding acts to alter both the spin-orbit coupling terms and the relative energetics of the singlet and triplet states.


Assuntos
Compostos de Boro/química , Halogênios/química , Cinética , Piridinas/química , Teoria Quântica , Solventes/química
2.
Molecules ; 24(19)2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31591340

RESUMO

The activation of halogen bonding by the substitution of the pentafluoro-λ6-sulfanyl (SF5) group was studied using a series of SF5-substituted iodobenzenes. The simulated electrostatic potential values of SF5-substituted iodobenzenes, the ab initio molecular orbital calculations of intermolecular interactions of SF5-substituted iodobenzenes with pyridine, and the 13C-NMR titration experiments of SF5-substituted iodobenzenes in the presence of pyridine or tetra (n-butyl) ammonium chloride (TBAC) indicated the obvious activation of halogen bonding, although this was highly dependent on the position of SF5-substitution on the benzene ring. It was found that 3,5-bis-SF5-iodobenzene was the most effective halogen bond donor, followed by o-SF5-substituted iodobenzene, while the m- and p-SF5 substitutions did not activate the halogen bonding of iodobenzenes. The similar ortho-effect was also confirmed by studies using a series of nitro (NO2)-substituted iodobenzenes. These observations are in good agreement with the corresponding Mulliken charge of iodine. The 2:1 halogen bonding complex of 3,5-bis-SF5-iodobenzene and 1,4-diazabicyclo[2.2.2]octane (DABCO) was also confirmed. Since SF5-containing compounds have emerged as promising novel pharmaceutical and agrochemical candidates, the 3,5-bis-SF5-iodobenzene unit may be an attractive fragment of rational drug design capable of halogen bonding with biomolecules.


Assuntos
Halogênios/química , Iodobenzenos/química , Desenho de Fármacos , Elétrons , Flúor/química , Iodetos/química , Iodo , Espectroscopia de Ressonância Magnética , Piridinas/química , Eletricidade Estática
3.
Chem Commun (Camb) ; 55(91): 13653-13656, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31593201

RESUMO

Blending synthetic biology and synthetic chemistry represents a powerful approach to diversity complex molecules. To further enable this, compatible synthetic tools are needed. We report the first Buchwald Hartwig amination reactions with unprotected halotryptophans under aqueous conditions and demonstrate this methodology is applicable also to the modification of unprotected tripeptides and the natural product barettin.


Assuntos
Oligopeptídeos/química , Peptídeos Cíclicos/química , Triptofano/análogos & derivados , Água/química , Aminação , Compostos de Anilina/química , Catálise , Halogênios/química , Oligopeptídeos/síntese química , Paládio/química , Triptofano/síntese química
4.
Phys Chem Chem Phys ; 21(42): 23355-23363, 2019 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-31621727

RESUMO

Penetrating cations are widely used for the design of bioactive mitochondria-targeted compounds. The introduction of various substituents into the phenyl rings of dodecyltriphenylphosphonium and the measurement of the flip-flop of the synthesized cations by the current relaxation method revealed that methyl groups accelerated significantly the cation penetration through the lipid membrane, depending on the number of groups introduced. However, halogenation slowed down the penetration of the analogues. This result is strictly opposite to the flip-flop acceleration observed for halogenated tetraphenylborate anions. Density functional theory and the polarizable continuum solvent model were used to calculate the solvation energies of methyltriphenylphosphonium and methyltriphenylborate analogues. A good agreement was demonstrated between the difference in the free energy of ion solvation in water and octane and the absolute value of the central free energy barrier estimated from experimental data. Our results reveal that increasing the size of the lipophilic ion can lead to both acceleration and deceleration of the transmembrane flip-flop rate depending on the substituent and sign of the ion. This finding also emphasizes the different nature of ion-water interactions for structurally similar substituted hydrophobic anions and cations.


Assuntos
Halogênios/química , Bicamadas Lipídicas/química , Teoria da Densidade Funcional , Eletricidade , Interações Hidrofóbicas e Hidrofílicas , Íons/química , Compostos Organofosforados/química , Solventes/química , Tetrafenilborato/química , Água/química
5.
Molecules ; 24(18)2019 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-31547416

RESUMO

Various types of σ-hole bond complexes were formed with FX, HFY, H2FZ, and H3FT (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) as Lewis acid. In order to examine their interactions with a protein, N-methylacetamide (NMA), a model of the peptide linkage was used as the base. These noncovalent bonds were compared by computational means with H-bonds formed by NMA with XH molecules (X = F, Cl, Br, I). In all cases, the A-F bond, which lies opposite the base and is responsible for the σ-hole on the A atom (A refers to the bridging atom), elongates and its stretching frequency undergoes a shift to the red with a band intensification, much as what occurs for the X-H bond in a H-bond (HB). Unlike the NMR shielding decrease seen in the bridging proton of a H-bond, the shielding of the bridging A atom is increased. The spectroscopic changes within NMA are similar for H-bonds and the other noncovalent bonds. The C=O bond of the amide is lengthened and its stretching frequency red-shifted and intensified. The amide II band shifts to higher frequency and undergoes a small band weakening. The NMR shielding of the O atom directly involved in the bond rises, whereas the C and N atoms both undergo a shielding decrease. The frequency shifts of the amide I and II bands of the base as well as the shielding changes of the three pertinent NMA atoms correlate well with the strength of the noncovalent bond.


Assuntos
Calcogênios/química , Halogênios/química , Proteínas/química , Acetamidas/química , Hidrogênio/química , Ligação de Hidrogênio , Ácidos de Lewis/química , Ressonância Magnética Nuclear Biomolecular , Espectrofotometria Infravermelho
6.
Chem Commun (Camb) ; 55(79): 11948-11951, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31531452

RESUMO

The toxic halogenated anilines 2,4,6-tribromoaniline, 2,4,6-trichloroaniline and their dibromochloro and bromodichloro derivatives were considered as compounds of exclusive synthetic origin. Labeling studies and kinetic experiments confirmed that these substances are also biosynthesized by a marine biofilm forming microalga. They represent a novel class of halogenated natural products.


Assuntos
Compostos de Anilina/química , Biofilmes , Produtos Biológicos/química , Halogênios/química , Microalgas/química , Vias Biossintéticas , Halogenação , Cinética
7.
Mater Sci Eng C Mater Biol Appl ; 104: 109919, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499980

RESUMO

An eco-friendly biosynthesized Pd NP anchored Thymbra spicata extract-modified graphene oxide (Pd NPs/rGO-T. spicata) nanohybrid material has been introduced. Initially, the herb, Thymbra spicata extract was immobilized on the surface of GO via their natural adhering capability. The polyphenolic function grafted in situ prepared RGO acted as the natural reductant of Pd precursor. The as-prepared nanocomposite (Pd NPs/rGO-T. spicata) was characterized using Fourier transform infrared (FTIR), UV-vis, X-ray diffraction (XRD), inductively coupled plasma (ICP), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), Fast Fourier Transform (FFT), Raman spectroscopy and EDX elemental mapping techniques. It has been observed that the Pd NPs with perfect crystal structure, uniform shape and size were dispersed homogeneously on the rGO surface. The material showed excellent water dispersibility due to the hydrophilicity of biomolecules attached over them, which is very essential in heterogeneous catalysis. The T. spicata contained biomolecules served as effective capping, reducing and stabilizing agents for the uniform immobilization of Pd precursors on graphene sheet surface without aggregation. The catalytic activity of this nano hybrid was assessed comprehensively in the cyanation of aryl halides with a wide range of substrates using K4[Fe(CN)6] as a cheap source of cyanide. The model reaction resulted outstanding catalytic performance with a great reusability of the catalysis.


Assuntos
Cianetos/química , Grafite/química , Halogênios/química , Nanopartículas Metálicas/química , Paládio/química , Extratos Vegetais/química , Catálise , Lamiaceae/ultraestrutura , Nanopartículas Metálicas/ultraestrutura , Espectrometria por Raios X , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Difração de Raios X
8.
Molecules ; 24(15)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382376

RESUMO

Radiosensitizing properties of substituted uridines are of great importance for radiotherapy. Very recently, we confirmed 5-iodo-4-thio-2'-deoxyuridine (ISdU) as an efficient agent, increasing the extent of tumor cell killing with ionizing radiation. To our surprise, a similar derivative of 4-thio-2'-deoxyuridine, 5-bromo-4-thio-2'-deoxyuridine (BrSdU), does not show radiosensitizing properties at all. In order to explain this remarkable difference, we carried out a radiolytic (stationary and pulse) and quantum chemical studies, which allowed the pathways to all radioproducts to be rationalized. In contrast to ISdU solutions, where radiolysis leads to 4-thio-2'-deoxyuridine and its dimer, no dissociative electron attachment (DEA) products were observed for BrSdU. This observation seems to explain the lack of radiosensitizing properties of BrSdU since the efficient formation of the uridine-5-yl radical, induced by electron attachment to the modified nucleoside, is suggested to be an indispensable attribute of radiosensitizing uridines. A larger activation barrier for DEA in BrSdU, as compared to ISdU, is probably responsible for the closure of DEA channel in the former system. Indeed, besides DEA, the XSdU anions may undergo competitive protonation, which makes the release of X- kinetically forbidden.


Assuntos
Halogênios/química , Radiossensibilizantes/química , Tiouridina/análogos & derivados , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Histonas/metabolismo , Humanos , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Radiossensibilizantes/farmacologia , Espectrometria de Massas em Tandem , Tiouridina/química , Tiouridina/farmacologia
9.
Molecules ; 24(15)2019 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-31382402

RESUMO

Complexes were formed pairing FX, FHY, FH2Z, and FH3T (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) with NH3 in order to form an A⋯N noncovalent bond, where A refers to the central atom. Geometries, energetics, atomic charges, and spectroscopic characteristics of these complexes were evaluated via DFT calculations. In all cases, the A-F bond, which is located opposite the base and is responsible for the σ-hole on the A atom, elongates and its stretching frequency undergoes a shift to the red. This shift varies from 42 to 175 cm-1 and is largest for the halogen bonds, followed by chalcogen, tetrel, and then pnicogen. The shift also decreases as the central A atom is enlarged. The NMR chemical shielding of the A atom is increased while that of the F and electron donor N atom are lowered. Unlike the IR frequency shifts, it is the third-row A atoms that undergo the largest change in NMR shielding. The change in shielding of A is highly variable, ranging from negligible for FSnH3 all the way up to 1675 ppm for FBr, while those of the F atom lie in the 55-422 ppm range. Although smaller in magnitude, the changes in the N shielding are still easily detectable, between 7 and 27 ppm.


Assuntos
Calcogênios/química , Halogênios/química , Espectroscopia de Ressonância Magnética , Elétrons , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética/métodos , Modelos Moleculares , Conformação Molecular
10.
Molecules ; 24(16)2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31398800

RESUMO

Next-generation quantum theory of atoms in molecules (QTAIM) was used to investigate the competition between hydrogen bonding and halogen bonding for the recently proposed (Y = Br, I, At)/halogenabenzene/NH3 complex. Differences between using the SR-ZORA Hamiltonian and effective core potentials (ECPs) to account for relativistic effects with increased atomic mass demonstrated that next-generation QTAIM is a much more responsive tool than conventional QTAIM. Subtle details of the competition between halogen bonding and hydrogen bonding were observed, indicating a mixed chemical character shown in the 3-D paths constructed from the bond-path framework set B. In addition, the use of SR-ZORA reduced or entirely removed spurious features of B on the site of the halogen atoms.


Assuntos
Benzeno/química , Halogênios/química , Hidrogênio/química , Teoria Quântica , Algoritmos , Ligação de Hidrogênio , Modelos Moleculares , Modelos Teóricos , Conformação Molecular
11.
Nat Commun ; 10(1): 3610, 2019 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-31399581

RESUMO

The natural DNA double helix consists of two strands of nucleotides that are held together by multiple hydrogen bonds. Here we propose to build an artificial double helix from fragments of two strands connected by covalent linkages therein, but with halogen bonding as the driving force for self-assembling the fragments to the double helix. We succeed in building such a double helix in both solution and solid state, by using a bilateral N-(p-iodobenzoyl)alanine based amidothiourea which in its folded cis-form allows double and crossed C-I···S halogen bonds that lead to right- or left-handed double helix when the two alanine residues are of the same L,L- or D,D-configuration. The double helix forms in dilute CH3CN solution of the micromolar concentration level, e.g., 5.6 µM from 2D NOESY experiments and exhibits a high thermal stability in solution up to 75 °C, suggesting cooperative and thereby strong intermolecular double crossed halogen bonding that makes the double helix stable. This is supported by the observed homochiral self-sorting in solution.


Assuntos
DNA/química , Halogênios/química , Conformação de Ácido Nucleico , Acetonitrilos , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Nucleotídeos , Estereoisomerismo
12.
Org Biomol Chem ; 17(32): 7493-7496, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31364664

RESUMO

The fluorinase enzyme from Streptomyces cattleya is shown to catalyse a direct displacement of bromide and iodide by fluoride ion from 5'-bromodeoxyadenosine (5'-BrDA) and 5'-iododeoxyadenosine (5'-IDA) respectively to form 5'-fluorodeoxyadenosine (5'-FDA) in the absence of l-methionine (l-Met) or S-adenosyl-l-methionine (SAM). 5'-BrDA is the most efficient substrate for this enzyme catalysed Finkelstein reaction.


Assuntos
Proteínas de Bactérias/química , Desoxiadenosinas/química , Halogênios/química , Oxirredutases/química , Catálise , Cinética , Metionina/química , Conformação Molecular , S-Adenosilmetionina/química , Streptomyces/enzimologia , Termodinâmica
13.
Molecules ; 24(15)2019 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-31357615

RESUMO

Relationships between interaction energy (Eint) and electron density properties at the X···X bond critical point or the d(X···X) distance were established for the large set of structures [(A)nY-X···X-Z(B)m] bearing the halogen bonds Cl···Cl, Br···Br, and I···I (640 structures in total). The best estimator of Eint is the kinetic energy density (Gb), which reasonably approximates the whole set of the structures as -Eint = 0.128Gb2 - 0.82Gb + 1.66 (R2 = 0.91, mean absolute deviation 0.39 kcal/mol) and demonstrates low dispersion. The potential and kinetic energy densities, electron density, and the d(X···X) distance behave similarly as estimators of Eint for the individual series Cl···Cl, Br···Br, and I···I. A number of the Eint(property) correlations are recommended for the practical application in the express estimates of the strength of the homo-halogen bonds.


Assuntos
Elétrons , Halogênios/química , Modelos Teóricos , Algoritmos , Teoria da Densidade Funcional
14.
Phys Chem Chem Phys ; 21(31): 17118-17125, 2019 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-31339118

RESUMO

The electronic structural origin of the THz and IR spectral changes occurring upon halogen-bond formation is examined by employing the technique of electron density analysis. Theoretical calculations and analyses are conducted for the complexes of pentafluoroiodobenzene (C6F5I) and nitryl chloride (O2NCl) formed with other (halogen-bond accepting) molecules taken as typical examples. It is shown that, in the case of the C-I stretching mode of C6F5I appearing in the THz spectral region, the intensity enhancement occurring upon halogen-bond formation arises from the intermolecular charge flux and (together with the vibrational frequency) is correlated to the partial charge-transfer and covalent nature of the halogen bond. For the N-Cl stretching vibration of O2NCl, it is shown that the high-frequency shift occurring upon complex formation with NH3 arises mainly from the electrostatic effect, while the reduction of its IR intensity arises from the polarization effect and, to a larger extent, from the intermolecular charge flux. These results indicate, therefore, that there are some observable spectroscopic properties in the THz and IR region that are mainly controlled by (and, hence, shed light on) the partial charge-transfer and covalent nature of halogen bonding.


Assuntos
Halogênios/química , Modelos Moleculares , Derivados de Benzeno/química , Hidrocarbonetos Halogenados/química , Nitritos/química , Teoria Quântica , Espectrofotometria Infravermelho , Eletricidade Estática
15.
Int J Mol Sci ; 20(14)2019 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-31336936

RESUMO

In this manuscript, we use the primary source of geometrical information, i.e., Cambridge Structural Database (CSD), combined with density functional theory (DFT) calculations (PBE0-D3/def2-TZVP level of theory) to demonstrate the relevance of π-hole interactions in para-nitro substituted pyridine-1-oxides. More importantly, we show that the molecular electrostatic potential (MEP) value above and below the π-hole of the nitro group is largely influenced by the participation of the N-oxide group in several interactions like hydrogen-bonding (HB) halogen-bonding (XB), triel bonding (TrB), and finally, coordination-bonding (CB) (N+-O- coordinated to a transition metal). The CSD search discloses that p-nitro-pyridine-1-oxide derivatives have a strong propensity to participate in π-hole interactions via the nitro group and, concurrently, N-oxide group participates in a series of interactions as electron donor. Remarkably, the DFT calculations show from strong to moderate cooperativity effects between π-hole and HB/XB/TrB/CB interactions (σ-bonding). The synergistic effects between π-hole and σ-hole bonding interactions are studied in terms of cooperativity energies, using MEP surface analysis and the Bader's quantum theory of atoms in molecules (QTAIM).


Assuntos
Halogênios/química , Hidrogênio/química , Modelos Químicos , Piridinas/química , Algoritmos , Teoria da Densidade Funcional , Ligação de Hidrogênio , Modelos Moleculares , Conformação Molecular , Eletricidade Estática
16.
Molecules ; 24(15)2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31349689

RESUMO

The discovery of the aggregation-induced emission (AIE) phenomenon in the early 2000s not only has overcome persistent challenges caused by traditional aggregation-caused quenching (ACQ), but also has brought about new opportunities for the development of useful functional molecules. Through the years, AIE luminogens (AIEgens) have been widely studied for applications in the areas of biomedical and biological sensing, chemosensing, optoelectronics, and stimuli responsive materials. Particularly in the application of chemosensing, a myriad of novel AIE-based sensors has been developed to detect different neutral molecular, cationic and anionic species, with a rapid detection time, high sensitivity and high selectivity by monitoring fluorescence changes. This review thus summarises the recent development of AIE-based chemosensors for the detection of anionic species, including halides and halide-containing anions, cyanides, and sulphur-, phosphorus- and nitrogen- containing anions, as well as a few other anionic species, such as citrate, lactate and anionic surfactants.


Assuntos
Ânions/análise , Medições Luminescentes , Ânions/química , Corantes Fluorescentes , Halogênios/análise , Halogênios/química , Medições Luminescentes/métodos , Processos Fotoquímicos
17.
Molecules ; 24(11)2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31159347

RESUMO

We employ a variety of natural bond orbital (NBO) and natural resonance theory (NRT) tools to comprehensively investigate the nature of halogen and pnicogen bonding interactions in RPH2···IF/FI binary complexes (R = CH3, OH, CF3, CN, and NO2) and the tuning effects of R-substituents. Though such interactions are commonly attributed to "sigma-hole"-type electrostatic effects, we show that they exhibit profound similarities and analogies to the resonance-type 3-center, 4-electron (3c/4e) donor-acceptor interactions of hydrogen bonding, where classical-type "electrostatics" are known to play only a secondary modulating role. The general 3c/4e resonance perspective corresponds to a continuous range of interatomic A···B bond orders (bAB), spanning both the stronger "covalent" interactions of the molecular domain (say, bAB ≥ ½) and the weaker interactions (bAB ˂ ½, often misleadingly termed "noncovalent") that underlie supramolecular complexation phenomena. We show how a unified NBO/NRT-based description of hydrogen, halogen, pnicogen, and related bonding yields an improved predictive utility and intuitive understanding of empirical trends in binding energies, structural geometry, and other measurable properties that are expected to be manifested in all such supramolecular interaction phenomena.


Assuntos
Halogênios/química , Hidrogênio/química , Modelos Teóricos , Elétrons , Ligação de Hidrogênio , Modelos Moleculares , Análise Espectral , Eletricidade Estática
18.
Int J Mol Sci ; 20(11)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167476

RESUMO

Antimicrobial resistance is now considered a major global challenge; compromising medical advancements and our ability to treat infectious disease. Increased antimicrobial resistance has resulted in increased morbidity and mortality due to infectious diseases worldwide. The lack of discovery of novel compounds from natural products or new classes of antimicrobials, encouraged us to recycle discontinued antimicrobials that were previously removed from routine use due to their toxicity, e.g., colistin. Since the discovery of new classes of compounds is extremely expensive and has very little success, one strategy to overcome this issue could be the application of synthetic compounds that possess antimicrobial activities. Polymers with innate antimicrobial properties or that have the ability to be conjugated with other antimicrobial compounds create the possibility for replacement of antimicrobials either for the direct application as medicine or implanted on medical devices to control infection. Here, we provide the latest update on research related to antimicrobial polymers in the context of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens. We summarise polymer subgroups: compounds containing natural peptides, halogens, phosphor and sulfo derivatives and phenol and benzoic derivatives, organometalic polymers, metal nanoparticles incorporated into polymeric carriers, dendrimers and polymer-based guanidine. We intend to enhance understanding in the field and promote further work on the development of polymer based antimicrobial compounds.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Polímeros/química , Polímeros/farmacologia , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Fenômenos Químicos , Desenvolvimento de Medicamentos , Resistência Microbiana a Medicamentos , Halogênios/química , Humanos , Estrutura Molecular , Polímeros/uso terapêutico , Vigilância da População , Relação Estrutura-Atividade , Tensoativos/química , Tensoativos/farmacologia , Tensoativos/uso terapêutico
19.
Dalton Trans ; 48(28): 10488-10504, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31210199

RESUMO

Reactions between halogen substituted terpyridine ligands F- (L1), Cl- (L2), Br- (L3) and I-4'-phenyl-terpyridine (L4) and ZnBr2 or ZnI2 led to the formation of complexes [Zn(Br)2L1] (1), [Zn(i)2L1] (2), [Zn(Br)2L2] (3), [Zn(i)2L2] (4), [Zn(Br)2L3] (5), [Zn(i)2L3] (6), [Zn(Br)2L4] (7), and [Zn(i)2L4] (8), respectively, which were characterized by elemental analysis, 1H NMR, IR and single crystal X-ray diffraction. Their photoluminescence properties, solution stabilities, hydrophilicity/lipophilicity properties and anti-proliferative activity against three cancer cell lines as well as structure-function relationships are analyzed. All the complexes, which show high solution stabilities and lipophilicity under determination conditions, reveal much higher antiproliferative activities than cisplatin against the human lung carcinoma cell line (A549), human hepatocellular carcinoma cell line (Bel-7042) and human breast cancer cell line (MCF-7) in vitro. Fluorescence spectroscopy and circular dichroic analysis reveal that the compounds have strong affinity binding with ctDNA and stack onto the base pairs of the ctDNA. The results obtained are further explained in terms of the electronic properties of the compounds by density functional theory (DFT) calculations, and it is found that the halogen anions play critical roles in the antitumor activity of these compounds. Their affinities to HSP90 proteins, ALK, EGFR and HER2 kinases and the binding sites on these proteins have been determined by computational docking analysis, and the results indicate that the only form of their binding is van der Waals forces.


Assuntos
Antineoplásicos/farmacologia , Teoria da Densidade Funcional , Simulação de Acoplamento Molecular , Compostos Organometálicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Halogênios/química , Halogênios/farmacologia , Humanos , Luminescência , Estrutura Molecular , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Processos Fotoquímicos , Proteínas/química , Piridinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Zinco/química , Zinco/farmacologia
20.
Molecules ; 24(10)2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31137795

RESUMO

The crystal structure of 4-iodobenzonitrile, which is monoclinic (space group I2/a) under ambient conditions, contains chains of molecules linked through C≡N···I halogen-bonds. The chains interact through CH···I, CH···N and π-stacking contacts. The crystal structure remains in the same phase up to 5.0 GPa, the b axis compressing by 3.3%, and the a and c axes by 12.3 and 10.9 %. Since the chains are exactly aligned with the crystallographic b axis these data characterise the compressibility of the I···N interaction relative to the inter-chain interactions, and indicate that the halogen bond is the most robust intermolecular interaction in the structure, shortening from 3.168(4) at ambient pressure to 2.840(1) Å at 5.0 GPa. The π∙∙∙π contacts are most sensitive to pressure, and in one case the perpendicular stacking distance shortens from 3.6420(8) to 3.139(4) Å. Packing energy calculations (PIXEL) indicate that the π∙∙∙π interactions have been distorted into a destabilising region of their potentials at 5.0 GPa. The structure undergoes a transition to a triclinic ( P 1 ¯ ) phase at 5.5 GPa. Over the course of the transition, the initially colourless and transparent crystal darkens on account of formation of microscopic cracks. The resistance drops by 10% and the optical transmittance drops by almost two orders of magnitude. The I···N bond increases in length to 2.928(10) Å and become less linear [

Assuntos
Halogênios/química , Nitrilos/química , Pressão , Cristalização , Diamante/química , Dimerização , Elétrons , Ouro/química , Conformação Molecular , Fônons , Espectrofotometria Ultravioleta , Análise Espectral Raman , Termodinâmica
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