Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 10 de 10
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
ACS Omega ; 4(7): 12146-12155, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31460329

RESUMO

An environmentally benign highly atom-economic protocol for the construction of the C-C bond has been developed under catalyst- and solvent-free conditions. This protocol involves the efficient coupling of 2-methyl quinazolinones with isatin for the highly diastereoselective access of schizocommunin derivatives in excellent yields (up to 97%). Furthermore, the preliminary cytotoxicity screening of selected schizocommunin analogues displayed promising anticancer activity against human cancer cell lines, and the cytotoxic potential of active compound 12ac was also validated by in silico molecular docking simulation studies.

2.
Inorg Chem ; 58(16): 10955-10964, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31380633

RESUMO

The study presents a rational synthesis of new dimethyltin carboxylates, Me2Sn(H2btec) (1), Me2Sn(btec)0.5(2), [Me2Sn(H2O)2(btec)0.5]·H2O (3), and [{Me2SnOSn(OH)Me2}(Me2SnOH)(btec)0.5]·H2O (4), derived from tetratopic 1,2,4,5-benzenetetracarboxylic acid (H4btec). The method relies upon hydrothermal reaction (130 °C, 72 h) of dimethyltin dichloride and H4btec under optimized pH (2 < pH < 8) conditions that allow control over dimethyltin speciation in aqueous medium as well as degree of deprotonation of the tetrafuntional carboxylic acid. The formation of a three-dimensional assembly in 1 is assisted by the bridging bidentate (µ2) mode of the carboxylate and O-H···O hydrogen bonds involving -COOH groups. The structure represents a unique example of the diorganotin framework derived from a partially deprotonated polyfuntional carboxylic acid. The structure of 2 adopts a three-dimensional motif wherein each pair of µ2-carboxylate groups (designated by C1 and C4) of the tetraanionic ligand form different spatial arrangements. For 3, the formation of one-dimensional motif with eight-coordinated tin atoms is assisted by the anisobidentate character of the carboxylate groups. The structure of 4 includes linear chains comprised of [Me2Sn(µ2-OH)]2 and the carboxylate ligand which extend to a layered motif with symmetrically substituted ladder-like distannoxanes acting as linkers. The underlying nets of 1, 2, and 4 exhibit sqc11, scu(sqc170), and sql topologies, respectively. Notably, these assemblies are extremely robust and show no sign of degradation upon exposure to neutral as well as weakly acidic/basic aqueous medium for 7 days.

3.
Dalton Trans ; 47(35): 12318-12336, 2018 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-30113615

RESUMO

Single crystal X-ray diffraction studies reveal the formation of six new coordination polymers (CPs) with the general formulas [Dy(3,5-pdc)(3,5-pdcH)(H2O)2]n·nH2O (1), [Pr2(3,5-pdc)3(H2O)2]n·2n(H2O) (2), [Sm2(3,5-pdc)3(H2O)3]n·nH2O (3), {[Eu2(3,5-pdc)3(H2O)3(CH3CHO)]n·n[2(H2O)(DMF)]} (4), {[Gd2(3,5-pdc)3 (H2O)2]n·2nH2O} (5) and [Er(3,5-pdc)(adip)0.5(H2O)]n (6) (where 3,5-pdc2- = fully deprotonated; 3,5-pdcH- = partially deprotonated 3,5-pyridinedicarboxylic acid; adip2- = fully deprotonated adipic acid; and DMF = dimethylformamide) by solvothermal self-assembly of lanthanide ions with rigid 3,5-pyridinedicarboxylic acid as a linker and adipic acid as an auxiliary flexible spacer (only coordinated in CP 6). CPs 1 and 2 crystallize in the triclinic P1[combining macron] space group, whereas CPs 3, 4 and 6 crystallize in the monoclinic P21/n, P21/c and C2/c space groups, respectively. CP 5 exhibits the trigonal R3 space group. The 3,5-pdc ligand exhibits eight diverse coordination modes in CPs 1-6, whereas the adipic acid spacer in CP 6 shows only one coordination mode (µ4-κO:κO,O:κO:κO,O). The organic ligands interconnect with metal ions to generate 3D metal-organic frameworks with a variety of intriguing topologies. Theoretical studies, DFT calculations and Hirshfeld surface analysis support the structures adopted by the various CPs. CPs 3 (Sm) and 4 (Eu) emit strong ligand-sensitized characteristic f-f luminescence. Weak ferromagnetic interactions have been studied at low temperatures for CP 1 and CP 5.

4.
Dalton Trans ; 47(13): 4722-4732, 2018 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-29537422

RESUMO

Single crystal diffraction studies reveal the formation of the following 10 new complexes of lighter Ln(iii) ions with general formulas {[Ln(µ2-L1)3·(H2O)2]·H2O}n (Ln = Nd (1) and Eu (2)), [Nd(µ2-L2)2·(CH3COO)·(H2O)2]n (3), [Ln2(µ2-L2)5·(L2)·(H2O)4]n (Ln = Sm (4), Ce (5), and Pr (6)), [La2(µ2-L2)6·(H2O)3·(DMF)]n (7) (DMF = dimethylformamide), [Ln(µ2-L2)2·(L2)·(H2O)3]2 (Ln = Eu (8) and Gd (9)) and [Gd(L2)·(CH3COO)2·(H2O)2]2 (10), where L1 and L2 are anions of 3,5- and 2,4-dinitrobenzoic acid, respectively. Complexes 1-7 are 1D coordination polymers, while 8-10 are dinuclear complexes. The luminescence properties of Nd(iii) and Eu(iii) analogues displayed metal-centred emission with L1 exhibiting weak but more efficient sensitization than L2. A study of the magnetic properties of the compounds clearly demonstrated the field-induced single ion magnet behaviour of the Nd(iii) compounds 1 and 3. Their behaviour has been compared to previously reported analogous Nd(iii) complexes and the role of the lattice solvent and polymorphism on the magnetic behaviour has been evaluated.

5.
Dalton Trans ; 44(36): 15774-8, 2015 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-26299199

RESUMO

Two non-isostructural homometallic 1D neodymium species displaying field-induced slow magnetization relaxations are presented together with theoretical studies. It is established that both systems are better described as organized 1D single molecule magnets (SMMs). Studies show great potential of Nd(III) ions to provide homometallic chains with slow magnetic relaxation.

6.
Org Biomol Chem ; 13(21): 5944-54, 2015 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-25927345

RESUMO

A wide range of 4,6-diarylated/heterylated pyridin-2(1H)-one derivatives were synthesized in good to excellent yields from 1,3-diarylated/heterylated-2-propen-1-ones (chalcones) in one pot under metal and base-free conditions. This domino reaction suggests a novel mechanism comprising of Michael addition followed by amination, subsequent intramolecular amidation and finally dehydronitrosation. The usefulness of the designed 4,6-diarylated/heterylated pyridin-2(1H)-one derivatives has further been demonstrated by synthesizing medicinally important 2,4,6-triaryl/heteryl pyridines via Pd-catalyzed cross-coupling reaction.


Assuntos
Chalconas/química , Piridinas/síntese química , Aminação , Catálise , Chalconas/síntese química , Ciclização , Modelos Moleculares , Paládio/química , Piridinas/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-25827375

RESUMO

A new series of donor-stabilized addition complexes of cobalt(II) with disubstituted diphenyldithiophosphates [{(ArO)2PS2}2CoL2] {Ar = 2,4-(CH3)2C6H3 [(1)-(3)] and 3,5-(CH3)2C6H3 [(4)-(6)]; L = C5H5N [(1), (4)], 3,4-(CH3)2C5H3N [(2), (5)] and 4-(C2H5)C5H4N [(3), (6)]} were successfully isolated and characterized by elemental analyses, magnetic moment measurements, IR and single-crystal X-ray analysis. Complexes (3), (4) and (5) crystallize in the monoclinic space groups P2(1)/n, P2(1)/n and P2(1)/c, respectively, whereas complex (6) crystallizes in the triclinic space group P1¯. X-ray diffraction analysis of complexes (3)-(6) reveals a six-coordinated distorted octahedral geometry for the CoS4N2 chromophore defined by two chelating diphenyldithiophosphate anions as well as two N-donor ligands. Two diphenyldithiophosphate ligands are coordinated to the cobalt ion as a bidentate ligand chelating via the two thiolate S atoms. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Co atom in a mutually trans position.

8.
Artigo em Inglês | MEDLINE | ID: mdl-25080255

RESUMO

Donor-stabilized addition complexes of nickel(II) with disubstituted diphenyldithiophosphates, [{(ArO)2PS2}2NiL2] {Ar = 2,4-(CH3)2C6H3 [(1), (5)], 2,5-(CH3)2C6H3 [(2), (6)], 3,4-(CH3)2C6H3 [(3), (7)] and 3,5-(CH3)2C6H3 [(4), (8)]; L = C5H5N [(1)-(4)] and C7H9N [(5)-(8)]}, were successfully isolated and characterized by elemental analysis, magnetic moment, IR spectroscopy and single-crystal X-ray analysis. Compound (4) crystallizes in the monoclinic space group P2(1)/n whereas compounds (7) and (8) crystallize in the triclinic space group P1. The single-crystal X-ray diffraction analysis of (4), (7) and (8) reveals a six-coordinated octahedral geometry for the NiS4N2 chromophore. Two diphenyldithiophosphate ions act as bidentate ligands with their S atoms coordinated to the Ni centre. Each of them forms a four-membered chelate ring in the equatorial plane. The N atoms from two donor ligands are axially coordinated to the Ni atom.

9.
Eur J Med Chem ; 76: 145-54, 2014 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-24583354

RESUMO

Among the biometals (Cu, Co, Ni-cofactors in many enzymes), copper derivatives of O, N, S-donor salicylaldehyde thiosemicarbazones have received considerable attention owing to their potential biological applications. Eight new complexes of salicylaldehyde-N-substituted thiosemicarbazones [5-MeO-2-HO-C6H4-C(2)(H)N(3)-N(2)H-C(1)(S)-N(1)HR; R = Me, H2L(1); Et, H2L(1), Ph, H2L(3), H, H2L(4)] with copper(II), namely, [Cu(κ(3)-O,N,S-L)( κ(2)-N,N-L')] {(L)(2-) = (L(1))(2-), L' = bipy, 1, phen, 2; (L)(2-) = (L(2))(2-), L' = bipy, 3, phen, 4; (L)(2-) = (L(3))(2-), L' = bipy, 5, phen, 6; (L)(2-) = (L(4))(2-), L' = bipy, 7, phen, 8} have been isolated. Complexes have slightly distorted square pyramidal geometry around the metal center (τ parameter = 0.243-0.357) and display weak to intense fluorescence in the region, 375-475 nm. These copper complexes have shown significant growth inhibitory activity (antimicrobial activity) against Staphylococcus aureus (MTCC740), methicillin resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae 1 (MTCC109), Shigella flexneri (MTCC1457), Pseudomonas aeruginosa (MTCC741) and Candida albicans (MTCC227). The activity against MRSA is an interesting observation as the commercially available gentamycin is found to be inactive against this bacterial strain. Specifically complex 5 formed by 5-methoxysalicylaldehyde-N-phenylthiosemicatbazone has shown novel antimicrobial activity against various bacteria and yeast investigated.


Assuntos
2,2'-Dipiridil/síntese química , Aldeídos/química , Antibacterianos/síntese química , Cobre/química , Fenantrolinas/síntese química , Tiossemicarbazonas/síntese química , 2,2'-Dipiridil/química , 2,2'-Dipiridil/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Cristalografia por Raios X , Testes de Sensibilidade Microbiana , Modelos Moleculares , Fenantrolinas/química , Fenantrolinas/farmacologia , Análise Espectral/métodos , Tiossemicarbazonas/química , Tiossemicarbazonas/farmacologia
10.
Acta Chim Slov ; 61(4): 866-74, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25551728

RESUMO

Diaryldithiophosphate complexes of mono- and dibutyltin(IV) corresponding to [(ArO)(2)PS(2)(n)Sn(nBu)xCl(4-x-n)] (Ar = o-CH(3)C(6)H(4), m-CH(3)C(6)H(4), p-CH(3)C(6)H(4), 4-Cl-3-CH(3)C(6)H(3), (3,5-CH(3))(2)C(6)H(3); n = 1, 2 for x = 1 and n = 2 for x = 2) were successfully isolated and characterized by elemental analyses, IR, multinuclear NMR ((1)H, (13)C, (31)P and (119)Sn) spectroscopy and X-ray analysis. The thermal properties of the complex [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)Sn(nBu)(2) (12) have been examined by combined DTA/ DTG thermal analyses. Single crystal X-ray analysis of [(3,5-CH(3))(2)C(6)H(3)O(2)PS(2)](2)S(n)(nBu)(2) (12) revealed that two diaryldithiophosphate ions are coordinated to tin atom in an anisobidentate fashion through the sulfur atoms of each dithiophosphate moiety leading to distorted skew-trapezoidal bipyramidal geometry. The antifungal activity depicts that these complexes are active against fungus Penicillium chrysogenium.


Assuntos
Antifúngicos/química , Organofosfatos/química , Compostos Orgânicos de Estanho/química , Penicillium chrysogenum/efeitos dos fármacos , Antifúngicos/síntese química , Cristalografia por Raios X , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Organofosfatos/síntese química , Compostos Orgânicos de Estanho/síntese química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA