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1.
Dalton Trans ; 53(35): 14710-14724, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39158052

RESUMEN

A combination of N,N',N''-tris(3-pyridyl)-1,3,5-benzenetricarboxamide (L1) and p-chlorobenzoic acid (HL2) with Zn(NO3)2·6H2O resulted in the formation of a dinuclear metallacycle [ZnL1(L2)2(DMF)2]2 (1(DMF)4). In 1(DMF)4, the Zn(II) centre adopts a square pyramidal geometry, while one of the pyridyl N out of the three pyridyl groups in L1 remained uncoordinated. Solvated DMF molecules are present in 1(DMF)4. The structural and chemical nature of 1(DMF)4 is effective for it to act as a potential fluorescent probe for the detection of nitroaromatic compounds. It is observed that the probe, 1(DMF)4, could selectively detect picric acid (PA) among various aromatic compounds in solution (DMSO), while the solid state (contact mode) detection showed a positive sensing response for the nitrophenols (PA: 87% quenching efficiency, 2,4-dinitrophenol (2,4-DNP): 57% quenching efficiency and 4-nitrophenol (4-NP): 40% quenching efficiency). The limit of detection (LOD) of PA by the probe in DMSO was found to be 6.8 × 10-11 M while the LOD in contact mode detection was estimated to be 0.49 ng cm-2. The mechanism of selective detection of PA by 1(DMF)4 in DMSO was analyzed through photophysical studies, 1H-NMR experiments and also by density functional theory (DFT) calculations. The effective overlap of the absorption spectrum of 1(DMF)4 and emission spectrum of PA in DMSO suggests that the Förster resonance energy transfer (FRET) is responsible for quenching phenomena in DMSO. The DFT calculations and molecular docking studies showed the adduct formation due to the favorable interactions between 1(DMF)4 and PA in DMSO, while negligible interactions were observed between 1(DMF)4 with other aromatic compounds. The experimental and DFT studies showed that the efficient sensing ability of PA by 1(DMF)4 in the solid-state was due to photoelectron transfer (PET) and FRET phenomena described herein.

2.
Org Biomol Chem ; 22(17): 3405-3414, 2024 05 01.
Artículo en Inglés | MEDLINE | ID: mdl-38587475

RESUMEN

BODIPY(aryl)iodonium salts were readily accessible from the high-yielding reaction of BODIPY with iodoarenes or hydroxyl(tosyloxy)iodoarenes in the presence of m-CPBA. The prepared BODIPY(aryl)iodonium salts bearing substituents of varied electronic nature were utilized for the direct syntheses of thiocyanate, azide, amine and acrylate functionalized BODIPYs and ß,ß'-bis-BODIPYs. The regioselective syntheses of α-piperidinyl and ß-piperidinyl substituted BODIPYs were achieved through the reaction of BODIPY(aryl)iodonium salts with piperidine in the absence and presence of copper(I). Expeditious and high yielding (79-82%) synthesis of ß,ß'-bis-BODIPYs was also developed through the palladium-catalyzed reductive coupling of the easily accessible BODIPY(aryl)iodonium salts. Some of the indole-appended BODIPYs and bis-BODIPYs displayed strong absorption in the visible region (∼610 nm). The BODIPY(aryl)iodonium salts also showed significant binding with serum albumin and were observed to be selective serum protein sensors with estimated limits of detection as low as 7 µg mL-1 in some cases.


Asunto(s)
Compuestos de Boro , Compuestos de Boro/química , Compuestos de Boro/síntesis química , Sales (Química)/química , Sales (Química)/síntesis química , Humanos , Estructura Molecular , Albúmina Sérica/química , Animales
3.
Dalton Trans ; 52(5): 1449-1460, 2023 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-36644963

RESUMEN

Using a dicarboxylic acid, [1,1'-biphenyl]-4,4'-dicarboxylic acid (H2L1) and an exobidentate ligand, (1E,1'E)-N,N'-(1,4-phenylene)bis(1-(pyridin-4-yl)methanimine) (L2), two 3D interpenetrated networks, {[Zn3(L1)3(L2)]·9H2O}n (Zn-MOF) and {[Co3(L1)3(L2)(DMF)]·0.5DMF}n (Co-MOF), have been prepared in good yields. The crystal structure analysis of Zn-MOF and Co-MOF revealed that both have a 3D pillared-layer structure based on pinwheel trinuclear metal-carboxylate clusters as secondary building units (SBUs). Furthermore, the structures also exhibited three-fold interpenetration. Although the overall networks in Zn-MOF and Co-MOF showed significant resemblances, there are marked differences in their crystal structures, which are associated with the coordination environment of the metal centre and the binding modes of the carboxylates. Gas adsorption studies (N2 at 77 K and 1 bar) indicated that Co-MOF is more porous than Zn-MOF. Magnetic measurements on Co-MOF indicate a significant antiferromagnetic interaction (45 K to 303 K) between trimeric Co(II) S = 3/2 spins through syn-syn carboxylato bridges. Both MOFs were studied for the Lewis acid catalyzed Knoevenagel condensation reactions between benzaldehydes and malononitrile with an active methylene group, where Zn-MOF was found to be a better catalyst than Co-MOF. This was supported by the Monte Carlo simulations indicating the better substrate binding ability of Zn-MOF than Co-MOF.

4.
Dalton Trans ; 51(21): 8169-8176, 2022 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-35583163

RESUMEN

Various ß-triazolyl tethered BODIPYs were efficiently prepared in a sequential one-pot protocol involving the initial reaction of BODIPY with iodobenzene diacetate (IBD) and sodium azide to in situ generate BODIPY azides followed by a copper-catalyzed azide-alkyne cycloaddition reaction. Under the optimized reaction conditions, various ß-triazolyl BODIPYs 5a-i were successfully prepared in good yields and adequately characterized by using UV, NMR, mass spectral data and XRD analyses. The UV-Visible spectra of the prepared ß-triazolyl BODIPYs 5a-i showed intense absorption bands (514-545 nm) with a 13-44 nm red shift when compared with those of the parent BODIPY. The selective recognition of compound 5d towards Ni2+ ions (detection limit 0.26 nM) led to significant quenching in the fluorescence intensity over other selected bivalent metal ions. The complex formed between 5d and Ni2+ in a stoichiometry of 2 : 1 was found to have a binding constant of 7.5 × 105 M-1. The fluorescence of compound 5i gets enhanced gradually upon interaction with bovine serum albumin due to its selective and high binding affinity (1.25 × 105 M-1) with protein and a concomitant decrease in the total non-radiative decay rate.


Asunto(s)
Yodo , Albúmina Sérica Bovina , Azidas/química , Compuestos de Boro , Yoduros , Iones , Níquel
5.
Dalton Trans ; 42(23): 8492-7, 2013 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-23629634

RESUMEN

The metal-organic frameworks of amide based "flexible" ligands has been explored. The reaction of bis-(3-pyridyl)ethanediamide with Cu(PF6)2 resulted in a 1D looped chain, where the PF6(-) anions interact with the amide groups of the chains. This resulted in unavailability of space for guest inclusion in the loops. The exchange of PF6(-) ion with ClO4(-) ion resulted in the intake of aromatic guest molecules, which were monitored by IR and UV-Vis spectroscopy. The capability of the flexible ethyl spacer of bis-(3-pyridyl)ethanediamide to adjust the conformation according to the requirements of the other components of the networks is observed in the present study. This resulted in reversible inclusion and removal of guest molecules triggered by the exchange of anions.

6.
Chem Commun (Camb) ; (40): 4169-79, 2006 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-17031423

RESUMEN

Coordination polymers have attracted an enormous interest among chemists due to their novel physical and chemical properties. This review describes the role of 4,4'-bipyridine in discovering various coordination polymers with novel topologies that range from one-dimensional to three dimensional. The geometries of coordination polymers of bipy include linear, zigzag, four-fold helices, molecular antenna, ladder, railroad, double, triple and quadruple chains, bilayer, square and rectangular grid, honeycomb layers, Lincoln Logs, 3D frames, diamondoid, 4(2) x 8(2) and cubic networks.

7.
Chem Commun (Camb) ; (17): 2229-31, 2005 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-15856105

RESUMEN

Two types of secondary building units of CuI (Cu2I2 and Cu4I4) were shown to generate 2D-coordination networks of (4,4)-topology (non-interpenetrated and interpenetrated) with exo-bidentate ligands that contain diamide as spacer.

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