Nickel tetrazolato complexes synthesized by microwave irradiation: Catecholase like activity and interaction with biomolecules
TL;DR: In this paper, a square-planar 1,3-Dipolar cycloaddition between nickel-ligated azide in [NiL(N3)] and two different organonitriles furnished two new squareplanar complexes viz.
Abstract: 1,3-Dipolar cycloaddition between nickel-ligated azide in [NiL(N3)] [HL = 3-(2-diethylamino-ethylimino)-1-phenyl-butan-1-one] and two different organonitriles furnished two new square-planar complexes viz. [NiL(5-phenyltetrazolato)] and [NiL{5-(4-pyridyl)-tetrazolato}]. Both the complexes have been characterized by spectroscopic tools and single-crystal X-ray crystallography. Interaction with different biomolecules revealed that both complexes bind strongly to serum albumin proteins and show moderate catecholase-like activity by catalyzing the oxidation of 3,5-ditertbutylcatechol (3,5-DTBC). Identification of intermediates formed in catechol oxidation has been explored by ESI-MS spectrometry.
Citations
More filters
TL;DR: In this paper, two new mononuclear iron(III) Schiff base complexes [Fe(L1)2]SCN (1) and [Fe (L2)(HL3)]ClO4 (2) were synthesized and characterized by elemental and several spectral analyses.
38 citations
21 Sep 2017
TL;DR: In this article, two new mononuclear cobalt(III) Schiff base complexes with azide or thiocyanate were synthesized and characterized by single crystal X-ray diffraction studies.
Abstract: Two new mononuclear cobalt(III) Schiff base complexes with azide or thiocyanate [Co(L1)(L′)(N3)] (1) and [Co(L2)(L“)(NCS)] (2) {where HL1=2((2(piperidin-1-yl)ethylimino)methyl)-6-ethoxyphenol, HL2=2-((3(dimethylamino)propylimino)methyl)-6-methoxyphenol, HL′=1-acetyl-2-naphthol and HL”=2,4-pentanedione} have been synthesized and characterized by single crystal X-ray diffraction studies Both complexes may be represented by a general formula: [Co(ABC)(DE)X], where ABC, DE and X represent tridentate, bidentate and monodentate ligands respectively Both complexes are reactive towards the aerial oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) and o-aminophenol (OAPH), and kinetics of the reactions are monitored spectrophotometrically Analyses of the kinetic data reveal that complex 2 is better catalyst than complex 1 for both oxidation reactions Tentative mechanistic implications of the catalytic oxidation reactions are also discussed Mechanistic investigations of the catalytic behaviors indicate that the oxidation reactions proceed through catalyst-substrate intermediates
27 citations
TL;DR: In this paper, a new cobalt(III) complex with a pendant Schiff base was synthesized and characterized by elemental and several spectral analyses, and extended supra-molecular assemblies were generated in the complex through weak noncovalent interactions.
22 citations
TL;DR: In this article, two potential Schiff base sensor compounds were synthesized by the one pot condensation method starting from 2-hydroxy-1-naphthaldehyde, and the detection limits for the ions were found to be in the order of 10−6 m to 10−7 m. Stability constants of the complexes formed by the receptors with the three metal ions were determined by the Benesi-Hildebrand plot method.
Abstract: Two novel and potential Schiff base sensor compounds were synthesized by the one pot condensation method starting from 2-hydroxy-1-naphthaldehyde. Both the Schiff bases were characterized by IR, UV,1H-NMR, 13C-NMR and mass spectral studies. The cation sensing expertise of the Schiff bases was evaluated by naked eye, UV–Vis and fluorescence spectroscopic methods in aqueous methanolic medium. The cobalt(II), nickel(II) and copper(II) ions were selectively detected by both the receptors. The detection limits for the ions were found to be in the order of 10−6 M to 10−7 M. Stability constants of the complexes formed by the receptors with the three metal ions were determined by the Benesi–Hildebrand plot method. Stoichiometry of the complexes were ascertained as 1:1 (M:R) by Job’s plot method. Mode of interactions were corroborated by 1H-NMR and IR titrations. The structure of the complexes formed during the recognition process was authenticated by the ESI–mass spectroscopy method. The metal ion sensing property of the receptor is applied in bio imaging studies of human Hela cells.
11 citations
TL;DR: In this article, two hexanuclear manganese(III) complexes belonging to the Mn6 family of single-molecule magnets (SMMs) have been synthesized and characterized structurally and magnetically.
5 citations
References
More filters
TL;DR: Assay on the cytotoxicity of Co, Ni and Cu hydrazone complexes against HeLa tumor cells and NIH 3T3 normal cells revealed that the complexes are toxic only against tumor cells but not to normal cells.
271 citations
TL;DR: 1 is observed to be effective even in TCC oxidation, a process never reported earlier, and a treatment on the basis of Michaelis-Menten model has been applied for kinetic study, suggesting that all five complexes exhibit very high turnover number.
Abstract: A series of dinuclear copper(II) complexes has been synthesized with the aim to investigate their applicability as potential structure and function models for the active site of catechol oxidase enzyme. They have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis: [Cu2(H2L22)(OH)(H2O)(NO3)](NO3)3·2H2O (1), [Cu(HL14)(H2O)(NO3)]2(NO3)2·2H2O (2), [Cu(L11)(H2O)(NO3)]2 (3), [Cu2(L23)(OH)(H2O)2](NO3)2, (4) and [Cu2(L21)(N3)3] (5) [L1 = 2-formyl-4-methyl-6R-iminomethyl-phenolato and L2 = 2,6-bis(R-iminomethyl)-4-methyl-phenolato; for L11 and L21, R = N-propylmorpholine; for L22, R = N-ethylpiperazine; for L23, R = N-ethylpyrrolidine, and for L14, R = N-ethylmorpholine]. Dinuclear 1 and 4 possess two “end-off” compartmental ligands with exogenous μ-hydroxido and endogenous μ-phenoxido groups leading to intermetallic distances of 2.9794(15) and 2.9435(9) A, respectively; 2 and 3 are formed by two tridentate compartmental ligands where the copper centers a...
165 citations
TL;DR: Density functional theory (DFT) calculations corroborate well with the experimental observations and support the proposed hypothesis of inactivity of 3,5-DTBC, and thus a radical mechanism has been proposed for the catecholase-like activity exhibited by 1 and 2.
Abstract: Three new mononuclear nickel(II) complexes, namely, [NiL1(H2O)3]I2·H2O (1), [NiL1(H2O)3]Br2·H2O (2), and [NiL1(H2O)3]Cl2·2H2O (3) [HL1 = 2-[(2-piperazin-1-ylethylimino)methyl]phenol], have been synthesized and structurally characterized. Structural characterization reveals that they possess similar structure: [NiL1(H2O)3]2+ complex cations, two halide counteranions, and lattice water molecules. One of the nitrogen atoms of the piperazine moiety is protonated to provide electrical neutrality to the system, a consequence observed in earlier studies (Inorg. Chem. 2010, 49, 3121; Polyhedron 2013, 52, 669). Catecholase-like activity has been investigated in methanol by a UV–vis spectrophotometric study using 3,5-di-tert-butylcatechol (3,5-DTBC) as the model substrate. Complexes 1 and 2 are highly active, but surprisingly 3 is totally inactive. The coordination chemistries of 1 and 2 remain unchanged in solution, whereas 3 behaves as a 1:1 electrolyte, as is evident from the conductivity study. Because of coord...
82 citations
TL;DR: In this article, the synthesis, structure, and gas adsorption properties of three metal organic frameworks (MOFs) synthesized from predesigned ligands 4-(1H-tetrazole-5-yl)benzoic acid (4-TBA) and 2-fluoro-4-( 1H-to-hexyl)-4-tohexyl (2F-4-tBA) along with Cu(II) as an metal precursor has been reported.
Abstract: Synthesis, structure, and gas adsorption properties of three Metal Organic Frameworks (MOFs) synthesized from predesigned ligands 4-(1H-tetrazole-5-yl)benzoic acid (4-TBA) and 2-fluoro-4-(1H-tetrazole-5-yl)benzoic acid (2F-4-TBA) along with Cu(II) as an metal precursor has been reported. Among these MOFs, Cu9(4-TBA)10(C2H5OH)2 (Cu-TBA-1) and Cu2(4-TBA)2(DMF)(C2H5OH) (Cu-TBA-2) are structural isomers. Whereas, Cu2(4-TBA)2(DMF)(C2H5OH) (Cu-TBA-2) and Cu2(2-F-4-TBA)2(DMF)2 (Cu-TBA-2F) have similar crystal structure. N2 adsorption isotherms of the activated sample of Cu-TBA-1 and -2 exhibit types-I sorption behavior with a Langmuir and Brunauer–Emmett–Teller (BET) surface area of 686, 402 m2/g and 616, 356 m2/g, respectively. It is noteworthy that Cu-TBA-1 and -2 adsorbs 1.16 and, 1.54 wt % H2, while Cu-TBA-2F adsorbs 0.67 wt % at 77 K and 1 atm. On the other hand, Cu-TBA-1 and -2 adsorb 3.08 and 2.54 mmol/g, while Cu-TBA-2F adsorbs 1.27 mmol/g of CO2 at 298 K and 1 bar pressure. H2 adsorption sites in Cu-TBA...
76 citations
TL;DR: Among all the complexes, was found to be the most promising molecule among the series due to its large binding affinity towards different bio-macromolecules and higher T.O.N in the catechol oxidation reaction.
Abstract: Four new mononuclear Ni(II) complexes [Ni(L1)]ClO4 (1a), [Ni(L2)]ClO4(1b), [Ni(SCN)3(CH3OH)(aminoethylpiperazineH)] (2a), and [Ni(DMSO)4(aminoethylpiperazineH)](ClO4)3(2b)have been synthesized from two Schiff base ligands [L1 = 1-phenyl-3-((2-(piperidin-4-yl)ethyl)imino)but-1-en-1-ol and L2 = 4-((2-(piperazin-1-yl)ethyl)imino)pent-2-en-2-ol] by exploiting the flexibility of the piperazinyl moiety. Structural analysis reveals that 1a and 1b are square planar complexes with piperazine rings in boat conformations whereas hydrolysis of Schiff bases (L1 and L2) occurs during formation of octahedral complexes (2a and 2b) with piperazine rings in chair conformations. Screening tests were conducted to quantify the binding ability of complexes (1a, 1b and 2a) towards DNA, BSA and HSA and it was found that square planar complexes (1a and 1b) showed more effective binding properties over octahedral complex (2a). Furthermore, enzyme kinetic studies reflect that square planar complexes (1a and 1b) are also effective in mimicking catecholase like activities over octahedral complex (2a). Among all the complexes, 1a was found to be the most promising molecule among the series due to its large binding affinity towards different bio-macromolecules and higher T.O.N in the catechol oxidation reaction.
75 citations