Solvent-Driven Self-Assembly of Discrete Ni(II)-Azide Complexes: Unraveling Unusual Behavior in Mimicking Jack Bean Urease.

The well-known inhibitory strength of 3d metal Schiff base complexes against urease enzymes has long been acknowledged, but their untapped potential to act as ureolytic mimics of active metallobiosites remained unexplored. To break the new ground, we present pyrrolidine-based mononuclear Ni(II)-azide complex {[NiL(HL)(N)]·1.5(HO)} using the N,N,O donor ligand, namely ()-4-bromo-2-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)phenol.

Biodistribution and toxickinetic variances of chemical and green Copper oxide nanoparticles in vitro and in vivo.

In this study, chemical (S1) and green (S2) Copper Oxide nanoparticles (NPs) were synthesized to determine their biodistribution and toxicokinetic variances in vitro and in vivo. Both NPs significantly released Copper ions (Cu) in lymphocytes and were primarily deposited in the mononuclear phagocyte system (MPS) such as the liver and spleen in mice. In particular, S2NPs seemed to be prominently stored in the spleen, whereas the S1NPs were widely stored in more organs including the liver, heart, lungs, kidney and intestine.

Surface modification minimizes the toxicity of silver nanoparticles: an in vitro and in vivo study.

Currently toxicological research in Silver nanoparticle is a leading issue in medical science. The surface chemistry and physical dimensions of silver nanoparticles (Ag-NPs) play an important role in toxicity. The aim of this present study was to evaluate the in vitro and in vivo toxicity of Ag-NPs as well as the alteration of toxicity profile due to surface functionalization (PEG and BSA) and the intracellular signaling pathways involved in nanoparticles mediated oxidative stress and apoptosis in vitro and in vivo system.

Unveiling the effects of the in situ generated arene anion radical and imine radical on catecholase like activity: a DFT supported experimental investigation.

Two new dinuclear nickel(ii) complexes namely [Ni(L)(OAc)(HO)]·CHCN (1) and [Ni(L)(SCN)(CHOH)]·CHOH (2) have been synthesized from the designed Schiff-base ligand 4-bromo-2-[(2-hydroxy-1,1-dimethyl-ethylimino)-methyl]-phenol (HL) and its reduced analogue 4-bromo-2-[(2-hydroxy-1,1-dimethyl-ethylamino)-methyl]-phenol (HL), respectively. Both 1 and 2 have been characterised by usual physicochemical techniques (UV-Vis, FT-IR, ESI-MS study and single crystal XRD) and their variable temperature magnetic study has been performed. The nickel(ii) centres in the dinuclear complexes 1 and 2 are antiferromagnetically coupled through participation of the bridging phenoxyl oxygen.

Thiocyanate mediated structural diversity in phenol based "end-off" compartmental ligand complexes of group 12 metal ions: Studies on their photophysical properties and phosphatase like activity.

The reaction of a pentadentate compartmental ligand LH, namely 4-tert-Butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol, with group 12 metal ions (Zn, Cd, Hg) followed by addition of NaSCN afforded one discrete dinuclear complex [Zn(L)(SCN)](1), and two polymeric 1D species [Cd(L)(SCN)(AcO)] (2) and [Hg(L)(SCN)] (3). All the complexes have been structurally characterized by single crystal X-ray diffraction. The crystal structure of the complexes reveals different coordination modes of thiocyanate anion that affect the different topology detected in the compounds: the anions are μ-NCS and μ-NCS connected in complex 1, while μ-NCS bridging mode is observed in 2, and μ-SCN and μ-NCS in 3.

Unique mononuclear Mn(II) complexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity.

Three new mononuclear manganese(ii) complexes, namely [Mn(HL)2]·2ClO4 (1), [Mn(HL)(N(CN)2)(H2O)2]·ClO4 (2) and [Mn(HL)(SCN)2] (3) [LH = 4-tert-butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol], have been synthesized and structurally characterized. An "end-off" compartmental ligand (LH) possesses two symmetrical compartments with N2O binding sites but accommodates only one manganese atom instead of two due to the protonation of the imine nitrogen of one compartment. Although all three complexes are mononuclear, complex 1 is unique as it has a 1 : 2 metal to ligand stoichiometry.

Influence of para substituents in controlling photophysical behavior and different non-covalent weak interactions in zinc complexes of a phenol based "end-off" compartmental ligand.

Three dinuclear zinc(II) complexes with "end-off" compartmental ligands, namely 2,6-bis(N-ethylmorpholine-iminomethyl)-4-R-phenol (R = -CH3, Cl, (t)Bu) have been synthesized with the aim of exploring the role of the para substituent present in the ligand backbone in controlling the structural diversity, photophysical properties and different weak interactions of the complexes. All three species, with the general formula {2[Zn2L(CH3COO)2][Zn(NCS)4]}, show the complex anion Zn(NCS)4(2-) as a common structural feature decisive for crystallization. Interestingly, all of them possess several non-covalent weak interactions where the nature of the "R" group plays an essential role as exposed by DFT study.

Relation between the catalytic efficiency of the synthetic analogues of catechol oxidase with their electrochemical property in the free state and substrate-bound state.

A library of 15 dicopper complexes as synthetic analogues of catechol oxidase has been synthesized with the aim to determine the relationship between the electrochemical behavior of the dicopper(II) species in the absence as well as in the presence of 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the catalytic activity, kcat, in DMSO medium. The complexes have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis in some cases. Fifteen "end-off" compartmental ligands have been designed as 1 + 2 Schiff-base condensation product of 2,6-diformyl-4-R-phenol (R = Me, (t)Bu, and Cl) and five different amines, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, and N-(2-aminoethyl)piperidine.

A combined experimental and theoretical investigation on the role of halide ligands on the catecholase-like activity of mononuclear nickel(II) complexes with a phenol-based tridentate ligand.

Three new mononuclear nickel(II) complexes, namely, [NiL(1)(H2O)3]I2·H2O (1), [NiL(1)(H2O)3]Br2·H2O (2), and [NiL(1)(H2O)3]Cl2·2H2O (3) [HL(1) = 2-[(2-piperazin-1-ylethylimino)methyl]phenol], have been synthesized and structurally characterized. Structural characterization reveals that they possess similar structure: [NiL(1)(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.

A radical pathway in catecholase activity with nickel(II) complexes of phenol based "end-off" compartmental ligands.

Seven dinuclear and one dinuclear based dicyanamide bridged polymeric Ni(II) complexes of phenol based compartmental ligands (HL(1)-HL(4)) have been synthesized with the aim to investigate their catecholase-like activity and to evaluate the most probable mechanistic pathway involved in this process. The complexes have been characterized by routine physicochemical studies as well as by X-ray single crystal structure analyses namely [Ni2(L(2))(SCN)3(H2O)(CH3OH)] (), [Ni2(L(4))(SCN)3(CH3OH)2] (), [Ni2(L(2))(SCN)2(AcO)(H2O)] (), [Ni2(L(4))(SCN)(AcO)2] (), [Ni2(L(2))(N3)3(H2O)2] (), [Ni2(L(4))(N3)3(H2O)2] (), [Ni2(L(1))(AcO)2(N(CN)2)]n () and [Ni2(L(3))(AcO)2(N(CN)2)] (), [SCN = isothiocyanate, AcO = acetate, N3 = azide, and N(CN)2 = dicyanamide anion; L(1-4) = 2,6-bis(R2-iminomethyl)-4-R1-phenolato, where R1 = methyl and tert-butyl, R2 = N,N-dimethyl ethylene for L(1-2) and R1 = methyl and tert-butyl, R2 = 2-(N-ethyl) pyridine for L(3-4)]. A UV-vis spectrophotometric study using 3,5-di-tert butylcatechol (3,5-DTBC) reveals that all the complexes are highly active in catalyzing the aerobic oxidation of (3,5-DTBC) to 3,5-di-tert-butylbenzoquinone (3,5-DTBQ) in methanol medium with the formation of hydrogen peroxide.