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Candida albicans, a pathogenic fungus, poses a significant threat, particularly in individuals with compromised immune systems, leading to elevated mortality rates. The problem is exacerbated by their ability to form biofilms on medical devices, such as catheters, thereby resisting treatments. To tackle this challenge, we have developed an innovative approach involving the detection and combatting of C. albicans biofilm and its associated stages in the presence of a unique antimicrobial nanocomposite (ZnO/Ag/RGO) coating. Microscopic assessments reveal the nanocomposite's exceptional inhibitory impact on C. albicans cells, demonstrating its efficacy. Time-kinetic experiments further elucidate the restraining effects of ZnO/Ag/RGO coatings on C. albicans biofilm formation over intervals. The absence of hypha structures on nanocomposite-coated surfaces was also noted. A concentration-dependent decrease in cell adhesion further validates the potency of the nanocomposite. To substantiate our findings, we employed advanced techniques such as electrochemical impedance spectroscopy (EIS) and cyclic voltage spectrometry (CV) for real-time electronic monitoring of biofilm dynamics. These experiments revealed differences in the time- and concentration-dependent curves. While the concentration-dependent curve maintained linearity, the time-dependent graph portrayed a distinct expression, probably due to cell association. This work stands out as one of the few endeavors seeking to map events within the biofilm matrix in response to an external agent, providing valuable insights into the interplay between ZnO, Ag, and RGO and biofilm dynamics. Our present approach, combining microscopy and electrochemical data, holds promise in contributing to the development of sensing strategies for microbial biofilms and their inhibition. [ABSTRACT FROM AUTHOR]

A non-porphyrinic [N.sub.4][O.sub.3]-coordinating heptadentate ligand was used to synthesis and characterize various properties of two new binuclear copper(II) complexes, [[Cu.sub.2]([H.sub.2]L)([mu]-OH)][(Cl[O.sub.4]).sub.2] and [[Cu.sub.2](L)[([H.sub.2]O).sub.2]P[F.sub.6]. The complexes were found to exhibit antiferromagnetic interaction in solid state and catecholase activity at pH 8.5.

Four new tetranuclear iron(lll) complexes of formula [(Fe(L)[sub2])[sub3]Fe], 1-4, have been prepared by reacting [Fe(ClO[sub4])[sub3]]∙6H[sub2]O with H[sub2]L in methanol. Here, L[sup2-] is the deprotonated form of N-(2-hyrdoxybenzyl)-L-valinol (H[sub2]L[sup1]), N-(2-hyrdoxybenzyl)-L-leucinol (H[sub2]L[sup2]), N-(5-chloro-2-hyrdoxybenzyl)-L-leucinol (H[sub2]L[sup3]), and N-(2-hyrdoxybenzyl)-L-phenylalaninol (H[sub2]L[sup4]). The complexes are prepared in an enantiomeric pure form. The complexes have been characterized with the help of lR, UV-vis, circular dichroism (CD), 1H, and elemental analyses. The complex [(Fe(L[sup2])[sub2])[sub3]Fe]-CH[sub3]OH-2H[sub2]O, 2∙CH[sub3]OH-2H[sub2]O, crystallizes in enantiomeric pure form containing a propeller-like Fe[sub4]O[sub6] core. [sup1]H and CD spectral studies of the four species are consistent with the structural similarities of the complexes in solution. Variable-temperature magnetic susceptibility of one case shows an intramolecular antiferromagnetic coupling between the Fe(lll) ions. Magnetic measurements are in accord with the S = 5 ground state and suggest single molecular magnet behavior. The magnetic exchange coupling constant between the iron centers within the molecule is interpreted using broken-symmetry density functional theory calculation. [ABSTRACT FROM AUTHOR]

The N4O3 coordinating heptadentate ligand afforded binuclear complex [Cu2(H2L)(μ-OH)](ClO4)2 (1) and [Cu2(L)(H2O)2]PF6 (2). In complex 1, two copper ions are held together by μ-phenoxo and μ-hydroxo bridges, whereas in complex 2, the copper centers are connected only by a μ-phenoxo bridge. In 1, both the Cu(II) centers have square pyramidal geometry (r = 0.01-0.205), whereas in the case of 2, one Cu(II) center has square pyramidal (r = 0.2517) and other one has square based pyramidal distorted trigonal bipyramidal (r = 0.54) geometry. Complexes 1 and 2 show an strong intramolecular and very weak antiferromagnetic interaction, respectively. Density-functional theory calculations were performed to establish the magneto structural correlation between the two paramagnetic copper(II) centers. Both of the complexes display a couple of one-electron reductive responses near -0.80 and -1.10 V. The complexes show significant catalytic activity at pH 8.5 on the oxidation of 3,5-di- tert-butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ), and the activity measured in terms of kcat = 29-37 h-1. [ABSTRACT FROM AUTHOR]

We report the synthesis, structure, and reactivity of [Fe(TlEt4iPrIP)(OTf)2] [1; TlEt4iPrlP = tris(l-ethyl-4-isopropylimidazolyl)phosphine]. Compound 1 reacts reversibly with nitric oxide to afford [Fe- (T1 Et4iPrIP ) (NO) (THF) (OTf)] (OTf) (2), which is the first example of a 6-coordinate {FeNO}7 S = 3/2 complex containing a linear Fe--?--O group. 2 exhibits the highest ν(NO) for compounds in this class. Density functional theory studies reveal an enhanced degree of β-electron transfer from π*(NO) to the Fe d orbitals accounting for the large stretching frequency. [ABSTRACT FROM AUTHOR]

Developing new anticancer agents can be useful, with the ability to diagnose and treat cancer worldwide. Previously, we focused on examining the effects of nonoxidovanadium(IV) complexes on insulin mimetic and cytotoxicity activity. In this study, in addition to the cytotoxic activity, we evaluated their bioimaging properties. This study investigates the synthesis of four stable nonoxido V IV complexes [V IV (L 1-4 ) 2 ] ( 1 - 4 ) using aroylhydrazone ligands (H 2 L 1-4 ) and their full characterization in solid state and the solution phase stability using various physicochemical techniques. The biomolecular (DNA/HSA) interaction of the complexes was evaluated by using conventional methods. The in vitro cytotoxicity of 1 - 4 was studied against A549 and LN-229 cancer cell lines and found that drug 2 displayed the highest activity among the four. Since 1 - 4 are fluorescently active, live cell imaging was used to evaluate their cellular localization activity. Complexes specifically target the lysosome and damage lysosome integrity by producing an excessive amount (9.7-fold) of reactive oxygen species (ROS) compared to the control, which may cause cell apoptosis. Overall, this study indicates that 2 has the greatest potential for the development of multifunctional theranostic agents that combine imaging capabilities and anticancer properties of nonoxidovanadium(IV)-based metallodrugs.

A series of mononuclear non-oxido vanadium(IV) complexes, [V IV (L 1-4 ) 2 ] ( 1-4 ), featuring tridentate bi-negative ONS chelating S-alkyl/aryl-substituted dithiocarbazate ligands H 2 L 1-4 , are reported. All the synthesized non-oxido V IV compounds are characterized by elemental analysis, spectroscopy (IR, UV-vis, and EPR), ESI-MS, as well as electrochemical techniques (cyclic voltammetry). Single-crystal X-ray diffraction studies of 1 - 3 reveal that the mononuclear non-oxido V IV complexes show distorted octahedral ( 1 and 2 ) or trigonal prismatic ( 3 ) arrangement around the non-oxido V IV center. EPR and DFT data indicate the coexistence of mer and fac isomers in solution, and ESI-MS results suggest a partial oxidation of [V IV (L 1-4 ) 2 ] to [V V (L 1-4 ) 2 ] + and [V V O 2 (L 1-4 )] - ; therefore, all these three complexes are plausible active species. Complexes 1 - 4 interact with bovine serum albumin (BSA) with a moderate binding affinity, and docking calculations reveal non-covalent interactions with different regions of BSA, particularly with Tyr, Lys, Arg, and Thr residues. In vitro cytotoxic activity of all complexes is assayed against the HT-29 (colon cancer) and HeLa (cervical cancer) cells and compared with the NIH-3T3 (mouse embryonic fibroblast) normal cell line by MTT assay and DAPI staining. The results suggest that complexes 1 - 4 are cytotoxic in nature and induce cell death in the cancer cell lines by apoptosis and that a mixture of V IV , V V , and V V O 2 species could be responsible for the biological activity.

The synthesis and characterization of one oxidoethoxidovanadium(V) [V V O(L 1 )(OEt)] ( 1 ) and two nonoxidovanadium(IV) complexes, [V IV (L 2-3 ) 2 ] ( 2 and 3 ), with aroylhydrazone ligands incorporating naphthalene moieties, are reported. The synthesized oxido and nonoxido vanadium complexes are characterized by various physicochemical techniques, and their molecular structures are solved by single crystal X-ray diffraction (SC-XRD). This revealed that in 1 the geometry around the vanadium atom corresponds to a distorted square pyramid, with a O 4 N coordination sphere, whereas that of the two nonoxido V IV complexes 2 and 3 corresponds to a distorted trigonal prismatic arrangement with a O 4 N 2 coordination sphere around each "bare" vanadium center. In aqueous solution, the V V O moiety of 1 undergoes a change to V V O 2 species , yielding [V V O 2 (L 1 )] - ( 1' ), while the nonoxido V IV -compounds 2 and 3 are partly converted into their corresponding V IV O complexes, [V IV O(L 2-3 )(H 2 O)] ( 2' and 3' ). Interaction of these V V O 2 , V IV O, and V IV systems with two model proteins, ubiquitin (Ub) and lysozyme (Lyz), is investigated through docking approaches, which suggest the potential binding sites: the interaction is covalent for species 2' and 3' , with the binding to Glu16, Glu18, and Asp21 for Ub, and His15 for Lyz, and it is noncovalent for species 1' , 2 , and 3 , with the surface residues of the proteins. The ligand precursors and complexes are also evaluated for their in vitro antiproliferative activity against ovarian (A2780) and prostate (PC3) human cancer cells and in normal fibroblasts (V79) to check the selectivity of the compounds for cancer cells.

We report the characterization of [Fe(T1Et4iPrIP)(sal)] ( 2 ) (T1Et4iPrIP = tris(1-ethyl-4-isopropyl-imidazolyl)phosphine; sal 2- = salicylate dianion), which serves as a model for substrate-bound salicylate dioxygenase (SDO). Complex 2 crystallizes in the monoclinic space group P 2 1 /n with a = 10.7853(12) Å, b = 16.5060(19) Å, c = 21.217(2) Å, β = 94.489(2)°, and V = 3765.5(7) Å 3 . The structure consists of Fe II bonded in distorted square pyramidal geometry ( τ = 0.32) with two salicylate oxygens and two T1Et4iPrIP nitrogens serving as the base and the apical position occupied by the other ligand nitrogen. [Fe(T1Et4iPrIP)(OTf) 2 ] ( 1 ), the precursor for 2 , catalyzes the cleavage of 1,4-dihydroxy-2-naphthoate in the presence of O 2 . Complex 1 is also capable of cleaving the salicylate aromatic ring in the presence of H 2 O 2 . The progression of this reaction toward product formation involves an Fe III -phenoxide species.

We report the synthesis, structure, and reactivity of [Fe(T1Et4iPrIP)(OTf)2] [1; T1Et4iPrIP = tris(1-ethyl-4-isopropylimidazolyl)phosphine]. Compound 1 reacts reversibly with nitric oxide to afford [Fe(T1Et4iPrIP)(NO)(THF)(OTf)](OTf) (2), which is the first example of a 6-coordinate {FeNO}(7) S = 3/2 complex containing a linear Fe-N-O group. 2 exhibits the highest ν(NO) for compounds in this class. Density functional theory studies reveal an enhanced degree of β-electron transfer from π*(NO) to the Fe d orbitals accounting for the large stretching frequency.