Phosphoester bond hydrolysis by a discrete zirconium-oxo cluster: mechanistic insights into the central role of the binuclear Zr-Zr active site.

Effective degradation of non-natural phosphate triesters (PTs) widely used in pesticides and warfare agents is of paramount relevance for human and environmental safety, particularly under acidic conditions where they are highly stable. Here, we present a detailed reactivity and mechanistic study pioneering discrete {ZrO} clusters, which are commonly employed as building blocks for Zr-MOFs and as non-classical soluble coordination compounds for the degradation of PTs using the pesticide ethyl paraoxon as a model. Combined computational studies, mechanistic experiments, and EXAFS analysis show that the reactivity of these clusters arises from their Zr-Zr bimetallic sites, which hydrolyze ethyl paraoxon under acidic conditions through an intramolecular pathway.

Homo- and Heterogeneous Benzyl Alcohol Catalytic Oxidation Promoted by Mononuclear Copper(II) Complexes: The Influence of the Ligand upon Product Conversion.

The catalytic properties of three copper complexes, [Cu()](ClO) (), [Cu()](ClO), () and [Cu()](ClO) () (where = ethylenediamine, amp = 2-aminomethylpyridine and = 2,2'-bipyridine), were explored upon the oxidation of benzyl alcohol (BnOH). Maximized conversions of the substrates to their respective products were obtained using a multivariate analysis approach, a powerful tool that allowed multiple variables to be optimized simultaneously, thus creating a more economical, fast and effective technique. Considering the studies in a fluid solution (homogeneous), all complexes strongly depended on the amount of the oxidizing agent (HO), followed by the catalyst load.

The influence of thioether-substituted ligands in dicopper(II) complexes: Enhancing oxidation and biological activities.

This paper describes the synthesis, structural analysis, as well as the magnetic and spectroscopic characterizations of three new dicopper(II) complexes with dinucleating phenol-based ligands containing different thioether donor substituents: aromatic (1), aliphatic (2) or thiophene (3). Temperature-dependent magnetometry reveals the presence of antiferromagnetic coupling for 1 and 3 (J = -2.27 cm and -5.

Spectroscopical and Molecular Studies of Four Manganese(I) PhotoCORMs with Bioinspired Ligands Containing Non-Coordinated Phenol Groups.

Carbonyl compounds are widely explored in medicinal inorganic chemistry and have drawn attention due to their signaling functions in homeostasis. Carbon-monoxide-releasing molecules (CORMs) were developed with the purpose of keeping the CO inactive until its release in the intracellular environment, considering its biological relevance. However, for therapeutic applications, the mechanisms of photorelease and which electronic and structural variations influence its rates must be fully understood.

New dimethacrylate monomers based on phenolphthalein and resveratrol for the application of dental materials.

Unlabelled: Potential estrogenic effects and changes in fertility are some of the health problems associated with bisphenol A (BPA) derivatives used to produce some polymers, including dental materials that contain Bis-GMA. Those issues drove this study proposing the synthesis of methacrylate resveratrol and phenolphthalein monomers that, combined with diluent monomers, generate copolymers. Their key characteristics were determined and analyzed on the chemical structure-property perspective considering monomer planarity and flexibility based on molecular dynamic simulations.

Bioinspired oxidation of benzyl alcohol: The role of environment and nuclearity of the catalyst evaluated by multivariate analysis.

Inspired by copper-containing enzymes such as galactose oxidase and catechol oxidase, in which distinct coordination environments and nuclearities lead to specific catalytic activities, we summarize here the catalytic properties of dinuclear and mononuclear copper species towards benzyl alcohol oxidation using a multivariate statistical approach. The new dinuclear [Cu(μ-L)(μ-pz)] (1) is compared against the mononuclear [CuLCl] (2), where (L) and (L) are the respective deprotonated forms of 2,6-bis((bis(pyridin-2-ylmethyl)amino)methyl)-4-methylphenol, and 3-((bis(pyridin-2-ylmethyl)amino)methyl)-2-hydroxy-5-methylbenzaldehyde and (pz) is a pyrazolato bridge. Copper(II) perchlorate (CP) is used as control.

Enhancing the biological properties of zinc complexes with bis(indolyl)methane groups: Synthesis, characterization, DNA interaction, and biocide activity.

The unprecedented mononucleated ligand (6,6-di(1H-indol-3-yl)-N,N-bis(pyridin-2-ylmethyl)hexan-1-amine (L) with an N-donor set and its complexes [Zn(L)Cl] • 2CHOH (1) and [Zn(L)](ClO) (2), were successfully prepared. All compounds were fully characterized by a suite of physicochemical methods. Fluid H and C NMR spectroscopy, as well as DFT and TD-DFT calculations, were carried out to propose a viable structural arrangement for both complexes.

Hydrolytic activity of new bioinspired MnMn and FeMn complexes as mimetics of PAPs: Biological and environmental interest.

Coordination compounds that mimic Purple Acid Phosphatases (PAPs) have drawn attention in the bioinorganic field due to their capacity to cleave phosphodiester bonds. However, their catalytic activity upon phosphate triesters is still unexplored. Thus, we report the synthesis and characterization of two binuclear complexes, [MnMn(L)(OAc)]BF (1) and [MnFe(L)(OAc)]BF (2) (HL = 2-[N,N-bis-(2- pyridilmethyl)aminomethyl]-4-methyl-6-[N-(2-hydroxy-3-formyl-5-methylbenzyl)-N-(2-pyridylmethyl)aminomethyl]phenol), their hydrolytic activity and antioxidant potential.

Luminescent PhotoCORMs: Enabling/Disabling CO Delivery upon Blue Light Irradiation.

The new luminescent carbonyl compounds [Mn(Oxa-H)(CO)Br] () and [Mn(Oxa-NMe)(CO)Br] () were synthesized and fully characterized. Complexes and showed CO release under blue light (λ). Spectroscopic techniques and TD-DFT and SOC-TD-DFT calculations indicated that and release the Oxa-H and Oxa-NMe coligands in addition to the carbonyl ligands, increasing the luminescence during photoinduction.

Modulation of electronic and redox properties in phenolate-rich cobalt(III) complexes and their implications for catalytic proton reduction.

We investigate the redox, spectroscopy and catalytic reactivity of new cobalt(iii) complexes based on phenolate-rich [N2O3] ligands. These complexes are described as [Co(III)(L(X))MeOH], where X indicates the presence of chloro (), bromo (), iodo (), or tert-butyl () substituents in the 3(rd) and 5(th) positions of each phenolate ring. These substituents modulate the Co(iii) ← PheO(-) LMCT bands of the parent complexes with (451) > (453) > (456) > (468 nm) and the redox potentials involved with the Co(iii)/Co(ii) and ligand reduction and with the phenolate/phenoxyl oxidation processes.

Electronic and interfacial behavior of gemini metallosurfactants with copper(II)/pseudohalide cascade cores.

In this paper we discuss the newly synthesized binuclear species [Cu2(L(PY18))2(μ1,1-N3)2(N3)2] (1) and [Cu2(L(PY18))2(μ1,3-SCN)2(NCS)2] (2), as obtained from the monometallic precursor [Cu(L(PY18))Br2]. These gemini metallosurfactants incorporate metal/anion cascade cores and are investigated by experimental and theoretical methods. Diagnostic IR stretches support the presence of μ1,1-bridged (end-on, 2075 cm(-1)) azide groups in 1 and μ1,3-bridged (end-to-end, 2117 cm(-1)) thiocyanate groups in 2.

In vitro and in vivo activity of a new unsymmetrical dinuclear copper complex containing a derivative ligand of 1,4,7-triazacyclononane: catalytic promiscuity of [Cu2(L)Cl3].

Here we present the synthesis of the dinuclear complex [Cu(II)2(L)Cl3] (1), where L is the deprotonated form of the 3-[(4,7-diisopropyl-1,4,7-triazacyclononan-1-yl)methyl]-2-hydroxy-5-methylbenzaldehyde ligand. The complex was characterized by single crystal X-ray diffraction, potentiometric titration, mass spectrometry, electrochemical and magnetic measurements, EPR, UV-Vis and IR. Complex 1 is able to increase the hydrolysis rate of the diester bis-(2,4-dinitrophenyl)phosphate (2,4-BDNPP) by a factor of 2700, and also to promote the plasmidial DNA cleavage at pH 6 and to inhibit the formazan chromophore formation in redox processes at pH 7.

A synthetic pathway for an unsymmetrical N(5)O(2) heptadentate ligand and its heterodinuclear iron(III)zinc(II) complex: a biomimetic model for the purple acid phosphatases.

One major field of interest in bioinorganic chemistry is the design and synthesis of inorganic compounds with low molecular mass, showing structural, spectroscopic, and reactivity properties that mimic enzymes, such as purple acid phosphatases (PAPs). In this study, the unsymmetrical heptadentate ligand 2-[(4,7-diisopropyl-1,4,7-triazacyclonon-1-yl)methyl]-6-{[(2-hydroxybenzyl)(pyridin-2-ylmethyl)-amino]methyl}-4-methylphenol (H(2)L) and its first mixed-valence complex [Fe(III)Zn(II)(L)(μ-OAc)(2)]ClO(4)(1) were synthesized. Physical and chemical measurements (crystal structure, conductometry, IR and UV/VIS spectroscopy, and electrochemistry) were performed for 1, and these properties are compared with those presented by the kbPAPs active sites.

Bioinspired FeIIICdII and FeIIIHgII complexes: synthesis, characterization and promiscuous catalytic activity evaluation.

In this work we report on the synthesis, crystal structure, and physicochemical characterization of the novel dinuclear [Fe(III)Cd(II)(L)(μ-OAc)(2)]ClO(4)·0.5H(2)O (1) complex containing the unsymmetrical ligand H(2)L=2-bis[{(2-pyridyl-methyl)-aminomethyl}-6-{(2-hydroxy-benzyl)-(2-pyridyl-methyl)}-aminomethyl]-4-methylphenol. Also, with this ligand, the tetranuclear [Fe(2)(III)Hg(2)(II)(L)(2)(OH)(2)](ClO(4))(2)·2CH(3)OH (2) and [Fe(III)Hg(II)(L)(μ-CO(3))Fe(III)Hg(II)(L)](ClO(4))(2)·H(2)O (3) complexes were synthesized and fully characterized.

Electronic structure and spectro-structural correlations of Fe(III)Zn(II) biomimetics for purple acid phosphatases: relevance to DNA cleavage and cytotoxic activity.

Purple acid phosphatases (PAPs) are a group of metallohydrolases that contain a dinuclear Fe(III)M(II) center (M(II) = Fe, Mn, Zn) in the active site and are able to catalyze the hydrolysis of a variety of phosphoric acid esters. The dinuclear complex [(H(2)O)Fe(III)(μ-OH)Zn(II)(L-H)](ClO(4))(2) (2) with the ligand 2-[N-bis(2-pyridylmethyl)aminomethyl]-4-methyl-6-[N'-(2-pyridylmethyl)(2-hydroxybenzyl) aminomethyl]phenol (H(2)L-H) has recently been prepared and is found to closely mimic the coordination environment of the Fe(III)Zn(II) active site found in red kidney bean PAP (Neves et al. J.

Oxygen-independent photonuclease activity of a new iron(II) complex.

A new iron(ii) complex was synthesized and its photonuclease activity against plasmid DNA was evaluated. After kinetic experiments a k(cat) of 18.86 +/- 2.

Unsymmetrical Fe(III)Co(II) and Ga(III)Co(II) complexes as chemical hydrolases: biomimetic models for purple acid phosphatases (PAPs).

The design and development of suitable biomimetic catalytic systems capable of mimicking the functional properties of enzymes continues to be a challenge for bioinorganic chemists. In this study, we report on the synthesis, X-ray structures, and physicochemical characterization of the novel isostructural [Fe(III)Co(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (1) and [Ga(III)Co(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (2) complexes with the unsymmetrical dinucleating ligand H(2)BPBPMP (2-bis[{(2-pyridyl-methyl)-aminomethyl}-6-{(2-hydroxy-benzyl)-(2-pyridyl-methyl)}-aminomethyl]-4-methylphenol). The previously reported complex [Fe(III)Zn(II)(BPBPMP)(mu-OAc)(2)]ClO(4) (3) was investigated here by electron paramagnetic resonance for comparison with such studies on 1 and 2.

New unsymmetric dinuclear Cu(II)Cu(II) complexes and their relevance to copper(II) containing metalloenzymes and DNA cleavage.

The new homodinuclear complexes, [Cu(2)(II)(HLdtb)(mu-OCH(3))](ClO(4))(2) (1) and [Cu(2)(II)(Ldtb)(mu-OCH(3))](BPh(4)) (2), with the unsymmetrical N(5)O(2) donor ligand (H(2)Ldtb) - {2-[N,N-Bis(2-pyridylmethyl)aminomethyl]-6-[N',N'-(3,5-di-tert-butylbenzyl-2-hydroxy)(2-pyridylmethyl)]aminomethyl}-4-methylphenol have been synthesized and characterized in the solid state by X-ray crystallography. In both cases the structure reveals that the complexes have a common {Cu(II)(mu-phenoxo)(mu-OCH(3))Cu(II)} structural unit. Magnetic susceptibility studies of 1 and 2 reveal J values of -38.

First-transition-metal complexes containing the ligands 6-amino-6-methylperhydro-1,4-diazepine (AAZ) and a new functionalized derivative: can AAZ act as a mimetic ligand for 1,4,7-triazacyclononane?

The structure and physicochemistry of the [Ni(II)(AAZ)(2)](ClO(4))(2) (1) complex (AAZ = 6-amino-6-methylperhydro-1,4-diazepine), as a system that is able to mimic some important chelate properties of 1,4,7-triazacyclononane, are reported. The syntheses of a new unsymmetric AAZ-functionalized ligand and the structure of its first heterodinuclear Fe(III)Zn(II) complex are also presented.