Percorrer por autor "Kirillov, Alexander M."
A mostrar 1 - 5 de 5
Resultados por página
Opções de ordenação
- A 3D MOF with Cu20/Cu6 clusters: self-assembly, CO2 encapsulation, structural features, and magnetic propertiesPublication . Sliwa, Ewelina I.; Nesterov, Dmytro S.; Klak, Julia; Kirillov, Alexander M.; Smolenski, PiotrAbstract Molecular design of multicopper clusters has been of increasing importance in inorganic chemistry, biomedical science, and functional materials. Herein, two new copper compounds were self-assembled from copper(II) monofluoroacetate or trifluoroacetate, elemental copper, and 1,3,5-triaza-7-phosphaadamantane (PTA). The reaction starting from copper(II) monofluoroacetate yielded a tetranuclear cluster, [Cu4II(μ3-OH)2(μ-L)6(PTA=O)2] (1), where L is monofluoroacetate(1−) and PTA=O is the oxide of PTA. Formation of 1 involves the oxidation of PTA and the incorporation of μ3-OH– ligands. In contrast, a similar reaction with copper(II) trifluoroacetate produced a unique three-dimensional metal–organic framework (3D MOF), formulated as [{Cu20II(CO3)(μ3-O)2(μ3-OH)22(μ-L′)12}{Cu6I(μ3-PTA)6(CH3CN)12}]n·6n(L′)·3n(H2O)·2n(CH3CN) (2), where L′ is trifluoroacetate. It comprises Cu20 clusters, with an encapsulated carbonate anion fixed from atmospheric CO2, which are bridged by {Cu6I(PTA)6} units into a 3D MOF. Control experiments confirmed that carbonate originates from ambient CO2 rather than from added carbonate salts. Both 1 and 2 were fully characterized, and their magnetic properties were investigated, revealing dominant antiferromagnetic interactions within the Cu4 and Cu20 clusters, respectively. Density functional theory (DFT) calculations confirmed the antiferromagnetic ground spin state of 1 and disclosed the stability of the Cu20 core in 2. This work highlights the influence of fluorinated carboxylates and atmospheric conditions on the assembly and architecture of multicopper clusters, and extends their family to new examples.
- Copper-organic frameworks assembled from in situ generated 5-(4-pyridyl) tetrazole building blocks: synthesis, structural features, topological analysis and catalytic oxidation of alcoholsPublication . Nasani, Rajendar; Saha, Manideepa; Mobin, Shaikh; Martins, Luisa; Pombeiro, Armando; Kirillov, Alexander M.; Mukhopadhyay, SumanTwo new metal- organic compounds {[Cu-3(mu(3)-4-(p)tz)(4)(mu(2)-N-3)(2)(DMF)(2)](DMF)(2)}(n) (1) and {[Cu(4ptz) (2)(H2O)(2)]}(n) (2) {4-ptz = 5-(4-pyridyl)tetrazolate} with 3D and 2D coordination networks, respectively, have been synthesized while studying the effect of reaction conditions on the coordination modes of 4-pytz by employing the [2 + 3] cycloaddition as a tool for generating in situ the 5-substituted tetrazole ligands from 4-pyridinecarbonitrile and NaN3 in the presence of a copper(II) salt. The obtained compounds have been structurally characterized and the topological analysis of 1 discloses a topologically unique trinodal 3,5,6-connected 3D network which, upon further simplification, results in a uninodal 8-connected underlying net with the bcu (body centred cubic) topology driven by the [Cu-3(mu(2)-N-3)(2)] cluster nodes and mu(3)-4-ptz linkers. In contrast, the 2D metal-organic network in 2 has been classified as a uninodal 4-connected underlying net with the sql [Shubnikov tetragonal plane net] topology assembled from the Cu nodes and mu(2)-4-ptz linkers. The catalytic investigations disclosed that 1 and 2 act as active catalyst precursors towards the microwave-assisted homogeneous oxidation of secondary alcohols (1-phenylethanol, cyclohexanol, 2-hexanol, 3-hexanol, 2-octanol and 3-octanol) with tert-butylhydroperoxide, leading to the yields of the corresponding ketones up to 86% (TOF = 430 h(-1)) and 58% (TOF = 290 h(-1)) in the oxidation of 1-phenylethanol and cyclohexanol, respectively, after 1 h under low power ( 10 W) microwave irradiation, and in the absence of any added solvent or additive.
- Hybrid silver(I)-doped soybean oil and potato starch biopolymer films to combat bacterial biofilmsPublication . Fernandes, Tiago; Costa, Inês F. M.; Jorge, Paulo; Sousa, Ana Catarina; Andre, Vania; Cabral, Rafaela G.; Cerca, N.; Kirillov, Alexander M.This study describes the preparation, characterization, and antimicrobial properties of novel hybrid biopolymer materials doped with bioactive silver(I) coordination polymers (bioCPs). Two new bioCPs, [Ag2(μ6-hfa)]n (1) and [Ag2(μ4-nda)(H2O)2]n (2), were assembled from Ag2O and homophthalic (H2hfa) or 2,6-naphthalenedicarboxylic (H2nda) acids as unexplored building blocks. Their structures feature 2D metal–organic and supramolecular networks with 3,6L64 or sql topology. Both compounds act as active antimicrobial agents for producing bioCP-doped biopolymer films based on epoxidized soybean oil acrylate (SBO) or potato starch (PS) as model biopolymer materials with a different rate of degradability and silver release. BioCPs and their hybrid biopolymer films (1@[SBO]n, 2@[SBO]n, 1@[PS]n, and 2@[PS]n) with a very low loading of coordination polymer (0.05–0.5 wt %) show remarkable antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis (Gram-positive) and Escherichia coli and Pseudomonas aeruginosa (Gram-negative) bacteria. Biopolymer films also effectively impair the formation of bacterial biofilms, allowing total biofilm inhibition in several cases. By reporting on new bioCPs and biopolymer films obtained from renewable biofeedstocks (soybean oil and PS), this study blends highly important research directions and widens a limited antimicrobial application of bioCPs and derived functional materials. This research thus opens up the perspectives for designing hybrid biopolymer films with outstanding bioactivity against bacterial biofilms.
- Silver(I) coordination polymers immobilized into biopolymer films for antimicrobial applicationsPublication . Fernandes, Tiago; Costa, Inês F. M.; Jorge, Paula; Sousa, Ana Catarina; André, Vânia; Cerca, N.; Kirillov, Alexander M.This study describes a template-mediated self-assembly synthesis, full characterization, and structural features of two new silver-based bioactive coordination polymers (CPs) and their immobilization into acrylated epoxidized soybean oil (ESOA) biopolymer films for antimicrobial applications. The 3D silver(I) CPs [Ag-4(mu(8)-H(2)pma)(2)](n)center dot 4nH(2)O (1) and [Ag-5(mu(6)-H(0.5)tma)(2)(H2O)(4)] (n)center dot 2nH(2)O (2) were generated from AgNO3 and pyromellitic (H(4)pma) or trimesic (H(3)tma) acid, also using N,N'-dimethylethanolamine (Hdmea) as a template. Both 1 and 2 feature the intricate 3D layer-pillared structures driven by distinct polycarboxylate blocks. Topological analysis revealed binodal nets with the flu and tcj/hc topology in 1 and 2, respectively. These CPs were used for fabricating new hybrid materials, namely, by doping the [ESOA](n) biopolymer films with very low amounts of 1 and 2 (0.05, 0.1, and 0.5%). Their antimicrobial activity and ability to impair bacterial biofilm formation were investigated in detail against both Gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacteria. Both silver(I) CPs and derived biopolymer films showed activity against all the tested bacteria in a concentration-dependent manner. Compound 1 exhibited a more pronounced activity, especially in preventing biofilm growth, with mean bacterial load reductions ranging from 3.7 to 4.3 log against the four bacteria (99.99% bacterial eradication). The present work thus opens up antibiofilm applications of CP-doped biopolymers, providing new perspectives and very promising results for the design of functional biomaterials.
- Synthesis, characterization and redox behaviour of benzoyldiazenido- and oxorhenium complexes bearing N,N- and S,S-type ligandsPublication . Kirillov, Alexander M.; Guedes Da Silva, M. Fátima C.; Martins, Luisa; Sousa, Catarina; Pombeiro, Armando; Alegria, ElisabeteThe reactions of [ReCl2{eta(2)-N2C(O)Ph}(PPh3)(2)](1) with 2-aminopyrimidine (H(2)Npyrm), 2,2'-bipyridine (bpy) and tetraethylthiuram disulfide (tds), in MeOH upon reflux, lead to the new eta(1)-(benzoyldiazenido)-rhenium(III) complexes [ReCl{eta(1)-N2C(O)Ph}(HNpyrm)(PPh3)(2)](2)and [ReCl2{eta(1)-N2C(O)Ph}(bpy)(PPh3)] (3), and the known oxo(diethyldithiocarbamato)dirhenium(v)complex [Re2O2(mu O){Et2NC(S)S}(4)](4), respectively. The Et2NC(S)S ligands in 4 result from S-S bond rupture of tds molecules. The obtained compounds have been characterized by IR, H-1, P-31{H-1} and C-13{H-1} NMR spectroscopies, FAB(+)-MS, elemental and single-crystal X-ray diffraction (for 2 and 4)analyses. Complex 2 represents the first structurally characterized Re compound derived from 2-aminopyrimidine. Besides, the redox behaviour of 2-4 in CH2Cl2 solution has been studied by cyclic voltammetry, and the Lever electrochemical ligand parameter (E-L)has been estimated, for the first time, for HNpyrm. The electrochemical results are discussed in terms of electronic properties of the Re centres and the ligands.