Complexes {Ag[NHCMes,R]}n (R = H, 2a; Me, 2b and 2b’; iPr, 2c; iBu, 2d), were prepared by treatment of imidazolium precursor compounds [ImMes,R] (2-(3-mesityl-1H-imidazol-3-ium-1-yl)acetate, 1a, (S)-2-alkyl(3-mesityl-1H-imidazol-3-ium-1-yl)acetate, 1b–d, and (R)-2-methyl(3-mesityl-1H-imidazol-3-ium-1-yl)acetate, 1b’, with Ag2O under appropriate conditions. They were characterised by analytical, spectroscopic (IR, 1H, and 13C NMR and polarimetry), and X-ray methods (2a). In the solid state, 2a is a one-dimensional coordination polymer, in which the silver(I) cation is bonded to the carbene ligand and to the carboxylate group of a symmetry-related Ag[NHCMes,H] moiety. The coordination environment of the silver centre is well described by the DFT study of the dimeric model {Ag[NHCMes,H]}2. The antimicrobial properties of these complexes were evaluated versus Gram-negative bacteria E. coli and P. aeruginosa. From the observed MIC and MBC values (minimal inhibitory concentration and minimal bactericidal concentration, respectively), complex 2b’ showed the best antimicrobial properties (eutomer), which were significantly better than those of its enantiomeric derivative 2b (distomer). Additionally, analysis of MIC and MBC values of 2a–d reveal a clear structure–antimicrobial effect relationship. Antimicrobial activity decreases when the steric properties of the R alkyl group in {Ag[NHCMes,R]}n increase.

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Antimicrobial Properties of Amino-Acid-Derived N-Heterocyclic Carbene Silver Complexes

We have described earlier that in aqueous solutions, the reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with maleic acid yielded a phosphonium-alkanoate zwitterion. The same reaction with 2-methylmaleic acid (citraconic acid) proceeded much slower. It is reported here, that in the case of glutaconic and itaconic acids (constitutional isomers of citraconic acid), formation of the corresponding phosphabetaines requires significantly shorter reaction times. The new phosphabetaines were isolated and characterized by elemental analysis, multinuclear NMR spectroscopy and ESI-MS spectrometry. Furthermore, their molecular structures in the solid state were determined by single crystal X-ray diffraction (SC-XRD). Synthesis of the phosphabetaines from PTA and unsaturated dicarboxylic acids was also carried out mechanochemically with the use of a planetary ball mill, and the characteristics of the syntheses in solvent and under solvent-free conditions were compared. In aqueous solutions, the reaction of the new phosphabetaines with Ag(CF3SO3) yielded Ag(I)-based coordination polymers. According to the SC-XRD results, in these polymers the Ag(I)-ion coordinates to the N and O donor atoms of the ligands; however, Ag(I)-Ag(I) interactions were also identified. The Ag(I)-based coordination polymer (CP1.2) formed with the glutaconyl derivative of PTA (1) showed considerable antimicrobial activity against both Gram-negative and Gram-positive bacteria and yeast strains

https://www.mdpi.com/1420-3049/25/22/5352/pdf

Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines.

Abstract Four new water-soluble bidentate ligands, namely, (cyclopentadienyl)ethyl-1,3,5-triaza-7-phosphadamantane (1), 1,2-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) ethane (2), 1,3-bis-(1,3,5-triaza-7-phosphaaadamantan-6-yl) propane (3) and 1,4-bis-(1,3,5-triaza-7-phosphaadamantan-6-yl) butane (4) have been synthesized and characterized by multi-nuclear NMR (1H, 13C and 31P), elemental analysis and mass spectrometry. Compound 1 was synthesized by using two different synthetic routes in excellent yields and is also the first example of water-soluble chelating cyclopentadienyl ligand containing 1,3,5-triaza-7-phosphaadamantane. GRAPHICAL ABSTRACT

Synthesis and characterization of 1,3,5-triaza-7-phosphaadamantane based water-soluble ligands

Celebrating the “25th Anniversary of Molecules” with a Special Issue dedicated to “Recent Advances in Inorganic Chemistry” strengthens the renewed role that inorganic chemistry, one of the oldest chemistry divisions, has lately earned thanks to cutting-edge perspectives and interdisciplinary applications, eventually receiving the veneration and respect which its age might require [...]

25th Anniversary of Molecules-Recent Advances in Inorganic Chemistry.

A double phosphabetaine formed from 1,3,5-triaza-7-phosphaadamantane (PTA) with acetylenedicarboxylic acid and its Ag(CF3SO3)-based coordination polymer

Water-soluble Ag(I)-based coordination polymers obtained by anion-directed self-assembly of various AgX salts and a phosphabetaine derived from 1,3,5-triaza-7-phophaadamantane

1,3,5-triaza-7-phosphaadamantane was alkylated under solvent-free conditions with CH3I, CH3-(CH2)3-Br, Br-(CH2)4-Br, OH-CH2-CH2Br, and CH3CH2OOCCH2Br in a planetary ball mill with yields over 90%. ...

Csenge Tamara Szolnoki

Papers

Water-soluble Ag(I)-based coordination polymers obtained by anion-directed self-assembly of various AgX salts and a phosphabetaine derived from 1,3,5-triaza-7-phophaadamantane

Mechanochemical P-derivatization of 1,3,5-Triaza-7-Phosphaadamantane (PTA) and Silver-Based Coordination Polymers Obtained from the Resulting Phosphabetaines.

Solvent-free N-alkylation of 1,3,5-triaza-7: phospha-adamantane (PTA)

A double phosphabetaine formed from 1,3,5-triaza-7-phosphaadamantane (PTA) with acetylenedicarboxylic acid and its Ag(CF3SO3)-based coordination polymer