RESUMEN

The novel structure of Hg(II) complexes including the pyridinium ylide C5H5NCHC(O)C6H4-m-Br (Y) were synthesized and reported in this study. In the first step, the pyridinium salt C5H5NCH2C(O)C6H4-m-Br (S) was produced by reacting 2,3'-dibromoactophenone and pyridine. then, treatment of S with K2CO3 gave the related pyridinium ylide Y. Finally, the reaction of Y with HgX2 and Hg(NO3)2·H2O leads to the formation of novel binuclear [HgY2][HgX4] (X=Cl (1); X=Br (2); X=I (3)) and polymeric [HgY(NO3)2]n (4) complexes. The structure of complex 2 was also determined by X-ray diffraction analysis. The obtained analyses proved the coordination through the ylidic carbon to metallic center. Additionally, Natural Bond Orbital (NBO), Energy Decomposition Analysis (EDA), and EDA-NOCV studies are also used to investigate the nature of metal-ligand bonding in the complexes. Finally, the antibacterial activity of 1-4 was also examined against Gram positive and negative represented significant levels of inhibitory potency respected to used standards.

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RESUMEN

The synthesis of new Pd/Pt metallacyclopropa[60]fullerene complexes containing unsymmetrical phosphorus ylides [Ph2P(CH2)nPPh2 = C(H)C(O)C6H4-p-OMe] (n = 1, (Y1); n = 2, (Y2)) has been reported. The synthesized complexes exhibit different structures, including two P,C- chelated [(η2-C60)Pd(κ2-Y1)] (1) and [(η2-C60)Pt(κ2-Y1)] (2) complexes and two P-coordinated [(η2-C60)Pd(Y2)2] (3) and [(η2-C60)Pt(Y2)2] (4) complexes with chain structures. Characterization of all compounds was performed by multi-neclear NMR spectroscopies (1H, 13C and 31P NMR) and other conventional techniques such as IR, UV-Vis, SEM and cyclic voltammetry (CV) analyses. In this regard, the presence of all characteristic chemical shifts in the IR and NMR spectra proposed the formation of desired products. Also, theoretical studies were used to investigate the nature of metal-ligands in all complexes. In addition, a comparison between the catalytic activity of Pd complexes 1 and 3 was evaluated in the Suzuki-Miyaura reaction of various aryl chlorides with phenylboronic acid, which revealed a meaningful difference between the catalytic activity of complexes 1 and 3.

RESUMEN

N-Heterocyclic carbene and phosphorus ylides are inorganic and organometallic ligands, and their coordination chemistry with transition elements, particularly group 11 metals, would be noticeable. This study seeks to characterize the structure and nature of the C→M bond of group 11 metals (M = Cu(i), Ag(i), Au(i)) in coordination with different monodentate phosphorus ylides {P(Ph)3CHR} and N-heterocyclic carbenes (NHC(R)) (where R = F, Cl, Br, CF3, CH3, H, C(CH3)3, Si(CH3)3, SiH3, Ph). In this regard, DFT calculations with the PBE/def2-TZVP level of theory were applied. The results show that the M←C bond interaction energies (ΔEint) related to [NHC(R) → MR'] and [{P(Ph)3CHR} → MCl] complexes (M = Cu(i), Ag(i), Au(i); R = F, Cl, Br, CF3, H, CH3, C(CH3)3, Si(CH3)3, SiH3, Ph; R' = Cl, OAc) are substantial and conform to the well-known V-shaped trend for the transition metals of the first, second, and third row in the following order: Ag(i) < Cu(i) < Au(i). The nature of the C→M bond in the complexes was analyzed using NBO, AIM, EDA, and ETS-NOCV. The nature of the C→M bond interactions in [NHC(R) → MR'] and [{P(Ph)3CHR} → MCl] complexes studied here is largely electrostatic, and this feature accounts for about 65%-74% of the total interaction energy. Furthermore, it is found that in the presence of electron-donating substituents, the group 11 metals form stronger bonds with NHC(R) rather than monodentate phosphorus ylides. Comparison of the EDA-NOCV results for the M←C bond with the same M atom and R substituent in [NHC(R) → MR'] and [{P(Ph)3CHR} → MCl] indicates that the monodentate phosphorus ylide ligands studied here ({P(Ph)3CHR}) are slightly better σ-donors and weaker π-acceptors than the corresponding NHC(R) ligands.

RESUMEN

The new palladacyclopropa[60]fullerene complexes incorporating α-keto stabilized phosphorus ylides were synthesized in a three-component reaction of the unsymmetrical phosphorus ylides [Ph2P(CH2)nPPh2[double bond, length as m-dash]C(H)C(O)C6H4-m-R] (n = 1, R = Br, NO2, (Y(1), Y(2)); n = 2, R = Br, NO2, (Y(3), Y(4))), C60 and Pd(dba)2 (dba = dibenzylideneacetone). The obtained novel P,C-chelated [(η(2)-C60)Pd(κ(2)-Y(1))] (1) and [(η(2)-C60)Pd(κ(2)-Y(2))] (2) complexes and P,P-coordinated [(η(2)-C60)Pd(Y(3))2] (3) and [(η(2)-C60)Pd(Y(4))2] (4) complexes were characterized successfully by IR, UV-Vis, ESI-MS and NMR ((1)H, (13)C and (31)P) spectroscopic methods. Complexes 1-4 are rare examples of palladacyclopropa[60]fullerene complexes with phosphorus ylide ligands. Spectroscopic results revealed that none of possible side products including P,P-coordinated [(η(2)-C60)Pd(Y(1))2] and [(η(2)-C60)Pd(Y(2))2] complexes and also P,C-chelated [(η(2)-C60)Pd(κ(2)-Y(3))] and [(η(2)-C60)Pd(κ(2)-Y(4))] complexes are formed. The EDA analysis indicated that in all the above complexes the metal-ligand bonds are mostly electrostatic in nature.

RESUMEN

The reaction of K2[PdCl4] and PdCl2 with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) proceeded with the formation of two different Pd complexes, PdL2Cl2 (1) and PdL2Cl4 (2c), corresponded to a substitution reaction and a substitution reaction along with unanticipated oxidation, respectively. The nature of the oxidizing agent is unknown. These compounds have been studied by elemental analysis, IR, (1)H and (13)CNMR, molar conductivity, and cyclic voltammetry. In addition, structural optimization by DFT calculations and simulation of NMR spectra have been performed and compared with the experimental data. NBO analysis, HOMO and LUMO, have been used to elucidate the information regarding charge transfer within the molecules. Theoretical studies confirmed that in 1 and 2c the trans structures are about 41 and 33 kJ mol(-1) more stable than cis ones. Antibacterial activity and in vitro cytotoxicity of these compounds, as respectively assessed in six bacterial strains and two human tumor cell lines, have been investigated. Results showed the title complexes have the capacity of inhibiting the metabolic growth of bacteria and tumor cells to different extents.

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RESUMEN

Several classes of antimicrobial compounds are presently available; microorganism's resistance to these drugs constantly emerges. In order to prevent this serious medical problem, the elaboration of new types of antibacterial agents or the expansion of bioactivity of the naturally known biosensitive compounds is a very interesting research problem. The synthesis and characterization of metal complexes with organic bioactive ligands is one of the promising fields for the search. The biological activities of the metal complexes differ from those of either the ligand or the metal ion. The results obtained thus far have led to the conclusion that structural factors, which govern antimicrobial activities, are strongly dependent on the central metal ion. A review of papers dealing with the Ag(I) and Hg(II) complexes of N donor ligands is presented. These metal complexes of N-chelating ligands have attracted considerable attention because of their interesting physicochemical properties and pronounced biological activities. This review will mainly focus on the preparation procedures and antibacterial properties of free organic ligands and the corresponding complexes. Finally, a research about antimicrobial properties of new Hg(II) complexes with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) and various halogen ions, HgL2X2 (X = Cl¯ (49), Br¯ (50), and I¯ (51)), is reported. Noteworthy antimicrobial activities, evaluated by minimum inhibitory concentration, for these complexes were observed.

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RESUMEN

In the title ylide, C(31)H(28)ClO(2)P [common name α-acetyl-α-p-chloro-benzoyl-methyl-enetri(p-tol-yl)phospho-rane], the dihedral angle between the 4-chloro-phenyl ring and that of the ylide moiety is 66.15 (10)°. The geometry around the P atom is slightly distorted tetra-hedral [angle range = 105.22 (8)-115.52 (9)°] and the carbonyl O atoms are syn-oriented with respect to the P atom. The ylide group is close to planar [maximum deviation from the least-squares plane = 0.006 (2) Å] and the P-C, C-C and C=O bond lengths are consistent with electron delocalization involving the O atoms.

RESUMEN

Reaction of sulfonium ylides (Me)(2)SCHC(O)C(6)H(4)R (R = H; m-NO(2); p-NO(2); p-OMe; p-Me and p-Br) with AgNO(3) in dichloromethane leads to various compounds. Single crystal X-ray diffraction analysis reveals that the adducts take 3 forms: (i) two-dimensional polymer, [AgNO(3)(Me(2)SCHC(O)C(6)H(5))](n) (1), with nitrate bridges in which each nitrate coordinates to three silver atoms through two oxygen atoms and two Me(2)SCHC(O)C(6)H(5) ligands coordinate to silver centers through carbon atoms; (ii) cationic binuclear, [Ag(Me(2)SCHC(O)C(6)H(4)-m-NO(2))(2)](2)(NO(3))(2)·2H(2)O (2), in which Me(2)SCHC(O)C(6)H(4)-m-NO(2) ligands simultaneously coordinate through both carbon and oxygen atoms with nitrate as a counter ion, and (iii) cationic mononuclear and anionic binuclear, [Ag(Me(2)SCHC(O)C(6)H(4)-p-NO(2))(2)](2)[{AgNO(3)(µ-NO(3)) (Me(2)SCHC(O)C(6)H(4)-p-NO(2))}(2)]·2CH(3)OH (3), in which nitrate groups act as bridging as well as terminal ligands, and Me(2)SCHC(O)C(6)H(4)-p-NO(2) ligands display C-coordination. Characterization of the obtained compounds was also performed by infrared, (1)H- and (13)C-NMR spectroscopy and analytical data indicated a 1 : 2 stoichiometry between the silver(I) nitrate and ylide p-OMe (4) and 1 : 1 for ylides p-Me (5) and p-Br (6). In addition, the antibacterial effects of DMSO-solutions of complexes 1-6 were evaluated by the agar disc diffusion method against three Gram positive and three Gram negative bacteria. All complexes displayed antibacterial activity against these bacteria, with high levels of inhibitory potency exhibited against the Gram negative species.

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RESUMEN

In the mol-ecule of the title compound, (2-thienylcarbon-yl)(triphenyl-phospho-nio)methanide, C(24)H(19)OPS, the geometry around the P atom is nearly tetra-hedral and the O-C-C-P torsion angle is 2.80 (3)°. The thio-phene ring is twisted through an angle of 4.33 (4)° with respect to the plane of the carbonyl group. Inter- and intra-molecular hydrogen bonds and C-H⋯π inter-actions are present in the crystal structure.

RESUMEN

Colourless needle-shaped crystals of the title compound, (C(26)H(21)BrOP)(2)[Hg(2)Br(6)], have been prepared by addition of a solution of HgBr(2) in methanol to a solution of (4-bromo-benzoyl-meth-yl)triphenyl-phospho-rane in dry methanol. The compound features Hg(2)Br(6) (2-) dianions, whose site symmetry is .