Hydroesterification of styrene using an in situ formed Pd(OTs)2(PPh3)2 complex catalyst

Hydroesterification of styrene to 3-phenyl propionate 1, and 2-phenyl propionate 2, has been studied using a Pd(OTs)₂(PPh₃)₂ catalyst formed in situ from Pd(OAc)₂, PPh₃ and p-toluenesulfonic acid (p-tsa). Because of the weakly coordinating properties of the TsO⁻ ligand, the catalyst has vacant coordination sites capable of easy activation of reactants. The presence of water is found to be necessary for the reaction and hydrogen enhances the catalytic activity under certain conditions (with Pd:p-tsa=1). The beneficial effect of hydrogen, p-tsa and water is discussed in terms of favoring the formation of a Pd–H species, which initiates the catalytic cycle through the insertion of styrene into this bond with formation of a Pd-alkyl intermediate, which inserts CO to give a Pd-acyl intermediate, which, upon nucleophilic attack of the alkanol on the carbon atom of the acyl ligand, yields the final product and the starting hydride back to the catalytic cycle. p-tsa would favor the formation of a Pd–H species by reactivating any Pd(0) species that may form during the course of catalysis. Water would favor the formation of a Pd–H species through a reaction closely related to the water–gas shift reaction. The effect of various ligands, promoters, solvents and alcohols on catalytic activity as well as selectivity pattern has been studied. Regioselectivity to the branched product, 2, increases with decrease in basicity of the phosphorous ligands as well as steric bulk around the palladium center and polarity of the medium.     

Addition of C2(CO2Me)2 to trans-MeIr(CO)(PPh3)2. Formation and isomerization of MeIr(CO)(PPh3)2[C2(CO2Me)2], and crystal structure of the thermodynamic isomer

The reaction of C₂(CO₂Me)₂ with trans-MeIr(CO)(PPh₃)₂ leads to a kinetic isomer which has been characterized by ¹H and ³¹P NMR and infrared spectra and to a thermodynamic isomer which has been characterized by ¹H and ³¹P NMR, infrared, microanalysis and X-ray crystallography. The isomerization occurs readily in solution at room temperature; somewhat more slowly at −20°C. The thermodynamically stable isomer of MeIr(CO)(PPh₃)₂[C₂(CO₂Me)₂] crystallizes in the centrosymmetric monoclinic space group P2₁/c with a 14.847(2), b 16.648(2), c 15.656(3) Å, β 90.595(14)°, V 3869.7(11) ų and Z = 4. Single-crystal X-ray diffraction data were collected with a Syntex P2₁ automated diffractometer (Mo-K_α radiation, 2θ 5–40°) and the structure was solved and refined to R_F 8.6% for all 3631 independent data (R_F 4.0% for those 2318 data with |F_o| > 6σ(|F_o|)). The Ir^I center has a trigonal-bipyramidal environment with the methyl ligand and one PPh₃ ligand occupying axial sites (Ir-Me 2.193(14), Ir-P(1) 2.425(4) Å). The C₂(CO₂Me)₂ ligand is π-bonded to the iridium atom and lies with its triple bond parallel to the equatorial coordination plane; the equatorial ligands are completed by the second PPh₃ ligand (Ir-P(2) 2.402(3) Å) and a CO ligand (Ir-CO 1.812(15) Å).     

Highly enantioselective hetero-Diels-Alder reaction between trans-1-methoxy-2-methyl-3-trimethylsiloxybuta-1,3-diene and aldehydes catalyzed by (R)-BINOL-Ti(IV) complex

An efficient enantioselective approach to 2,5-disubstituted dihydropyrones was developed. Some easily accessible inexpensive diol ligand metal complexes were employed, and [(R)-BINOL]₂-Ti(OiPr)₄ complex was found to be the most effective catalyst (up to 99% yield and 99% ee in the presence of 5 mol% catalyst) for the hetero-Diels-Alder reaction between trans-1-methoxy-2-methyl-3-trimethylsiloxybuta-1,3-diene (1) and aldehydes. The potential and generality of this catalyst were evaluated by a variety of aldehydes including aromatic, heteroaromatic, α,β-unsaturated and aliphatic aldehydes. Based on the isolated intermediate from the reaction of benzaldehyde being confirmed by ¹H, ¹³C NMR and HRMS data, the mechanism was proposed as a Mukaiyama aldol pathway.     

Propylene Dimerization by（η^5—C9H7）2 Nickel（Ⅱ）Catalytic System

The catalytic performance of Ni(η^5-Ind)2 complex in the dimerization of propylene was studied in combimation with an organoaluminum co-catalyst,eventually in the presence of a phosphine ligand.The effects of the type of aluminum co-catalyst and its relative amount,the nature of phosphine ligand and P/Ni ratio as well as the reaction temperature were examined.The results indicated that the nickel precatalyst exhibited high productivity for the propylene dimerization together with organoaluminum.It was likely to strongly modify the reactivity in the catalytic sytem when using phosphine ligand as additives,especially at the reaction temperature below 0℃.The catalytic system based on Ni(η^5-Ind)2 complex displaed an extremely high productivity(TOF up to 16900h^-1)and a good regioselectivity to 2,3-dimethylbutenes (2,3-DMB) in dimers(66.4%)under proper reaction parameters.     

Reactions of 1,4-diaza-3-methylbutadien-2-ylpalladium(II) derivatives with chloro-bridged rhodium(I) complexes

The reactions of the organometallic 1,4-diazabutadienes, RN=C(R′)C(Me)=NR″ [R = R″ = p-C₆H₄OMe, R′ = trans-PdCl(PPh₃)₂ (DAB); R = p-C₆H₄OMe, R″ = Me, R′ = trans-PdCl(PPh₃)₂ (DAB^I; R = R″ = p-C₆H₄OMe, R′ = Pd(dmtc)-(PPh₃), dmtc = dimethyldithiocarbamate (DAB^II); R = R″ = p-C₆H₄OMe, R′ = PdCl(diphos), diphos = 1,2-bis(diphenylphosphino)ethane (DAB^III)] with [RhCl(COD)]₂ (COD = 1,5-cyclooctadiene, Pd/Rh ratio = $\text{1}\text{2}$) depend on the nature of the ancillary ligands at the Pd atom in group R′. In the reactions with DAB and DAB^I transfer of one PPh₃ ligand from Pd to Rh occurs yielding [RhCl(COD)(PPh₃)] and the new binuclear complexes [Rh(COD) {RN=C(R?)-C(Me)=NR″}], in which the diazabutadiene moiety acts as a chelating bidentate ligand. Exchange of ligands between the two different metallic centers also occurs in the reaction with DAB^II. In this case, the migration of the bidentate dmtc anion yields [Rh(COD)Pdmtc] and [Rh(COD) {RN=C(R?)C(Me)=NR″}]. In contrast, the reaction with DAB^III leads to the ionic product [Rh(COD)- (DAB^III)][RhCl₂(COD)], with no transfer of ligands. The cationic complex [Rh(COD)(DAB^III)]⁺ can be isolated as the perchlorate salt from the same reaction (Pd/Rh ratio = 1/1) in the presence of an excess of NaClO₄. In all the binuclear complexes the coordinated 1,5-cyclooctadiene can be readily displaced by carbon monoxide to give the corresponding dicarbonyl derivatives. The reaction of [RhCl(CO)₂]₂ with DAB and/or DAB^I yields trinuclear complexes of the type [RhCl(CO)₂]₂(DAB), in which the diazabutadiene group acts as a bridging bidentate ligand. Some reactions of the organic diazabutadiene RN=C(Me)C(Me)=NR (R = p-C₆H₄OMe) are also reported for comparison.     

The reaction of H2Os3(CO)10 with trifluoroacetonitrile and the x-ray crystal structure of HOs3(CO)9(μ3-η2-HNCCF3)

The reaction of H₂Os₃(CO)₁₀ with CF₃CN in hexane at 80°C leads to two isomeric products. The isomer constituting the major product contains a 1,1,1-tri-fluoroethylidenimido ligand which bridges one edge of the Os₃ triangle via the nitrogen, atom and may be formulated as (μ-H)Os₃(CO)₁₀(μ-NC(H)CF₃) (I). The minor product, formulated as (μ-H)Os₃(CO)₁₀(μ-η²-HNCCF₃) (II), contains a 1,1,1-trifluoroacetimidoyl ligand which is also edge-bridging, being N-bonded to one Os atom and C-bonded to the other. Thermolysis of I and II in solution results in loss of a CO group in each case to give (μ-H)Os₃(CO)_9^? (μ₃-η²-NC(H)CF₃) (III) and (μ-H)Os₃(CO)₉(μ₃-η²-HNCCF₃) (IV), respectively, which, it is proposed, are structurally related to I and II, but with the CN group coordinated also to the third Os atom in place of a CO group. In the case of IV this proposal has been confirmed by an X-ray crystallographic analysis. The compound crystallises in space group C2/c with a = 14.258(7), b = 13.486(10), c = 18.193(8) Å, β = 92.68(4)°, and Z = 8. The structure was solved by a combination of direct methods and Fourier difference techniques, and refined by full-matrix least squares to R = 0.054 for 2489 unique observed diffractometer data. Reaction of I with Et₃P gives a 1 : 2 adduct which is formulated as (μ-H)Os₃(CO)₁₀[μ-N?C(H)(CF₃)PEt₃] (V) on the basis of NMR evidence.     

Studies on metal—acetylene complexes : VI. Crystal and molecular structure of [diethylbis(1-pyrazolyl)borato]methyl(1-phenylpropyne)-platinum(II), [(C2H5)2B(N2C3H3)2](CH3)Pt(C6H5CCCH3)

The crystal and molecular structure of [diethylbis(1-pyrazolyl)borato]methyl(1-phenylpropyne)platinum(II), ([(C₂H₅)₂B(N₂C₃H₃)₂](CH₃)Pt(C₆H₅CCCH₃)), has been determined by a single crystal X-ray diffraction study using diffractometer techniques. The compound crystallizes in the monoclinic space group P2₁/c with a = 13.239(6), b = 11.077(5), c = 15.619)7) Å and β = 114.53(2)°. The observed density of 1.71(2) g cm^?3 agrees well with the calculated value, 1.687 g cm^?3, assuming four molecules in the cell. A conventional agreement factor of 0.036 was obtained by least-squares refinement on F using 3289 observations and 194 variables. The coordination about the platinum atom is square planar, if the acetylene is assumed to occupy one coordination site. The substituents of the acetylene are cis-bent away from the Pt atom, the methyl substituent by 17.7(1.0)°, and the phenyl substituent by 21.2(9)°. The coordinated triple bond length is 1.227(10) Å. These results indicate that the acetylene is moderately perturbed on coordination, consistent with the observation that Δν(CC) is 211 cm^?1. The conformation of the ring formed by the bidentate polypyrazolylborate ligand is that of a “shallow” boat. One of the methylene H atoms on the ethyl substituents on the polypyrazolylborate ligand when placed in an idealized position is 2.65 Å distant from the Pt atom.     

The influence of the Si(OC2H5)4/(CH3O)3Si(CH2)3SH ratio on the structure-adsorption characteristics of xerogels formed and accessibility of functional groups in their surface layers

It was shown for the example of the Si(OC₂H₅)₄/(CH₃O)₃Si(CH₂)₃SH system that successively increasing the fraction of tetraethoxysilane in it (from 1: 1 to 5: 1 (mol)) successively decreased the content of 3-mercaptopropyl groups in xerogels synthesized by the sol-gel method (in the presence of methanol as a solvent and fluorine ions as a catalyst) from 5.0 to 1.9 mmol/g, whereas the specific surface area of such xerogels simultaneously increased from 13 to 631 m²/g. The sorption volume of pores also increased, their mean diameter varying insignificantly. The mean diameter of pores (2.2–2.5 nm) was close to the boundary between meso-and micropores, which was in agreement with the form of nitrogen adsorption isotherms (type I according to the IUPAC classification). It was shown by scanning electron microscopy that virtually nonporous xerogels formed at a 1: 1 ratio between alkoxysilanes consisted of spherical partially united particles 2.5–3 μm in diameter. All the 3-mercaptopropyl groups of this and other samples were, however, accessible to silver(I) ions. It follows that these groups are situated in the surface layer of xerogels. The number of thiol groups per 1 nm² of the surface of nonporous xerogels was 1.7–7.0 groups/nm² and depended on the ratio between reacting alkoxysilanes and s _sp.     

Synthesis, structural elucidation and biological activities of organotin(IV) derivatives of (E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoic acid

A new series of di- and tri-organotin(IV) compounds with the general formula R_4?n SnL _n , where R?=?Me (1,2), Et (3), n-Bu (4,5), n-Oct (6), Ph (7) and L?=?(E)-3-(4-methoxyphenyl)-2-(4-chlorophenyl)-2-propenoate, were synthesized by reaction of silver salt of ligand or ligand acid with diorganotin dichloride/oxide and triorganotin chloride in 2:1 and 1:1 molar ratio, respectively. These compounds were characterized by elemental analyses, FT-IR, multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR and mass spectrometry. The spectroscopic results revealed that all the diorganotin(IV) compounds possess trigonal bipyramidal structures in solution and octahedral geometry in the solid state around the tin atom. A linear polymeric trigonal bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non-coordinating solvents has been proposed for the triorganotin(IV) compounds. All synthesized compounds were tested in vitro against a number of microorganisms to assess their biocidal activity. These studies revealed that ligand acid and some of its organotin compounds show promising activity against different strains of bacteria and fungi but lowered than reference drugs.     

Synthesis,spectroscopic characterization and thermal behavior of metal complexes formed with (Z)-2-oxo-2-(2-(2-oxoindolin-3-ylidene)hydrazinyl)-N-phenylacetamide (H2OI)

Complexes of Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and U(IV)O₂ with (Z)-2-oxo-2-(2-(2-oxoindolin-3-ylidene)hydrazinyl)-N-phenylacetamide (H₂OI) are reported and have been characterized by various spectroscopic techniques like (IR, UV–Vis, ESR ¹H and ¹³C NMR) as well as magnetic and thermal (TG and DTA) measurements. It is found that the ligand behaves as a neutral tridentate, neutral tetradentate, monoanionic tridentate, monoanionic tridentate and dianionic tridentate. An octahedral geometry for all complexes except [Cu₂(H₂OI)(OAc)₄](H₂O)₂ and [Cu(HOI)Cl](H₂O)₂ which have a square planar geometry. Furthermore, kinetic parameters were determined for each thermal degradation stage of some studied complexes using Coats–Redfern and Horowitz–Metzger methods. The bond lengths, bond angles, HOMO, LUMO and dipole moments have been calculated to confirm the geometry of the ligand and the investigated complexes.     

1,2- and 3,4-rich polyisoprene synthesized by Mo(VI)-based catalyst with phosphorus ligand

Polyisoprene with relatively high content of 1,2/3,4 structure was synthesized using a novel catalyst system composed of MoO₂Cl₂ supported by phosphorus ligand and Al(OPhCH₃)(i-Bu)₂ as co-catalyst. The effects of phosphites, phosphates and phosphoric acid as ligands were investigated in the coordination polymerization of isoprene in the chosen catalyst system. The studied ligands significantly affected the catalytic activity of the Mo–Al catalytic active center without significant effect on the stereoselectivity. Mo(VI)-based catalyst system was proved to be highly effective in the polymerization of isoprene even at low [Al]/[Mo] ratio (10), affording polyisoprene with 1,2- and 3,4-% structural units in the range of 44.6–52.5%, high molecular weights M_n ~ 10⁵, and relatively broad molecular weight distributions (M_w/M_n = 3.0–4.4). The effect of molar ratio of phosphorous ligand to Mo-catalyst on catalyst activity of isoprene polymerization was discussed, and the structures of Mo–phosphite complexes were preliminarily studied by IR.     

Rapid access to 3-(N-substituted)-aminoquinolin-2(1H)-ones using palladium-catalyzed C-N bond coupling reaction

A series of 3-(N-substituted)-aminoquinolin-2(1H)-ones have been synthesized by the palladium-catalyzed C-N coupling reaction starting from 3-bromoquinolin-2-(1H)-ones. Various nucleophiles including amines, amides, sulfonamides, carbamates and ureas have been used successfully. In all the cases, the reactions take place rapidly in 1,4-dioxane and proceed in good to excellent yield using palladium acetate as a catalyst, Xantphos as a ligand and Cs₂CO₃ as a base.     

Reaction of alkenes with trans-MeOIr(CO)(PPh3)2. Crystal and molecular structure of the pentacoordinate alkoxy-alkene iridium(I) complex,MeOIr(CO)(PPh3)2(TCNE)

The reaction of trans-MeOIr(CO)(PPh₃)₂ with TCNE (tetracyanoethylene) gives rise to the stable adduct MeOIr(CO)(PPh₃)₂(TCNE), the structure of which has been determined via a single-crystal X-ray diffraction study. This complex crystallizes in the centrosymmetric orthorhombic space group Pbca (D¹⁵_2h; No. 61) with a 17.806(4), b 20.769(4), c 20.589(6) Å, V 7614(3) ų and Z = 8. Diffraction data (Mo-K_α, 2θ = 5–45°) were collected on a Syntex P2₁ automated four-circle diffractometer and the structure was solved and refined to R_F 6.2% for 3502 data with |F₀| > 3σ(|F₀|) (R_F 4.3% for those 2775 data with |F₀| > 6 σ(|F₀|)). The central iridium atom has a distorted trigonal bipyramidal coordination geometry in which the methoxy group (Ir-OMe 2.057(8) Å) and carbonyl ligand (Ir-CO 1.897(14) Å) occupy axial sites with ∠MeOIrCO 174.7(4)°. The two triphenylphosphine ligands occupy equatorial sites (IrP(1) 2.399(3), IrP(2) 2.390(3) Å, ∠P(1)IrP(2) 110.32(11)° and the TCNE ligand is linked in an η² “face-on” fashion with the olefinic bond parallel to the equatorial coordination plane (IrC(4) 2.176(10), IrC(7) 2.160(12) Å) and lengthened substantially from its value in the free olefin (C(4)C(7) 1.539(17) Å).     

Reactions of [ReN(Cl)(Me2PhP)2(HEt2tcb)] with Lewis Acids. Synthesis,Characterization and Structures of [Re(NBBr3)Br2(Me2PhP)3], [Re(NGaCl3)Cl(Me2PhP)2(H2Et2tcb)][GaCl4] and [Re{NB(C6F5)3}Cl(Me2PhP)2(HEt2tcb)] (H2Et2tcb=N,N-diethylthiocarbamoylbenzamidine)

Reactions of [ReN(Cl)(Me₂PhP)₂(HEt₂tcb)] (HEt₂tcb⁻=N,N-diethylthiocarbamoylbenzamidinate, Me₂PhP=dimethylphenylphosphine) with Lewis acidic compounds such as BBr₃, (C₆F₅)₃B or gallium(III) chloride yield nitrogen-bridged binuclear complexes with covalent bonds between the nitrido ligand and boron or gallium. The reactions go along with activation of the transition metal centre which can lead to ligand re-arrangements and reactions with solvent molecules.The reaction with BBr₃ results in cleavage of the bonds to the chelating ligand. [Re(NBBr₃)Br₂(Me₂PhP)₃] was isolated as the only product with a nitrido bridge. The bis-chelate [ReN(HEt₂tcb)₂] was formed as a side-product.Upon formation of a nitrido bridge to GaCl₃ the first co-ordination sphere of rhenium is retained. The co-ordinated thiocarbamoylbenzamidinate, however, undergoes protonation and is bonded as a neutral, bidentate ligand in the product [Re(NGaCl₃)Cl(Me₂PhP)₂(H₂Et₂tcb)][GaCl₄].In [Re{NB(C₆F₅)₃}Cl(Me₂PhP)₂(HEt₂tcb)], which can be obtained in good yield from the reaction of [ReN(Cl)(Me₂PhP)₂(HEt₂tcb)] with (C₆F₅)₃B, the co-ordination environment of the metal remains essentially unchanged.X-ray structural studies on the products suggest that the strong structural trans influence of the terminal nitrido ligand in the starting complex decreases significantly as a consequence of the formation of the N–B/Ga bonds. The rhenium–nitrogen multiple bond distances, however, remain almost unchanged.     

The crystal and molecular structure of triphenylphosphoniodithio-carboxylato-ss'-carbonylbis (trikphenylphosphine) iridium(I) tetrafluoroborate [Ir(S2CPPh3) (CO) (PPh3)2]BF4.

Crystal and molecular structures of the title compound have been determined from a three-dimensional X-ray analysis using diffractometer data. The crystals are monoclinic, space group P2₁/c, with Z = 4 in a unit cell of dimensions a = 10.5876(9), b = 31.518(10), c = 16.2164(5) Å, β = 92.521(1)°. The observed and calculated densities are 1.38 and 1.374 g cm^-1 respectively. The crystals decompose under X-rays, and three crystals were required to complete data collection. The structure was solved and refined by convetional methods to final residuals R and R_w of 0.087 and 0.107 respectively.The crystals contain monomeric cations, and BF₄ anions. The iridium atom is in a distorted trigonal bipyramidal environment consisting of the two sulphur atoms (one axial, one equatorial) of a bidentate triphenylphosphoniodi-thiocarboxylate ligand, two triphenylphosphine groups (equatorial) and the carbonyl ligand (axial). The non-equivalent Ir-s distances are 2.377 and 2.307(5) Å, the Ir-P distances are 2.334, 2.331(5) Å. Within the zwitterion, the C-S distances are 1.66 and 1.70(2) Å, while P-C is 1.78(2) Å. The condensation of PPh₃ and CS₂ to form the PH₃P⁺-CS₂ zwitterion is in contrast to that predicted previously.It is probable that the other complexes of iridium and rhodium prepared in a similar manner [2] should now be reformulated as containing Ph₃P⁺-CS₂^- ligands.     

Synthesis of 5,6-O-Cyclohexylidene-1-amino-3-azahexane and Its Co(II), Ni(II), Cu(II) Complexes

5,6-O-Cyclohexylidene-1-amino-3-azahexane (L) is synthesized from 1-chloro-2,3-O-cyclohexylidenepropane, which is prepared by the reaction between epichlorohydrin and cyclohexanone. In this reaction, BF₃ · OEt₂ is used as a catalyst. Complexes of Co(II), Ni(II) and Cu(II) acetates with this ligand are prepared. The structures of the ligand and its complexes are proposed based on elemental analysis, IR and UV-VIS spectroscopy, magnetic susceptibility, conductometry, and ¹H and ¹³C NMR spectroscopy.     

Cu(I) cloride complexes with 4,5-(2-pyridylethylene)dithio-1,3-dithiol-2-thione and triphenylphosphine

Heteroligand binuclear complexes of CuCl with triphenylphosphine and 5-pyridine-2-yl-5,6-dihydro-[1,3]dithiolo[4,5-b][1,4]dithiine-2-thione (L¹) of the compositions [CuCl(PPh₃)(L¹)]₂ (I) and [CuCiL¹]₂ (II) are synthesized and studied by X-ray diffraction method. Crystals I are monoclinic; space group P2₁/n, a=8.9520(18) Å, b=18.926(4) Å, c=16.841(3) Å, β=94.96(3)°, Z=2. The Cu(I) atom has a quasi-tetrahedral surrounding involving the tetraphenylphosphine P atom, the pyridyl N atom of the molecule L¹, and two bridging Cl atoms. Crystals II are monoclinic; space group P2₁/c, a=9.3520(19) Å, b=8.1490(16) Å, c=18.660(4) A, β = 104.43(3)°, Z = 2. Both L¹ ligands in complex II act as bridges. The Cu(I) atom also has a quasi-tetrahedral surrounding formed by the Cl atoms, the pyridyl N atoms and thiol S atom of one L¹ ligand, and the thione S atom of the second L¹ ligand. Similar binuclear complexes with the bridging function of the L¹ ligand were also detected in a solution of II by the ESI method.     

Synthesis and base hydrolysis of chloro(N-(2-pyridinylmethylene)-N′-[3-[(2-pyridinylmethylene)amino]-propyl]-1,3-propanediamine)cobalt(III) perchlora

Synthesis of [Co(pyDPT)Cl](ClO₄)₂ from pentadentate ligand and cobalt(II) yields one cis isomer. Hydrolysis in base is extremely rapid (k_OH 1.8 × 10⁶ M^?1 s^?1 at 250°) in this complex, where the geometry and ligand character fix the single site for conjugate base formation as cis to the leaving group.     

Silver(I) thiosemicarbazone complex [Ag(catsc)(PPh3)2]NO3: Synthesis,characterization, crystal structure,and antibacterial study

We report the synthesis, characterization and crystal structure of a new mononuclear silver(I) complex, [Ag(catsc)(PPh₃)₂]NO₃ (catsc = 3-phenylpropenalthiosemicarbazone). The complex was prepared by the reaction of catsc and AgNO₃ in the presence of PPh₃ and characterized by elemental analysis (CHN), FTIR, ¹H, ¹³C and ³¹P NMR spectroscopy, and single-crystal X-ray diffraction. In the complex, catsc acts as a bidentate NS ligand while the nitrate is a counter ion. The silver ion is coordinated by a bidentate ligand and two PPh₃ in the form of a distorted tetrahedron. In addition, the antibacterial effect of the complex was studied against the standard strains of two gram-positive (Staphylococcus aureus and Enterococcus faecalis) and two gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria.     

Cluster condensation reactions. The synthesis and crystal and molecular structure of Os6(CO)14(μ2-PPh2)2(μ3-S)3(μ4-S)

Thermal degradation of the cluster compound Os₃(CO)₈(PPh₂H)(μ₃-S)₂ (I) at 125°C leads to decarbonylation and formation of the new ligand bridged hexanuclear cluster Os₆(CO)₁₄(μ-PPh₂)₂(μ₃-S)₃(μ₄-S) (II) in 11% yield. Space Group: P$\text{1}$, No. 2, a 10.427(5), b 13.552(3), c 17.919(3) Å, α 84.87(2), β 75.41(3), γ 78.43(3)°, V 2399(2) ųZ = 2, _?calc 2.82 g cm^?3. The structure was solved by the heavy atom method and refined (3223 reflections) to the final residuals R = 0.042 and R_w = 0.036. The molecule consists of two sulfido bridged open triosmium clusters which are linked by a bridging sulfido ligand and a bridging diphenylphosphino ligand.