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The addition−elimination equilibrium involving a platinum(0) nucleophile [Pt(N,N‘-chelate)(olefin)] (1), an organometal electrophile RmMXn (M = Hg, Sn; X = Cl, Br, I; R = hydrocarbyl group), and th...

Excess molar enthalpies, HEm, of binary liquid mixtures containing dibutyl ether or ethylene glycol monoethyl ether or ethylene glycol dimethyl ether or ethylene glycol diethyl ether or diethylene glycol ethyl ether or diethylene glycol diethyl ether or triethylene glycol monoethyl ether + benzyl alcohol have been measured over the entire range of composition at 308.15 K and at atmospheric pressure using a flow microcalorimeter. Data were fitted to the Redlich-Kister equation. The results show how the enthalpy of mixing is influenced by both the steric and electronic characteristic of the terminal groups that belonging the OP = [CH2OCH2] central unit of the ether, and on the hydrogen bonding.

Excess molar enthalpies, , of binary liquid mixtures containing as component 1 ethylene glycol, propylene glycol, di(ethylene glycol), tri(ethylene glycol), tetra(ethylene glycol), or some PEGs, such as PEG200, PEG300, PEG400, PEG600, and 2-phenylethyl alcohol (2), have been measured over the entire range of mole fraction x1 at 308.15 K and at atmospheric pressure, using a flow microcalorimeter. The values of vary from a value of −600 J·mol-1 (mixture containing PEG600) up to a maximum of 254 J·mol-1 (mixture containing propylene glycol) decreasing as the chain length of glycols or PEGs increase. Curves are not symmetric, and in the case of mixtures containing PEGs, an intersection among the curves at x1 ≈ 0.65 has been observed. Results were fitted to the Redlich−Kister polynomial to estimate the adjustable parameters and the standard deviations between experimental and calculated values. Qualitative discussion of H bonding in the liquid state is given.

The reaction of sodium cyanopentacarbonylmetalates Na[M(CO)5(CN)] (M=Cr; Mo; W) with cationic Fe(II) complexes [Cp(CO)(L)Fe(thf)][O3SCF3], [L=PPh3 (1a), CN-Benzyl (1b), CN-2,6-Me2C6H3 (1c); CN-But (1d), P(OMe)3 (1e), P(Me)2Ph (1f)] in acetonitrile solution, yielded the metathesis products [Cp(CO)(L)Fe(NCCH3)][NCM(CO)5] [M=W, L=PPh3 (2a), CN-Benzyl (2b), CN-2,6-Me2C6H3 (2c); CN-But (2d), P(OMe)3 (2e), P(Me)2Ph (2f); M=Cr, L=(PPh3) (3a), CN-2,6-Me2C6H3 (3c); M=Mo, L=(PPh3) (4a), CN-2,6-Me2C6H3 (4c)]. The ionic nature of such complexes was suggested by conductivity measurements and their main structural features were determined by X-ray diffraction studies. Well-resolved signals relative to the [M(CO)5(CN)] moieties could be distinguished only when 13C NMR experiments were performed at low temperature (from −30 to −50 °C), as in the case of [Cp(CO)(PPh3)Fe(NCCH3)][NCW(CO)5] (2a) and [Cp(CO)(Benzyl-NC)Fe(NCCH3)][NCW(CO)5] (2b). When the same reaction was carried out in dichloromethane solution, neutral cyanide-bridged dinuclear complexes [Cp(CO)(L)FeNCM(CO)5] [M=W, L=PPh3 (5a), CN-Benzyl (5b); M=Cr, L=(PPh3) (6a), CN-2,6-Me2C6H3 (6c), CO (6g); M=Mo, L=CN-2,6-Me2C6H3 (7c), CO (7g)] were obtained and characterized by infrared and NMR spectroscopy. In all cases, the room temperature 13C NMR measurements showed no broadening of cyano pentacarbonyl signals and, relative to tungsten complexes [Cp(CO)(PPh3)FeNCW(CO)5] (5a) and [Cp(CO)(CN-Benzyl)FeNCW(CO)5] (5b), the presence of 183W satellites of the 13CN resonances (JCW ∼ 95 Hz) at room temperature confirmed the formation of stable neutral species. The main 13C NMR spectroscopic properties of the latter compounds were compared to those of the linkage isomers [Cp(CO)(PPh3)FeCNW(CO)5] (8a) and [Cp(CO)(CN-Benzyl)FeCNW(CO)5] (8b). The characterization of the isomeric couples 5a–8a and 5b–8b was completed by the analyses of their main IR spectroscopic properties. The crystal structures determined for 2a, 5a, 8a and 8b allowed to investigate the geometrical and electronic differences between such complexes. Finally, the study was completed by extended Huckel calculations of the charge distribution among the relevant atoms for complexes 2a, 5a and 8a.

Excess molar enthalpies, H-m(E), were determined as a function of molar fraction at 308.15 K and at atmospheric pressure for the binary mixtures containing dimethyl sulfoxide with ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, poly(ethylene glycol)-200, poly(ethylene glycol)-300, poly(ethylene glycol)-400, and poly(ethylene glycol)-600. All curves are negative over the entire composition range with minima ranging from -430 J.mol(-1) (propylene glycol) up to -1080 J.mol(-1) (poly(ethylene glycol)-600). The results were correlated using the Redlich-Kister polynomial, and the adjustable parameters were obtained by the least-squares method. The dependence of H-m(E) on mixture composition is qualitatively discussed in terms of molecular interactions.

Densities, Á, kinematic viscosities, ½, and refractive indices, nD, were determined for poly(ethylene glycol) 200 and 400 + 1,3-dioxolane, + 1,4-dioxane, + oxolane (tetrahydrofuran, THF), and + oxane (tetrahydropyran, THP) binary mixtures over the entire range of composition at 303.15 K and at atmospheric pressure. The excess molar volumes, Vm alla E , deviations in viscosities, ”· , and deviations in molar refractions, ”R, calculated from experimental measurements, are always negative. The results were correlated with the Redlich-Kister polynomial. The McAllister multibody interaction model was used to correlate the kinematic viscosities of liquid mixtures with mole fractions. The viscosity dependence on temperature was investigated between 297.15 and 309.15 K for some solutions in a restricted composition range.

Densities, ρ, viscosities, η, and refractive indices, nD, of binary mixtures containing n-hexane + α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), + β-pinene (6,6-dimethyl-2-methylene bicyclo[3.1.1]heptane), + p-cymene (1-methyl-4-[1-methylethyl]benzene), + (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene], + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane), and + linalool (3,7-dimethyl-1,6-octadien-3-ol) were determined at 298.15 K and at atmospheric pressure using a digital density meter, a Schott viscosity measuring system, and an Abbe refractometer, respectively. The excess molar volumes, , deviations in viscosities, Δη, and deviations in molar refractions, ΔR, calculated from experimental measurements, are always negative, with the exception of the curve referring to the hexane + linalool mixture, which shows an inversion of sign. Results were fitted to the Redlich−Kister polynomial and qualitatively discussed in terms of molecular interactions. The McAllister multibody intera...

Densities, ρ, viscosities, η, refractive indices, nD, and excess molar enthalpies, , of binary mixtures containing methyl tert-butyl ether (MTBE) + α-pinene (2,6,6-trimethylbicyclo[3.1.1]hept-2-ene), + β-pinene (6,6-dimethyl-2-methylenebicyclo[3.1.1]heptane), + p-cymene [1-methyl-4-(1-methylethyl)benzene], + (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene], + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2.2.2]octane), and + linalool (3,7-dimethyl-1,6-octadien-3-ol) were determined at 298.15 K and at atmospheric pressure using a digital density meter, a Schott measuring system, an Abbe refractometer, and a flow microcalorimeter, respectively. The excess molar volumes, , the deviations in viscosities, Δη, and in refractive indices, ΔR, and the excess molar enthalpies, , were calculated from experimental measurements. Results were fitted to the Redlich−Kister equation to obtain the adjustable parameters and standard deviations. Results were also qualitatively discussed in terms of molecular intera...

Densities, ρ, viscosities, η, and excess molar enthalpies, , of binary mixtures containing (S)-(−)-limonene [(−)-1-methyl-4-(1-methylethenyl)cyclohexene] + 1,8-cineole (1,3,3-trimethyl-2-oxabicyclo[2,2,2]octane), (S)-(−)-limonene + linalool (3,7-dimethyl-1,6-octadien-3-ol), and cineole + linalool were determined at (298.15 and 313.15) K and at atmospheric pressure using a digital density meter, a Schott measuring system, and a flow microcalorimeter, respectively. The excess molar volumes, , the viscosity deviations, Δη, and the 's were calculated from experimental measurements. Results were fitted to the Redlich−Kister polynomial to obtain the adjustable parameters and standard deviations. Results were also qualitatively explained in terms of molecular interactions.

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing 1,3-dioxolane or 1,4-dioxane + α-pinene, + β-pinene, or + p-cymene were determined at (298.15 and 313.15) K and at atmospheric pressure over the entire composition range using a flow microcalorimeter and a digital density meter. and are always positive, and the temperature dependence is more marked for values. Results were fitted to the Redlich−Kister polynomials to obtain the binary adjustable parameters and the standard deviations

The new Au8{Fe(CO)4}4(P^P)2 and Au6Cu2{Fe(CO)4}4(P^P)2 (P^P=dppm, dppe) neutral cluster compounds were isolated in good yields by condensation of the [Au3{Fe(CO)4}2(P^P)]- anions with Au(SEt2)Cl and CuCl, respectively, and have been characterized by IR, NMR and microanalyses. The molecular structures of Au8{Fe(CO)4}4(dppe)2 and Au6Cu2{Fe(CO)4}4(dppe)2 have been determined by X-ray diffraction studies. Both molecules adopt a stereogeometry of the heavy atoms consisting of a triangulated and corrugated ribbon twisted around the elongation direction. Contrary to the expectations the latter displays the two copper atoms in the sites of highest connectivity. This implies that site exchange between copper and gold occurs during the synthesis.

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing dimethyl carbonate (DMC), or diethyl carbonate (DEC) + α-pinene, + β-pinene, or + p-cymene have been determined using a flow microcalorimeter and a digital density meter at atmospheric pressure and at (298.15 and 313.15) K. All and data are positive and show symmetrical curves versus composition. The influence of temperature is marked for volumetric measurements while almost negligible for enthalpic data. Results have been correlated using the Redlich−Kister polynomial to estimate the binary interaction parameters. The calculated quantities have been qualitatively discussed in terms of thermodynamic interactions between the mixing compounds.

Dynamic viscosities, η, densities, ρ, and enthalpies of mixing of binary mixtures containing propylene carbonate + anisole, or + phenetole have been determined at (293.15, 303.15, and 313.15) K and at atmospheric pressure over the whole range of composition. From these results, the deviations in viscosity, Δη, the excess molar volumes, VmE, and the excess molar enthalpies, HmE, have been calculated. Both Δη and VmE are always negative, while positive values have been obtained for HmE. Minima of Δη and VmE and maxima of HmE are the following: −0.248 mPa·s, −0.744 cm3·mol-1, and 347 J·mol-1 for the mixtures propylene carbonate + anisole; −0.248 mPa·s, -0.146 cm3·mol-1, and 766 J·mol-1 for the mixtures propylene carbonate + phenetole. The temperature effect has shown more marked differences for HmE. Results have been correlated using the Redlich−Kister polynomial.

Excess molar enthalpies, H m E , of binary mixtures containing phenetole (ethoxy benzene)+α-pinene, or β-pinene have been determined in the range (288.15–313.15) K, and at atmospheric pressure using a flow microcalorimeter. H m E curves are symmetrical with positive values over the entire concentration range and show higher values for the mixture containing α-pinene (the maximum value for H m E is 1072 J mol −1 ). Only a slight influence of temperature on excess molar enthalpies has been observed for both systems. Experimental results have been correlated using the Redlich–Kister polynomial and the adjustable parameters have been evaluated by least-squares analysis. Results have also been interpreted by an extended modified cell model of Prigogine.

The reaction of [Rh12C2(CO)24]2- (as K+ salt) with RhI derivatives yields an uncharacterized intermediate (1) from which, by reaction with halides, the new carbido-carbonyl cluster anions [Rh15C2(CO)24X2]3- (X = Cl, 2a; Br, 2b; I, 2c) have been obtained. The molecular structures of 2b and 2c as [N(n-Pr)4]+and [NEt4]+ salts, respectively, have been determined by single-crystal X-ray diffractometry. The two anions are isostructural and contain a Rh15C2 cluster that can be described as a C2v centered and tetracapped pentagonal prism. The carbide atoms occupy octahedral interstices, and the halide ligands span basal edges of the prism. The CO ligands have been found partially ordered in the dibromo derivative and totally ordered in the diiodo one, adopting an unprecedented and peculiar asymmetric stereogeometry. The room-temperature solution 13C NMR spectrum indicates that in compound 2c a fraction of the carbonyl ligands is fluxional, probably those found disordered in the solid state structure of 2b.

Excess molar enthalpies, H m E , of binary mixtures containing propylene carbonate + six n -alkoxyethanols have been determined using an LKB flow microcalorimeter at 288.15, 298.15, and 313.15 K and at atmospheric pressure. The alkoxyethanols were 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, and 2-(2-butoxyethoxy)ethanol. From the experimental data, deviations in H m E have been determined and fitted to the Redlich–Kister polynomial to estimate the binary interactions parameters.

Excess molar enthalpies, , and excess molar volumes, , of binary mixtures containing dimethyl carbonate or diethyl carbonate + anisole or + phenetole have been determined at (298.15 and 313.15) K and at atmospheric pressure. Standard deviations have been calculated from correlation of data by the Redlich−Kister polynomial. The calculated quantities have been qualitatively discussed in terms of thermodynamic interactions between the mixing components. Only a slight influence of temperature on the excess properties has been observed.

Excess molar enthalpies and excess molar volumes of diethyl carbonate + some alkoxyethanol mixtures have been determined by an LKB flow microcalorimeter and an Anton Paar density meter as a function of mole fraction of diethyl carbonate at (298.15 and 313.15) K. The alkoxyethanols are 2-methoxyethanol, 2-ethoxyethanol, 2-buthoxyethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, and 2-(2-butoxyethoxy)ethanol, respectively.

The new [Fe 3 (μ 3 -O)(μ 3 -AuPPh 3 )(μ-CO) 3 (CO) 6 ] − and [Fe 3 (μ 3 -S)(μ-AuPPh 3 )(CO) 9 ] − monoanionic congeners have been obtained by reacting the [Fe 3 (μ 3 -E)(CO) 9 ] 2− (E=O, S) dianions with one equivalent of Au(PPh 3 )Cl. The gold adduct of the oxygen derivative has been crystallized as tetraethylammonium and trimethylbenzylammonium salt either from THF and n-hexane or acetone and isopropyl alcohol, and structurally characterized in its tetraethylammonium salt (monoclinic, C 2 /c (No. 15), a =15.859(2), b =12.859(2), c =40.217(8) A, β =96.41(1)° Z =8). The [Fe 3 (μ 3 -S)(μ-AuPPh 3 )(CO) 9 ] − gold adduct, in contrast, partially reverts to the parent dianion upon crystallization under the above experimental conditions, and could be precipitated only as the [Au 6 (μ 3 -S) 2 (PPh 3 ) 6 ][Fe 3 (μ 3 -S)(μ-AuPPh 3 )(CO) 9 ] 2 salt (triclinic, P 1 (No. 2), a =18.998(8), b =19.933(8), c =22.94(1) A, α =99.91(4), β =98.91(4), γ =107.42(3)°, Z =2), by addition of an equivalent of the [Au 3 (μ 3 -S)(PPh 3 ) 3 ] + sulfonium cation to the reaction mixture. The [Fe 5 (μ 3 -S) 2 (CO) 14 ] 2− dianion does not form a gold adduct even in the presence of the sulfonium cation and only the corresponding [Au 6 (μ 3 -S) 2 (PPh 3 ) 6 ][Fe 5 (μ 3 -S) 2 (CO) 14 ] salt could be obtained. The [Fe 3 (μ 3 -O)(μ 3 -AuPPh 3 )(μ-CO) 3 (CO) 6 ] − and [Fe 3 (μ 3 -S)(μ-AuPPh 3 )(CO) 9 ] − gold adducts are not isostructural and the possible factors leading to their structural diversities are discussed. The [Au 6 (μ 3 -S) 2 (PPh 3 ) 6 ][Fe 3 (μ 3 -S)(μ-AuPPh 3 )(CO) 9 ] 2 and [Au 6 (μ 3 -S) 2 (PPh 3 ) 6 ][Fe 5 (μ 3 -S) 2 (CO) 14 ] salts represent further examples of ionic solids assembled from cluster-cations and cluster-anions.

The structure of the centrosymmetric dimeric copper(II) title compound, [Cu 2 (C 14 H 10 Cl 2 NO 2 ) 4 (C 3 H 6 O) 2 ].C 2 H 4 O, has been determined and compared with the structures of analogous O-bridged Cu II dimers. Polarographic experiments on aqueous solutions containing a mixture of the Cu II ion and diclofenac have been used to determine both the formation constant [1 (1) × 10 8 ] and the solubility product [2 (1) × 10 -12 ] of the complex.

Excess molar enthalpies HmE of binary mixtures containing diethyl carbonate + 1-butanol, + 2-butanol, + 2-methyl-1-propanol, and + 2-methyl-2-propanol have been determined using a flow microcalorimeter in the range (288.15−318.15) K and at atmospheric pressure. All mixtures are strongly endothermic, with maxima of HmE varying from 1900 (mixture containing 1-butanol) to 2550 (mixture containing 2-butanol) J·mol-1. The HmE curves are nearly symmetrical and show values increasing as the temperature increases. Data have been correlated using the Redlich−Kister equation, and experimental results have been qualitatively discussed.

Excess molar enthalpies, , and excess molar volumes, , of propylene carbonate + seven pentanol isomers, namely, 1-, 2-, and 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, and 3-methyl-2-butanol, have been determined at 298.15 K and at atmospheric pressure using a flow microcalorimeter and a digital densimeter. and values are always positive, with the exception of the volumetric data for the mixture propylene carbonate + 3-methyl-2-butanol, showing a sign inversion of . The Redlich−Kister equation, fitted to the experimental results, provides a satisfactory mathematical representation of and in all mixtures. Results have been qualitatively discussed.

Excess molar enthalpies of binary mixtures containing diethyl carbonate + fourteen n -alkyl alkanoates (six acetates, four propanoates and four butyrates) have been determined at 298.15 K and at atmospheric pressure using an LKB flow microcalorimeter. The experimental data have been fitted to the Redlich-Kister equation to estimate the binary parameters. The results have been qualitatively discussed.

The 1,3-addition of methylmagnesium chloride to dialdose derived nitrones 3 and 7 afforded N- benzylhydroxylamines 4 5 and 8 9 , respectively, in high yields. The stereoselectivity of the addition reaction was improved by the use of trimethylsilyl triflate. The NO bond reductive cleavages of N-benzylhydroxylamines took place in good yields and offered an easy access to N-benzylaminosugars. The potential of these aminosugars is demonstrated by the synthesis of glycosidase inhibitor 6-deoxynojirimycin 1a.

The reactions of [Fe2{µ-CN(Me)R}(µ-CO)(CO)2(Cp)2]SO3CF3 (Cp = η-C5H5, R = Me 2a or CH2Ph 2b) with a variety of carbon nucleophiles result in C–C bond formation at different sites of the molecules depending on the nature of the carbanions: (i) R′Li (R′ = Me, Bun or Ph) and R′MgCl (R′ = Me, CH2Ph or Pri) added at the Cp ligand giving η4-cyclopentadiene complexes [Fe2{µ-CN(Me)R}(µ-CO)(CO)2(η4-C5H5R′)(Cp)] 3; (ii) Li2Cu(CN)R′2 (R′ = Me or Bun) and LiCCR′ (R′ = Ph or p-tolyl) afforded the stable acyl complexes [Fe2{µ-CN(Me)R}(µ-CO)(CO){C(O)R′}(Cp)2] 4 and [Fe2{µ-CN(Me)R}(µ-CO)(CO){C(O)CCR′}(Cp)2] 5, respectively. With R ≠ Me the NMR spectra of type 3–5 derivatives show the presence of two isomers arising from the double-bond character of the µ-CN group ascertained from the crystal structure of [Fe2(µ-CNMe2)(µ-CO)(CO){C(O)Bun}(Cp)2] 4b. The structural study reveals the presence of interligand interactions involving the acyl oxygen and the µ-CNMe2 moiety which is also in accord with an extended-Huckel calculation of the charge distribution.

The molecular and crystal structures of three salts of the same anion, N-(2-hydroxyethyl)piperidinium 2-(2,6-dichlorophenylamino)phenylacetate, C 7 H 16 NO + .C 14 H 10 Cl 2 NO 2 - , N-(2-hydroxyethyl)morpholinium 2-(2,6-dichlorophenylamino)phenylacetate, C 6 H 14 NO 2 + .C 14 H 10 Cl 2 NO 2 - , N-(2-hydroxyethyl)piperazinium 2-(2,6-dichlorophenylamino)phenylacetate, C 6 H 15 N 2 O + .C 14 H 10 Cl 2 NO 2 - , have been determined by X-ray diffraction. Strong anion-cation interactions via hydrogen bonds are the prime driving force for crystal self-assembly. Packing is determined by weak hydrogen-bonding interactions (C-H...O and C-H...Cl). The three compounds are isomorphous and are characterized by the same network of hydrogen bonds. Structural results are related to the different solubilities of the three salts.

A straightforward synthesis of tetrahydro-2-benzyl-3-(1-benzyloxyethyl)-furo[2,3-d]isoxazol-5(2H)ones is reported, based on the Lewis acid-catalysed addition of 2-trimethylsilyloxyfuran to the N-benzyl nitrone of (S)-lactaldehyde.

The reactions of the µ-cyano(amino)alkylidene complexes [Fe2(CO)2(cp)2(µ-CO){µ-C(CN)(NR2)}][cp η5-C5H5, NR2 [graphic omitted]H21a or NMe21b] with [W(CO)5(thf)](thf = tetrahydrofuran), MeSO3CF3 and HSO3CF3 electrophiles promotes µ-C–CN bond cleavage with formation of the corresponding [Fe2(CO)2(cp)2(µ-CO)(µ-CNR2)]+3. In the case of [W(CO)5(thf)] the unexpected salts [Fe2(CO)2(cp)2(µ-CO)(µ-CNR2)][(OC)5WCNW(CO)5] have been prepared and characterized by the crystal structure of 3a[NR2= [graphic omitted]H2]. The structure [monoclinic, space group P21/n,a= 11.196(3), b= 17.389(3), c= 17.938(3)A, β= 95.19(2)°, Z= 4, R= 0.032] contains ordered cations and anions. Distances of interest are Fe–µ-C(N) 1.875(6), C–N 1.280(8)A in the cation and W–C(N) 2.184(8), W–N(C) 2.187(7) and C–N 1.15(1)A in the anion, where the cyanide ligand symmetrically bridges two W(CO)5 units. Electrophilic addition to phosphorus in [Fe2(CO)2(cp)2(µ-CO){µ-C(CN)(PEt2)}]2 has been observed and the adduct [Fe2(CO)2(cp)2(µ-CO){µ-C(CN)[PEt2W(CO)5]}]4 spectroscopically characterized. The different reactivity of 1 and 2 with electrophilic reagents is attributed to the strong tendency to CN double-bond formation.

A straightforward synthesis of tetrahydro-2-benzyl-3-(1-benzyloxyethyl)-furo[2,3-d]isoxazol-5(2H)ones is reported, based on the Lewis acid-catalysed addition of 2-trimethylsilyloxyfuran to the N-benzyl nitrone of (S)-lactaldehyde.

Five-coordinate olefin complexes of platinum(II) of the general formula [Pt(2,9-Me2-1,10-phen)(SnRnX3-n)X(olefin)] have been synthesized through oxidative addition of organotin halides RnSnX4-n to three-coordinate platinum(O) complexes [Pt(2,9-Me2-1,10-phen)(olefin)]. The X-ray crystal structure of the title complex has been determined. This crystallizes in the monoclinic system, space group P21/n with a = 13.858(8), b = 13.730(6), c = 16.820(8) A, β = 102.44(5)°, and Z = 4. Refinement converged at R = 0.04 (Rw = 0.044). The geometry of the five-coordinate platinum complex is bipyramidal, with anionic ligands inapical positions and the olefinic double bond in the equatorial plane. Some general features of the addition process, and the structural and NMR properties of the complexes, are also discussed.

The role of the steric requirements of the NN′ chelate ligand in the stabilization of trigonal-bipyramidal [Pd(NN′)(olefin)RX] complexes is discussed. The crystal structure of the precursor (2,9-dimethyl-1,10,phenanthroline)methylchloropalladium(II) (1a) has been determined. The molecule adopts a significantly distorted square-planar coordination geometry in order to accomodate the crowding in the coordination plane. The most significant distortions involves the coordinated methyl group and the dimethylphenanthroline molecule, whose mean plane lies out of the coordination plane by 39.3°. There is ready CO insertion into the PdMe bond of 1a to give an acyl derivative. The formation of a five-coordinate acyl derivative by subsequent uptake of an olefin also illustrates the importance of the steric effects of NN′ ligands.

The compounds [MLNi(H2O)2LM][ClO4]2·4H2O [M = Cu or Ni; H2L =N,N′-bis(3-amino-2,2-dimethylpropyl)oxamide] were prepared and characterized by means of structural, magnetic and spectroscopic measurements. The crystals of both compounds are triclinic, space group P and Z= 2, with a= 12.080(1), b= 13.054(1), c= 14.775(2)A, α= 101.97(1), β= 90.82(1) and γ= 101.88(1)°, for M = Cu and a= 12.099(5), b= 13.060(4), c= 14.750(7)A, α= 101.98(3), β= 90.28(4) and γ= 102.25(3)° for M = Ni. The structural unit of both complexes consists of trinuclear dipositive cations, two perchlorate anions and four lattice water molecules. The central and terminal metal ions are antiferromagnetically coupled, J= 90(1) cm–1 in the case of M = Cu.

In the title compound, hexaaquamagnesium bis{[2-(2,6-a dichloroanilino)phenyl]acetate} dihydrate, [Mg(H 2 O) 6 ]-e (C 14 H 10 Cl 2 NO 2 ) 2 .2H 2 O, the two centrosymmetric hexaaquamagnesium ions, the two [2-(2,6-dichloroanilino)-phenyl]acetate anions and the two water molecules are tied into an elaborate network of hydrogen bonds.

Five-coordinate olefin complexes of palladium(II) of general formula PdClMe(N-N')(η 2 -olefin) have been prepared by reaction of the dimeric complex [PdClMe(Me 2 S)] 2 with planar sterically crowded nitrogenous bidentate ligands and the appropriate olefin. The X-ray crystal structure of the complex having N-N'=2,9-dimethyl-1,10-phenanthroline and olefin=maleic anhydride has been determined

The asymmetric unit of the title compound, C 4 H 12 N 2 2+ .-2C 14 H 10 Cl 2 NO 2 - .2H 2 O, consists of two piperazinium dications located around two non-equivalent centers of symmetry, two 2-(2,6-dichlorophenylamino)phenyl-acetate anions in general positions and two water molecules. The solid-state structure is strongly hydrogen bonded.

The title compounds were obtained by oxidative addition of hydrogen halides to suitable [Pt( N,N -chelate) (olefin)] species. The properties of the ligands and of the electrophile which allow the isolation of stable products must meet very strict requirements. The crystal structure of [PtCl(H)(2,9-Me 2 -1,1O-phenanthroline) (dimethyl maleate)] was determined by single-crystal X-ray diffraction. Substitution, insertion, and elimination reactions were performed on one hydride complex.

Densities, viscosities, and refractive indices for binary systems containing mixtures of poly(ethylene glycols) at the same number-average molecular mass (M-n approximate to 300) but different polydispersities (molecular mass distribution between 1.15 and 1.98) with dimethyl carbonate or diethyl carbonate were determined at 313.15 K and at atmospheric pressure. The measurements were carried out over the whole range of composition, using a vibrating-tube density meter, Ubbelohde viscometers with a Schott-Gerate AVS 310 unit, and an Abbe refractometer. Densities, viscosities, and refractive indices were used to compute the excess volumes, V-E, viscosity deviations, Deltaeta, and deviations in molar refraction, DeltaR. Results were fitted to the Redlich-Kister polynomial, and the adjustable parameters were obtained using least-squares methods. The viscosity dependence on temperature was investigated between (309.15 and 327.15) K for some solutions in a restricted composition range. A qualitative discussion on these quantities in terms of molecular interactions is reported.

Excess enthalpies have been determined at atmospheric pressure and at 308.15 K over the entire range of composition for binary mixtures containing propylene glycol (PG), dipropylene glycol (DPG), tripropylene glycol (TPG), poly(propylene glycol)-400, -725, -1200, -2000 + dimethyl carbonate (DMC). From the experimetal data, excess enthalpies, H E , and standard deviations in enthalpy, σ ( H E ) have been calculated. The experimental data were fitted to a Redlich–Kister polynomial to obtain the binary adjustable parameters, a k . The H E values are positive over the entire range of composition, decreasing with the increase of the molecular weight of glycols. The mixtures containing polydisperse glycols behave as regular solutions. Conclusions were qualitatively discussed in terms of molecular interactions.

Excess molar enthalpies and excess molar volumes of binary mixtures containing ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, or poly(ethylene glycol)s (PEG200, PEG300, PEG400, and PEG600) + benzyl alcohol were determined at 308.15 K and at atmospheric pressure using a flow microcalorimeter and a digital density meter. Results were fitted to the Redlich-Kister polynomial to estimate the binary interaction parameters. The results are interpreted in terms of molecular interactions between the components.

Excess molar enthalpies, H m E , were determined as a function of molar fraction at 308.15 K and at atmospheric pressure for the binary mixtures containing propylene carbonate with ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, poly(ethylene glycol)-200, poly(ethylene glycol)-300, poly(ethylene glycol)-400, and poly(ethylene glycol)-600. Values of H m E range from a maximum of about 1640 J mol −1 (propylene glycol) to a minimum of about −386 J mol −1 (PEG-600). All mixtures containing monodisperse glycols have positive values of H m E . Also PEG-200 presents a curve of H m E versus x 1 (the molar fraction of glycol, component 1) always positive, whereas PEG-600 presents negative values of the heat of mixing over the whole range of the molar fraction. Finally, PEG-300 and PEG-400 show an inversion of sign of H m E , at about x 1 =0.7 and 0.3, respectively. The experimental data were correlated using the Redlich–Kister polynomial and the adjustable parameters were obtained by the least-squares method. A qualitative discussion have been made in terms of intermolecular H-bonds.

Excess molar enthalpies, H m E , of binary mixtures containing poly(ethylene glycol) (PEG) 200+1,3-dioxolane, PEG 200+1,4-dioxane, PEG 200+oxolane and PEG 200+oxane were determined using a flow microcalorimeter at (288.15, 298.15 and 313.15) K and at atmospheric pressure. The H m E curves are always positive, with maxima varying from 393 J mol −1 (1,3-dioxolane) to 658 J mol −1 (oxolane), showing asymmetrical trends. The effect of the temperature is well marked on the calorimetric data that increase as the temperature is increased. The Redlich–Kister polynomial was used to estimate the binary fitting parameters. Root-mean-square deviations from the regression lines are reported.

Densities, rho, viscosities, eta, refractive indices, n(D), and excess molar enthalpies, H-m(E), of poly(ethylene glycol) 200 and 400 + dimethoxymethane and + 1,2-dimethoxyethane were determined over the entire range of composition, at 298.15 K and at atmospheric pressure. Excess molar volumes, V-m(E), viscosity deviations, Deltaeta, deviations in molar refractions, DeltaR, and excess molar enthalpies, H-m(E), were evaluated from experimental data. Deviations are negative with the exception of those of H-m(E), which are all positive. The excess or bulk properties were fitted to the Redlich-Kister polynomial to estimate the binary interaction parameters. The McAllister multibody interaction model was used to correlate the kinematic viscosities of liquid mixtures with mole fractions.

Excess molar enthalpies of the 10 binary systems containing ethylbenzene or (2-chloroethyl)benzene+ 2-propanone,+2-butanone,+2-pentanone,+2-octanone and+2-undecanone have been determined using an LKB low microcalorimeter. The experimental data were correlated by means of the Redlich-Kister equation

In the solid-state structure of N-(2-hydroxyethyl)pyrrolidinium (2-[(2,6-dichlorophenyl)amino]phenyl)acetate, C6H14NO+. C14H10Cl2NO2-, the asymmetric unit contains two independent ion pairs differing mainly in the conformation of the cation. A complex network of inter- and intramolecular hydrogen bonds is present.