Synthesis and Structure of a Molecular Zinc Phosphate [(C12H8N2Zn)2(HPO4)(H2PO4)2]

A hydrothermal reaction of a mixture of ZnCO₃, phosphoric acid, 1, 10‐phenanthroline in H₂O gave rise to large plates of a new zinc phosphate, [(C₁₂H₈N₂Zn)₂(HPO₄)(H₂PO₄)₂], I . The structure consists of ZnO₃N₂ distorted trigonal‐bipyramidal and PO₄ tetrahedral units linked through their vertices to give rise to a zero‐dimensional molecular solid (monomer). The structure of the monomer appears to be similar to the secondary building unit (SBU) 4 = 1, commonly found in many fibrous zeolites. To our knowledge, this is the first time this building unit has been isolated. The structure, with a unique composition, is stabilized by hydrogen bond interactions between the terminal —OH groups forms a one‐dimensional molecular wire and also by strong π…π interactions between the 1, 10‐phenanthroline units. Photoluminescence studies show that there is a ligand‐to‐metal charge transfer (LMCT). Crystal data: orthorhombic, space group = Fdd2 (no. 43), a = 40.4669(1), b = 7.4733(2), c = 17.4425(5)Å, V = 5274.9(2)ų, Z = 8.     

Complexation of the triply-bonded dirhenium(II) complex Re(2)Cl(4)(mu-dppm)(2) (dppm = Ph(2)PCH(2)PPh(2)) by up to three acetylene molecules

The triply bonded dirhenium(II) synthons Re(2)X(4)(mu-dppm)(2) (X = Cl, Br; dppm = Ph(2)PCH(2)PPh(2)) react with acetylene at room temperature in CH(2)Cl(2) and acetone to afford the bis(acetylene) complexes Re(2)X(4)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH) (X = Cl (3), Br(4)). Compound 3 has been derivatized by reaction with RNC ligands in the presence of TlPF(6) to give unsymmetrical complexes of the type [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH)(CNR)]PF(6) (R = Xyl (5), Mes (6), t-Bu (7)), in which the RCN ligand has displaced the chloride ligand cis to the eta(2)-HCCH ligand. The reaction of 3 with an additional 1 equiv of acetylene in the presence of TlPF(6) gives the symmetrical all-cis isomer of [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(eta(2)-HCCH)(2)]PF(6) (8). The two terminal eta(2)-HCCH ligands in 8 are very labile and can be displaced by CO and XylNC to give the complexes [Re(2)Cl(3)(mu-dppm)(2)(mu:eta(2),eta(2)-HCCH)(L)(2)]Y (L = CO when Y = PF(6) (9); L = CO when Y = (PF(6))(0.5)/(H(2)PO(4))(0.5) (10); L = XylNC when Y = PF(6) (11)). These substitution reactions proceed with retention of the all-cis stereochemistry. Single-crystal X-ray structure determinations have been carried out on complexes 3, 5, 8, 10, and 11. In no instance have we found that the acetylene ligands undergo reductive coupling reactions.     

Biosynthesis of TiO2 Nanoparticles Using Edible Mushroom (Pleurotus djamor) Extract: Mosquito Larvicidal,Histopathological, Antibacterial and Anticancer Effect

Journal of Cluster Science - The titanium dioxide nanoparticles (TiO2NPs) were synthesized by the aqueous extract from P. djamor. The UV–Vis spectrum of TiO2NPs showed maximum absorption at...     

Greener synthetic approach for the preparation of substituted flexible dimeric pyridinium salts and its importance

We have prepared substituted flexible dimeric pyridinium bromide using conventional and greener approach. Solvent-free solid phase (greener) approach is superior than the conventional owing to nontoxic, easy workup procedure, and 20 times lesser reaction time. Toxic organic solvents and column chromatography are avoided. Aldol condensation reaction is studied with various substituted aromatic aldehyde and compared with available recent literatures. Synthesized substituted flexible dimeric pyridinium salts acted as potential catalysts because of their better performance even in low concentration, recyclability, and activation of two molecules of aldehydes at the same time for aldol condensation reaction.     

Thermodynamic characterization of chromium tellurate

The standard Gibbs energy of formation of chromium tellurate, Cr₂TeO₆ was determined from the vapour pressure measurement of TeO₂(g) over the phase mixture Cr₂TeO₆(s) + Cr₂O₃(s) in the temperature range 1,183–1,293 K. A thermogravimetry (TG)-based transpiration technique was used for the vapour pressure measurement. This technique was validated by measuring the vapour pressure of CdCl₂(g) over CdCl₂(s). The temperature dependence of the vapour pressure of CdCl₂(g) could be represented as logp (Pa) (±0.02) = 12.06 ? 8616.3/T (K) (734 ? 823 K). A ‘third-law’ analysis of the vapour pressure data yielded a mean value of 185.1 ± 0.4 kJ mol^?1 for the enthalpy of sublimation of CdCl₂(s). The temperature dependence of vapour pressure of TeO₂(g) generated by the incongruent vapourisation reaction, $ {\text{Cr}}_{ 2} {\text{TeO}}_{ 6} (\rm s) \to {\text{Cr}}_{ 2} {\text{O}}_{ 3} (\rm s) + {\text{TeO}}_{ 2} (\rm g) + 1/2\,{\text{O}}_{ 2} (\rm g) $ could be represented as logp (Pa) (±0.04) = 18.57 – 21,199/T (K) (1,183 – 1,293 K). The temperature dependence of the Gibbs energy of formation of Cr₂TeO₆ could be expressed as $ \{ \Updelta G_{\text{f}}^{ \circ } ({\text{Cr}}_{ 2} {\text{TeO}}_{ 6} ,{\text{ s}}){\text{ (kJ}}\,{\text{mol}}^{ - 1} )\pm 4. 0 {\text{\} = }} - 1 6 2 5. 6 { \,+\, 0} . 5 3 3 6\,T({\text{K}}) \, (1{,}183 - 1{,}293\,{\text{K}}). $ A drop calorimeter was used for measuring the enthalpy increments of Cr₂TeO₆ in the temperature range 373–973 K. Thermodynamic functions viz., heat capacity, entropy and Gibbs energy functions of Cr₂TeO₆ were derived from the experimentally measured enthalpy increment values. $ \Updelta H_{{{\text{f}},298\,{\text{K}}}}^{ \circ } ({\text{Cr}}_{ 2} {\text{TeO}}_{ 6} ) $ was found to be ?1636.9 ± 0.8 kJ mol^?1.     

Thermodynamic investigation on M–Te–O (M = Sc, Y) system

The standard Gibbs energy of formation of M₂TeO₆ and M₆TeO₁₂ (where M = Sc, Y), was determined from its vapor pressure measurements by employing thermogravimetry-based transpiration technique. This technique was validated by measuring the vapor pressure of well-studied substances such as TeO₂(s) and CdCl₂(s). The temperature dependence of the vapor pressure of TeO₂(g) over the mixtures M₆TeO₁₂ + M₂O₃ (where M = Sc, Y), generated by the incongruent vaporization reaction, M₆TeO₁₂(s) → 3M₂O₃(s) + TeO₂(g) + ½O₂(g) were measured in the temperature range 1,413–1,473 K and 1,623–1,743 K for Sc₆TeO₁₂(s) and Y₆TeO₁₂(s), respectively. Similarly, the vapor pressure of TeO₂(g) over the mixtures M₂TeO₆(s) + M₆TeO₁₂(s) generated by the vaporization reaction, 3M₂TeO₆(s) → M₆TeO₁₂(s) + 2TeO₂(g) + O₂(g) was measured in the temperature range (1,223–1,293 K) and (1,333–1,423 K) for Sc₂TeO₆(s) and Y₂TeO₆(s), respectively. From the vapor pressure measurements, the standard Gibbs energy of formation of M₆TeO₁₂ and M₂TeO₆ were derived.     

Thermal analysis of interaction between 2-PAM chloride and various excipients in some binary mixtures by TGA and DSC

Pralidoxime chloride known as 2-PAM chloride is used as antidote for nerve agent’s poisoning. This study was undertaken to establish the compatibility of 2-PAM chloride with a number of commonly used excipients by using thermoanalytical technique viz., differential scanning calorimetry (DSC) and thermogravimetry/differential thermogravimetry (TG/DTG) used in pharmaceutical formulation. The TG and DSC both results demonstrated that polyvinyl alcohol, polyacrylamide, microcrestline cellulose, hydroxypropyl cellulose, cellulose acetate, ethyl cellulose found to be compatible with 2-PAM chloride and chosen for the preparation of antidote against chemical warfare agents.     

Solvent-Free Esterification of Carboxylic Acids and Alcohols in the Presence of Silphos [PCl3-n(SiO2)n] as a Heterogeneous Phosphine Reagent

An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, and tertiary alcohols using a heterogeneous phosphine reagent, silphos [PCl_3-n(SiO₂)_n], in good yields is reported.