Spectral,crystallographic, theoretical and antibacterial studies of palladium(II)/platinum(II) complexes with unsymmetric diphosphine ylides

The reaction of α‐keto‐stabilized diphosphine ylides [Ph₂P(CH₂)_nPPh₂═C(H)C(O)C₆H₄‐p‐CN] (n = 1 (Y¹); n = 2 (Y²)) with dibromo(1,5‐cyclooctadiene) palladium(II)/platinum(II) complexes, [Pd/PtBr₂(cod)], in equimolar ratio gave the new cyclometalated Pd(II) and Pt(II) complexes [Br₂Pd(κ²‐Y¹)] ( 1 ), [Br₂Pt(κ²‐Y¹)] ( 2 ), [Br₂Pd(κ²‐Y²)] ( 3 ) and [Br₂Pt(κ²‐Y²)] ( 4 ). These compounds were screened in a search for novel antibacterial agents and characterized successfully using Fourier transfer infrared and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. Also, the structures of complexes 1 and 2 were characterized using X‐ray crystallography. The results showed that the P,C‐chelated complexes 1 and 2 have structures consisting of five‐membered rings, while 3 and 4 have six‐membered rings, formed by coordination of the ligand through the phosphine group and the ylidic carbon atom to the metal centre. Also, a theoretical study of the structures of complexes 1 – 4 was conducted at the BP86/def2‐SVP level of theory. The nature of metal–ligand bonds in the complexes was investigated using energy decomposition analyses (EDA) and extended transition state combined with natural orbitals for chemical valence analyses. The results of EDA confirmed that the main portions of ΔE_int, about 57–58%, in the complexes are allocated to ΔE_elstat.     

Ultrasound and Sonochemistry for Radical Polymerization: Sound Synthesis

The use of ultrasound as an external stimulus for promoting polymerization reactions has received increasing attention in recent years. In this Review article, the fundamental processes that can lead to either the homolytic cleavage of polymer chains, or the sonolysis of solvent (or other) small molecules, under the application of ultrasound are described. These reactions promote the production of reactive radicals, which can be utilized in chain-growth radical polymerizations under the right conditions. A full historical overview of the development of ultrasound-assisted radical polymerization is provided, with special attention given to the recently described systems that are “controlled” by methods of reversible (radical) deactivation. Perspectives are shared on what challenges still remain in polymer sonochemistry, as well as new areas that are yet to be explored.     

Synthesis of 5‐substituted 1H‐tetrazoles using a recyclable heterogeneous nanonickel ferrite catalyst

An efficient method was developed for the [2 + 3] cycloaddition of sodium azide with nitriles to afford 5‐substituted 1H‐tetrazoles using nanonickel ferrite (NiFe₂O₄) as an effective heterogeneous catalyst in dimethylformamide. The main advantages of this method are high yields, simple methodology and easy work‐up. The catalyst can be recovered and reused for several cycles with predictable activity. Copyright © 2015 John Wiley & Sons, Ltd.     

Nano-[Mn-PSMP]Cl2 as a new Schiff base complex and catalyst for the synthesis of N,N'-alkylidene bisamides

Research on Chemical Intermediates - Nano-Mn-[phenyl-salicylaldimine-methyl-pyranopyrimidinedione]Cl2 {Nano-[Mn-PSMP]Cl2} as a new Schiff base complex was prepared and characterized by various...     

Asymmetric cross-aldol reaction of isatin and ketones catalyzed by crude earthworm extract as efficient biocatalyst

ABSTRACT

The asymmetric cross-aldol reaction of simple ketones (acetone, cyclohexanone) with isatin derivatives in the presence of crude extract from earthworms as green and effective biocatalyst proceeds easily in MeCN/H₂O (1:1) as solvent to afford 3-hydroxy-2-oxindoles derivatives. Ten compounds were synthesized in high yields (62–88%) and moderate ee (29–42%). Structure of the synthesized compounds has been characterized on the basis of NMR spectra and CHN analysis. The ee of the obtained compounds was determined by chiral phase HPLC analysis.     

Energy,exergy and pinch analyses of an integrated cryogenic natural gas process based on coupling of absorption–compression refrigeration system,organic Rankine cycle and solar parabolic trough collectors

Journal of Thermal Analysis and Calorimetry - The natural gas entering the liquefaction cycle usually consists of nitrogen, ethane, propane and also heavier hydrocarbons which are economically...