Three tetrahydroisoquinolinedione derivatives

N‐(2‐Chloro­benzyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂ClNO₂, crystallizes in P2₁/n with three crystallographically independent mol­ecules in the asymmetric unit, which differ slightly in conformation, N‐(2‐bromo‐4‐methyl­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₆H₁₂BrNO₂, crystallizes in P2₁/n with one mol­ecule in the asymmetric unit andN‐(2,3‐di­chloro­phenyl)‐1,2,3,4‐tetra­hydro­iso­quinoline‐1,3‐dione, C₁₅H₉Cl₂NO₂, crystallizes in P2₁/c with one mol­ecule in the asymmetric unit. In all three structures, the heterocyclic rings adopt approximately planar conformations. The pyridine rings are orthogonal to the substituted phenyl rings. In all three structures, the crystal packing is stabilized by intermolecular C—H?O hydrogen bonds.     

Synthesis,crystal structure and reactivity of trans-diaquo N,N′-ethylenebis-(3-methoxysalicylideneiminato)chromium(III)

A new chromium(III) Schiff base complex, [Cr(3-methoxysalen)(H₂O)₂]ClO₄, where salen=N,N-ethylenebis- (salicylideneimine), has been synthesized and characterized by spectroscopic techniques. Single crystal X-ray data reveals that the complex assumes a trans-diaquo structure with formulation [Cr(C₁₈H₂₂N₂O₆)]ClO₄ but, unlike in Cr (salen)(H₂O)₂ ⁺, the two trans-water molecules are equidistant from Cr^III. The effect of the substituent on the phenyl ring in respect of redox reactivity has been investigated. The kinetics of the oxidation of [Cr(Schiff base)- (H₂O)₂]ClO₄, where Schiff base=salen, (1) and 3-OMe-salen, (2) by PhOI has been studied. The bimolecular rate constant for the formation of the O=Cr^v Schiff base in case of (2) was four times faster than that of (1). The introduction of the OMe group substituent on the phenyl ring influences not only the structure and crystal packing, but also the reactivity of the complex and the electronic environment around the metal ion.     

Sorption of Sb(III) on carbon steel surface in presence of molybdate and selenite in citric acid medium

Sorption of Sb(III) on carbon steel surface in aqueous medium (pH 2.8) in presence of different oxyanions like molybdate and selenite has been studied. It is observed that the presence of molybdate or selenite in solution reduced Sb(III) adsorption and surface precipitation to a great extent. The solution at different stages of the adsorption experiment has been analyzed by inductively coupled plasma-atomic emission spectroscopy technique. X-ray diffraction and X-ray photoelectron spectroscopy (XPS) techniques have been used to characterize the precipitate layer and the adsorbed layer. A detailed analysis of the XPS data reveals the mechanism involved in the two cases.     

Scanning electrochemical microscopy in the 21st century. Update 1: Five years after

This Perspective is an update to our more extensive survey of scanning electrochemical microscopy (SECM) published in 2007. During this time, the SECM field retained its momentum by expanding into new areas and meeting the emerging scientific and technological challenges. Here we focus on most prominent developments such as high-resolution imaging, investigation of structures and processes on the nanoscale, alternative energy applications, and new approaches to solving "real world" problems. The fabrication of novel SECM probes and related theoretical advances are also discussed.