Synthesis and Supramolecular Structure of a (5-(3-(1H-tetrazol-5-yl)phenyl)-1H-tetrazole) Cobalt Complex

The reaction of CoCl2·6H2O with m-BDTH2 (1,3-benzeneditetrazol-5-yl) leads to [Co(C8H6N8)2(H2O)2(CH3CN)2]Cl2 (1). Both tetrazolic groups remain protonated existing in a 1H tautomeric form. A trifurcated chlorine atom and stacking interactions assemble compound 1 into a three-dimensional network

A nickel(II) complex with an unsymmetrical tetradentate chelating ligand derived from pyridine-2,6-dicarbaldehyde and 2-aminothiophenol

[(2-{[6-(1,3-Benzo­thia­zol-2-yl)pyridin-2-yl]carbonyl­aza­nid­yl}phen­yl)sulf­anido]nickel(II), [Ni(C$_{19}$H$_{11}$N$_3$OS$_2$)], crystallizes in the centrosymmetric monoclinic space group $P2_1/n$ with one mol­ecule in the asymmetric unit. The expected ligand, a bis-Schiff base derived from pyridine-2,6-dicarbaldehyde and 2-amino­thio­phenol, had modified in situ in a both unexpected and unsymmetrical fashion. One arm had cyclized to form a benzo[$d$]thia­zol-2-yl functionality, while the imine linkage of the second arm had oxidized to an amide group. The geometry about the central Ni$^{II}$ atom is distorted square-planar N$_3$S. The mol­ecules form supra­molecular face-to-face dimers via rather strong π–π stacking inter­actions, with these dimers then linked into chains via pairwise C—H$\cdot\cdot\cdot$O inter­actions

An undecanuclear ferrimagnetic Cu9Dy2 SMM achieved through ligand fine-tuning

We describe the concept of increasing the nuclearity of a previously reported high-spin Cu5Gd2 core using a “fine tuning” ligand approach. Thus two Cu9Ln2 coordination clusters, with Ln = Dy (1), Gd(2) were synthesized with the Gd compound having a ground spin state of 17/2 and the Dy analogue showing SMM behavior in zero field

Systematic studies of hexanuclear {MIII4LnIII2} complexes (M = Fe, Ga; Ln = Er, Ho): structures, magnetic properties and SMM behavior

Four isostructural MIII4LnIII2 coordination clusters, [M4Ln2(μ3-OH)2(nbdea)4(C6H5COO)8]•MeCN (M = Fe, Ln = Er (1); M = Ga, Ln = Er (2); M = Fe, Ln = Ho (3); M = Ga, Ln = Ho (4)) have been synthesized and characterized. Single-crystal X-ray diffraction and X-ray powder diffraction studies revealed that all four compounds crystallize isomorphously to each other, and to the previously reported MIII4DyIII2 (M = Fe or Ga) and FeIII4YIII2 analogues. DC magnetic susceptibility measurements for compounds 1-4, taken in combination with those for the FeIII4YIII2 analogue, indicated that the interactions between ErIII ions are weakly ferromagnetic and the FeIII-ErIII interactions are very weakly antiferromagnetic, while the HoIII-HoIII and FeIII-HoIII interactions are both negligible. By comparison, for the FeIII4DyIII2 analogue, the DyIII-DyIII interactions are antiferromagnetic while the FeIII-DyIII are ferromagnetic. Both Er analogues 1 and 2 display single-molecule magnet (SMM) behavior with the effective energy barrier Ueff increasing from 12.8 K (for Fe4Er2 1) to 53.5 K (for Ga4Er2 2), indicating that the very weak 3d-4f interaction enhances the QTM effect

Synthesis of N-(2,4-dinitrophenyl) derivatives of D-ribosylamines; unexpected reaction and hydrolysis products

Reaction of 2,3-O-isopropylidene-d-ribofuranosylamine with 2,4-dinitrofluorobenzene afforded the crystalline 2,3-O-isopropylidene-N-(2,4-dinitrophenyl)-β-d-ribofuranosylamine (3) and a 1:1 crystalline complex of 2,3-O-isopropylidene-N-(2,4-dinitrophenyl-α-d-ribofuranosylamine and 2,3-O-isopropylidene-β-d-ribofuranose; controlled acidic hydrolysis of 3 afforded N-(2,4-dinitrophenyl-α-d-ribopyranosylamine and not the expected β-d-furanosylamine derivative. The structures of the new compounds were confirmed by NMR spectroscopy and X-ray crystallography

Tetranuclear CuII2DyIII2 coordination cluster as Suzuki (C–C) coupling reaction promoter

The air stable and high yielding tetranuclear coordination cluster [CuII2DyIII2L4(NO3)2(CH3CN)2]·2(CH3CN) promotes the Suzuki coupling reaction of phenylboronic acid with substituted aryl halides in environmentally benign conditions

Synthesis, structure and electrochemical characterization of the isopolytungstate (W4O16) held by MnII anchors within a superlacunary crown heteropolyanion {P8W48}

An isopolyanion {W4O16} within archetypal {P8W48} heteropolyanion assembly [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2] 15- (Mn10W4-P8W48) has been synthesized by the reaction of the cyclic superlacunary anion [H7P8W48O184] 33− and Mn(ClO4)2.6H2O in I M LiCl soultion medium at pH 8. The isolated compound has been characterized by single crystal X-ray crystallography, powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) spectroscopy, elemental analysis and thermogravimetric analysis. Electrochemical studies were also performed on Mn10W4-P8W48 confirmed the presence of Mn centres bonded to the tunsgtic framework. The novel polyanion [(P8W48O184)(W4O16)K10Li4Mn10Na(H2O)50Cl2] 15- is the first example of macrocyclic complex where an isopolyanion (W4O16) 8- is embedded within in the inner cavity of the {P8W48} and is placed in position by six MnII cations as anchors. Whereas, the exocyclic coordination of the four MnII atoms to {P8W48} yields extended structure by linking neighbouring polyanions through {W−O−Mn−O−W} bridges. Further, the polyanion Mn10W4-P8W48 is the first derivative of {P8W48} with six MnII ions (largest) coordinated to the inner side the crown ring as anchors

A multifunctional use of bis(methylene)bis(5-bromo-2-hydroxyl salicyloylhydrazone): From metal sensing to ambient catalysis of A3 coupling reactions

The potential use of bis(methylene)bis(5-bromo-2-hydroxylsalicyloylhydrazone) as a multifunctional fluorescence sensor for Cu(2+), Ni(2+), Co(2+) and Fe(2+) ions was investigated. The optical behaviour shows an increase in an absorption band at 408 nm which can be ascribed to the d–d transition (UV-vis) of the metal ions and a concomitant decrease in fluorescence intensity at 507 nm. The crystallographic analysis shows the binding site of the sensor to two Cu(2+) ions and confirms the stoichiometry of 1 : 2 (ligand to metal) which is in good agreement with a Job plot analysis. Furthermore the Cu(2+)-complex catalyses A3 coupling reactions at 1 mol% catalytic loading; chiral propargylamine derivatives were obtained in high yield after 24 h reaction time under ambient conditions