Columnar metallomesogens based on vanadyl(VI) and cobalt(II) complexes of N,N'-bis[3-(3,4-dialkoxyphenyl)3-oxopropenyl]ethylenediamines

The preparation, characterization and mesomorphic properties of vanadyl(VI) and cobalt(II) complexes derived from N, N -bis[3-(3,4-dialkoxyphenyl)-3-oxopropenyl]ethylenediamines are described. These half-disk-shaped molecules exhibited columnar mesophases over a wide range of temperature, as characterized by DSC analysis and polarizing optical microscopy. The structure of the mesophases was also confirmed as columnar hexagonal (Col_ho) by powder XRD. The vanadyl complexes were found to have substantially higher clearing temperatures and wider mesophase temperatures than the analogous cobalt complexes. The influence of the metal centres on the mesomorphic temperatures may be attributed to better intermolecular dative association in the vanadyl complexes than in the cobalt complexes.     

Crystal structure of [N,N'-bis(5-chlorosalicylidene)-1,3-diaminopropane]iron(II).

The crystal structure of the title compound has been determined. The coordination geometry about the iron(II) center is a tetrahedrally distorted square plane formed by the four-coordinate N2O2 donor set of the Schiff-base imine-phenol ligand. Molecules of the title compound are not planar. The two Schiff-base moieties, which themselves are reasonably planar, are inclined at an angle of 31.5(1) degrees.     

Oxidomolybdenum(VI) complexes with atrane-type [O3N] ligands

Dioxomolybdenum(VI) complex [MoO₂Cl₂(dmso)₂] reacts with a series of tetradentate O₃N-type aminoalcohol–bisphenol ligands to form oxomolybdenum(VI) complexes of type [MoOCl(Lⁿ)]. The reaction of H₃L¹ produces [MoOCl(L¹)] as two separable isomers, whereas the reaction of H₃L² or H₃L³ yields a single product. The X-ray analyses of cis- and trans-[MoOCl(L¹)] reveal that the complexes are formed of monomeric molecules. The ligands have tetradentate coordination through three oxygen donors and one nitrogen donor, which is located trans to the terminal oxo group. The sixth coordination site is occupied by a chloro ligand.     

Synthesis and Crystal Structure of Bisaqua-[N,N'-bis(3,5-dichlorosalicylidene)-1,3-diaminopropano]zinc(II)

1 INTRODUCTION N,N?-Bis(salicylidene)-1,3-diaminopropane (BSDP) is a versatile tetradentate ligand, which forms stable complexes with a large number of transition metals[1～3]. However, the complexes related to the BSDP deriva- tive,N,N?-bis(3,5-dichlorosalicylidene)-1,3-diamino- propane (BCDP), have been seldom reported. The prime interest in these complexes is their ability to afford functional solid materials with potentially controllable properties and novel molecular struc- tur…     

Synthesis and characterisation of cobalt(II), cobalt(III) and rhodium(III) complexes ofN,N′, N″, N‴-tetra(2-cyanoethyl) cyclam [TCEC] andN,N′, N″, N‴-tetra)3-aminopropyl) cyclam [TAPC]

Summary Complexes of cobalt(II), cobalt(III) and rhodium(III) with TCEC and TAPC have been synthesised. TCEC with cobalt(II) gave [Co(TCEC)Br]Br and [Co(TCEC)Cl]Cl, five coordinate high spin square pyramid complexes, but the corresponding cobalt(III) complex could not be characterised. Rhodium(III) gave a six coordinate [Rh(TCEC)Cl₂]Cl complex, in which the two coordinated chlorides have acis-geometry and the four pendant arms lie on one side of the N₄ plane with none of the —CN groups coordinated TAPC on the other hand gives the cobalt(III) complex, [Co(TAPC)Br]Br₂, in which one of the amino groups of the four pendant arms is coordinated to cobalt. Rhodium(III) with TAPC gave [Rh(TAPC)Cl]Cl₂ in which one axial site is occupied by the amino group of one of the pendant arms and the other by Cl^–.     

Synthesis and characterization of N,N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide with para substituted of phenols based on charge-transfer complexes

The interaction of charge-transfer (CT) complexes resulted from the reaction of N,N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide (BHENDI) with some various acceptors like as substituted phenols in para position; 4-aminophenol (4AP), 4-methylphenol (4MP) and 4-nitrophenol (4NP) have been studied in methanol at room temperature. The reaction was studied using electronic (UV-vis), mid infrared, and (1)H NMR spectra and thermal measurements (TGA and DTG) as well as elemental analysis CHN. The chemical analysis data of the resulted CT-complexes, BHENDI-acceptors, reveal that the formation of a 1:2 CT complexes in all cases. The interaction of N,N'-bis[2-hydroxyethyl]-1,4,6,8-naphthalenediimide and phenolic acceptors were investigated spectrophotometrically and found two detected CT bands have n-pi(*) transition. The donor site involved in CT interaction is the diimide two nitrogen atoms by forming hydrogen bonding. The kinetic thermodynamic parameters like DeltaE, DeltaH, DeltaS and DeltaG are calculated from the DTG diagrams using Coats-Redfern method. The electrical conductivity properties for the solid CT complexes were measured within the temperature of room 25 degrees C.     

N,N'-Bis(3-triethylsilylpropyl)thiourea S-Dioxide and Poly[N,N'-bis(silsesquioxanylpropyl)thiourea S-Dioxide] as Reductants

The reducing power of organosilicon thiourea S-dioxides, N,N'-bis(3-triethylsilylpropyl)thiourea S-dioxide and poly[N,N'-bis(silsesquioxanylpropyl)thiourea S-dioxide], was studied. The first, monomeric dioxide readily reduces cyclohexanone to cyclohexanol. In its presence, under phase-transfer conditions, dipropyl disulfide reacts with bromobenzene to form propyl phenyl sulfide, and tellurium reacts with ethyl bromide to form diethyl telluride. The reducing power of the polymeric dioxide was demonstrated by the example of reduction of potassium permanganate. Irrespective of the medium (neutral, acidic, or alkaline), this polymer reduces Mn(VII) to Mn(IV).     

Nickel(II) and cobalt(II) complexes of 2,4-diaminothieno[2,3-d]-pyrimidines

Summary The reactions of methyl-2-amino-4-diethylamino thieno-[2,3-d]pyrimidine 6-carboxylate, methyl-2-amino-4-ethyl-phenylamine thieno-[2,3-d]pyrimidine-6-carboxylate) and methyl-2-amino, 4-morpholino-thieno-[2,3-d]pyrimidine-6-carboxylate with Ni^II and Co^II halides produced complexes of the general formula ML₂X₂ (where L is thieno pyrimidine and X is Cl or Br). The complexes were characterized by elemental analyses, conductivity and magnetic susceptibility measurements and spectroscopy. All of the complexes were found to have pseudotetrahedral structures with the metal coordinated through the N(1) site of the thieno-[2,3-d]-pyrimidine.     

Synthesis, structural characterization, thermal and electrochemical studies of the N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine and its Cu(II), Co(II) and Ni(II) metal complexes

In this study, N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine (L) and its Cu(II), Co(II) and Ni(II) complexes were prepared and characterized by the analytical and spectroscopic methods. The analytical data show the composition of the metal complex to be [M(2)L(Cl)(4)(H(2)O)(2)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. The compound (L) behaves as a monodentate ligand. But, obtained complexes have binuclear nature. The electrochemical properties of the metal complexes are dependent on reversible, irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of the metal ions. The single crystal of the ligand (L) was obtained from CH(3)CN solution. Space group and crystal system of the ligand are P2(1)/C and monoclinic, respectively.