Search

The title compounds (IV) are obtained by three-component coupling of pyridine-2-carboxaldehyde/quinoline-2-carboxaldehyde (I), secondary amines (III), and terminal alkynes (II).

Living cationic polymerization behaviors of isobutyl vinyl ethers (IBVE), initiated by iodomethyl methyl ether (IMME)/zinc iodide (ZnI2) have been investigated. The polymerization was carried out at 0, −15, and −30°C in toluene. It was found that the rate of polymerization increased as the IMME concentration increased and decreased as temperature decreased. 100% conversion was always achieved without exception. Furthermore, the number-average molecular weight\((\bar M_n )\) of polymers increased in direct proportion to monomer conversion. The molecular weights of polymers were in good agreement with the theoretical values, calculated on the basis that one polymer chain was formed by one IMME molecule and the values of polydispersity index are always less than 1.2, revealing the living nature. The living nature was also confirmed by synthesis of poly(IBVE-b-TBVE) by subsequent monomer addition of t-butyl vinyl ether (TBVE).

Polycrystalline 1 : 2 complexes of ZnI2 with N-oxides of pyridine, picoline, and 2,6-lutidine were studied by IR spectroscopy, dielectrometry, and conductometry. An equilibrium between three solid phases was observed. These phases are characterized by different enthalpies of formation of intermolecular bonds and different mechanism of electronic effect transmission via these bonds. Gas-like thermal molecular motion in one of the phases of the 2,6-lutidine N-oxide complex was observed. Reversible chemical reactions on the surface of the crystalline 3-picoline N-oxide complex are initiated on exposure to an alternating electric field. Two complexes, similarly to the ZnCl2 complexes, are ionized in the cumulative mode on fast heating from 18-19 to 26-45°C. Partial activation energies of electrical conductivity of different ions were determined for a number of complexes and inorganic salts.

This study concerns the living cationic polymerization of two vinyl ethers (VEs) having pendant glucose residues, in which the hydroxyl groups are protected by acetyl and isopropylidene functions. Living cationic polymerization of VE having an acetyl-protected glucose was achieved by employing an initiating system consisting of the CF3COOH adduct of isobutyl VE (IBVE) and ethylaluminium dichloride in the presence of an added base at 0 °C. In contrast, the use of the HCl adduct of IBVE in conjunction with zinc iodide at −15 °C was more suitable for the controlled polymerization of VE having an isopropylidene-protected glucose. Polymers obtained under these reaction conditions had narrow molecular weight distributions (Mw/Mn ∼ 1.1) and controlled molecular weights. © 2001 Society of Chemical Industry

The structure of ZnI2 · 2CO(NH2)2 is determined by single-crystal X-ray diffraction. The crystals are monoclinic, a = 12.694(3) A, b = 6.886(2) A, c = 13.161(3) A, β = 110.58(2)°, Z = 4, space group P21/a, and R = 0.0337 for 2481 reflections. Similar to the chloride analogue, the structure consists of discrete molecules with tetrahedrally coordinated Zn atoms. The bond lengths and angles are as follows: Zn-I, 2.5749(8) and 2.5473(8) A; Zn-O, 1.954(3) and 1.985(4) A; IZnI, 113.74(3)°; OZnO, 100.5(2)°; and IZnO, 108.5°–113.1(1)°. The crystal structure agrees with the IR and electronic absorption spectra of the crystals.

Asymmetric group transfer polymerization(AGTP) of N-cyclohexylmaleimide(CHMI) was carried out using ketene silyl acetal as initiator in the presence of Lewis acid-chiral ligand complexes to afford optically active poly(CHMI)([α]43525 −6.6° to +31.0°). Lewis acids used as GTP catalyst, probably activating the monomer by coordination, were zinc iodide, zinc bromide, zinc triflate, titanium tetrachloride, aluminum chloride and copper bromide. The zinc catalysts tended to accelerate the polymerization. The addition of trimethylsilyl iodide to the system accelerated the polymerization in spite of low temperature. Poly(CHMI) obtained in a poor yield with zinc triflate as Lewis acid and chiral bisoxazoline(Bnbox) showed low specific optical rotation and had the highest degree of polymerization(DP=421, Mn=75400).

Dehydration of 1-substituted-1,2-tetralindiols with zinc iodide aAorded the corresponding 2-tetralones in excellent yields. This procedure was found to be superior to the more conventional BF3-catalyzed rearrangement of 1-substituted-1,2-epoxytetralins. # 2000 Elsevier Science Ltd. All rights reserved.

An efficient cobalt(I)-catalysed homo Diels–Alder reaction of acyclic 1,3-dienes and acetylene derivatives is described. The catalyst system consists of a mixture of a readily available CoBr2(dppe) complex, zinc iodide as a cocatalyst, and tetrabutylammonium borohydride as reducing agent. This system increases the reactivity of the cobalt(I) catalyst, so that acyclic dienes and acetylenes can be transformed to the 1,4-dihydroaromatic products in good yield and excellent purity. The regioselectivity of the homo Diels–Alder reaction greatly favours the 1,4-substitution pattern of the formed product.

Polymer electrolytes were prepared from oxymethylene-linked polyethylene glycol 200 with lithium perchlorate at O:Li mole ratios of 10, 25 and 70, and with zinc iodide at an O:Zn mole ratio of 70. At the higher salt concentrations (O:Li less than or equal to 25), the electrolytes were amorphous at temperatures down to -20 degrees C. Conductivity was measured over a range of temperatures (eg for O:Li = 25, sigma ranged from 4 x 10(-8) S cm(-1) at -10 degrees C to 2 x 10(-4) S cm(-1) at 70 degrees C). A prototype electrochromic device was constructed for which the progression of a colour front was temperature dependent. Such a device could be utilized as a time-temperature integrating sensor for indicating whether frozen goods have been stored correctly. (C) 2000 Society of Chemical Industry.

A low-temperature zinc plasma was generated by secondary ionization using an electron cyclotron resonance argon plasma. The ionization efficiency of zinc samples of the metal, the bromide, and the iodide were examined at different sample crucible temperatures. It was found that the ionization rate of zinc metal is the highest among the tested samples. The observed reaction rate constants , defined as = nZn+/nZnnAr+ in the present work, are 1.8 × 10-18 m-3, 1.7 × 10-19 m-3 and 3.7 × 10-19 m-3 for zinc metal, zinc bromide, and zinc iodide, respectively. The large reaction constant of zinc metal may be due to the small dissociation energy into atom vapour, compared with the large dissociation energies of the zinc halides.

(p-2,2-Difluorovinyloxyphenyl)dimethylamine, readily obtained from 2,2,2-trifluoroethanol, is treated with zirconocene equivalent ‘Cp2Zr’ to generate thermostable 1-fluorovinylzirconocene via a CF bond cleavage. This 1-fluorovinylzirconocene can be used for CC bond formation through the cross-coupling with aryl iodides in the presence of palladium catalyst and zinc iodide, leading to (Z)-1-aryl-2-(p-dimethylaminophenoxy)-1-fluoroolefins in good yields.

The bicyclic acetal 6,8-dioxabicyclo[3.2.1]octane, 6,8-DBO, was polymerized in toluene solvent using 1-chloroethyl isobutyl ether as the initiator and zinc iodide as the activator. Initiation of the polymerization proceeded by Lewis acid promoted ionization of 1-chloroethyl isobutyl ether to oxacarbenium ions that subsequently added to 6,8-DBO. The molecular weight control of the polymerization increased with decreasing temperature. For polymerizations conducted at −16 °C the number-averaged molecular weights (Mn) of the polymer as a function of conversion correlated most closely with the expected values (DPn = ([6,8-DBO]0−[6,8-DBO]t/[1-chloroethyl isobutyl ether]0), and the molecular weight distributions averaged Mw/Mn ∼ 1.3. The cationic ring-opening polymerization of 6,8-DBO using 1-chloroethyl isobutyl ether/zinc iodide at −16 °C, therefore, can be considered a controlled polymerization.

An instrumentally simple and cost-effective method for the direct analysis of methyl bromide in ambient air is described. The method is based on the separation of sample components by gas chromatography, the conversion of methyl bromide to methyl iodide by reaction with an inorganic iodide salt, and the detection of the methyl iodide thereby produced by an electron-capture detector. Of the 20 different inorganic salts investigated here for conversion of methyl bromide to methyl iodide, zinc iodide was found to provide the greatest conversion efficiency. In addition, zinc iodide was found to provide high conversion efficiency at a modest reaction temperature, thereby minimizing both the thermal decomposition of compounds within the reaction volume and the level of column bleed introduced to the detector. The reactions of several other brominated and chlorinated organic compounds with zinc iodide have also been characterized. The successful application of this instrument to the quantitative determination of methyl bromide in a local background air sample is then demonstrated.

At 228 K crystals of ZnI2(dmf)2 show a reversible phase transition which does not disrupt the lattice. Above the transition temperature the space group is C2/c and the cell contains eight symmetrically equivalent molecules. Cooling to below the transition temperature has little effect on the cell parameters or on the Zn- and I-atom positions, but the space group is now P21/n and the asymmetric unit comprises two conformationally different molecules. These arise from cooperative rotations of either ca +25 or −43° about the Zn—O bond of one of the dmf ligands in the high-temperature form. This displacive transition involves large movements of some atoms. The corresponding chloride and bromide are isomorphous with the higher temperature C2/c form, but it is only with the iodide that the weaker intermolecular forces permit the unusual phase change. The transition has been followed by differential scanning calorimetry, which gives an enthalpy change of 1.44 (5) kJ mol−1.

Ring-opening polymerization of the cyclobutane adduct (1) of tetracyanoethylene (TCNE) and ethyl vinyl ether (EVE) was carried out with protonic acid/Lewis acid or EVE-acetic acid adduct (2)/ZnI 2 as initiating systems in CH 3 NO 2 at ambient temperature. Polyls with narrow molecular weight distribution (MWD) were obtained with the systems acetic acid(AcOH)/ZnI 2 or 2/ZnI 2 . In the polymerization with 2/ZnI 2 , the number-average molecular weight (M n ) of the polymers decreases with increasing amount of 2/ZnI 2 , and increases in direct proportion to the monomer conversion. Furthermore, M n increases on addition of a fresh feed of monomer at the end of the first-stage polymerization. The MWD remains narrow throughout the reaction. On the basis of the reaction of 1 with an equimolar amount of 2 in the presence of ZnI 2 and the diene 5 as a by-product formed by elimination of hydrogen cyanide from 1 in the polymerization, it was proposed that ZnI 2 activates both the CH-OAc terminal groups of the growing polymer chain and monomer 1.

2-Benzoyloxyethy vinyl ether (BOEVE) was cationically polymerized with the hydrogen iodide/zinc iodide (HI/ZnI 2 ) initiating system in toluene at -15°C to form a narrow molecular weight distribution (MWD). The poly(BOEVE) obtained had a narrow MWD (M W /M n

The zinc iodide -osmium tetroxide (ZIO) fixation/staining method was applied for neurocytological study and also to examine several other tissue samples including human blood and bone marrow on nerve endings in the median eminence, epidermal langerhans cells of lymphoid tissue. Although precise specificity can not be attributed to the staining reaction. Interesting staining patterns for different cell types in lymph node were observed by one of the ZIO staining solutions. The significance of ZIO positivity is briefly discussed.

The addition of trimethylsilyl cyanide (TMSCN) to diacylferrocenes [Fc (COR)2] (R = Me, Et, Ph, p-ClC6H4, m-ClC6H4, o-ClC6H4, p-MeOC6H4, Fc = C5H4FeC5H4), catalysed by zinc iodide an acetonitrile provided the corresponding cyanohydrin trimethylsilyl ethers in moderate to high yields. Factors affecting the reaction and yields of adducts were investigated. In addition, the adduct of 1,1′-diacetylferrocene was structurally determined by X-ray crystallography.

In this paper, we report the successful growth of complex compound of zinc iodide with thiocarbamide by slow evaporation method. The single crystal XRD study reveals that the crystal belongs to monoclinic system with centrosymmetric space group and powder XRD analysis shows that the perfect crystalline nature of the crystal. The presence of functional group and element were confirmed from FT-IR and EDAX analysis. Optical absorbance of the grown crystal was studied by UV–Vis spectrophotometer. The optical constants were calculated from the optical absorbance data such as refractive index (n), extinction coefficient (K) and reflectance (R). The optical band gap (Eg) of thiocarbamide zinc iodide crystal is 4.22 eV. The magnetic properties of grown crystal have been determined by Vibrating Sample Magnetometry (VSM). Room temperature magnetization revealed a ferromagnetic behaviour for the grown crystal. The antibacterial and antifungal activities of the title compound were performed by well diffusion method and MIC method against the standard bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and against fungus like Aspergillus niger, Rhizopus sps and Penicillium sps. Thermal behaviour of the crystal has been investigated using thermogravimetric analysis (TGA) and differential thermal analysis (DTA).

The combination of a chiral bicyclic guanidinium salt and zinc iodide is an efficient catalytic system for the enantioselective alkylation of oxindoles (I) and (XI).

Group transfer polymerization (GTP) was used to prepare semifluorinated polymers based on acrylic and methacrylic monomers. In the first case, electrophilic catalyzed GTP was applied with l-methoxy-2-methyl-l-trimethylsilyloxy-1-propene (MMTP) as initiator, zinc iodide as catalyst and 1H,1H,2H,2H-perfluorooctyl acrylate as monomer. In this way it has been possible to obtain oligomers. Higher molecular weight polymers were prepared by means of the nucleophilic tetrabutylammonium benzoate as catalyst. With MMTP as initiator, 1H,1H,2H,2H-perfluoroalkyl methacrylates, F(CF 2 ) m (CH 2 ) 2 OCOC(CH 3 )=CH 2 , were polymerized to molecular weights>4.5 kg mol −1 . The polydispersity was found to depend strongly on the length of the perfuoroalkyl side chain, i.e. M w / M n decreases with increasing m .

Catalytic, enantioselective cyclopropanation of a broad range of allylic alcohols and one homoallylic alcohol was carried out. The cyclopropanation reagent employed was bis(iodomethyl)zinc generated by the method of Furukawa, and the chiral promoter used (10 mol %) was the N,N-bis(methanesulfonyl) derivative of (R,R)-1,2-diaminocyclohexane. Three experimental features were found to be critical for the rapid and selective cyclopropanation: (1) use of the ethylzinc alkoxide of the allylic alcohol as the substrate by prior deprotonation of the allylic alcohols by diethylzinc, (2) the formation of the zinc complex of the promoter by prior deprotonation of the bis-sulfonamide with diethylzinc, and (3) the use of added zinc iodide generated in situ from diethylzinc and iodine. The stereoselectivity of cyclopropanation was found to be independent of olefin geometry and worked well for substrates bearing both aliphatic and aromatic substituents at either or both 3-positions of the allylic alcohol. However, a methyl substituent on the 2-position of the allyl alcohol was not well tolerated and led to slow reactions and poor enantioselectivities. A rationale for the observed selectivities is proposed.

Amphiphilic block copolymers of vinyl ethers (VEs) of the type —[CH2CH(OCH2CH2OR)]m—[CH2CH(OiBu)]n—were synthesized by living cationic polymerization, where R is a D-glucose residue, and m and n are the degrees of polymerization (m = 20–50; n = 11–89). To obtain them, sequential living block copolymerization of isobutyl vinyl ether (IBVE) and the vinyl ether carrying 1,2:5,6-diisopropylidene-D-glucose residue was conducted by using the HCl adduct of IBVE, CH3CH(OiBu)Cl, as initiator in conjunction with zinc iodide. These precursor block copolymers had a narrow molecular weight distribution (Mw/Mn ∼ 1.1) and a controlled composition. Treatment of them with a trifluoroacetic acid/water mixture led to the target amphiphiles. The solubility of the amphiphilic block copolymers in various solvents depended strongly on composition or the m/n ratio. Their solvent-cast thin films were observed, under a transmission electron microscope, to exhibit various microphase-separated surface morphologies such as spheres, cylinders, and lamellae, depending on composition. © 1997 John Wiley & Sons, Inc.

A series of selenothioic acid S-esters and diselenoic acid esters have been synthesized by the following three types of methods : (1) reactions of terminal acetylenes with n-butyllithium, selenium and thiols; (2) reactions of selenoic acid O-methyl esters with aluminum chalcogenolates; (3) reactions of selenothioacetic acid S-esters with aldehydes and/or allylic bromides in the presence of a base. On the basis of synthetic results, the general trends for the relative stability of the esters have been proposed. Among several types of esters, one of the most simple esters, i.e., selenium and sulfur counterparts of acetic acid esters are the most stable. The introduction of aromatic substituents does not necessarily enhance the stability of the esters. Reactions of the esters toward heavy metal salts, such as nickel chloride, zinc iodide, and cadmium acetate, electron deficient alkynes, and reducing agents provided new synthetic methods of a variety of organoselenium compounds.

Fluorenone derivatives were generated from aryl-substituted propiolates via a cobalt-catalyzed Diels–Alder reaction/DDQ-oxidation and Friedel–Crafts-type cyclization. Several functional groups are tolerated, and good to excellent overall yields (up to 89%) could be achieved. For the synthesis of anthraquinone derivatives, aroyl-substituted propiolates were applied in a zinc iodide catalyzed Diels–Alder reaction with 1,3-dienes. The subsequent DDQ oxidation and Friedel–Crafts-type cyclization led to symmetrical as well as some unsymmetrical anthraquinones in good to excellent yields of up to 87% over the three-step reaction sequence.

In this work, synthesis of a new series of zinc halide/pseudohalide complexes of a bidentate Schiff base ligand entitled as bis (3-(4-dimethylaminophenyl)-allylidene)-1,2-diaminoethane(L) is described. The ligand and its zinc complexes were characterized by various techniques such as elemental analysis, FT-IR, UV–visible, 1 H and 13 C NMR spectra, cyclic voltammetry, and conductometry. Accordingly ZnLX 2 (X = Cl − , Br − , I − , SCN − and N 3 − ) was suggested as molecular formula of the complexes. Redox behaviors of ligand and its zinc complexes were investigated by cyclic voltammetry method. Furthermore, the ligand and its zinc halide/pseudohalide complexes were tested for their in vitro antibacterial activities against two gram positive bacteria (Staphylococcus aureus and Bacillus subtilis ) and two gram negative bacteria ( Escherichia coli and Pseudomonas aeruginosa ). Also in vitro antifungal activities of them against Candida albicans and Aspergillus niger were investigated. The results indicated that all compounds are antibacterial and antifungal active. Thermal behaviors of ligand and its zinc complexes were studied from room temperature to 1100 °C under argon atmosphere. It was found that the ligand and zinc iodide are decomposed completely via three and four steps respectively while other zinc complexes leave out the metal or organometallic compounds as final residuals after 3–4 decomposition steps at above temperature range. Moreover evaluation of some thermo-kinetic parameters such as activation energy (∆E ⁎ ), enthalpy (∆H ⁎ ), entropy (∆S ⁎ ) and Gibbs free energy change (∆G ⁎ ) of the thermal decomposition steps were performed based on the Coats–Redfern relation.

2,2-Difluorovinyl p-toluenesulfonate, readily obtained from 2,2,2-trifluoroethanol, is treated with zirconocene equivalent “Cp 2 Zr” to generate the remarkably themostable nonsubstituted 2,2-difluorovinylzirconocene, which in turn couples with aryliodides in the presence of palladium catalyst and zinc iodide to afford monosubstituted gem-difluoroolefins in high yields. The reaction proceeds via 2,2-difluorovinylzinc as confirmed by 19 F-NMR measurement.

Optically active 1-alkoxybicyclo[4.1.0]heptane was converted using zinc iodide as a catalyst to 2-alkoxymethylidenecyclohexane without loss of optical purity. The mechanism of the isomerization was studied using a stereochemical analysis of the product and deuterium labeling experiments. The results indicated that the isomerization takes place through a stepwise mechanism that involves an attack of zinc iodide on the cyclopropane ring to cause ring opening, followed by an intramolecular 1,2-hydride shift with liberation of the zinc iodide.

The diffusion of some zinc and cobalt salts in water have been measured using an improved version of the capillary technique. In this technique, diffusion proceeds in the absence of stirring in the bulk solution. The amount of diffusing substance which remains in the capillary is analyzed after a chosen time. Nanis' solution for three-dimensional diffusion from a capillary has been used to calculate the experimental values. The values of diffusion coefficient of zinc iodide, cobalt bromide and cobalt iodide have been obtained with a diffusion run time of four hours. A comparison has been made between the experimental and theoretical values obtained from Onsager-Fuoss theory. An attempt has also been made to explain the deviation between the experimental and theoretical values over the concentration range studied.

The phase diagrams of the systems PbPbI2, PbI2NaI and PbI2ZnI2 have been determined by differential scanning calorimetry. PbI2NaI and PbI2ZnI2 are simple eutectic systems; the system PbPbI2 shows an immiscibility of two liquids.

Sodium cyanoborohydride in the presence of zinc iodide is found to reduce epimeric tertiary alcohols, whose carbinol group is a stereogenic center in a a stereoconvergent way

The authors report here the effects of systematic cation and dissolved salt variation on n-WSe{sub 2}/aqueous polyiodide photoelectrochemistry. It is shown that Ag{sup +}, highly soluble in concentrated iodide electrolytes, enhances photopotential and photoelectrochemical cell power. The variation of four highly soluble iodide salts containing Na{sup +}, K{sup +}, Li{sup +}, or Zn{sup 2+} cations are discussed in conjunction with activity and conductivity. Zinc iodide permits the nominal dissolution of up to 27 m I{sup {minus}} into the photoelectrolyte. Lithium polyiodide electrolytes enhance observed photocurrent and appear to be preferred cation at conventional illumination. The effects of other cations, Mg{sup 2+}, NH{sub 4}{sup +}, H{sup +}, Cd{sup 2+}, and Ca{sup 2+} on illuminated n-WSe{sub 2} in polyiodide are also reported, and the passivation by certain CaI{sub 2} electrolytes and the decomposition of certain CdI{sub 2} electrolytes discussed.

Molecular dynamics calculations of structural correlations in molten zinc chloride, zinc bromide and zinc iodide are reported. Two-body interaction potentials consisting of a coulomb interaction and a closed-shell overlap repulsion term are used. The calculated pair distribution function, partial structure factors and angular distribution functions exhibit structural features which have been discovered experimentally and attributed to stable local tetrahedra connected in a network via chlorine sharing. The prepeak position in total structure factors changes with anion size confirming the neutron scattering data by Allen et al. (1991) and the HNC theoretical approach by Vashishta et al. (1993).

The rate and selectivity of catalytic enantioselective cyclopropanation of cinnamyl alcohol utilizing bisiodomethyl zinc and 4a/4b is greatly dependent on the order of addition of the reagents. The independent preformation of the ethylzinc cinnamyloxide and bis(iodomethyl)zinc was found to be crucial. The reaction displayed autocatalytic behavior which was shown to be due to the generation of zinc iodide.

Gel polymer electrolytes (GPEs) have an upsurge interest among scientists due to their fascinating advantages such as leak proof nature, long term stability and good performance. They have been extensively tested for various devices including rechargeable cells, dye sensitised solar (DSS) cells, electrochromic devices and super capacitors. When GPEs are employed for DSS cells, the salt in the electrolyte has been known to play a major role in governing the cell performance. All DSS cells that use iodide/triiodide redox couple comprise a GPE complexed with an iodide salt. Therefore it has been accepted in principle, that GPE should assist iodide ion conductivity. In this study, GPEs based on several iodide salts were prepared and their performance in DSS cells were evaluated. As such, three different iodide salts, namely, potassium iodide (KI), zinc iodide (ZnI2) and tetrapropylammonium iodide (Pr4NI) were chosen for the study. The selection was mainly based on salts with cations having dissimilar sizes and valencies. Among them, KI based gel polymer electrolyte had the highest conductivity. However, the dye sensitised solar cell based on Pr4NI exhibited the highest performance. Gel polymer electrolyte based on ZnI2 had the lowest conductivity and also the lowest performance in DSS cells.

A model for cobalamin was synthesized using a new monoanionic tetradentate nitrogen donor ligand; 2-(4-tolyl)-1,3-bis(2-isopropylpyridyl)propenediimine (Tol-BDI((2-pp)2)H) (1), which utilizes isopropylpyridines as pendant arms on a β-diketiminate (BDI) backbone. During the synthesis of 1, the rearrangement product, Tol-BDI((2-pp)(4-pp))H (2) was observed. Metalation of 1 with zinc iodide and cobalt chloride yielded the corresponding Tol-BDI((2-pp)2)ZnI (3) and Tol-BDI((2-pp)2)CoCl (4) complexes. The redox properties of 4 in comparison to cobalamin were examined through electrochemical studies. Electrochemical and bulk reduction of complex 4 gave a diamagnetic cobalt(I) complex, Tol-BDI((2-pp)2)Co (5). Reactivity of 5 toward C-X bonds was investigated using methyl iodide and 1-iodo-2-(trimethylsilyl)acetylene, yielding Tol-BDI((2-pp)2)Co(CH(3))I and Tol-BDI((2-pp)2)Co(C(2)Si(CH(3))(3))I respectively. Synthesis and characterization details for these complexes, including the crystal structure of 3, are reported.

With the aim of discovering novel urease inhibitors, six new mononuclear complexes of five-coordinated Zn(II) bromide and iodide with terpyridine derivatives have been synthesized and their solid state structures were characterized by X-ray crystallography. Among these complexes, the zinc complexes bearing an electron withdrawing aryl group at the 4′-position show medium urease inhibitory activities, with IC50 values much lower than those of previously reported zinc species, at concentrations lower than 100 mM.

Germanium(II) iodide reacts with allyl bromide in the presence of zinc iodide to afford allylgermanium(IV), which adds to carbonyl compounds to give the corresponding homoallylic alcohols in good yields.

The coordination characteristics of the ligands 1,1,1-tris(monomethylaminomethyl)ethane (TSN) and 1,1,1-tris(dimethylaminomethyl)ethane (TTN) have been investigated by the preparation and characterization of their zinc iodide and cadmium iodide complexes. The structures of the complexes were established from 1H nuclear magnetic resonance (NMR) spectroscopy, IR spectroscopy and complementary physical-chemical studies. The zinc iodide complexes TSNZnI2 and TTNZnI2 are isomorphous with their chloro and bromo analogues, which indicates that the size of the halo group has no effect on the stereochemistry. The ligands in all of these zinc complexes are bidentate; the bound and free “legs” of the TSN ligands in these complexes exchange rapidly on the NMR time scale, while those of the TTN ligands do not. In contrast, cadmium iodide forms an ionic complex, [TSNCdI][CdI3], and a covalent complex, TTNCdI2, which differ stereochemically from the LZnX2 complexes. In both cadmium complexes, the ligands are tridentate, due to a combination of the larger size of cadmium and the ability of these tripod systems to distort outwards about the C3 ligand axis, thus lessening the steric interactions between the adjacent donor centres. Consequently, the cation [TSNCdI]+ and the neutral complex TTNCdI2 have bicyclic, cage-like structures featuring tetra- and pentacoordinated cadmium centres, respectively.

This experimental study concerns with the influence of Zinc Iodide penetrant on the damage evolution of carbon/epoxy laminates submitted to creep loading. It appears that impregnation under stress very much accelerates the damage evolution, with the initiation and propagation of numerous cracks. The higher the applied stress is, the more important is the Znl 2 influence. Then, a very strict methodology has to be followed in order to quantify the only creep damage.

The title Schiff base zinc(II) complex, [Zn(C(13)H(10)ClN(2)O)I(CH(3)OH)], was synthesized by the reaction of 5-chloro-salicyl-aldehyde, 2-amino-methyl-pyridine and zinc iodide in methanol. The Zn(II) atom is five-coordinated by one phenolate O atom, one imine and one pyridine N atom of the Schiff base ligand, one methanol O atom and one I atom, forming a distorted square-pyramidal geometry, with the I atom at the apical site. The dihedral angle between the benzene and pyridine rings is 22.9 (2)°. In the crystal, centrosymmetrically related mol-ecules are linked through inter-molecular O-H⋯O hydrogen bonds, forming dimers.

Fluorescence excitation spectra of ZnI produced in a supersonic jet discharge are presented. Two band systems, B 2 Σ + ←X 2 Σ + and C 2 Π 1/2 ←X 2 Σ + , were excited with a tunable ultraviolet (UV) laser operating between ≃ 356 and 304 nm. The spectra were found to be vibrationally warm (υ''≤13) but rotationally cold. While the analysis of the C-X band system is in good agreement with published results, transitions from the ground state were found to probe higher B ion-pair state vibrational levels than previously known (36≤υ'≤59). Precise B ion-pair state vibrational constants valid between υ'=0 and 59 have been determined. The relative change in equilibrium bond lengths between B 2 Σ + and X 2 Σ + was found to be 0.88(3) A by Franck-Condon calculations

New sequence-regulated macromonomers (3) with a vinyl ether terminal were prepared by the HI/ZnI2-mediated living cationic polymerization of vinyl ethers: CH3CH(OR1)CH2CH(OR2)C(COOEt)2CH2CH2OCHCH2 (3a: R1 = nBu, R2 = CH2CH2OCOPh; 3b: R1 = iOct, R2 = CH2CH2Cl). The synthesis consisted of three consecutive steps: (i) quantitative addition of hydrogen iodide to the first vinyl ether into an adduct [CH3CH(OR1)l]; (ii) propagation of a second vinyl ether from the adduct in the presence of zinc iodide; and (iii) quenching the resulting AB-type heterodimeric living intermediate with a carbanion [θC(COOEt)2CH2CH2OCHCH2] carrying a vinyl ether group. The HI/ZnI2-initiated living cationic polymerization of 3a and 3b yielded narrowly distributed polymers consisting of a poly(vinyl ether) backbone and sequence-regulated oligomer branches. The terminal vinyl ether function of 3 was also utilized to prepare pentamers and hexamers with controlled sequence of functional vinyl ethers by selective dimerization and chain extension reactions with HI/ZnI2. © 1993 John Wiley & Sons, Inc.

A series of multifunctional malonate anions, [Na⊕⊖C(COOEt)2CH2]mC6H6−m(I; m = 2–4), were examined as polymer coupling agents for the living cationic polymerization of vinyl ethers initiated with the hydrogen iodide/zinc iodide (HI/ZnI2) initiating system. The bifunctional anion (2;I, m = 2), 1,4-[Na⊕⊖C(COOEt)2CH2]2C6H4, terminated living polymers of isobutyl vinyl ether (IBVE) (DPn = 10) almost quantitatively in toluene at −15°C to give coupled living polymers with doubled molecular weights in 96% yield; the dianion 2 was dissolved in tetrahydrofuran containing 18-crown-6 for maintaining the solution homogeneous. The yield of the coupled polymers was increased with shorter living chains or in less polar solvents. Also by coupling via 2, ABA block copolymers were obtained from living AB block polymers of IBVE and an ester-functionalized vinyl ether (CH2CHOCH2CH2OCOCH3). Coupling of living poly(IBVE) with the trifunctional anion (3; I, m = 3) led to tri-armed polymers in 56% yield, whereas with the tetrafunctional version (4; I, m = 4), only three out of the four anions reacted to give another tri-armed polymer in 85% yield. © 1993 John Wiley & Sons, Inc.

A wide range of unsaturated aryl-, alkenyl-, alkynylcopper compounds can be selectively homologated by a methylene unit using (iodomethyl)zinc iodide or bis(iodomethyl)zinc. These reactions allow the generation of mixed allylic zinc-copper compounds which can be efficiently trapped with carbonyl compounds. An application to a general preparation of functionalized α-methylene-γ-butyrolactones is described. The homologation of alkynylcoppers with (iodomethyl)zinc iodide allows a one-pot preparation of propargylic copper reagents which in the presence of a carbonyl compound provide various homopropargylic alcohols in excellent yields. In the absence of an electrophile, a clean quadruple methylene homologation of alkynylcoppers occurs to furnish dienic copper reagents