Synthesis of molecular chains: phenylene thioether and sulfoxide oligomers

The application of a general synthetic approach to prepare molecular chains is reported. It is based on a step-by-step method each consisting first in a Pd-catalyzed reaction between ArI and HXAr′Br (Ar=aryl, Ar′=arylene) to give ArXAr′Br followed by a Cu-catalyzed replacement of Br by I to give ArXAr′I that can be reacted with HXAr′Br in the following step. The application of this method is here illustrated to prepare phenylene sulfide oligomers (X=S). Starting from RC₆H₄I-4 (R=H, MeO, NO₂, NH₂) and HSC₆H₄Br-x (x=2, 4) it is possible to grow chains in one direction to give X(C₆H₄S-m)_nC₆H₄R-4 (n=1, X=Br, m=4, R=H, MeO, NO₂, NH₂, SMe and m=2, R=H, MeO, NO₂; n=1, X=I, m=2 or 4, R=H, MeO, NO₂; n=2, X=Br, m=2 or 4, R=H, MeO, NO₂; n=2, X=I, m=4, R=MeO, NO₂; n=3, X=Br, m=4, R=MeO, NO₂; n=3, X=I, m=4, R=NO₂ and n=4, X=Br or I, m=4, R=NO₂). From HSC₆H₄Br-x and IC₆H₄I-4 the chains can grow in two directions to give X(C₆H₄S-4)_nC₆H₄X-4 (n=2 or 4, X=Br or I), 2-XC₆H₄(SC₆H₄-4)_nSC₆H₄X-2 (n=3 or 5, X=Br). Using diiodomesitylene the dithioethers C₆HMe₃-2,4,6-(SC₆H₄X-4)₂-1,3 (X=Br, I) have been prepared. The series of sulfoxides X(C₆H₄S(O)-4)_nC₆H₄R-4 (X=Br, n=1, R=MeO, n=3, R=NO₂, n=4, R=Br; X=R=I, n=2) has been obtained from the corresponding thioethers and PhICl₂.     

Dipole moments of compounds containing a cobalttin bond

The molecular electric dipole moments are reported for the series of tin-substituted tetracarbonyl cobalt compounds R_nY_m?nSn{Co(CO)₄}_4?m (m = 1–3; n ? m; R = alkyl, phenyl; Y = halogen). The effect of the substituents at the tin atom on the nature of the CoSn bond is established on calculating the (CO)₄CoSn group dipole moments. It is shown that the charge transfer in the CoSn bond is mainly determined by the inductive properties of the ligands attached to tin.     

Fastener effect on magnetic properties of chain compounds of dinuclear ruthenium carboxylates

Chlorido-bridged chain complexes of dinuclear ruthenium benzoate analogues, [Ru₂{3,4,5-(C _m H_2m+1O)₃C₆H₂CO₂}₄Cl] _n (mCl) (m = 3, 5–7, 9, 11, 13, 15, 17), were synthesised and the crystal structure of 3Cl · 2nH₂O was revealed. The magnetic measurements for a series of the complexes mCl (m = 2–18) revealed that all the complexes show an antiferromagnetic interaction between the dinuclear unit, with a fastener effect giving the stronger interaction as the alkyl-chain length m increases.     

Synthesis of phosphate-type fluorocarbon-hydrocarbon hybrid surfactants and their adsorption onto calcium hydroxyapatite

Five novel phosphate-type hybrid surfactants, C_mF_2m+1C₆H₄CH[OPO₂(OC₆H₅)Na]C_nH_2n+1 (FmPHnPPhNa: m = 4, 6, 8; n = 3, 5), have been synthesized. When compared with sulfate-type hybrid surfactants, C_mF_2m+1C₆H₄CH(OSO₃Na)C_nH_2n+1 (C₆H₄ = p-phenylene), the new hybrid surfactants were found to have comparable abilities to lower the surface tension of water. The critical micelle concentrations of FmPHnPPhNa followed Klevens’ rule and their occupied areas per molecule increased with increasing m and n. Calcium hydroxyapatite (CaHAp) pellets modified with FmPH3PPhNa gave high hydro and lipophobic surfaces. The hybrid surfactants are expected to be useful as new dental reagents for oral hygiene.     

Synthesis and characterization of partially fluorinated ethers

A series of partially fluorinated ethers PFE-m,n with general formula F(CF₂)_mCH₂CH₂O(CH₂)_nH (m = 4, 6, 8 and n = 2, 3, 5, 8, 14, 18, 21) has been synthesized and characterized. The present work aimed to investigate the synthesis of PFE-m,n and evaluate some of their fundamental physico-chemical properties such as: specific gravity, refractive index, viscosity, solid-solid transitions, solubility and amphiphile surface activity in a variety of solvents. Further, a comparison between PFE-m,n and the well known semifluorinated n-alkanes F(CF₂)_m-(CH₂)nH (FHm, n) with the same value of the m/n ratio have been reported.     

Neighbouring group participation in reactions between iodine and Ph3Sn(CH2)nS(O)mC6H4Me-p

Reaction of Ph₃Sn(CH₂)_nS(O)_mC₆H₄Me-p (n = 2, 3, or 4; m = 0, 1 or 2) with iodine in CCl₄ result in phenyltin bond cleavage. The relative reactivities indicate intramolecular nucleophilic catalysis by the sulphur-containing substituents.     

Synthesis and reactions of cyano-pentafluorophenyl aurate(I) and -(III)

The preparation of Q[Au(C₆F₅)_n(CN)_m] (Q = bulky cation; n = 1 or 3, m = 1; n = 2, m = 2) is described and the f     

Preparation and spectroscopic studies of diorganotin oxycarbonates

The synthesis, ^119mSn Mössbauer and infrared spectra of a series of diorganotin oxycarbonates of the type, (R₂Sn)₂OCO₃·nH₂O, where R = Me, Et, Ph, n = 0; R = Pr, Bu, Oct, n = 1, are reported.Structures are proposed for these compounds in the solid state, on the basis of their spectroscopic data.     

Photoelectron spectroscopy of transition metal-sulfur cluster anions

Metal (M)-sulfur cluster anions (M = Ag, Fe and Mn) have been studied using photoelectron spectroscopy (PES) with a magnetic-bottle type time-of-flight electron spectrometer. The M_nS _m ^? cluster anions were formed in a laser vaporization cluster source. For Ag-S, the largest coordination number of Ag atoms (n _max) is generally expressed as n _max =2m ? 1 in each series of the number of S atoms (m). For Fe?S and Mn?S, it was found that the stable cluster ions are the ones with compositions of n=m and n=m±1. Their electron affinities were measured from the onset of the PES spectrum. For Ag?S, the EAs of Ag₁S_m are small and around 1 eV, whereas those of Ag_nS_m (_n ≥ 2) become large above 2 eV. The features in the mass distribution and PES suggest that Ag₂S unit is preferentially formed with increasing the number of Ag atoms. For Fe?S and Mn?S, the PES spectra of Fe_nS _m ^? /Mn_nS _m ^? show a unique similarity at n ≥ m, indicating that the Fe/Mn atom addition to Fe_nS _n ^? /Mn_nS _n ^? has little effect on the electronic property of Fe_nS_n/Mn_nS_n. The PES spectra imply that the Fe_nS_n cluster is the structural framework of these clusters, as similarly as the determined structure of the Fe_nS_n cluster in nitrogenase enzyme.     

Synthesis and reactivity of ω-haloalkyltin compounds

ω-Haloalkyltin trihalides, X(CH₂)_nSnX₃ (n ≧ 3; X = halogen) can readily be prepared in high yields by the direct reaction of stannous halides with α,ω-dihaloalkanes, catalysed by trialkylantimony compounds. The compounds are versatile starting materials for the synthesis of a variety of ω-functionallysubstituted organotin compounds R_3-mX_mSn(CH₂)_n Y (R = alkyl, phenyl; m = 0-3; X = Cl, Br, O; Y = Br, NMe₂, NEt₂, COOH, CHOHR, R₃Sn). ¹H-NMR spectral data for a series of such compounds are presented. The trends observed in the chemical shifts and the ¹¹⁹Sn—methyl proton coupling constants of Me_3-m Br_mSn(CH₂)_nBr (m = 0-3; n = 3-5) are discussed in terms of inductive effects. Intramolecular coordination between the ω-bromine atom and tin could not be demonstrated.     

Some binuclear complexes of iron and cobalt with isocyanide ligands

Whereas Co₂(CO)₈ and RNC (R= Me, Et, and Cy) react to give mixtures of [(RNC)₅Co] [Co(CO)₄] and the covalent, carbonyl-bridged [(RNC)_mCo₂(CO)_8?m] derivatives (m = 1–3), [(π-dienyl)Fe(CO)₂]₂ give only [(π-dienyl)₂Fe₂(CO)_4?n(CNR)_n] complexes (dienyl = C₅H₅, MeC₅H₄ and C₉H₇; n = 1–2) that exist in solution as mixtures of cis- and trans-CO- and RNC-bridged tautomers with the μ-RNC species decreasing in importance as the bulk of R increases.     

Synthesis,structures, sorption and magnetic properties of coordination polymers based on 3d metal pivalates and polydentate pyridine-type ligands

The reactions of 3d metal pivalates with pyridine-containing ligands of different structures afforded the 1D coordination polymers [Co₂(Piv)₄(dpe)₂] _n , [Ni(Piv)₂(dpe)(EtOH)₂] _n , [Cu₂(Piv)₄(dpe)] _n , [Cu(Piv)₂(dpe)] _n , [Ni(Piv)₂(4-ptz)(EtOH)₂] _n , and [Cu₂(Piv)₄(4-ptz)· ·mSolv] _n (Solv is EtOH, m = 2; Solv is C₆H₆, m = 1; Piv^? is pivalate, dpe is trans-1,2-bis(4-pyridyl)ethylene, 4-ptz is 2,4,6-tris(4-pyridyl)-1,3,5-triazine), as well as the 3D coordination polymer [{Cu₂(Piv)₄}₃(3-ptz)₂] _n (3-ptz is 2,4,6-tris(3-pyridyl)-1,3,5-triazine). The sorption and magnetic properties of a series of the synthesized compounds and magnetic properties of the earlier characterized coordination polymer [Mn₂(O₂CC₆H₅)₄(dpe)₂·dpe] _n were studied. It was shown that the desolvation of the complexes [Ni(Piv)₂(4-ptz)(EtOH)₂] _n and [Cu₂(Piv)₄-(4-ptz)·2EtOH] _n resulted in the formation of the crystal structures, in which the pores are accessible to nitrogen and hydrogen at 78 K (S _BET are up to 92 m² g^?1). The temperature dependences of the molar magnetic susceptibility for [Co₂(Piv)₄(dpe)₂] _n , [Mn₂(O₂CC₆H₅)₄-(dpe)₂·dpe] _n , [Ni(Piv)₂(dpe)(EtOH)₂] _n , [Ni(Piv)₂(4-ptz)(EtOH)₂] _n , and [Cu₂(Piv)₄-(4-ptz)·2EtOH] _n are described in terms of models taking into account the zero-field splitting and exchange interactions or isotropic exchange Hamiltonians.     

Photoelectron spectroscopy of silicon and germanium-fluorine binary cluster anions (SinF m − , GenF m − )

Electronic properties of silicon-fluorine and germanium-fluorine cluster anions (Si_nF _m ^? n = 1–9, m = 1–3, Ge_nF _m ^? ; n =1–9, m = 1–3) were investigated by photoelectron spectroscopy using a magnetic-bottle type electron spectrometer. The binary cluster anions were generated by a laser vaporization of a silicon/germanium rod in an He carrier gas mixed with a small amount of SiF₄ or F₂ gas. Comparison between photoelectron spectra of Si_nF^?/Ge_nF^? and Sin /Gen (n = 4–9) gives the insight that the doped F atom can remove one electron from the corresponding Sin _n ^? /Ge _n ^? cluster without any serious rearrangement of Sin/Gen framework, because only the first peak of Si _n ^? /Ge _n ^? , corresponding singly occupied molecular orbital (SOMO), disappears and other successive spectral features are unchanged with the F atom doping     

Excess molar quantities of (a halogenated n-alkane + an n-alkane) A comparative study of mixtures containing either 1-chlorobutane or 1,4-dichlorobutane

Excess molar volumes V_m^E at 298.15 K were obtained, as a function of mole fraction x, for series I: {x1-C₄H₉Cl + (1 ? x)n-C_lH_{2l + 2}}, and II: {x1,4-C₄H₈Cl₂ + (1 ? x)n-C_lH_{2l + 2}}, for l = 7, 10, and 14. 10, and 14. The instrument used was a vibrating-tube densimeter. For the same mixtures at the same temperature, a Picker flow calorimeter was used to measure excess molar heat capacities C_{p, m}^E at constant pressure. V_m^E is positive for all mixtures in series I: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.277 for l = 7, 0.388 for l = 10, and 0.411 for l = 14. For series II, V_m^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆} is small and S-shaped, the maximum being situated at x_max = 0.178 with V_m^E(x_max)/(cm³ · mvl^?1) = 0.095, and the minimum is at x_min = 0.772 with V_m^E(x_min)/(cm³ · mol^?1) = ?0.087. The excess volumes of the other mixtures are all positive and fairly large: at x = 0.5, V_m^E/(cm³ · mol^?1) is 0.458 for l = 10, and 0.771 for l = 14. The C_{p, m}^Es of series I are all negative and |C_{p, m}^E| increases with increasing l: at x = 0.5, C_{p, m}^E/(J · K^?1 · mol^?1) is ?0.56 for l = 7, ?1.39 for l = 10, and ?3.12 for l = 14. Two minima are observed for C_{p, m}^E of {x1,4-C₄H₈Cl₂ + (1 ? x)n-C₇H₁₆}. The more prominent minimum is situated at x′_min = 0.184 with C_{p, m}^E(x′_min)/(J · K^?1 · mol^?1) = ?0.62, and the less prominent at x″_min = 0.703 with C_{p, m}^E(x″_min)/(J · K^?1 · mol^?1) = ?0.29. Each of the remaining two mixtures (l = 10 and 14) has a pronounced minimum at low mole fraction (x_min = 0.222 and 0.312, respectively) and a broad shoulder around x = 0.7.     

Extraction of palladium with thiacalix[4]arenes from nitric acid nitrate-nitrite solutions

Calix[4]arene 1, thiacalix[4]arenes 2(LH₄), and calix[4]arenethioether 3 were compared in palladium extraction from nitric acid solutions; D _Pd for 2 was shown to be 2?C3 orders of magnitude larger than for 1 at pH > 3 (comparable with 3) because of cation-exchange and coordination extraction of palladium. It was shown by extraction methods and IR spectroscopy that thiacalixarenes 2 extract complex species [Pd _n L _m H_{4 ? 2n} ] (m = 1, n = 1 and 2) and [(PdA₂) _n L _m H₄] (A = m = 1, n = 1?C4) from nitric acid solutions at pH 3. Extraction constants for these palladium species that satisfactorily describe experimental data were calculated. As distinct from 3, thiacalixarenes 2 are promising for the combined extraction of palladium and silver from alkaline solutions and the selective extraction of fission palladium from nitric acid solutions. Phosphorylated at the upper rim thiacalixarenes 2 can be considered as bifunctional extractants for the separation of fission radionuclides.     

Synthesis of phosphate-type fluorocarbon-hydrocarbon hybrid surfactants and their adsorption onto calcium hydroxyapatite

Five novel phosphate-type hybrid surfactants, C_mF_2m+1C₆H₄CH[OPO₂(OC₆H₅)Na]C_nH_2n+1 (FmPHnPPhNa: m = 4, 6, 8; n = 3, 5; C₆H₄ = p-phenylene, C₆H₅ = phenyl), have been synthesized. When compared with sulfate-type hybrid surfactants, C_mF_2m+1C₆H₄CH(OSO₃Na)C_nH_2n+1 (C₆H₄ = p-phenylene), the new hybrid surfactants are found to have comparable abilities to lower surface tension of water. The critical micelle concentrations of FmPHnPPhNa follow Klevens rule and their occupied areas per molecule increase with increasing m and n. Calcium hydroxyapatite (CaHAp) pellets modified with FmPH3PPhNa gives high hydrophobic and lipophobic surfaces. The hybrid surfactants are expected as new dental reagents for oral hygiene.     

IR Emission Spectra of Carbonate-Chloride Melts 2CsCl-NaCl-Cs2CO3 Containing Lithium and Beryllium Ions

The IR emission spectra of the molten systems NaCl-CsCl-Cs₂CO₃-MCl _n (M = Li, Be) have been obtained. Spectral data shows that, at a definite limiting molar ratio n _lim = [CO₃]/[Mⁿ⁺] characteristic for each Mⁿ⁺, carbonate-chloride melts based on the NaCl-CsCl eutectic contain carbonate complexes [Li(CO₃)₃]^5? and [Be(CO₃)₃]^4? and, if n < n _lim, carbonato chloro complexes [M(CO₃) _m Cl_4?m ], where m = 1–2.     

Phase equilibria in the water-alkali metal or ammonium sulfate-synthanol systems

Solubility was studied for the first time in ternary aqueous phase-separating systems containing synthanol DS-10 or ALM-10 (polyethylene glycol monoalkyl ethers based on primary fatty alcohols, C _n H_{2n ? 1}O(C₂H₄O) _m H, where m = 8–10 and n = 10–18 (synthanol DS-10) or 12–14 (synthanol ALM-10)) and inorganic salt (NH₄)₂SO₄, Na₂SO₄, or Li₂SO₄ at 25°C. The boundaries of two-phase liquid equilibrium regions were determined. It was proposed to use the studied phase-separating systems for liquid extraction of metal ions.     

Ab-initio study of optical response properties of nonstoichiometric lithium-hydride and sodium-fluoride clusters with one- and two-excess electrons

Structural and optical response properties of Li _n H _n-m and Na_nF _n-m (n = 2-6, m = 1, 2) clusters containing one- and two-excess electrons are studied using ab-initio methods accounting for electron correlation. The common feature of the optical response obtained for the most stable structures of Na_nF _n-1 (n = 2-6) clusters is the appearance of a dominant intense transition in the infrared regime independently whether the single excess electron is localized at the cuboid corner vacancy (surface F-center) or at the external atom attached to the filled cuboid. In contrast, Li_nH _n-1 (n = 2-6) clusters exhibit substantially different spectroscopic patterns with respect to halides also for the cases with the common structural properties. Optical response features of Li_nH _n-2 (n = 3-6) clusters with two-excess electrons are characterized by dominant transitions in the visible regime reflecting segregation in “metallic” and ionic parts. In contrast, Na_nF _n-2 = 3-6) can be divided according to their optical and structural properties into cuboid “lattice” defect species (Na₄F _n , Na _n F₄) and segregated metallic-ionic systems. For the former, the intense transitions occur in the infrared-visible, and for the latter only in the visible regime. It will be shown that the calculated absorption patterns are excellent fingerprints of structural and bonding properties.