Synthesis,structures, and physicochemical properties of Sr<Subscript>2</Subscript>A<Superscript>II</Superscript>UO<Subscript>6</Subscript> (A<Superscript>II</Superscript> = Mg,Ca, Sr,Ba, Mn,Fe, Co,Ni, Zn,and Cd) compounds

Sr₂A^IIUO₆ (A^II = Mg, Ca, Sr, Ba, Mn, Fe, Co, Ni, Zn, and Cd) compounds were synthesized by high-temperature reactions in the solid phase. The crystal structure (space group P2₁/n) was refined by the Rietveld method for Sr₂MgUO₆, (Sr_0.5Ba_0.5)₂SrUO₄, and Sr₂CdUO₆, which were synthesized for the first time. IR spectral characteristics were studied. The standard enthalpies of formation of the compounds were determined by reaction calorimetry.     

Visible‐Light‐Driven,Tunable, Photoelectrochemical Performance of a Series of Metal‐Chelate,Dye‐Organized,Crystalline, CdS Nanoclusters

CdS nanoclusters of four different sizes were integrated with ruthenium‐complex dyes. The cluster–dye crystalline composites, [Cd₄(SPh)₁₀][Ru(bpy)₃], [Cd₈S(SPh)₁₆][Ru(bpy)₃], [Cd₈S(SPh)₁₃?Cl?(CH₃OCS₂)₂][Ru(phen)₃], [Cd₁₇S₄(SPh)₂₈][Ru(bpy)₃], and [Cd₃₂S₁₄(SPh)₄₀][Ru(phen)₃]₂ (phen=1,10‐phenanthroline and bpy=bipyridine), show intense absorption in the visible‐light region. They also exhibit size‐dependent photocurrent responses under the illumination of visible light. The photocurrent increases with increased cluster size. The dyes also have significant influence on the photocurrent generation of the composite.     

Synthesis and characterization of polyamides containing octadecanedioic acid: Nylon‐2,18, nylon‐3,18, nylon‐4,18, nylon‐6,18, nylon‐8,18, nylon‐9,18, and nylon‐12,18

High‐aliphatic‐content linear nylons were produced with an 18‐carbon diacid with diamines containing both odd and even methylene segments. The resulting polymers were characterized with viscosimetric, thermal, and spectroscopic techniques. Solid‐state ¹⁵N NMR was used to determine the nylon crystalline form present. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 936–945, 2005     

Intra‐ and Intermolecular H‐Bonds of Alcohols in DMSO, 1H‐NMR Analysis of Inter‐Residue H‐Bonds in Selected Oligosaccharides: Cellobiose,Lactose, N,N′‐Diacetylchitobiose,Maltose, Sucrose,Agarose, and Hyaluronates

Inter‐residue H‐bonds of oligosaccharides in (D₆)DMSO have been assigned on the basis of a combined interpretation of the chemical shift (δ(OH)), coupling constant (J(H,OH)), and temperature dependence (Δδ(OH)/ΔT) of OH signals. Cellobiose, lactose, and N,N′‐diacetylchitobiose possess a completely persistent C(3)OH⋅⋅⋅OC(5′) H‐bond. Maltose is characterised by flip‐flop H‐bonds between HO−C(3) and HO−C(2′), and agarose by two weakly persistent inter‐residue H‐bonds. Sucrose forms an equilibrium of differently H‐bonded species, and hyaluronates possess four strong inter‐residue H‐bonds.     

cis,cis,cis‐Tetra­methyl 1,2,4,5‐cyclo­hexane­tetra­carboxyl­ate

The title compound, C₁₄H₂₀O₈, was synthesized from the hydrogenation of tetra­methyl 1,4‐cyclo­hexa­diene‐1,2,4,5‐tetra­carboxyl­ate with a catalytic amount of palladium/carbon. All four carbonyl moieties of the methyl ester groups are on the same face of the chair‐conformed ring. The substantial ring distortion associated with the 1,3‐diaxial methoxycarbonyl substituents is reflected in the large difference between bond angles as well as torsion angles, respectively, that in undistorted cyclo­hexanes would be approximately the same.     

B,B, B-Trimethyl-N,N, N-triäthylborazin- und B,B, B-Triäthyl-N,N, N-trimethylborazin-molybdäntricarbonyl

The title compounds have been prepared in low yields starting with cis-(CH₃CN)₃-Mo(CO)₃ or Mo(CO)₆ (photochemical route). The new complexes are generally less stable than the corresponding hexaalkylborazine-chromium compounds and react very smoothly with Lewis bases by cleavage of the borazine-metal bond. The IR.-spectra indicate the similarity of type of bonding in hexaalkylborazine-molybdenum and -chromium complexes.     

Synthesis,solid‐state,and charge‐transport properties of conjugated polythiophene‐S,S‐dioxides

An alkylated semiconducting polymer comprising alternating bithiophene‐[all]‐S,S‐dioxide and aromatic monothiophene units in the polymer backbone was synthesized with the intent of modifying the energy gap and lowest unoccupied molecular orbital for use as a stable n‐type semiconductor. Films spun from this semiconducting polymer were characterized utilizing X‐ray scattering, near edge X‐ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, and thin‐film field effect transistors to determine how oxidation of the thiophene ring systems impacts the structural and electronic properties of the polymer. The thiophene‐S,S‐dioxide polymers have lower optical and electrical band gaps than corresponding thiophene polymers. X‐ray scattering results indicate that the polymers are well ordered with the π–π stacking distances increased by 0.4 Å relative to analogous thiophene polymers. The electrical stability of these polymers is poor in transistors with a drop in the field effect mobility by approximately one order of magnitude upon addition of just 5% of the thiophene‐S,S‐dioxide unit in a copolymer with thiophene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Molecular structure,p<Emphasis Type="Italic">K</Emphasis>a,lipophilicity, solubility,absorption, polar surface area,and blood brain barrier penetration of some antiangiogenic agents

The methods of theoretical chemistry have been used to elucidate molecular properties of selected and novel antiangiogenic agents (semaxanib, sunitinib, N-methylsunitinib, sorafenib, motesanib, ABT-869, vatalanib, vandetanib, AEE 788, CP-547632, A-1, A-2, A-3, and A-4). The geometries and energies of these drugs have been computed using HF/6-31G(d), Becke3LYP/6-31G(d) and Becke3LYP/6-31++G(d,p) model chemistries. Wherever possible the most stable conformations of inhibitors studied are stabilized by means of intramolecular hydrogen bonds. Water has a remarkable effect on the geometry of the antiangiogenic agents studied. Computed partition coefficients (ALOGPS method) varied between 2.3 and 5. Compounds studied are described as lipophilic inhibitors. Semaxanib is inhibitor with lowest lipophilicity. The antiangiogenic agents studied are only slightly soluble in water; their computed solubility (log S) from interval between −3.4 and −5.4 is sufficient for fast absorption. Selection criteria for drug-like properties of VEGFR2 inhibitors investigated were designed. Based on these criteria, three compounds (A-2, A-3, and A-4) were selected for synthesis and biological testing for antianiogenic activity on VEGFR2 receptor.     

Synthesis and Structure of a 2, 8, 9‐Trioxa‐3, 5, 7‐trisila‐1‐titanaadamantane

The title compound has been prepared from [Ti(η⁵‐C₅Me₅)Cl₃] and cis‐cis‐(t‐BuSi(OH)—CH₂)₃ in hexane solution in the presence of Et₃N. The pale yellow complex was characterized by NMR and MS spectra, as well as by a crystal structure determination. The two crystallographic independent molecules in the triclinic unit cell (space group P1¯, No. 2, Z = 4) both have a nearly identical adamantane‐like TiO₃Si₃C₃ cage of approximate C_3v symmetry. The exocyclic C—C—C bond angles in the Cp‐ligand range from 123° to 129°. A quantum chemical calculation of the free molecule predicts this range to be 124° to 127°. The arrangement of the molecules in the crystal is characteristic for an offset face‐to‐face ππ stacking of the aromatic η⁵‐C₅Me₅ rings.     

Preparation of novel,liquid, solvent‐free,polyolefin‐based adhesives

An innovative procedure for functionalization of polyolefins was developed. It was found that synthesized polyolefins end‐capped with trimethoxysilane (silylated polyolefins) are new polyolefin‐based adhesives. To prepare the mentioned materials,1‐octene as a higher α‐olefin was cooligomerized with two linear, nonconjugated dienes (ie, 1,5‐hexadiene and 1,7‐octadiene) by using metallocene catalyst system, Cp₂HfCl₂/MAO, at room temperature. Then, amine‐terminated trimethoxysilane (3‐aminopropyltrimethoxysilane) was reacted with unsaturated bonds of synthesized cooligomers in the presence of palladium(II) acetate. Embedding of the dienes on 1‐octene oligomeric chains was explored by Fourier transform infrared (FTIR), ¹H, and ¹³C‐NMR spectroscopy. On the basis of the results, 1,5‐hexadiene showed both 1‐butene branch and five‐member ring. On the other hand, 1,7‐octadiene was incorporated by 1,2‐addition, forming both 1‐hexene branch and seven‐member ring in the cooligomer backbone. Mole percentage of C?C and cyclic moieties reached to a value of 28.54, 18.59% mol in 1‐octene/1,5‐hexadiene, and 38.04, 6.71% mol in 1‐octene/1,7‐octadiene cooligomers, respectively. Reaction of synthesized cooligomers with 3‐aminopropyltrimethoxysilane was confirmed by FTIR spectroscopy, which yielded targeted adhesives. To study the adhesion properties, resulting adhesives were applied to different substrates. Obtained results demonstrated that tensile shear strength of synthesized adhesives to polar substrates was 2.21% to 2.84% more than nonpolar substrates. Among studied systems, the best performance was achieved by1‐octene/1,7‐octadiene–based adhesive and Al substrate with tensile shear strength of 1.45 N/mm².     

A Novel Conversion of 2, 4‐Diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepines into 2, 4‐Diaryl‐3 H‐1, 5‐benzodiazepines

A novel conversion of 2, 4‐diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepins into 2, 4‐diaryl‐3 H‐1, 5‐benzodiazepines by the reaction with m‐chloroperbenzoic acid (MCPBA) was reported.     

Synthesis,structures, IR spectra,and thermal characteristics of compounds of general formula Ba(M<Stack><Subscript>2/3</Subscript><Superscript>III</Superscript></Stack>U<Subscript>1/3</Subscript>)O<Subscript>3</Subscript> (M<Superscript>III</Superscript> = Sc,Y, In,Nd-Lu)

Compounds with the composition Ba(M _2/3 ^III U_1/3)O₃ (M^III = Sc, Y, In, Nd-Lu) were synthesized by high-temperature solid-state reactions. The structures of the compounds were studied by X-ray diffraction analysis, including the high-temperature method, and IR spectroscopy.