Polymerization of monoisocyanates by the Pruitt–Baggett adduct

n-Butyl isocyanate (nBIC) was polymerized in bulk by the Pruitt–Baggett adduct (PBA) at ?23, 0.0, and 25.0°C. Polymerization was accompanied by trimerization to the cyclicisocyanurates at all temperatures. Spectroscopic evidences supported the nylon-1 structure for both trimer and polymer. The polymer/trimer ratio and the molecular weight of produced polymers were found to increase with decreasing temperature. The Pruitt–Baggett catalyst (PBC), which is the reaction product of (PBA + H₂O) system, also polymerized nBIC, but with a relatively slower rate. In aromatic and etheric solutions, nBIC was only trimerized by PBA. Copolymerization of nBIC with propylene oxide by PBA and PBC failed. Some selected monoisocyanates were also polymerized by PBA. © 1993 John Wiley & Sons, Inc.     

两种钴离子支撑钼磷多金属氧酸盐的水热合成及晶体结构

利用水热技术合成了2个新型钴支撑的磷钼多金属氧酸盐超分子化合物:(C2N2H10)5[(P4Mo6O25(OH)6)2Co](1)和(Co(H2O)6)2(C5NH6)6[(P4Mo6O25(OH)6)2Co]·10H2O(2).并通过元素分析、红外光谱、热重分析和X射线单晶衍射对2个化合物进行了表征.结果表明:化合物1属于三斜晶系,P-1空间群;晶胞参数a=1.179 9(2)nm,b=1.337 7(2)nm,c=1.479 7(3)nm,α=73.435(2)°,β=74.383(2)°,γ=66.499(2)°,V=2.020 5(6)nm3,F(000)=1 327,Z=1;化合物2属于属于三斜晶系,P-1空间群;晶胞参数a=1.220 68(11)nm,b=1.381 08(13)nm,c=1.687 18(15)nm,α=92.275(1)°,β=104.774(1)°,γ=114.475(1)°,V=2.468 8(4)nm3,F(000)=1 649,Z=1.     

Synthesis and characterization of a tetramethyl furanone functionalized diiminedioxime,a potential ligand for Cu radiopharmaceuticals,and its copper(II) and nickel(II) complexes

As part of our on-going effort to develop ⁶⁴Cu-based radiopharmaceuticals for PET (positron emission tomography) imaging of multidrug resistance in cancer, we prepared a tetramethylfuranone-functionalized diiminedioxime ligand, TMFPreH (TMFPreH = 4-[3-(4-hydroxyimino-2,2,5,5-dimethyl-dihydro-furan-3-ylideneamino)-propylimino]-2,2,5,5-tetramethyl-dihydrofuran-3(2H)-one oxime) and its Cu(II) and Ni(II) complexes. When the copper(II) complex was prepared from Cu(ClO₄)₂ in ethanol, it was isolated as a Cu(II)-bridged dimer, but when it was prepared from Cu(OAc)₂ and heated in acetone, an unusual example of an acetone adduct of the ligand is formed by reduction of one of the imine double bonds by the solvent. The Ni(II) complex is square pyramidal with the perchlorate counterion at the apex.     

EPR/Spin‐trapping study of free radical intermediates in the photolysis of trifluoromethyl ketones with initiators

Photolysis of trifluoromethyl ketones (TFMKs) 1a–1e versus the non‐fluorinated ketones 2a–2b in the presence of radical initiators by electron paramagnetic resonance spectroscopy has been studied for the first time. The transient radicals generated after irradiation of the ketones were identified by trapping with 2‐methyl‐2‐nitrosopropane (MNP) and 2,4,6‐tri‐tert‐butylnitrosobenzene (TTBNB) as spin traps. TTBNB is a powerful, particularly useful spin trap in these kinds of processes producing anilino and nitroxyl spin adducts due to the ambivalent reactivity on the N and O atoms. In the presence of t‐butylperoxide, short‐chain TFMKs, such as 1,1,1‐trifluoroacetone (1d) and hexafluoroacetone (1e), give rise to detection of the elusive trifluoromethyl radical. In contrast, long‐chain TFMKs did not provide clues to prove formation of the trifluoromethyl radical but instead to radicals derived by abstraction of one α‐methylene proton to the carbonyl. Although TFMKs are quite stable to photodegradation in the absence of initiator, methyl ketone 2b and phenyl ketone 3 produce radicals resulting from abstraction of a γ‐hydrogen to the carbonyl group. Copyright © 2010 John Wiley & Sons, Ltd.     

Structural study and thermal behavior of novel interaction product of 4-amino-5-(furan-2-yl)-4H-1,2,4-triazole-3-thione with molecular iodine

Abstract

As a part of investigation of thyreostatic activity of mercapto-substituted triazoles, the structure, spectroscopic properties of 4-amino-5-(furan-2-yl)-4H-1,2,4-triazole-3-thione were obtained. 4-amino-5-(furan-2-yl)-4H-1,2,4-triazole-3-thione forms steady charge-transfer complex in dilute chloroform solution, coordinating one iodine molecule (lgβ?=?3.47). The reaction product of 4-amino-5-(furan-2-yl)-4H-1,2,4-triazole-3-thione is presented by uncharged adduct: C₆H₆N₄OS·I₂. The crystal structure of the adduct was studied in detail by single crystal X-ray diffraction. The results of thermogravimetric analysis revealed the stability of adduct in a solid state at the temperature range 50–500?°C.     

金属冠醚的合成进展

金属冠醚是一类新型的超分子大环化合物, 它开拓了主客体化学分子识别和超分子化学的全新领域. 综述了近年来金属冠醚的研究成果.     

Macrotricyclic host molecules with basket shaped cavities

The syntheses of several macrotricyclic hexalactams (1–3) and of a corresponding hexalactone (4) are described in detail for the first time. The molecules have a basket shaped skeleton and contain a non-collapsible cavity, the size and shape of which is varied by use of spacer groups. Compounds1–3 selectively form crystalline adducts with ethanol as guest; the macrotricyclic hexaester4 does not. Evidence for an interaction of1 with ethanol was obtained by exchange experiments with perdeuteroethanol. Complexation experiments in solution did not show significant host/guest interactions with the guest chosen.     

Replacing the hydrogen in the intermolecular hydrogen bond of the cyanuric acid-bipyridyl adduct by Ag(I)

A complex between cyanuric acid (CA), 4,4′-bipyridyl (BP) and Ag(I), with the composition, [Ag₂(C₃H₂N₃O₃-κN)₂ (C₁₀H₈N₂-κN)] has been prepared. Crystal structure analysis shows that it has a chain structure in which the CA molecules are linked to the BP units through silver atoms by the formation of N-Ag-N bonds, wherein one of the hydrogens of CA is replaced by Ag(I), showing thereby the chains connected to one another by N-H...O hydrogen bonds formed between the CA molecules. This intermolecular chain structure resembles the chain structure of the CA.BP adduct where CA-BP-CA chains formed by N-H...N hydrogen bonds are linked to one another by N-H...O hydrogen bonds between the CA molecules.     

A facile one-pot three-component synthesis of ferrocene-grafted dispiro pyrrolidine/pyrrolizidine scaffolds through intermolecular [3+2] cycloaddition reaction of ferrocenyl Baylis-Hillman adduct

A one-pot synthesis of ferrocene-grafted dispiropyrrolidine/pyrrolizidine scaffolds has been accomplished in good yields through a facile 1,3-dipolar cycloaddition of various azomethine ylides derived from diketones and secondary amino acids with Baylis-Hillman adduct derived from ferrocene carbaldehyde. The regiochemical and stereochemical outcomes of the cycloaddition reaction were ascertained by X-ray crystallographic studies of one of the cycloadducts.     

Anisotropy of second-order nonlinear optical susceptibilities of arsenic triiodide-sulfur addition complex: AsI3 · 3S8

We report the anisotropic linear and second-order nonlinear optical (NLO) properties of arsenic triiodide-octa-sulfur (1:3) adduct, AsI₃ · 3S₈, which spontaneously crystallizes in the trigonal rhombohedral non-centrosymmetric space group R3m. The trigonal symmetry of the AsI₃ · 3S₈ molecule coincides with the crystal symmetry. The crystals are optically uniaxial with n_o/n_e of about 1.2 and show dichroism at the UV-visible wavelengths. Second harmonic generation (SHG) tensor elements were determined from Maker fringes measured with an Nd:YAG laser (∼10 ns pulse, 1064 nm). The coefficient d_222,eff = 32.0 pm/V for the light polarized parallel to the layers of iodine and sulfur atoms in the AsI₃ · 3S₈ crystal ab plane is markedly larger than d₃₃₃ = 11.6 pm/V for the polarization of light parallel to the crystal c axis. The anisotropy parameter, defined as the d_222,eff/d₃₃₃ ratio, is about 2.7 for the AsI₃ · 3S₈ crystal, smaller than that for the isomorphous CHI₃ · 3S₈ crystal (7.3) but larger than for the SbI₃ · 3S₈ crystal (0.7). Highly anisotropic components of the first hyperpolarizability tensor of an AsI₃ · 3S₈ molecule, β, were derived from the quadratic nonlinear susceptibility tensor of the crystal.