金属蒸气合成在金属有机合成中的应用

本文简要地介绍了金属蒸气合成法的基本原理、仪器和实验技术, 并按金属原子分别与炔、单烯、多烯、环烯、芳烃体系、卤代烃、有机混和物的反应及有机金属硼化合物的合成, 对金属蒸气合成法在金属有机合成中的应用进行了讨论。     

自组装和共缩聚法制备磺酸基修饰的硅柱磷酸锆

以十六胺插层磷酸锆为原料, 利用十二烷基二甲基苄基氯化铵为导向模板剂, 通过正硅酸乙酯和巯丙基三甲氧基硅烷的层间共水解缩聚, 并结合双氧水对巯丙基的熏蒸氧化, 制备了磺酸基修饰的硅柱磷酸锆材料。通过XRD、SEM、N2吸附-脱附和FT-IR等方法对柱撑材料进行了结构表征。结果表明, 通过调变预撑剂和模板剂中的碳链长度可以优化材料的柱撑结构和孔结构, 磺酸基修饰的材料孔径分布在2.17 nm左右, 比表面积可达163 m²·g^-1, 且保留有规整有序的柱撑磷酸锆层板结构。磺酸基的修饰则成功调变了材料的酸位性质, Brönsted酸量最高可达2.71 mmol·g^-1, 总酸量可达5.20 mmol·g^-1。利用柠檬酸与正丁醇的酯化反应为探针反应, 由于磺酸基修饰的硅柱磷酸锆材料具有独特的空间反应效应和较为丰富的Brönsted酸位, 酯化反应转化率最高可达95.74%。     

Synthesis and Characterization of Monofunctionalized Polyhedral Oligomeric Silsesquioxanes by Cohydrolytic and Cocondensation of Propyltrimethoxysilane and Vinyltrimethoxysilane

A monofunctional POSS [Si₈O₁₂(CH?CH₂)(C₃H₇)₇] was synthesized by the cohydrolysis and cocondensation of propyltrimethoxysilane and vinyltrimethoxysilane in methanol solvent under acidic conditions. Then, the structure of the product was investigated using FT-IR, ¹H-NMR, ²⁹Si-NMR and XRD. Experimental results indicated that the mole rate of propyls and vinyls attached on POSS was approximately 7:1, which was controlled through altering the ratio of two monomers. Furthermore, the TGA result also showed a rapid mass loss began at temperature over 218°C due to the degradation or sublimation of POSS itself. The new method, in comparison with the conventional corner-capping method, offered us another simple and effective access to preparing this kind of monofunctional POSS.     

The reductive cocondensation of chlorotrimethylsilane and dichlorodimethylsilane

Linear and cyclic permethyloligosilanes were prepared by the Wurtz-type cocondensation of chlorotrimethylsilane and dichlorodimethylsilane in the presence of sodium metal or samarium iodide as reducing agents. The yields and composition of the reaction products depend on the cocondensation conditions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1520–1522, June, 1996.     

Cocondensation of urea with methylolphenols in acidic conditions

The reactions of urea with methylolphenols under acidic conditions were investigated using 2- and 4-hydroxybenzyl alcohol and crude 2,4,6-trimethylophenol as model compounds. The reaction products were analyzed with ¹³C-NMR spectroscopy and GPC. From the reaction of urea with 4-hydroxybenzyl alcohol, the formations of 4-hydroxybenzylurea, N,N′-bis (4-hydroxybenzyl) urea, and tris(4-hydroxybenzyl) urea were confirmed and the formations of N,N-bis(4-hydroxybenzyl) urea and tetrakis (4-hydroxybenzyl) urea were suggested. From the reaction of urea and 2-hydroxybenzyl alcohol, 2-hydroxybenzylurea and N,N′-bis(2-hydroxybenzyl) urea were identified. Further, the alternative copolymer of urea and phenol could be synthesized by the reaction of urea with 2,4,6-trimethylophenol. It was also found that the cocondensation between p-methylol group and urea prevails against the self-condensation of the methylolphenol even at the low pH below 3.0, and that p-methylol group has the stronger reactivity to urea than o-methylol group. © 1992 John Wiley & Sons, Inc.     

Synthesis,isolation, and characterization of polytitanasiloxanes and zirconasiloxanes by the hydrolytic cocondensation of tetraethoxysilane and titanium or zirconium tetraisopropoxide

Polytitanasiloxanes and polyzirconasiloxanes were synthesized through the hydrolytic cocondensation of tetraethoxysilane (TEOS) and tetraisopropoxytitanium (TPT) or tetraisopropoxyzirconium (TPZ) 2‐propanol adduct (process A) and through the reaction of partially hydrolyzed TEOS with TPT or TPZ (process B) and were isolated as acetylacetonato derivatives stable against self‐condensation. In both processes, acetylacetone was added to provide acetylacetonato derivatives of polytitanasiloxanes and polyzirconasiloxanes. In process A, titanium‐ or zirconium‐rich polymetallasiloxanes were formed during the initial stage of the process, whereas the molar ratio of silicon to titanium or zirconium was gradually increased up to almost unity with an increasing reaction time. In process B, the molar ratio gradually increased below and above unity as the molar ratio of water to TEOS increased. When the acetylacetonato derivatives of polymetallasiloxanes were subjected to heat treatment, the titania or zirconia component was crystallized. The crystallization temperature increased as the silica content and the molar ratio of water to TEOS increased, and this demonstrated that the crystallization was dependent on the sequence in the main chain of the polymetallasiloxanes. The ²⁹Si NMR spectra of the polymetallasiloxanes led to the idea that the backbone metallasiloxane linkages consisted of random and block sequences for processes A and B, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 763–772, 2005     

自组装和共缩聚法制备磺酸基修饰的硅柱磷酸锆

以十六胺插层磷酸锆为原料,利用十二烷基二甲基苄基氯化铵为导向模板剂,通过正硅酸乙酯和巯丙基三甲氧基硅烷的层间共水解缩聚,并结合双氧水对巯丙基的熏蒸氧化,制备了磺酸基修饰的硅柱磷酸锆材料。通过XRD、SEM、N2吸附-脱附和FT-IR等方法对柱撑材料进行了结构表征。结果表明,通过调变预撑剂和模板剂中的碳链长度可以优化材料的柱撑结构和孔结构,磺酸基修饰的材料孔径分布在2.17 nm左右,比表面积可达163 m2·g-1,且保留有规整有序的柱撑磷酸锆层板结构。磺酸基的修饰则成功调变了材料的酸位性质,Br觟nsted酸量最高可达2.71 mmol·g-1,总酸量可达5.20 mmol·g-1。利用柠檬酸与正丁醇的酯化反应为探针反应,由于磺酸基修饰的硅柱磷酸锆材料具有独特的空间反应效应和较为丰富的Br觟nsted酸位,酯化反应转化率最高可达95.74%。     

Luminescence behavior of Eu3+ in polytitanasiloxane solution

Polytitanasiloxane solutions containing Eu³⁺ ions have been prepared by the hydrolytic cocondensation of tetraethoxysilane and tetrabutyl titanate. The UV‐vis absorption and the luminescence intensity were both found to increase with the increase of tetrabutyl titanate/tetraethoxysilane (TBT/TEOS) molar ratio. This revealed that the incorporation of TiO₂ can result in the increase of absorption energy of the Ti? O group by near‐UV excitation and in the increase of energy transfer to the metal ion. At the same time, the intensity ratio of ⁵D₀→⁷F₂ to ⁵D₀→⁷F₁ increases as the TBT/TEOS molar ratio increases, indicating the formation of Eu³⁺? O^2?? Ti⁴⁺ bonding. A longer decay time means that the Eu³⁺ ions are better dispersed and less clustered with the increase of TBT/TEOS molar ratio. The results on the luminescence properties of the Eu³⁺ in different media containing ethanol or water suggest that the incorporation of TiO₂ can shield Eu³⁺ ions from the effect of water and ethanol molecules, which leads to an improvement of the Eu³⁺ surroundings. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1357–1363, 2006     

Azide/alkyne‐“click”‐reactions on amino resin materials: An LC‐ESI‐TOF analysis

This article describes the reaction of amino resins with functional molecules using the azide/alkyne‐“click”‐reaction, opening a simple chemical modification of amino resins under aqueous conditions. Alkyne‐modified melamine‐formaldehyde resins are prepared via a direct cocondensation approach using propargylic alcohol (21.6–86.3 mmol) as additive. Subsequently, alkyne‐modified mono‐, bi‐, and trinuclear melamine‐species are identified via LC‐ESI‐TOF methods proving the covalent incorporation of alkyne‐moieties in amounts of up to 3.9 mol %. Subsequent modification of the alkyne‐modified resins was accomplished by reaction of functional azides (octyl azide (1), (azidomethyl)benzene (2), 1‐(6‐azidohexyl) thymine (3), and 4‐azido‐N‐(2,2,6,6‐tetramethylpiperidin‐4‐yl)benzamide (4)) with Cu(I)Br and DIPEA as a base. The formation of triazolyl‐modified MF‐resins was proven by LC‐ESI‐TOF methods, indicating the successful covalent modification of the amino resin with the azides 1 – 4 . © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010