Novel bifunctional periodic mesoporous organosilicas, BPMOs: Synthesis, characterization, properties and in-situ selective hydroboration-alcoholysis reactions of functional groups
Novel bifunctional periodic mesoporous organosilicas, BPMOs: Synthesis, characterization, properties and in-situ selective hydroboration-alcoholysis reactions of functional groups
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DOI：
10.1021/ja0037320
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发表时间：
2001-09-05
影响因子：
15
通讯作者：
Ozin, GA
中科院分区：
文献类型：
--
作者：
Asefa, T;Kruk, M;Ozin, GA
合成并表征了一类新的双功能周期介孔有机硅（BPMOs），该材料在介孔基质中含有两个不同键合的有机基团。通过在壁上加入桥键乙烯基团，并在通道空间中加入末端键乙烯基，可以改变所得到的BPMO的化学和物理性质。该材料具有周期性介孔结构，其中桥接乙烯起结构和机械作用，乙烯基易于进行化学转化。材料中的乙烯基与BH3发生硼氢化反应。用H2O2/NaOH或NaBO3将四氢呋喃和BPMO中生成的有机硼烷定量转化为醇。4 h (2) O。在随后的原位反应后，材料保持有序结构，孔隙体积、比表面积和孔径分布基本不变。其它有机功能化BPMO材料可以以类似的方式或通过进一步功能化所得到的硼化或醇功能化BPMO材料来合成。研究了BPMO材料的热性能，并与周期性介孔有机硅（PMO）材料进行了比较。值得一提的热事件涉及BPMOs中残余硅烷醇或大气氧与有机物之间的通道内反应。它们在300°c左右开始，并顺利地将桥接乙烯转化为末端乙烯基，将末端乙烯转化为气态乙烯和乙烷，最终在900°c下生成周期性介孔二氧化硅，该二氧化硅具有良好的结构秩序，并且相对于母体BPMO，单位孔尺寸减小。
A new class of bifunctional periodic mesoporous organosilicas (BPMOs) containing two differently bonded organic moieties in a mesoporous host has been synthesized and characterized. By incorporating bridge-bonded ethylene groups into the walls and terminally bonded vinyl groups protruding into the channel space, both the chemistry and physical properties of the resulting BPMO could be modified. The materials have periodic mesoporous structures in which the bridging ethylene plays a structural and mechanical role and the vinyl groups are readily accessible for chemical transformations. The vinyl groups in the material underwent hydroboration with BH3. THF and the resulting organoborane in the BPMO was quantitatively transformed into an alcohol using either H2O2/NaOH or NaBO3. 4H(2)O. The materials retained ordered structures after subsequent in situ reactions with largely unchanged pore volumes, specific surface areas and pore size distributions. Other organic functionalized BPMO materials may be synthesized in a similar manner or by further functionalizing the resulting borylated or alcohol functionalized BPMO materials. The thermal properties of the BPMO materials have also been investigated and are compared to those of the periodic mesoporous organosilica (PMO) materials. Noteworthy thermal events concern intrachannel reactions between residual silanols or atmospheric oxygen and organics in BPMOs. They begin around 300 degreesC and smoothly interconvert bridging ethylene to terminal vinyl groups and terminal vinyl to gaseous ethene and ethane, ultimately producing periodic mesoporous silica at 900 degreesC that exhibits good structural order and a unit-cell size decreased relative to that of the parent BPMO.