Molecular engineering of microporous crystals: (IV) Crystallization process of microporous aluminophosphate AlPO4-11
Molecular engineering of microporous crystals: (IV) Crystallization process of microporous aluminophosphate AlPO4-11
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微孔晶体的分子工程：（四）微孔磷酸铝AlPO4-11的结晶过程
DOI：
10.1016/j.micromeso.2011.11.034
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发表时间：
2012-04
影响因子：
5.2
通讯作者：
Xu, R. R.
中科院分区：
文献类型：
--
作者：
Yu, J. H.;Sun, H.;Deng, F.;Xu, R. R.
对不同晶化时间的微孔磷酸铝AlPO 4 -11进行了冷冻干燥，并用XRD和NMR技术进行了表征。从AlPO_4 -11的骨架中分离出六个以Al和P为中心的大碎片和34个小碎片，分别为二聚体（Al-P）、三聚体（Al-P-Al和P-Al-P）、四聚体（Al-P_3和P-Al_3）、五聚体（Al-P_4和P-Al_4）以及四元环和六元环。六个大碎片中的每一个都包含围绕中心原子的两个完整的配位层。用量子力学密度泛函理论计算了碎片中Al和P原子的屏蔽张量。实验观察到的Al或P从结晶良好的AlPO 4 -11的化学位移被分配到屏蔽张量的中心原子的六个大的碎片，并进一步用作参考的Al或P原子的化学位移的测定中的小片段。通过对小碎片中Al和P原子化学位移的计算与不同晶化阶段分离产物的实验数据的比较表明，AlPO 4 -11的晶化过程中可能存在二聚体、Al-P-Al形式的三聚体、P-Al 3形式的四聚体和五聚体碎片。根据这些关于假定的小碎片的观察，提出了AlPO 4 -11的可能结晶过程。
The products of microporous aluminophosphate AlPO4-11 crystallized for different periods of time were freeze-dried and characterized by XRD and NMR techniques. Six crystallographically distinct Al- and P-centered large fragments and 34 small fragments of dimer (Al–P), trimer (Al–P–Al and P–Al–P), tetramer (Al–P3and P–Al3), pentamer (Al–P4and P–Al4), and 4- and 6-membered rings were extracted from the framework of AlPO4-11. Each of the six large fragments contained two completed coordination layers surrounding the centered atom. The shielding tensors of the Al and P atoms of the fragments were calculated using the quantum mechanics density functional theory. The experimentally observed chemical shifts of Al or P from the well-crystallized AlPO4-11 were assigned to the shielding tensors of the center atoms of the six large fragments and were further used as references in the determination of the chemical shifts of the Al or P atoms in the small fragments. A comparison of the calculated chemical shifts of the Al and P atoms in the small fragments to the experimental data of the products isolated at different crystallization periods suggested that the fragments of dimers, trimers of the form Al–P–Al, tetramers of the form P–Al3, and pentamers may exist in the crystallization process of AlPO4-11. On the basis of these observations regarding the putative small fragments, a possible crystallization process of AlPO4-11 was proposed.
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影响因子：
4.6
作者：
S. Oliver;A. Lough;G. Ozin
通讯作者：
S. Oliver;A. Lough;G. Ozin
DOI：
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发表时间：
2007-09
期刊：
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影响因子：
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作者：
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影响因子：
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DOI：
10.1002/(sici)1521-3765(19990702)5:7
发表时间：
1999-07
期刊：
Chemistry: A European Journal
影响因子：
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作者：
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通讯作者：
A. Heppeler;S. Froidevaux;H. Mäcke;E. Jermann;M. Béhé;P. Powell;M. Hennig
DOI：
10.1016/s1351-4180(10)70329-9
发表时间：
2009
期刊：
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影响因子：
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作者：
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通讯作者：
A. Chester;E. Derouane