Chiral open frameworks

Indium Phosphates with Extra-large Pores and Chiral Open Frameworks... 

The synthesis of chiral open-framework uranyl molybdates... 

More recently, several chiral open-framework uranyl molybdates have been successfully synthesized by Krivovichev et al., and this greatly enriches the family of... 

One feasible method for the exploration of chiral open-framework compounds is the use of chiral chemical units as primary building blocks by coordinating with metal or other assembly methods to form 2-D layer or 3-D open-framework structures with optical activity. A notable example is the enantiomerically pure zinc phosphonate based on a mixed phosphonic acid-phosphine oxide chiral building block reported by Bujoli and coworkers in 2001.[91] The reaction procedures are shown as follows. 

S. Krivovichev, C. Cahill, E. Nazarchuk, P. Burns, T. Armbruster, and W. Depmeier, Chiral Open-framework Uranyl Molybdates. 1. Topological Diversity Synthesis and Crystal... 

S. Ayyappan, X. Bu, A. Cheetham, and C. Rao, Synthesis and Structural Characterization of a Chiral Open-framework Tin(II) Phosphate, [CNdlghSi P O KGlJAN-SnPO). Chem. Mater., 1998, 10, 3308-3310. 

Dybtsev DN, Nuzhdin AL, Chun H, Bryliakov KP, Talsi EP, Fedin VP, et al. Permanent microporosity and enantioselective sorption in a chiral open framework. Angew Chem Int Ed 2006 45 916-20. 

Ramamurthy and coworkers have utilized zeolites modified with chiral organic compounds [17,18]. Zeolites are crystalline aluminosilicates with open framework structures. In this approach, the zeolite is first loaded with a chiral inductor and the compound to be photolyzed is then added in a second, separate adsorption step. Asymmetric induction ensues as a result of the close proximity enforced between reactant and chiral inductor in the confined space of the zeolite supercage. The zeolite method has the disadvantage that the size of the substrate is limited by the pore size of the zeolite being used. Most of the work using the chirally modified zeolite approach was compared with the ionic chiral auxiliary method by Scheffer and coworkers. The enantiodifferentiations by the zeolites are usually low to moderate. 

Figure 5.25 The one-dimensional chain in [ Ce(H20)7 2Mn4Si2 Vi806s(H20)2] [73], (Reproduced with permission from W.L. Chen, et al, An inorganic aggregate based on a sandwich-type polyoxomet-alate with lanthanide and potassium cations from ID chiral ladder-like chains to a 3D open framework, European Journal of Inorganic Chemistry, 2007, no. 15, 2216-2220 (Figure 2). Wiley-VCH Verlag GmbH Co. KGaA.)...

W.T.A. Harrison, T.E. Gier, G.D. Stucky, R.W. Broach, and R.A. Bedard, NaZnP04 H20, an Open-framework Sodium Zincophosphate with a New Chiral Tetrahedral Framework Topology. Chem. Mater., 1996, 8, 145-151. 

W. Yan, J. Yu, Z. Shi, and R. Xu, A Novel Open-framework Aluminophosphate [A1P206(0H)2][H30] containing Propeller-like Chiral Motifs. Chem. Commun., 2000, 1431-1432. 

Most chiral phosphates are prepared in the presence of organic amines or metal complexes with or without chiral features. By using chiral metal complexes as the SDAs, low-dimensional structures or interrupted open-framework structures tend to... 

Coordination and Condensation of Chiral Building Blocks - the Formation of Open-framework with Optical Activity... 

H-bonding interactions exert dominant roles in the chirality transfer of guest chiral SDAs to host open-framework metal phosphates based on their systematic work by using chiral cationic cobaltammine complexes as the SDAs.[901... 

In 1995, Morgan et al. synthesized a layered aluminophosphate compound by using a chiral cobaltammine complex as the template for the first time.[61] Recently, the Jilin group has synthesized a number of 2-D layered and 3-D open-framework metal phosphates by using a racemic mixture or an optically pure chiral metal complex as the template, and has systematically studied the chirality transfer from the guest chiral complex templates to the host inorganic open frameworks.1901 Table 7.15 lists some metal phosphates and oxides with open-framework structures templated by optically pure or racemic cobalt ammine complexes. 

Table 7.15 Open-framework compounds templated by chiral complexes...

Com(en)3][ZngP6024Cl] 2H20 (JLU-8)[1071 is a 3-D open-framework zinc phosphate. As shown in Figure 7.51, a pair of enantiomers (D3 symmetry) of chiral complexes induce a pair of enantiomers (C3 symmetry) of caplike chiral structural motifs in the 3-D open-framework structure of JLU-8, which is similar to that of JLU-7. The above... 

A remarkable stereospecificity between the chiral templates and the chiral inorganic structural motifs is illustrated in open-framework zinc phosphate [Con(en)3] [Zn4(H2 P04)3(HP04)2(P04)(H20)2] (JLU-9).[90] It crystallizes in the orthorhombic space group Pbcn with a = 10.4787(8) A, b = 20.0091(14) A, and c= 14.9594(10) A. The asymmetric unit, as shown in Figure 7.52, contains two unique Zn atoms and four unique P atoms. Both Zn(l) and Zn(2) are tetrahedrally coordinated, making four Zn—O—P... 

Alternatively, it is helpful to view the framework of JLU-10 as being built up from a simple structural motif composed of aZn(l)-centered tetrahedron with four dangling P04 groups [Figure 7.57(a)]. These units are connected through Zn(2) atoms to form the 3-D open framework. It is notable that such a structural motif is chiral and that it has the same... 

P-10 - Synthesis and characterization of an open-framework alumino-phosphate [AIP206(0H)2] [H3O] containing propeller-like chiral motifs... 

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