Calixarenes phosphorus-containing

Reaction of the tetra-/-butyl calixarene 103 with PCI5 gave rise to an unusual calixarene 104 containing 4-, 5- and 6-coordinate phosphorus. The isolated molecule, which was characterised by P nmr and X-ray crystallography, adopted a non-standard geometry between partial cone and 1,2-alternate conformations. ... 

Interest in phosphorus-containing calixarenes continues. Structures reported include hexa(diethoxyphosphoryloxy)calix[6]arene (8), inherently chiral 1,2-bridged calix[4]arene diphosphates, and a calixarene like C3 symmetric receptor with a phosphate function at the cavity bottom. " The purification of phosphate substituted calixarenes has been studied by chiral HPLC and by normal reverse phase HPLC. Mono(6-0-diphenoxyphosphoryl)-P-cyclodextrin (9) and mono(6-0-ethoxyhydroxyphosphoryl)-p-cyclodextrin (10) have been synthesised and show enantioselective inclusion of D and L amino acids e.g. 3.6 for D/L serine in the case of 9). ... 

Phosphorus-containing chiral cyclodextrins, calixarenes, and cyclophanes 06COC2307. 

Phosphorus-containing calixarenes (5,390c) andresorcinarenes (5.390d) have recently been reviewed [197]. Phosphonated calixarenes have recently been utilised to obtain Ag nanoparticles [198]. Phosphorylated calix[8] arenes have been prepared [170]. 

Despite the overall decline in output, the year has produced ftirther interesting developments in the fteld of hypervalent phosphorus chemistry. These include phosphoranes containing acetylenic links, the synthesis and enantiomeric separation of a bicyclic phosphorane with chirality only at phosphorus, and a wide range of phosphoranes incorporated within macrocyclic ring systems (Houlla et al). In addition Lattman has reported on phosphoranes bound to transition metals or enclosed within calixarene skeletons and Holmes and his co-workers have made further substantial contributions on the X-ray crystal structures of phosphoranes containing eight-membered rings. 

A potential for large ring and cavity formation extends to many P-containing organic molecules, in addition to the inorganic phosphates discussed above. These compounds include phosphate derivatives of fashionable structures such as crown ethers, calixarenes, carceplexes, catenanes, rotaxanes, self-assembly molecules and so on, and varieties which are discussed in Chapter 10, such as cyclo-dextrins, phosphosaccharides, phosphoproteins and nucleic acids. Phosphorus analogues of cyclo-polypyridyls and porphyrins are discussed in Chapters 7 and 8. 

Just as phosphorus heteroatoms can be appended to the lower calixarene rim, so can functional groups that contain a nitrogen atom. Among the nitrogen containing substituents that can be introduced onto the lower rim of a calixarene are the amide and amine moieties. Compounds having an amide substituent can be prepared by the sequence of reactions shown in Scheme 1 [13]. A similar calix[4]arene with amide substituents on the lower rim has been used as a ligand for the encapsulation of... 

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