Alkali metal complexes cavity size

Fig. 18 Top-. Structures of alkali metal complexes of 2.2.2-crypt, 9 (hydrogen atoms omitted for clarity) 139—42. Bottom Torsion angles defined by the two triangles obtained by linking the two sets of three oxygen atoms. The smaller the torsion angle, the higher the distance between the two pivot nitrogen atoms (and the larger the cavity size of the cryptand)...

Adenosine triphosphate alkali metal complexes, 34 vanadyl complexes, 568 Alane, 123 amine adducts, 107 phosphine adducts, 111 Alane, alkoxy-, 124 Alane, amino-, 109 Alane, imino-, 109 Alkali metal complexes, 1-70 acid anions, 30 acid salts, 30 bipyridyl, 13 crown ethers cavity size, 38 cryptates... 

Polypyridine Torand 1. Complexes of alkali metal triflates and picrates have been prepared from the monotriflate salt of torand 1, which is isolated directly from the macrocyclization reaction mixture. As shown in Figure 3, neutralization of the triflate salt with alkali metal hydroxides or carbonates gives the alkali metal complexes. With triflate or picrate counterions, torand complexes and salts partition selectively into chlorofonn rather than water. Thus 1 can be shuttled back and forth between the triflate salt and various complexes simply by washing the chloroform solution with aqueous acid or base. The free ligand is prepared by reaction of the triflate salt with tetra-n-butylammonium hydroxide in butanol/acetonitrile. Combustion microanalysis showed that the Li, Na, K, Rb and Cs complexes all have 1 1 host/guest stiochiome-try, despite the cavity/ion size mismatch at both ends of the series. The X-ray crystal... 

Crown ethers are cyclic polyethers designated [n]crown-m where n is the ring size and m the number of oxygen atoms, for instance [18] crown-6 1. They show a high affinity for cationic guest molecules, especially alkali metal cations, where the cation is commonly complexed within the cavity of macrocycle or sand-... 

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