135075-51-3Relevant academic research and scientific papers
Molecular Architecture. 2.1 Synthesis and Metal Complexation of Heptacyclic Terpyridyl Molecular Clefts
Bell, Thomas W.,Cragg, Peter J.,Firestone, Albert,Kwok, Albert D.-I.,Liu, Jia,Ludwig, Richard,Sodoma, Andrej
, p. 2232 - 2243 (1998)
Methods are described for the synthesis of a series of functionalized derivatives of 9-butyl-1,2,3,4,5,6,7,8-octahydroacridine (9), a building block for several types of highly preorganized host compounds. A key intermediate is 5-benzylidene-9-butyl-2,3,5,6,7,8-hexahydroacridin-4(1H)-one (23), which can also be used in the syntheses of torands and hydrogen-bonding hexagonal lattice receptors. A tridentate cleft (20), consisting of 2,2′;6′,2″-terpyridine imbedded in a heptacyclic framework, and a corresponding pentadentate diketone (6) were synthesized from 9 in five and seven steps, respectively. The picrate extraction method was used to estimate the solution stabilities of alkali metal complexes of heptacyclic terpyridyls 6 and 20, which was also compared with a flexible terpyridyl (37). Alkali metal complexes of both heptacyclic terpyridyls showed relatively high KS values, but low size selectivity. Pentadentate host 6 binds Na+ and K+ more strongly than do most hexadentate crown ethers; flexible tridentate analogue 37 failed to extract alkali metal picrates into chloroform. The complexation abilities of 6 and 20 are attributed to enforced orientation of functional group dipoles toward the center of the molecular cleft. Sodium and potassium picrate complexes of pentadentate cleft 6 were synthesized (1:1 stoichiometry), and a 2:1 complex of calcium triflate (62·(Ca(CF3SO3)2)was also prepared.
