10.1021/jo9720041.s001 Thomas W. Bell Thomas W. Bell Peter J. Cragg Peter J. Cragg Albert Firestone Albert Firestone Albert D.-I. Kwok Albert D.-I. Kwok Jia Liu Jia Liu Richard Ludwig Richard Ludwig Andrej Sodoma Andrej Sodoma Molecular Architecture. 2. Synthesis and Metal Complexation of Heptacyclic Terpyridyl Molecular Clefts American Chemical Society 1998 heptacyclic framework Alkali metal complexes 2. Synthesis functionalized derivatives heptacyclic terpyridyls alkali metal complexes Pentadentate host 6 Metal Complexation hexadentate crown ethers preorganized host compounds group dipoles heptacyclic terpyridyls 6 pentadentate diketone alkali metal picrates building block complexation abilities Molecular Architecture solution stabilities size selectivity tridentate analogue 37 Heptacyclic Terpyridyl Molecular Clefts Methods lattice receptors picrate extraction method tridentate cleft pentadentate cleft 6 potassium picrate complexes calcium triflate 1998-03-13 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Molecular_Architecture_2_Synthesis_and_Metal_Complexation_of_Heptacyclic_Terpyridyl_Molecular_Clefts/3708894 Methods are described for the synthesis of a series of functionalized derivatives of 9-butyl-1,2,3,4,5,6,7,8-octahydroacridine (<b>9</b>), 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(1<i>H</i>)-one (<b>23</b>), which can also be used in the syntheses of torands and hydrogen-bonding hexagonal lattice receptors. A tridentate cleft (<b>20</b>), consisting of 2,2‘;6‘,2‘‘-terpyridine imbedded in a heptacyclic framework, and a corresponding pentadentate diketone (<b>6</b>) were synthesized from <b>9</b> in five and seven steps, respectively. The picrate extraction method was used to estimate the solution stabilities of alkali metal complexes of heptacyclic terpyridyls <b>6</b> and <b>20</b>, which was also compared with a flexible terpyridyl (<b>37</b>). Alkali metal complexes of both heptacyclic terpyridyls showed relatively high <i>K</i><sub>s</sub> values, but low size selectivity. Pentadentate host <b>6</b> binds Na<sup>+</sup> and K<sup>+</sup> more strongly than do most hexadentate crown ethers; flexible tridentate analogue <b>37</b> failed to extract alkali metal picrates into chloroform. The complexation abilities of <b>6</b> and <b>20</b> are attributed to enforced orientation of functional group dipoles toward the center of the molecular cleft. Sodium and potassium picrate complexes of pentadentate cleft <b>6</b> were synthesized (1:1 stoichiometry), and a 2:1 complex of calcium triflate (<b>6</b><sub>2</sub>·Ca(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>) was also prepared.