2913-24-8Relevant academic research and scientific papers
Self-Assembling [ n. n]Paracyclophanes: A Structure-Property Relationship Study
Abboud, Khalil A.,Castellano, Ronald K.,Fagnani, Danielle E.,Henderson, Will R.,Liu, Guancen,Zhu, Yu
, (2020/01/09)
Reported here is the synthesis, characterization, and isodesmic supramolecular polymerization of [3.3]paracyclophane-5,8,14,17-tetracarboxamide ([3.3]pCpTA). The self-assembling monomer, a bridge-expanded homolog of [2.2]paracyclophane-4,7,12,15-tetracarboxamide ([2.2]pCpTA), forms homochiral assemblies in nonpolar solution and the solid state through double-helical intermolecular and transannular hydrogen bonding. The additional methylene unit in the [3.3]paracyclophane bridge results in a weakened supramolecular assembly for [3.3]pCpTA compared to [2.2]pCpTA in solution. Likely origins of the change in assembly strength, revealed through X-ray crystallography, computational analysis, and solution-phase spectroscopy, are an increase in (a) the intramolecular and intermolecular deck-to-deck spacing compared to [2.2]paracyclophane resulting from larger amide dihedral angles accompanying transannular hydrogen bonding in the [3.3]paracyclophane and (b) monomer entropy associated with the scissoring motion of the [3.3]paracyclophane bridge.
Multibridged [3(n)] cyclophanes, 11(+): A synthetic and structural study of 17,18-dicyano[32](1,6)cyclooctatetraeno-(1,4)cyclophane generated by photolysis of [32](1,4)barrelenophane
Matsuda-Sentou, Wakana,Shinmyozu, Teruo
, p. 3195 - 3203 (2007/10/03)
[32]Cyclooctatetraenophane (6) has been generated by photolysis of [32](1,4)barrelenophane (5), which, in turn, has been found to be most conveniently obtained by the uncatalyzed cycloaddition of dicyanoacetylene to [32](1
Hemicarcerands that encapsulate hydrocarbons with molecular weights greater than two hundred
Cram, Donald J.,Jaeger, Ralf,Deshayes, Kurt
, p. 10111 - 10116 (2007/10/02)
Syntheses are reported for the globe-shaped hemicarcerands 1 and 2 composed of two rigid bowl-like units (polar caps) attached to one another at their rims through four OCH2C≡CC≡CCH2O units (equatorial spacers). Eight pendant CH3(CH2)4 groups in 1 and C6H5CH2CH2 groups in 2 attached in assemblies of four to each polar cap render the hosts soluble in organic solvents. The important shell-closing reactions 2Ar(OCH2C≡CH)4 + [O] → Ar(OCH2C≡CC≡CCH2O)4Ar went in 5-8% yields in pyridine-O2-Cu(OAc)2 to give a hemicarcerand free of pyridine. The higher solubility of 1 (compared to that of 2) in organic solvents led to an examination of its binding properties. By heating 1 dissolved either in potential guests or in 1,3,5-[(CH3)3C]3C6H3 (too large to enter 1) containing dissolved potential guests at 80-140 °C for 2-7 days, 1:1 hemicarceplexes mixed with the empty host were isolated in those cases when the potential guests were just small enough to enter the host's portals at high temperatures but large enough not to depart during isolation as stable solids. Thus, constrictive bonding played a large role in kinetic stabilization of the hemicarceplexes. The 1H NMR spectra of both the host and the guest were markedly modified upon complexation. The half-lives in hours of representative complexes dissolved in CDCl3 at 25 °C were as follows: 1·1,3,5-[(CH3)2CH]3C6H 3, 1628; 1·1,3,5-Et3C6H3, 960; 1·4-Et[2.2]paracyclophane, 24; 1·1,3-dimethyladamantane, 13.5; 1-[3.3]paracyclophane, 13; 1·tetradehydro[2.2]paracyclophane, 11; 1·[2.2]paracyclophane, 5; 1·4,12-dihydroxy[2.2]paracyclophane, 4; and 1·[2.3]paracyclphane, 0.5. Complexes of smaller guests such as CHCl3, ferrocene, adamantane, and 1,3,5-trimethylbenzene were unstable to room-temperature isolation conditions. Larger guests such as [3.4]paracyclophane and 4,12-dinitro[2.2]paracyclophane did not enter the portals of 1 at temperatures under which host 1 was stable, whereas smaller guests such as CH2Cl2 and pyridine entered and departed the host at 25 °C rapidly on the NMR time scale. Catalytic reduction (H2, PdC) of the eight acetylenic bonds of 1 produced an empty host of much more flexible structure, 3, whose binding properties have not yet been examined.
New Synthetic Method of Cyclophanes via Diselenacyclophanes
Higuchi, Hiroyuki,Tani, Keita,Otsubo, Tetsuo,Sakata, Yoshiteru,Misumi, Soichi
, p. 4027 - 4036 (2007/10/02)
Syntheses of cyclic diselenides through diselenolates and the following deselenation reactions by means of three ways were studied.The preparation of the cyclic diselenides in the presence of excess sodium borohydride gave thirty-eight diselenides containing diselenacyclophanes and alicyclic diseleno compounds in high yields in addition to two triple-bridged selenacyclophanes.Photodeselenation of the diselenides in tris(dimethylamino)phosphine afforded series of cyclophanes in much higher yields than those of the other two methods, i.e. benzyne-Stevens rearrangement/Raney nickel hydrogenolysis and pyrolytic deselenation at ca. 650 deg C.The present study demonstrates that the photodeselenation method combined with the synthesis of their precursor diselenides, is much superior to the conventional dechalcogenation methods.
