Transannular π-π Interaction in Cyclophanes

Transannulare π-π-Wechselwirkung in Cyclophanen

A single crystal of Ag 12−A (zeolite LTA) was prepared by the dynamic ion-exchange of Na 12−A with aqueous 0.05 M AgNO 3. It was washed with CH 3OH and allowed to react with a stream of 0.05 M KCl in CH 3OH at 294 K. The crystal structure of the product |K 2.35Ag 1.1(Ag 4Cl 4) 0.45(C 3H 3O 3) 1.1(K 3Cl) 3.45(K 3(OH) 2) 0.55(H 2O) ≥3.0|[Si 12Al 12O 48]− LTA ( a = 12.292(1) A) was determined by single-crystal X-ray diffraction in the cubic space group Pm3 m at 294 K. It was refined to the final error index, R 1 = 0.052, based on the 371 reflections for which F o > 4σ( F o). Ag 4Cl 4 nanoclusters were found in about 45% of the sodalite cavities. Each Ag 4Cl 4 cluster (interpenetrating tetrahedra; symmetry T d, Ag−Cl = 3.105(17) A) is held in place by the coordination of each of its four Ag + ions to three oxygens of the zeolite framework (Ag−O = 2.493(5) A) and by the coordination of each of its four Cl − ions to a K + ion through a 6-ring (Cl−K = 2.70(3) A). In each of the remaining 55% of the sodalite cav...

Single Crystal Structure of Zeolite A (LTA) Containing Ag 4Cl 4 Nanoclusters and Reduced 1,3,5-Tripyrylium Dimers with Remarkably Short 2.43 Å Interplanar Spacings

4,10b-Methano-8H-benzo[ab]cyclodecen-8-one (C14H10O), a stable derivative of so-called 1,6-methano[10]annulene, forms reddish orange crystals of the space group Pbca, with eight molecules in a unit cell with dimensions of a=16.567, b=14.090, and c=8.418 A. The structure was solved by the symbolic addition method and refined by the block-diagonal least-squares method. The final R factor was 0.080 for the 1386 independent observed reflections. The lengths of the peripheral bonds of the [10]annulene nucleus do not exhibit any apparent alternation. The peripheral eight atoms are approximately coplanar. The C–O distance (1.236 A) is longer than those in quinones and tropones, and it is consistent with the large dipole moment and high basicity of the present molecule.

The Crystal and Molecular Structure of 4,10b-Methano-8H-benzo[ab]cyclodecen-8-one

Mit Hilfe von Rontgenstrukturanalysen der im Titel aufgefuhrte [3.2]Paracyclophanverbindung 1 und der [3.2]Metacyclophanverbindung 2, die jeweils durch eine 1,8-Naphthalino- und eine Ethanogruppe verbruckt sind, wurden wannenformige Deformationen der Phenylenringe festgestellt. Auf Grund von entgegengesetzten Abweichungen der in peri-Stellung substituierten C-Atome von den planaren Naphthalinsystemen und wegen Torsionen um die Ethanobrucken sind beide Cyclophane geringfugig chiral verdrillt. Die [3.2]Metacyclophanverbindung 2 liegt in der syn-Konformation vor.



Crystal and Molecular Structures of two [3.2]Cyclophanes: [2.0.0](1,4)Benzeno(1,8)naphthalino-(1,4)benzenophane and [2.0.0](1,3)Benzeno(1,8)naphthalino(1,3)benzenophane



The X-ray analyses of the two title compounds, a [3,2]paracyclophane derivative (1) and a [3.2]metacyclophane derivative (2) bridged by a 1,8-naphthalino and an ethano group, revealed boat-like deformations of the phenylene rings. The peri-C-atoms deviate in opposite directions from the naphthaline planes. The ethano bridges show a torsion angle. Because of this small twist both cyclophanes are chiral. The [3.2]metacyclophane compound 2 shows a syn-conformation.

Kristall‐ und Molekularstruktur von zwei [3.2]Cyclophanen: [2.0.0](1,4)Benzeno(1,8)naphthalino(1,4)benzenophan und [2.0.0](1,3)Benzeno(1,8)naphthalino(1,3)benzenophan

: A crystal structure analysis of 8,16-oxido-cis(2.2)metacyclophane-1,9-diene has been carried out at -160C. The crystal is orthorhombic, Pbca, with a=11.96, b=17.13, c=10.67 A, Z=8, formula C16H10O. The structure was determined by computer-programmed symbolic addition procedures, and was refined by block-diagonal least-squares to a conventional R index of 0.069. Within the limits of experimental error the molecule has mm symmetry. It is folded to a dihedral form so that the angle between the six-membered rings is 123.6. Strain is inferred from the nonplanarity of these rings. The bond angle subtended by the oxygen atom is 99.7, and the length of the double bond in the C-C bridge is 1.359 A. (Author)

http://journals.iucr.org/b/issues/1969/11/00/a06974/a06974.pdf

K. Huml

Papers

THE CRYSTAL STRUCTURE OF 8,16-OXIDO--cis(2,2)-METACYCLOPHANE-1,9-DIENE,