Synthesis and X-ray structures of new concave π-prismand hydrocarbon [2.2.1]m,p,p- and [2.2.1]p,p,p-cyclophanes

Abstract

The synthesis of the smaller analogues of the well-known [2.2.2]p,p,p-cyclophane (1) p-prismand were performed via a well-established pyrolysis route from the corresponding disulfones. In spite of their smaller size and increased rigidity, these cyclophanes showed remarkably similar complexation behaviour with Ag`ions compared to [2.2.2]p,p,p-cyclophane. X-Ray crystal structure determinations showed the bis-sulÐde 12 (1,10-dithia[3.3.1]m,p,pcyclophane) to be helically chiral. The single crystal X-ray analysis showed that the reduction of the ring size from 17-membered hydrocarbon 17 to 16-membered hydrocarbon 16 has only a slight e †ect on the size and shape of the cavity. In the Ag`complex of [2.2.1]m,p,p-cyclophane (18) the interaction between silver and hydrocarbon is accomplished by the coordination of silver to one double bond in two phenyl rings and to only one carbon of the third phenyl ring. However, in the case of [2.2.1]p,p,p-cyclophaneÈAg`triÑate (19), silver is bonded to one of the double bonds in each phenyl ring. Similarly to larger [2.2.2]cyclophanes the conformations of the parent [2.2.1]m,p,p-(16) and [2.2.1]p,p,p-cyclophanes (17) do not change dramatically upon the complexation with the Ag`ion.

Synthesis and Properties of Cryptands with a Thioether Bridge and π‐Donors – Silver(I) and Copper(I)‐Complexes

“…This value is clearly larger than the sum of the van der Waals radii of Ag + (3.1-3.2 Å). [30,31] The average distance to the nitrogen atoms was found to be 2.44 Å which compares well with those recorded for 6·Ag + and 8·Ag + ( [20][21][22][23][24][25] One carbon atom per ring is much closer to the silver ion than the other sp 2 centers. For three phenyl rings this is a ortho carbon (average distance 2.48 Å), only in one case is the silver ion closest to the ipso-carbon (2.50 Å).…”

“…This brings one carbon atom per ring close to the metal center. The distance between these carbon atoms of the phenyl rings and the metal ion (average 2.47 Å, see [20][21][22][23][24][25] For 33·Ag + we observe in the 1 H NMR spectrum two triplets at δ = 2.83 and 2.99 ppm for the hydrogen atoms at centers 1 and 2 (see Figure 2). Six of the aromatic hydrogen atoms are shifted towards higher field due to the complexation and give rise to a doublet at δ = 6.96 ppm.…”

Fabrication of Bioactive Surfaces by Plasma Polymerization Techniques Using a Novel Acrylate‐Derived Monomer

“…The synthesis of the PFM followed a general synthesis pathway for acrylate derivatives with a yield of 85% which represents a 2.5 fold increase compared to yields previously reported using p ‐cyclophane derivatives 27. Sterically hindered pyridine was used as proton acceptor to limit the extent of an undesired side reaction: Michael addition of the pyridine to the acrylate.…”

Single Crystal Structure of Zeolite A (LTA) Containing Ag4Cl4Nanoclusters and Reduced 1,3,5-Tripyrylium Dimers with Remarkably Short 2.43 Å Interplanar Spacings

“…73 for both of these, the two ring carbon atoms are bonded to a single methylene group and so may be viewed as meta members of the same ring. (Even shorter distances can be seen in [2.2]metacyclophanes where the two aromatic rings are approximately perpendicular, very far from parallel and not of interest here.…”