Self-Assembly of Discrete Cyclic Nanostructures Mediated by Transition Metals

Hydrogen bonds are like human beings in the sense that they exhibit typical grouplike behavior. As an individual they are feeble, easy to break, and sometimes hard to detect. However, when acting together they become much stronger and lean on each other. This phenomenon, which in scientific terms is called cooperativity, is based on the fact that 1+1 is more than 2. By using this principle, chemists have developed a wide variety of chemically stable structures that are based on the reversible formation of multiple hydrogen bonds. More than 20 years of fundamental studies on these phenomena have gradually developed into a new discipline within the field of organic synthesis, and is nowadays called noncovalent synthesis. This review describes noncovalent synthesis based on the reversible formation of multiple hydrogen bonds. Starting with a thorough description of what the hydrogen bond really is, it guides the reader through a variety of bimolecular and higher order assemblies and exemplifies the general principles that determine their stability. Special focus is given to reversible capsules based on hydrogen-bonding interactions that exhibit interesting encapsulation phenomena. Furthermore, the role of hydrogen-bond formation in self-replicating processes is actively discussed, and finally the review briefly summarizes the development of novel materials (nanotubes, liquid crystals, polymers, etc.) and principles (dynamic libraries) that recently have emanated from this intriguing field of research.

Noncovalent synthesis using hydrogen bonding

Within the wr-orbital axis vector theory, the total rehybridization required for closure of the fullerenes is approximately conserved. This result allows the development of a structure-based index of strain in the fullerenes, and it is estimated that about 80 percent of the heat of formation of the carbon atoms in C60 may be attributed to a combination of v strain and steric inhibition of resonance. Application of this analysis to the geometries of structurally characterized organometallic derivatives of C60 and C70 shows that the reactivity exhibited by the fullerenes may be attributed to the relief of a combination of local and global strain energy. C60 is of ambiguous aromatic character with anomalous magnetic properties but with the reactivity of a continuous aromatic molecule, moderated only by the tremendous strain inherent in the spheroidal structure.

https://science.sciencemag.org/content/sci/261/5128/1545.full.pdf

Chemistry of the fullerenes: the manifestation of strain in a class of continuous aromatic molecules.

Polyhedral skeletal electron pair approach

Although carbon has been subjected to far more study than all other elements put together, the buckminsterfullerene hollow-cage structure, recently proposed to account for the exceptional stability of the C(60) cluster, has shed a totally new and revealing light on several important aspects of carbon's chemical and physical properties that were quite unsuspected and others that were not previously well understood. Most significant is the discovery that C(60) appears to form spontaneously, and this has particularly important implications for particle formation in combustion and in space as well as for the chemistry of polyaromatic compounds. The intriguing revelation that 12 pentagonal "defects" convert a planar hexagonal array of any size into a quasi-icosahedral cage explains why some intrinsically planar materials form quasi-crystalline particles, as appears to occur in the case of soot. Although the novel structural proposal has still to be unequivocally confirmed, this article pays particular attention to the way in which it provides convincing explanations of puzzling observations in several fields, so lending credence to the structure proposed for C(60).

https://science.sciencemag.org/content/sci/242/4882/1139.full.pdf

Space, stars, c60, and soot.

Total synthesis of dodecahedrane

Synthese par photocyclisation d'un cetoester intermediaire prepare en 10 etapes a partir de l'anion cyclopentadienure. La structure est confirmee par analyse RX

Total synthesis of a monosubstituted dodecahedrane. The methyl derivative

A strategy for the synthesis of monosubstituted dodecahedrane and the isolation of an isododecahedrane

Dissolving-metal reduction of a hemispherical dichloro diester. Tests of relative enolate nucleophilicity within a mixed dianion and oxidative behavior of a trisecododecahedryl alcohol

Robert J. Ternansky

Papers

Total synthesis of dodecahedrane

Total synthesis of a monosubstituted dodecahedrane. The methyl derivative

A strategy for the synthesis of monosubstituted dodecahedrane and the isolation of an isododecahedrane

Dissolving-metal reduction of a hemispherical dichloro diester. Tests of relative enolate nucleophilicity within a mixed dianion and oxidative behavior of a trisecododecahedryl alcohol

Total synthesis of dodecahedrane