Molecules with Linear π‐Conjugated Pathways between All Substituents: Omniconjugation

Advanced Functional Materials (Impact Factor: 10.44). 02/2004; 14(3):215 - 223. DOI: 10.1002/adfm.200305003

ABSTRACT In this paper, omniconjugation is introduced as a topological phenomenon in π-conjugated systems. Omniconjugated molecules are defined by the fact that they provide direct and fully π-conjugated pathways between all substituents attached to them. Surprisingly, until now such topologies have never been explicitly recognized or investigated from this point of view. A topological design scheme is presented as a tool, which enables for the systematic construction of this novel class of π-electron molecular structures. Molecular building blocks with three or more connection points to the external moieties are proposed, which for the first time allows for the interconnection of many functional entities in a fully conjugated manner. In being truly conjugated, these pathways are expected to provide high transmission probabilities for holes and/or electrons. Omniconjugated structures may play an important role in the design of complex electronic circuitry based on organic molecules. On a larger scale, they may also give rise to special material properties. Although omniconjugation is based on a valence-bond description of the system, it is shown that our concept is in good agreement with results obtained from a molecular-orbital description of the electron probability distribution in the frontier orbitals.

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    ABSTRACT: The configurations of single and double bonds in polycyclic hydrocarbons are abstracted as Kekule states of graphs. Sending a so- called soliton over an open channel between ports (external nodes) of the graph changes the Kekule state and therewith the set of open channels in the graph. This switching behaviour is proposed as a basis for molecular computation. The proposal is highly speculative but may have tremen- dous impact. Kekule states with the same boundary behaviour (port assignment) can be regarded as equivalent. This gives rise to the abstraction of Kekule cells. The basic theory of Kekule states and Kekule cells is developed here, up to the classification of Kekule cells with ≤ 4 ports. To put the theory in context, we generalize Kekule states to semi-Kekule states, which form the solutions of a linear system of equations over the field of the bits 0 and 1. We briefly study so-called omniconjugated graphs, in which every port assignment of the right signature has a Kekule state. Omniconjugated graphs may be useful as connectors between computa- tional elements. We finally investigate some examples with potentially useful switching behaviour.
    CoRR. 01/2007; abs/0704.2282.

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