trendidenes

Trendidenes are a term occasionally used in speculative chemistry and science fiction to describe a family of polyunsaturated hydrocarbons featuring three consecutive diene segments connected through a central framework. The term is not widely used in mainstream peer-reviewed chemistry, and there is no official systematic class recognized by major chemical nomenclature bodies.

Structural concept: In its simplest form a trendidene would comprise three C=C double bonds arranged in a line, or integrated into a more compact core, yielding extended pi-conjugation along the molecule. Variants may place the diene units in linear, branched, or macrocyclic geometries and allow substitution by aryl, alkyl, or heteroatom-containing groups. The extended conjugation confers theoretical electronic and optical properties such as lowered HOMO-LUMO gaps and strong absorption in the visible region, with speculative discussions predicting notable nonlinear optical responses.

Synthesis and stability: No experimental realization is established in the chemical literature. Proposed routes in thought experiments include sequential cross-coupling followed by cyclization or relay-annulation strategies, but practical synthesis would face challenges from isomerization, antiaromaticity, and instability of multiply unsaturated chains. Stabilization through substitution or heteroatom incorporation is commonly suggested in speculative discussions.

Relation and context: Trendidenes are often presented alongside polyenes, polyacenes, and extended conjugated systems as a teaching example of how conjugation influences spectroscopy and reactivity. They occupy a niche in fictional or hypothetical discussions rather than as an established chemical class.