Anion Recognitions via Cocrystallizations with Organic π-Acids in the Efficient Self-Assembly of Nanoscopic One-Dimensional Molecular Chains (Wires)

• Published in: Crystal growth & design 2008-04, Vol.8 (4), p.1327-1334
• Main Authors: Han, Bing, Lu, Jianjiang, Kochi, Jay K
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals; Physics; Self-assembly; Solid-solid transitions; Specific phase transitions; Structure of solids and liquids; crystallography
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg701138n

The self-assembly of various anions (e.g., thiocyanate, nitrite/nitrate, sulfite/sulfate, tetrahalometallates, etc.) with prototypical π-acids (consisting of cyano- and nitrosubstituted pyrazine and benzene, as well as tetracyanoethylene) occurs rapidly and selectively to yield a series of novel one-dimensional structures. The wire-like molecular chains all consist of parallel stacks of π-acids and alternate anions of different sizes and shapes that establish the dihedral angles α and φ sufficient to define these unique structures. Analogy of such linear arrays to nanoscopic wires is reinforced by the protective sheath of countercations that are completely arrayed around the linear cores. The critical feature of these efficient self-assemblies is shown to derive from anion/π-recognitions via charge-transfer forces between the electron-rich anions acting as electron donors and the electron-poor π-acids acting as electron acceptors to spontaneously generate synthons according to Mulliken theory.