Ethylene-Bridged Hexadentate Bis(amidines) and Bis(amidinates) with Variable Binding Sites

Hexadentate bis­(amidines) form versatile networks of hydrogen bonds
both in solid state and solution, as revealed by X-ray crystallography,
IR, and NMR spectroscopy. Moreover, the corresponding bis­(amidinates)
produce blue and green emissions in THF solution. Tethered tetradentate
bis­(amidines) have emerged in coordination chemistry, enantioselective
catalysis, as building blocks for polyfunctional heterocycles, and
in photoluminescent materials. The next generation of flexible bis­(amidine)/bis­(amidinate)
platforms with up to six N-donor sites has now been
established.