An aminotetracyanocyclopentadienide system: light-induced formation of a thermally stable cyclopentadienyl radical

Abstract

Crystals of the aminotetracyanocyclopentadienyl radical were obtained from the reaction of CaCl2 with Ag[C5(CN)4(NH2)] and recrystallization in MeOH was performed in sunlight.

Tricyanated Ferrocenes; Isolation, structure, electrochemistry and DFT calculations

“…[17a] The yields of dicyanoferrocene were 71 %, 97 % and 16 %, respectively Two old claims on "decacyanoferrocene" could later be shown to be erroneous and the obtained compounds were found to be Fe nitrile-complexes. [21] Since we are working for quite a while on the coordination chemistry of tetra-and pentacyanocyclopentadienide and obtained so far only monomeric or polymeric N-coordinated complexes, [22] we found it worthwhile to look for synthetic pathways towards π-coordinated polycyanocyclopentadienyl complexes. Recently we reported the serendipitous synthesis of tricyanocymantrene.…”

Observation of Discrete Valence Tautomers in Crystalline Cyclopentadienyl Radicals

“… a Cp radicals with known solid-state structures; A and B lack from crystallographic disorder problems. − …”

“…In contrast to cyclobutadiene, the distortion of the neutral C 5 H 5 · radical results in two geometrically nonidentical valence tautomers. Although spectroscopic studies in the gas phase and in matrices at low temperatures indicate the presence of a Jahn–Teller distortion, − the structural changes during the transition from one valence tautomer to the other are very small, which is why the crystallographic detection of the valence tautomers is an enormous challenge and has therefore not yet been successful, despite several attempts. − …”