1,1'-Bis(pyrazol-3-yl)ferrocene: A Clip Ligand That Forms Supramolecular Aggregates and Prismatic Hexanuclear Coinage Metal Complexes.

Two ferrocene derivatives with appended pyrazole substituents, namely, 1,1'-bis(5-methyl-1H-pyrazol-3-yl)ferrocene (H2LH) and 1,1'-bis(5-trifluoromethyl-1H-pyrazol-3-yl)ferrocene (H2LF), were synthesized. In solid state they form distinct H-bonded dimers with orthogonal (H2LH, C2 symmetry) or antiparallel (H2LF, C2h symmetry) arrangement of the two ferrocene/pyrazole hybrid molecules. Supramolecular dimerization was also detected in solution at low temperatures, though diffusion-ordered spectroscopy and variable-temperature NMR spectroscopy revealed several dynamic processes.

Crowning of coinage metal pyrazolates: double-decker homo- and heteronuclear complexes with synergic emissive properties.

A new pyrazole ligand with flexible thioether chelate arms was synthesized and was used to obtain an unprecedented class of hexanuclear coinage metal complexes of general formula [MM'L]3Y3 (M, M' = Cu, Ag, Au; Y = OTf, BF4). Three of them were characterized by X-ray crystallography, namely, homometallic [Ag2L]3(OTf)3 and [Ag2L]3(BF4)3 as well as heterometallic [CuAgL]3(OTf)3, revealing that the classical [M(μ-pz)]3 core is crowned by a second deck of S-bound M' ions. Depending on the solvent, these oligonuclear systems undergo rapid dynamics and show cation-anion aggregation in solution, which has been investigated by DOSY and temperature dependent NMR spectroscopy.