ic5b00898_si_002.cif (4.3 MB)
1,1′-Bis(pyrazol-3-yl)ferrocene: A Clip Ligand That Forms Supramolecular Aggregates and Prismatic Hexanuclear Coinage Metal Complexes
dataset
posted on 2015-07-20, 00:00 authored by Mattia Veronelli, Sebastian Dechert, Serhiy Demeshko, Franc MeyerTwo 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. Redox potentials of the ferrocene derivatives are affected
by the nature of the pyrazole substituent (Me, CF3). In
their deprotonated form [LR]2–, both
ferrocene/pyrazole hybrids serve as ligands and form oligonuclear
CuI, AgI, and AuI complexes that
were identified by matrix-assisted laser desorption ionization mass
spectrometry. X-ray crystallography revealed the structures of Cu6L3H and
Ag6L3F, which both contain two parallel and eclipsed [M(μ-pz)]3 metallamacrocycles (M = Cu, Ag) linked by three ferrocene
units. MI···MI distances between
the two triangular M3N6 decks are shorter in
Ag6L3F (3.28–3.30 vs 3.44–3.51 Å in the case of Cu6L3H),
indicating substantial intramolecular closed-shell
Ag(d10)–Ag(d10) interactions. However,
Cu6L3H features close intermolecular Cu···Cu
contacts as short as 3.37 Å. Mössbauer data for both the
ligands and complexes were collected, and electrochemical properties
were measured; preliminary luminescence data are reported.