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@ARTICLE{Metzelaars:902604,
      author       = {Metzelaars, Marvin and Sanz, Sergio and Rawson, Jeff and
                      Hartmann, Rudolf and Schneider, Claus M. and Kögerler,
                      Paul},
      title        = {{F}using pyrene and ferrocene into a chiral, redox-active
                      triangle},
      journal      = {Chemical communications},
      volume       = {57},
      number       = {54},
      issn         = {0009-241X},
      address      = {Cambridge},
      publisher    = {Soc.},
      reportid     = {FZJ-2021-04399},
      pages        = {6660 - 6663},
      year         = {2021},
      abstract     = {Fundamental understanding and control of electron transfer
                      processes in molecular building blocks are key to construct
                      nanoscale (spin)electronic devices. Ferrocene (Fc) has been
                      studied extensively in this context due to high conductance
                      and stability, and its well-defined and reversible
                      redox-switching behaviour.1 The integration of multiple Fc
                      groups into a single, nonlinear molecule (e.g. stars2 or
                      macrocycles3) generates materials with extraordinary
                      electronic properties that might not be observed in linear
                      analogues. So far only a handful of shape-persistent and
                      cyclic Fc-based compounds have been synthesised by linking
                      Fc groups either directly3g,h or via simple bridging units,
                      like diethynylbenzene derivatives.3c–eUsing the larger
                      aromatic building block pyrene (Py), we can tune the
                      properties for a range of applications. The Py group is
                      fundamental in host–guest chemistry, used in metallacycles
                      and -cages to entrap fullerenes and other guests.4 Preuß et
                      al. used linear ferrocenyl–pyrenes to disentangle and
                      functionalise carbon nanotubes via π–π stacking.5 We
                      showed that a Fc-bridged pyrenophane can be sublimed onto
                      ferromagnetic surfaces to craft 3D spin interfaces.6 The
                      photophysical properties of pyrene have been exploited in
                      phototransistors, “turn-on” sensors and fluorescence
                      switches based on Fc–Py dyads.7To construct a macrocycle
                      with two different functional units often entails
                      protracted, stepwise synthesis. We recently demonstrated a
                      one-step Suzuki–Miyaura cross-coupling (SMC) route to an
                      insoluble, pyrene-based cyclophane in $<1\%$ yield (Chart 1,
                      cyclophane). By this method, we synthesised a soluble
                      macrocycle of three Fc–Py dyads bonded into a triangle
                      (Chart 1, 3). Employing 2,7-bis(Bpin)pyrene as linear and
                      1,1′-diiodoferrocene as angular building blocks, our
                      optimised conditions gave a yield of $6\%$ (PdCl2(dtbpf) in
                      DMF). The Fc group adopts a range of angles to serve as a
                      vertex in linear and larger cyclic oligomers with low
                      solubility, which we could detect by mass spectrometry of
                      crude reaction mixtures, albeit not isolate. Soluble side
                      products, likely generated via dehalogenation or
                      deborylation of acyclic intermediates, were also identified
                      (see Fig. S12 and S13†). We synthesised noncyclic
                      molecules 1 and 2 that complete the series in Chart 1. The
                      identity of dyad 1, stack 2 and triangle 3 were confirmed by
                      1H/13C-NMR (Fig. S1–S7†), MALDI-HRMS (Fig. S8–S11†),
                      and elemental analysis.},
      cin          = {PGI-6},
      ddc          = {540},
      cid          = {I:(DE-Juel1)PGI-6-20110106},
      pnm          = {5223 - Quantum-Computer Control Systems and Cryoelectronics
                      (POF4-522)},
      pid          = {G:(DE-HGF)POF4-5223},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:34128505},
      UT           = {WOS:000661559200001},
      doi          = {10.1039/D1CC02191E},
      url          = {https://juser.fz-juelich.de/record/902604},
}