2 research outputs found
Synthesis, Photophysical, Electrochemical, and Halochromic Properties of <i>peri</i>-Naphthoindigo
A facile synthesis of <i>peri</i>-naphthoindigo (PNI)
was reported for the first time from simple precursor. Installation
of a chromophore at the <i>peri</i>-position of naphthalene
is very unique in terms of synthetic challenges and properties. PNI
exists in monoenol form, undergoes halochromism in acidic medium,
and displays a wide and strong absorption band (ε = 33390 M<sup>–1</sup>cm<sup>–1</sup>) with maxima at 632 nm (chloroform).
The dye undergoes oxidation and reduction at +0.30 and −0.58
V (vs Fc/Fc<sup>+</sup>), respectively, in chloroform
Giant Electroactive M<sub>4</sub>L<sub>6</sub> Tetrahedral Host Self-Assembled with Fe(II) Vertices and Perylene Bisimide Dye Edges
Self-assembly of octahedral FeÂ(II)
ions and linear perylene bisimide
(PBI) dyes with 2,2′-bipyridine groups covalently attached
at the imide positions quantitatively yields an Fe<sub>4</sub>(PBI)<sub>6</sub> tetrahedron by the directional bonding approach. With an
edge length of 3.9 nm and estimated internal volume >950 Ã…<sup>3</sup>, tetrahedron <b>T</b> is one of the largest M<sub>4</sub>L<sub>6</sub> tetrahedra ever reported. Importantly, many of the
desirable photo- and electroactive properties of the PBI ligands are
transferred to the nanoscale metalloÂsupraÂmolecule. Tetrahedron <b>T</b> absorbs strongly across the visible spectrum out to 650
nm and exhibits a total of 7 highly reversible electrochemical oxidation
and reduction waves spanning a 3.0 V range. This facile cycling of
34 electrons between +18 and −16 charged species is likely
enabled due to the porous nature of the tetrahedron that allows the
necessary counterions to freely flow in and out of the host. Host–guest
encapsulation of C<sub>60</sub> by <b>T</b> in acetonitrile
was studied by <sup>13</sup>C NMR spectroscopy, UV–vis spectroscopy,
and ESI-MS, confirming that the tetrahedron is a suitable host for
large, functional guest molecules