Synthesis and Characterization of Redox-Active Mononuclear Fe(κ2-dppe)(η5-C5Me5)-Terminated π-Conjugated Wires
摘要:
Several new redox-active Fe(kappa(2)-dppe)(eta(5)-C5Me5) arylacetylide complexes featuring pendant ethynyl (Fe(kappa(2)-dppe)(eta(5)-C5Me5)-[{C equivalent to C(1,4-C6H4)}(n)C equivalent to CH] (1b-d; n = 1-3), Fe(kappa(2)-dppe)(eta(5)-C5Me5)[C equivalent to C(1,3-C6H4)C equivalent to CH] (2)) or ethenyl (Fe(kappa(2)-dppe)(eta(5)-C5Me5)[CE equivalent to C(1,4-C6H4)CH equivalent to CH2] (3)) groups have been synthesized and characterized under their Fe(II) and Fe(III) states. In contrast to the known ethynyl Fe(III) complex [Fe(kappa(2)-dppe)(eta(5)-C5Me5)(C7 equivalent to CH)][PF6] (1a[PF6]), most of the new Fe(III) derivatives turned out to be kinetically stable in solution. A consistent picture of the electronic structure of the latter complexes in both redox states emerged from experimental data and DFT calculations. This study revealed that beyond the first 1,4-phenylene ring, modification or extension of the carbon-rich linker using (4-phenylene)ethynylene spacers will have only a minor influence on their electronic properties in their ground state, while still maintaining some (weak) electronic interaction along the carbon-rich backbone.
molecules in which 9H-carbazole (electron donor, D) and 2,2':6',2''-terpyridine (electron acceptor, A) are connected through rigid π-conjugated bridges (D-π-A systems) have been synthesized and their photophysical properties examined in detail, with the support of DFT calculations. The bridges are made of different sequences of ethynylene, phenylene, and anthracene groups. The synthetic strategies involve
aperture reported in the metal–organic frameworks is 8.5 nm, and the value for covalentorganicframeworks (COFs) is only 5.8 nm. Herein, we construct a series of COFs with record pore aperture values from 7.7 to 10.0 nm by designing building blocks with large conformational rigidness, planarity, and suitable local polarity. All of the obtained COFs possess eclipsed stacking structures, high crystallinity