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Cuprous selenide nanocrystals have hallmark attributes, especially tunable localized surface plasmon resonances (LSPRs) and super-ionic behavior. These attributes of cuprous selenide are now integrated with a one-dimensional morphology. Essentially, Cu 2 Se nanowires (NWs) of micrometer-scale lengths and about 10 nm diameter are prepared. The NWs exhibit a super-ionic phase that is stable at temperatures lower than in the bulk, owing to compressive lattice strain along the radial dimension of the NWs. The NWs can be switched between oxidized and reduced forms, which have contrasting phase transition and LSPR characteristics. This work thus makes available switchable, one-dimensional waveguides and ion-conducting channels., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We have investigated the aromaticity of singly twisted Möbius aromatic and doubly twisted Hückel antiaromatic bis(palladium(II)) [36]octaphyrins in the lowest triplet state (T 1 ) by spectroscopic measurements and quantum calculations. The T 1 state of the singly twisted Möbius [36]octaphyrin shows broad and weak absorption spectral features that are analogous to those of antiaromatic expanded porphyrins while the T 1 state of the doubly twisted Hückel [36]octaphyrin exhibits intense and distinct spectral features, indicating the aromatic nature. These results along with theoretical calculations support the hypothesis that the aromaticity is reversed in the T 1 state. Furthermore, we show that the degree of structural smoothness affects the aromaticity reversal in the T 1 state., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Complexation of novel multiply N-confused expanded calix[n]phyrins with boron difluoride afforded a new class of cyclic BODIPY (boron-dipyrromethene) arrays. The structures of circularly arranged BODIPY subunits linked in an N-confused fashion give rise to such photophysical properties unique to the macrocycles as redshifted emission wavelengths along with apparent large Stokes shifts, long emission lifetimes, and solid-state lasing. The DFT calculations support the size-dependent excited-state dynamics of the macrocycles., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Aromaticity reversal in the lowest triplet state, or Baird's rule, has been postulated for the past few decades. Despite numerous theoretical works on aromaticity reversal, experimental study is still at a rudimentary stage. Herein, we investigate the aromaticity reversal in the lowest excited triplet state using a comparable set of [26]- and [28]hexaphyrins by femtosecond time-resolved infrared (IR) spectroscopy. Compared to the relatively simple IR spectra of [26]bis(rhodium) hexaphyrin (R26H), those of [28]bis(rhodium) hexaphyrin (R28H) show complex IR spectra the region for the stretching modes of conjugated rings. Whereas time-resolved IR spectra of R26H in the excited triplet state are dominated by excited state IR absorption peaks, while those of R28H largely show ground state IR bleaching peaks, reflecting the aromaticity reversal in the lowest triplet state. These contrasting IR spectral features serve as new experimental aromaticity indices for Baird's rule., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The aromaticity reversal in the lowest triplet state (T1 ) of a comparable set of Hückel/Möbius aromatic metalated expanded porphyrins was explored by optical spectroscopy and quantum calculations. In the absorption spectra, the T1 states of the Möbius aromatic species showed broad, weak, and ill-defined spectral features with small extinction coefficients, which is in line with typical antiaromatic expanded porphyrins. In combination with quantum calculations, these results indicate that the Möbius aromatic nature of the S0 state is reversed to Möbius antiaromaticity in the T1 state. This is the first experimental observation of aromaticity reversal in the T1 state of Möbius aromatic molecules., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A set of 5,15-biphenylene-bridged porphyrin wheels, namely, [n]cyclo-5,15-porphyrinylene-4,4'-biphenylenes [n]CPB, have been synthesized through the platination of 5,15-bis(4-(pinacolboranyl)phenyl) nickel(II) porphyrin and subsequent reductive elimination of Pt(II) (cod)-bridged cyclic porphyrin intermediates. The calculated strain energies for [3]CPB, [4]CPB, [5]CPB, and [6]CPB are 49.3, 32.9, 23.5, and 16.0 kcal mol(-1) , respectively. UV/Vis absorption spectra and cyclic voltammetry indicated characteristic ring-size-dependent absorption-peak shifts and redox-potential shifts, which presumably reflect the degree of strain in the π-systems. Excitation-energy hopping (EEH) times were determined to be 5.1, 8.0, 8.0, and 9.6 ps for [3]CPB, [4]CPB, [5]CPB, and [6]CPB, respectively, in a pump-power-dependent TA experiment., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Reductive metalation of [44]decaphyrin with [Pd2(dba)3] provided a Hückel aromatic [46]decaphyrin Pd(II) complex, which was readily oxidized upon treatment with DDQ to produce a Hückel antiaromatic [44]decaphyrin Pd(II) complex. In CH2Cl2 solution the latter complex underwent slow tautomerization to a Möbius aromatic [44]decaphyrin Pd(II) complex which exists as a mixture of conformers in dynamic equilibrium. To the best of our knowledge, these three Pd(II) complexes represent the largest Hückel aromatic, Hückel antiaromatic, and Möbius aromatic complexes to date., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The treatment of an antiaromatic norcorrole Ni(II) complex with a kinetically stabilized silylene provided ring-expansion products in excellent yields through the highly regio- and stereoselective insertion into the β-β pyrrolic CC bonds. The resultant Ni(II) porphyrinoid monoinsertion product exhibited relatively strong near-IR absorption bands due to the small HOMO-LUMO gap in spite of the disrupted cyclic π-conjugation by the silicon atom., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Stable antiaromatic expanded porphyrins were designed by the judicious implementation of meso-imidazolyl groups, which cause stabilization through the creation of a hydrogen-bonding network that overcomes antiaromatic electronic destabilization. Both the [28]hexaphyrin 1 and the [36]octaphyrin 2, which contain imidazolyl groups at two opposite meso positions, are shown to be stable Hückel antiaromatic species., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)