Tethered PProDOTs: conformationally restricted 3,4-propylenedioxythiophene based electroactive polymers
作者:Ryan M. Walczak、John S. Cowart、John R. Reynolds
DOI:10.1039/b610232h
日期:——
Herein we report a complete family of conformationally restricted PProDOT derivatives with varying alkylene tether lengths. It was found that variation of the tether length and structure of the electropolymerizable monomer was successful in the fine-tuning of the electrochemical and optical properties of the subsequent material. It was found that the band gap of the materials could be varied between 1.94 and 2.26 eV, with the “sweet spot” for obtaining the maximum electronic band gap existing at the n = 6 tether length, while maintaining low redox potentials. It was also found that these polymers exhibited stable electrochromic behavior with colors varying from blue–purple to orange in their neutral states and transmissive in their doped states.
Orientedcalix[6]arene-basedpseudorotaxanes and rotaxanes where the axial component bears a terpyridine ligand as a stopper positioned at the upper rim of the calixarene have been synthesized. The binding ability of the terpyridine unit present in the axle toward zinc salts is affected by the presence of the wheel, its distance with respect to the calix[6]arene upper rim, and the nature of the counterion
A series of calix[4]arene semitubes (4a–c) having alkyl bridging spacers of different lengths and flexibilities on their lower rim was synthesised and characterised in solution and in the solid state by 1H NMR spectroscopy and X-ray crystallography. The binding properties of these novel ditopic hosts toward a series of N-alkylpyridinium ion pairs were investigated in low polar media by 1H NMR and UV-vis
合成了一系列杯状[4]芳烃半管(4a–c),其下边缘具有不同长度和柔性的烷基桥接间隔基,并通过1 H NMR光谱和X射线晶体学对其进行了溶液化和固态表征。通过1 H NMR和UV-vis光谱在低极性介质中研究了这些新颖的双位宿主对一系列N-烷基吡啶鎓离子对的结合特性,并与相应的杯[4]芳烃单位宿主5进行了比较。这些研究表明,在低极性溶剂中,杯[4]芳烃半管表现为同位宿主,随氮的增加而增加。-烷基吡啶鎓离子对与主客体化学计量比为1:2的超分子加合物。
Medium and Large <i>N</i>-Heterocycle Formation via Allene Hydroamination with a Bimetallic Rh(II) Catalyst
作者:Kelton G. Forson、Benjamin O. Bohman、Coriantumr Z. Wayment、Rachel N. Owens、Caitlyn E. McKnight、Rhen C. Davis、Lillian R. Stillwell、Stacey J. Smith、David J. Michaelis
DOI:10.1021/jacs.1c10534
日期:2022.1.12
We report the synthesis of a 2-phosphinoimidazole-derived bimetallic Rh(II) complex that enables intramolecular allene hydroamination to form 7- to 10-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of various N-heterocycles. Macrocyclizations that form 11- to 15-member N-heterocycles are
Abstract Tris-(N-phenylureido)-calix[6]arenes are heteroditopic non-symmetric molecular wheels that, in apolar media, bind viologen-based molecular axles in a pseudorotaxane-type fashion. Because of the precise kinetic requirements associated with the threading process, in apolar solvents, the dicationic portion of the axle enters the calixarene annulus exclusively from the upper rim. With the general