Iptycene substitution enhances the electrochemical activity and stability of polyanilines

One-Pot Synthesis of Bis(arylamino)pentiptycenes by TiCl4-DABCO Assisted Reductive Amination of Pentiptycene Quinone

The previously eight-step synthesis of bis(arylamino)pentiptycenes (2) from pentiptycene quinone (1) can now be achieved in a single step with 18-90% yields through TiCl4-DABCO assisted reductive amination with anilines. Both the dual amination of 1 and the in situ reduction of quinone diimines are unprecedented. The π system of 2 can be further expanded, including the formation of bis(diarylamino)pentiptycenes. This work also provides mechanistic insights into the challenges encountered in the dual reductive amination of 1 with other amines.

Porous Supramolecular Assembly of Pentiptycene-Containing Gold(I) Complexes: Persistent Excited-State Aurophilicity and Inclusion-Induced Emission Enhancement

We report herein a porous supramolecular framework formed by a linear mononuclear Au(I) complex (1) via the tongue-and-groove-like joinery between the pentiptycene U-cavities (grooves) and the rod-shaped π-conjugated backbone and alkyl chains (tongues) with the assistance of C-H···π and aurophilic interactions. The framework contains distorted tetrahedral Au₄ units, which undergo stepwise and persistent photoinduced Au(I)-Au(I) bond shortening (excited-state aurophilicity), leading to multicolored luminescence photochromism. The one-dimensional pore channels could accommodate different solvates and guests, and the guest inclusion-induced luminescence enhancement (up to 300%) and/or vapochromism are characterized. A correlation between the aurophilic bonding and the luminescence activity is uncovered by TDDFT calculations. Isostructural derivatives 2 and 3 corroborate both the robustness of the porous supramolecular assembly and the mechanisms of the stimulation-induced luminescence properties of 1. This work demonstrates the cooperation of aurophilicity and structural porosity and adaptability in achieving novel supramolecular photochemical properties.

Preparation and Characterization of Intrinsic Porous Polyamides Based on Redox-Active Aromatic Diamines with Pentiptycene Scaffolds

The electrochromic (EC) polyamides (Ether-PentiTPA1 and Ether-PentiTPA8) from the electroactive pentiptycene-derived triphenylaminediamine monomers (PentiTPA1 and PentiTPA8) were designed and prepared via polycondensation. The incorporation of rigid and contorted H-shaped pentiptycene scaffolds could restrain polymer chains from close packing and further form intrinsic microporosity in the polymer matrix which could be confirmed by the measurements of WXRD, BET, and PALS. With the existence of intrinsic microporosity, the diffusion rate of counterions between the electroactive polymer film and electrolyte can be promoted during the electrochemical procedure. Therefore, the prepared polyamide Ether-PentiTPA1 exhibits enhanced EC behaviors, such as lower driving potential (1.11 V), smaller redox potential difference ΔE (0.24 V), and shorter switching response time (3.6/5.2 s for coloring/bleaching). Consequently, the formation of intrinsic microporosity can be a useful approach for the enhancement of EC response performance.

A Molecular Rotor That Probes the Helical Inversion of Stiff-Stilbene

Probing the inversion kinetics of a molecular helix is inherently a challenging task. We demonstrate herein that a fast-rotating pentiptycene component could function as an external NMR probe to afford the kinetic information on the inversion of a neighboring helical stiff-stilbene unit.

Electrochromic Response Capability Enhancement with Pentiptycene-Incorporated Intrinsic Porous Polyamide Films

Enhancing switching response capability of electrochromic (EC) polymers has been a topical issue. Herein, the H-shaped nonplanar pentiptycene scaffold is successfully introduced into the polyamide film derived from N,N'-bis(4-aminophenyl)-N,N'-di(methoxyphenyl)-1,4-phenylenediamine (TPPA), and the resulting copolymer shows enhanced EC behaviors, including lower oxidation potential and shorter switching response time, as compared to the corresponding TPPA-derived homopolymer.