skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Correlating structure and photophysical properties in thiazolo[5,4- d ]thiazole crystal derivatives for use in solid-state photonic and fluorescence-based optical devices
Title: Correlating structure and photophysical properties in thiazolo[5,4- d ]thiazole crystal derivatives for use in solid-state photonic and fluorescence-based optical devices
In thiazolo[5,4-d]thiazole (TTz)-based crystals, synergistic non-covalent interactions govern photophysical properties. Therefore, by modulating molecular-packing, TTz-based crystals can be tailored to fit optical and photonic applications such as white-light emissive organic phosphors.  more » « less
Award ID(s):
2307007 2043215
PAR ID:
10485183
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ;
Publisher / Repository:
Royal Society of Chemistry
Date Published:
Journal Name:
Materials Advances
Volume:
4
Issue:
23
ISSN:
2633-5409
Page Range / eLocation ID:
6321 to 6332
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; (, Journal of Physics: Condensed Matter)
    Abstract Single crystals of disordered Mn4–xCrxAl11have been synthesized via the flux method. EDS on several crystals of various sizes and shapes revealed an average molar ratio of 17:9:74 for Mn:Cr:Al, while X-ray diffraction on three different crystals yield compositions Mn2.26Cr1.74Al11(Mn4–xCrxAl11,x= 1.74), Mn0.83Cr3.17Al11, and Mn1.07Cr2.93Al11. This compound crystallizes in space groupP–1, isostructural with both Mn4Al11and Cr4Al11. Magnetic measurements on several crystals show that this disordered compound is ferrimagnetic with a low effective moment ofμeff≈1.012±0.004 μB/f.u. and a non-reachable transition temperature. DFT calculations display opening of a bandgap in the spin-up channel near the Fermi level with increasing Cr content, an indication of half-metallicity. 
    more » « less
  2. ; ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract Understanding photoreaction dynamics in crystals is important for predicting the dynamic property changes accompanying these photoreactions. In this work, we investigate the photoreaction dynamics ofp‐phenylenediacrylic acid dimethyl ester (p‐PDAMe) in single crystals that show reaction front propagation, in which the photoreaction proceeds heterogeneously from the edge to the center of the crystal. Moreover, we find thatp‐PDAMesingle crystals exhibit a distinctive crystal shape change from a parallelogram to a distorted shape resembling a fluttering flag, then to a rectangle as the photoreaction proceeds. Density functional theory calculations predict the crystal structure after the photoreaction, providing a reasonable explanation of the distinctive crystal shape change that results from the spatially heterogeneous photoreaction. These results prove that the spatially heterogeneous photoreaction dynamics have the ability to induce novel crystal shape changes beyond what would be expected based on the equilibrium reactant and product crystal shapes. 
    more » « less
  3. ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract Single crystals that do not obey translational symmetry have been reported in various material systems. In polymers, twisted crystals are typically formed in banded spherulites, while a class of non‐flat polymer single crystals (PSCs) has been observed. Herein, we report the formation of scrolled single crystals of biodegradable polymer poly(L‐lactic acid) (PLLA). While classical 2‐dimensional single crystals formed in solution‐crystallized PLLA are flat, we show that PLLA crystals bend into scrolls when the polymer molecular weight is low. The formation of these unique scrolled PLLA single crystals depends on polymer chain ends and the polymer molecular weight. This work, therefore, demonstrates a new mechanism to break translational symmetry in PSC growth. 
    more » « less
  4. ; ; ; (, Journal of Polymer Science)
    ABSTRACT Crystals of poly(ethylene glycol) grown in thin films of the room temperature ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium ethyl sulfate were examined by electron microscopy as a first step toward exploiting nonvolatile liquids for nanoscale imaging of solvated/dissolved polymeric materials. The crystals were generated by cooling supported (over surfaces of varied polarity) and freestanding solution films to room temperature. This “open,” that is, without liquid cell, microscopy was performed on unstained, as‐grown crystals in the presence of the IL. A variety of nearly two‐dimensional crystal morphologies were observed, including rods, fibers, spherulites, compact faceted single crystals, and interconnected networks, with characteristic sizes ranging from tens of nanometers to tens of microns. Electron diffraction patterns for the rods and fibers revealed single crystal‐like long‐range order. The nature of the IL support little affected the morphology, but film thickness and cooling rate proved important. To assess the role of solvent polarity, crystals were also grown from 1‐ethyl‐3‐methylimidazolium ethyl sulfate mixed with the second IL, the less polar ethyl‐tributyl‐phosphonium diethyl phosphate; here, although the morphologies were similar to those made with pure IL, fibrillar morphologies were more prevalent. © 2020 Wiley Periodicals, Inc. J. Polym. Sci.2020,58, 478–486 
    more » « less
  5. ; ; ; ; ; ; ; (, Angewandte Chemie International Edition)
    Abstract Aryl fluorosulfates of varying complexities have been used in amination reactions in water using a new Pd oxidative addition complex (OAC‐1) developed specifically to match the needs of the fine chemicals industry, not only in terms of functional group tolerance, but also reflecting time considerations associated with these important C−N couplings. Also especially noteworthy is that they replace both PFAS‐related triflates and nonaflates, which are today out of favor due to recent government regulations. The new complex based on the BippyPhos ligand is used at low loadings and under aqueous micellar conditions. Moreover, it is easily prepared and stable to long term storage. DFT calculations on the OAC precatalyst compare well with the X‐ray structure of the crystals with π‐complexation to the aromatic system of the ligand and also confirm the NMR data showing a mixture of conformers in solution that differ from the X‐ray structure in rotation of the phenyl andt‐butyl ligand substituents. An extensive variety of coupling partners, including pharmaceutically relevant APIs, readily participate under mild and environmentally responsible reaction conditions. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email