scholarly journals Crystal chemistry and photomechanical behavior of 3,4-dimethoxycinnamic acid: correlation between maximum yield in the solid-state topochemical reaction and cooperative molecular motion

IUCrJ ◽  
2015 ◽  
Vol 2 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Manish Kumar Mishra ◽  
Arijit Mukherjee ◽  
Upadrasta Ramamurty ◽  
Gautam R. Desiraju
Keyword(s):  
Solid State ◽  
Crystal Packing ◽  
Maximum Yield ◽  
Structure Property ◽  
Crystal Forms ◽  
Individual Crystal ◽  
Structure Property Relationships ◽  
Molecular Movement ◽  
Truxillic Acid ◽  
The Individual

A new monoclinic polymorph, form II (P21/c,Z= 4), has been isolated for 3,4-dimethoxycinnamic acid (DMCA). Its solid-state 2 + 2 photoreaction to the corresponding α-truxillic acid is different from that of the first polymorph, the triclinic form I (P\bar 1,Z= 4) that was reported in 1984. The crystal structures of the two forms are rather different. The two polymorphs also exhibit different photomechanical properties. Form I exhibits photosalient behavior but this effect is absent in form II. These properties can be explained on the basis of the crystal packing in the two forms. The nanoindentation technique is used to shed further insights into these structure−property relationships. A faster photoreaction in form I and a higher yield in form II are rationalized on the basis of the mechanical properties of the individual crystal forms. It is suggested that both Schmidt-type and Kaupp-type topochemistry are applicable for the solid-statetrans-cinnamic acid photodimerization reaction. Form I of DMCA is more plastic and seems to react under Kaupp-type conditions with maximum molecular movements. Form II is more brittle, and its interlocked structure seems to favor Schmidt-type topochemistry with minimum molecular movement.

scholarly journals Designing Singlet Fission Candidates from Donor-Acceptor Copolymers

2020 ◽  
Author(s):  
Jacob Terence Blaskovits ◽  
Maria Fumanal ◽  
Sergi Vela ◽  
Clemence Corminboeuf
Keyword(s):  
High Throughput Screening ◽  
Molecular Design ◽  
Crystal Packing ◽  
Cost Effective ◽  
Frontier Molecular Orbital ◽  
Structure Property ◽  
Singlet Fission ◽  
Structure Property Relationships ◽  
Large Databases ◽  
Donor Acceptor

<p>Singlet Fission (SF) has demonstrated significant promise for boosting the power conversion efficiency (PCE) of solar cells. Traditionally, SF is targeted as an intermolecular process, however its dependence on crystal packing makes molecular design difficult. In contrast, intramolecular SF (iSF) enables the exploration of tunable bi-chromophoric systems following well-defined structure-property relationships. In this work, we propose a set of parameters to screen conjugated donor-acceptor copolymer candidates with potential iSF behaviour. We focus our analysis on the E(S<sub>1</sub>)>2E(T<sub>1</sub>) thermodynamic condition and on the appropriate charge transfer (CT) character of S<sub>1</sub>. We map the CT character with respect to the frontier molecular orbital (FMO) energies of the constituent monomers, providing a cost-effective protocol for an accelerated screening of promising iSF donor-acceptor pairs, while minimizing the number of computations. These parameters are applied to a chemically diverse, curated library of 81 truncated dimers of synthetically feasible donor-acceptor copolymers. From our dataset, four candidates are flagged for iSF, two of which were previously experimentally reported. This protocol is envisioned to be scaled up for the high-throughput screening of large databases of donor-acceptor dimers for the design and identification of conjugated polymers capable of iSF. </p>

scholarly journals Surface Modification by Polyzwitterions of the Sulfabetaine-Type, and Their Resistance to Biofouling

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1014 ◽  
Author(s):  
Eric Schönemann ◽  
André Laschewsky ◽  
Erik Wischerhoff ◽  
Julian Koc ◽  
Axel Rosenhahn
Keyword(s):  
Structural Diversity ◽  
Negative Control ◽  
Butyl Methacrylate ◽  
Structure Property ◽  
High Molar Mass ◽  
Zwitterionic Polymers ◽  
Chemical Structures ◽  
Structure Property Relationships ◽  
Repeat Units ◽  
The Individual

Films of zwitterionic polymers are increasingly explored for conferring fouling resistance to materials. Yet, the structural diversity of polyzwitterions is rather limited so far, and clear structure-property relationships are missing. Therefore, we synthesized a series of new polyzwitterions combining ammonium and sulfate groups in their betaine moieties, so-called poly(sulfabetaine)s. Their chemical structures were varied systematically, the monomers carrying methacrylate, methacrylamide, or styrene moieties as polymerizable groups. High molar mass homopolymers were obtained by free radical polymerization. Although their solubilities in most solvents were very low, brine and lower fluorinated alcohols were effective solvents in most cases. A set of sulfabetaine copolymers containing about 1 mol % (based on the repeat units) of reactive benzophenone methacrylate was prepared, spin-coated onto solid substrates, and photo-cured. The resistance of these films against the nonspecific adsorption by two model proteins (bovine serum albumin—BSA, fibrinogen) was explored, and directly compared with a set of references. The various polyzwitterions reduced protein adsorption strongly compared to films of poly(n‑butyl methacrylate) that were used as a negative control. The poly(sulfabetaine)s showed generally even somewhat higher anti-fouling activity than their poly(sulfobetaine) analogues, though detailed efficacies depended on the individual polymer–protein pairs. Best samples approach the excellent performance of a poly(oligo(ethylene oxide) methacrylate) reference.

New Second-Order Nonlinear Optical Organic Crystals

1989 ◽  
Vol 173 ◽  
Author(s):  
D.S. Donald ◽  
L.-T. Cheng ◽  
G. Desiraju ◽  
G. R. Meredith ◽  
F. C. Zumsteg
Keyword(s):  
Nonlinear Optical ◽  
Near Infrared ◽  
Crystal Packing ◽  
Screening Program ◽  
Molecular Crystals ◽  
Molecular Properties ◽  
Organic Crystals ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Near Ultraviolet

ABSTRACTThe design of molecular crystals with specific optical properties, which are thought to arise from constituent molecules’ polarizability properties, is a desirable but currently unachievable goal. One can partially achieve this goal by choosing compounds with specific molecular attributes and empirically determining the manner in which these are translated into crystal properties. Besides the fact that there are no certain rules for prediction of crystal packing arrangements, there is also a problem in specifying molecular properties from what are today incomplete polarizability structure-property relationships. We have, realizing these limitations, identified new molecular crystals by a nonlinear optical (powder-SHG) scouting-screening program from lists of compounds chosen because of desirable molecular properties. Examination of successful materials has revealed interesting, new alignment motifs. Some of these materials, a set of halogen and cyano derivatives of aromatic compounds, are described relating properties and structures of molecules and crystals. In particular, the orientation directing influence of intermolecular halogen-cyano interactions and the use of heterocyclic compounds to improve transparency in the near infrared and in the blue and near ultraviolet spectral regions are demonstrated.

Structure/Property Relationships for Polyamide 6 / Organoclay Nanocomposites in the Melt and in the Solid State

2005 ◽  
Vol 221 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Vitaly M. Karaman ◽  
Valery P. Privalko ◽  
Eleonora G. Privalko ◽  
Bjorn Lehmann ◽  
Klaus Friedrich
Keyword(s):  
Solid State ◽  
Polyamide 6 ◽  
Structure Property ◽  
Structure Property Relationships

scholarly journals Molecular and Crystalline Requirements for Solid State Fluorescence Exploiting Excited State Intramolecular Proton Transfer

2019 ◽  
Author(s):  
Michael Dommett ◽  
Miguel Rivera ◽  
Matthew T. H. Smith ◽  
Rachel Crespo Otero
Keyword(s):  
Excited State ◽  
Solid State ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Extensive Study ◽  
Structure Property ◽  
Aggregation Induced Emission ◽  
Organic Systems ◽  
Structure Property Relationships ◽  
Formidable Challenge

Aggregation induced emission offers a route to the development of emissive technologies based on solely organic systems. However, maximising fluorescence quantum efficiencies (QE) is a formidable challenge in attaining first-principles materials design, due to the interplay between the electronic structure of the chromophore and the molecular crystal. The identification of radiative and nonradiative channels, and how these are affected by aggregation, can rationalise the emissive properties of materials and aid in the design of yet more efficient fluorophores. In the current work, we examine the mechanism behind aggregation induced emission in two related families of compounds with lasing properties, which undergo excited state intramolecular proton transfer (ESIPT). We systematically investigate competing excited state decay channels in a total of eleven crystals to evaluate the factors needed for efficient ESIPT fluorophores, aided by a full evaluation of the crystal structures, exciton coupling, and exciton hopping rates. We show that in addition to the restriction of nonradiative pathways, an efficient ESIPT is essential to maximise the QE in the solid state. This extensive study of structure-property relationships for fluorophores based on the ESIPT mechanism bridges the understanding of molecular photophysics with crystal structure, accelerating the development of highly efficient solid state emitters.

scholarly journals Designing Singlet Fission Candidates from Donor-Acceptor Copolymers

2020 ◽  
Author(s):  
Jacob Terence Blaskovits ◽  
Maria Fumanal ◽  
Sergi Vela ◽  
Clemence Corminboeuf
Keyword(s):  
High Throughput Screening ◽  
Molecular Design ◽  
Crystal Packing ◽  
Cost Effective ◽  
Frontier Molecular Orbital ◽  
Structure Property ◽  
Singlet Fission ◽  
Structure Property Relationships ◽  
Large Databases ◽  
Donor Acceptor

<p>Singlet Fission (SF) has demonstrated significant promise for boosting the power conversion efficiency (PCE) of solar cells. Traditionally, SF is targeted as an intermolecular process, however its dependence on crystal packing makes molecular design difficult. In contrast, intramolecular SF (iSF) enables the exploration of tunable bi-chromophoric systems following well-defined structure-property relationships. In this work, we propose a set of parameters to screen conjugated donor-acceptor copolymer candidates with potential iSF behaviour. We focus our analysis on the E(S<sub>1</sub>)>2E(T<sub>1</sub>) thermodynamic condition and on the appropriate charge transfer (CT) character of S<sub>1</sub>. We map the CT character with respect to the frontier molecular orbital (FMO) energies of the constituent monomers, providing a cost-effective protocol for an accelerated screening of promising iSF donor-acceptor pairs, while minimizing the number of computations. These parameters are applied to a chemically diverse, curated library of 81 truncated dimers of synthetically feasible donor-acceptor copolymers. From our dataset, four candidates are flagged for iSF, two of which were previously experimentally reported. This protocol is envisioned to be scaled up for the high-throughput screening of large databases of donor-acceptor dimers for the design and identification of conjugated polymers capable of iSF. </p>

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