PUMA publications for /user/theochem/MIDAhttps://puma.ub.uni-stuttgart.de/user/theochem/MIDAPUMA RSS feed for /user/theochem/MIDA2024-03-28T21:35:15+01:00Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self-Assemblyhttps://puma.ub.uni-stuttgart.de/bibtex/2ccaea3575a6fec76aa8abe557cd67c14/theochemtheochem2019-02-06T13:16:24+01:00köhn theoretische stuttgart liquid_crystals chemie columnar koehn boronate from:alexanderdenzel MIDA quantum_chemical_calculation theochem smectic <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Tobias Wöhrle" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/0"><span itemprop="name">T. Wöhrle</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Rafet Gündemir" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/1"><span itemprop="name">R. Gündemir</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Frey" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/2"><span itemprop="name">W. Frey</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Friederike Knecht" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/3"><span itemprop="name">F. Knecht</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Andreas Köhn" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/4"><span itemprop="name">A. Köhn</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sabine Laschat" itemprop="url" href="/person/1d0eb833ea984bea24784bf60c8e3b8e2/author/5"><span itemprop="name">S. Laschat</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Chem. - A Eur. J.</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">23 </span></span>(<span itemprop="issueNumber">17</span>):
<span itemprop="pagination">4149–4159</span></em> </span>(<em><span>2017<meta content="2017" itemprop="datePublished"/></span></em>)</span>Wed Feb 06 13:16:24 CET 2019Chem. - A Eur. J.174149–4159{Thermotropic MIDA Boronates as a Case Study for the Role of Dipolar Interactions in Liquid Crystalline Self-Assembly}232017köhn theoretische stuttgart liquid_crystals chemie columnar koehn boronate from:alexanderdenzel MIDA quantum_chemical_calculation theochem smectic A series of MIDA (N-methylimino diacetic acid) boronates carrying 4-alkoxy, 3,4-bisalkoxy, or 3,4,5-trisalkoxyphenyl substituents were synthesized and their mesomorphic properties characterized by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) techniques such as small- and wide-angle X-ray scattering (SAXS and WAXS, respectively). Most derivatives were liquid crystalline. In the case of mono- and bisalkoxy-substituted derivatives, C6 chains already induced smectic A (SmA) mesophases despite the bulky MIDA head group. With increasing chain length, columnar hexagonal (Colh) phases replaced SmA phases in the disubstituted series. Quantum chemical calculations on a series of MIDA boronates show that the B−N bond is a dative bond with a positive charge on the boron atom and negative charges on the nitrogen and oxygen atoms. In addition, no π-interaction between the aryl moiety and B−N bond was found, thus the mesogenic unit is electronically decoupled from the MIDA head group. These theoretical findings were supported by IR and Raman spectra as well as by asingle crystal structure analysis of 4-ethoxyphenyl MIDA boronate. Calculations of the electrostatic potential of the MIDA boronate reveal a special polarity pattern that can support the formation of a two-dimensional network and is likely to explain the liquid crystalline self-assembly. The absence of any electronic cross-talk between the MIDA head group and B-aryl or B-alkyl substituents allows the efficient tailoring of the mesophase type through variation of the substituents.