Bifunctional Adsorbent-Catalytic Nanoparticles for the Refining of Renewable Feedstocks

A hybrid adsorbent-catalytic nanostructured material consisting of aminopropyl groups and nickel nanoparticles immobilized in mesoporous silica nanoparticles (AP-Ni-MSN) was employed to selectively capture free fatty acids (FFAs) and convert them into saturated hydrocarbons. The working principle of these sorbent-catalytic particles was initially tested in the hydrogenation of oleic acid. Besides providing selectivity for the capture of FFAs, the adsorbent groups also affected the selectivity of the hydrogenation reaction, shifting the chemistry from hydrocracking-based (Ni) to hydrotreating-based and improving the carbon economy of the process. This approach was ultimately evaluated by the selective sequestration of FFAs from crude microalgal oil and their subsequent conversion into liquid hydrocarbons, demonstrating the suitability of this design for the refinery of renewable feedstocks

Expanded Indenofluorenes: From Structure to Theory

As humanity moves into the future, the demand for new electronic devices increases. Flexible electronics that could be bendable, wearable, and/or biocompatible are more desired and, fortunately, closer to our grasp than ever. In order to produce these new devices, electronic materials not based on ridged, brittle crystals are needed. One candidate for these new electronics are organic electronic materials. Organic electronic materials have the potential to lead to devices that are flexible, simple to produce and that can take advantage of state-of-the-art processes like non-linear optics, spintronics and singlet fission. In order to access these exciting new devices, however, a better understanding of the type of conjugated organic molecules on which they will be based is needed. This dissertation explores the expansion of the indenofluorene project from a rotation student’s small spin off to an examination of a full class of materials. First, this document details the synthesis of donor-acceptor-donor triads using indenofluorene starting material, the dione, as the acceptor portion. What follows is an in-depth examination of the aromatic and antiaromatic properties of the class of materials we deemed diarenoantiaromatics. The computational techniques used are expanded along with the antiaromatic core of each molecule in order to evaluate the diradical character of the core expanded molecules being synthesized by my lab mates. Finally, the synthesis and characterization of a nine ring, linear dianthracenoindacene and the progress toward the thirteen ring dipentacenoindacene isomers are described.10000-01-0

Synthesis and Optoelectronic Properties of Indeno[1,2‑<i>b</i>]fluorene-6,12-dione Donor–Acceptor–Donor Triads

We report the synthesis of donor–acceptor–donor triads based on the indeno­[1,2-<i>b</i>]­fluorene-6,12-dione (IF) scaffold. Arylethynyl donor group attachment expands the light absorption of these molecules to the 600–700 nm region compared to derivatives with nondonating silylethynyl substituents yet does not affect the electron-accepting capabilities of the IF core. All triads show reduction potentials at similar or less negative potentials compared to the silylethynyl derivatives. Protonation studies using the bis­(dibutylanilino) triad verify the charge transfer nature of the expanded absorption profile

Modulating Paratropicity Strength in Diareno-Fused Antiaromatics

Understanding and controlling the electronic structure of molecules is crucial when designing and optimizing new organic semiconductor materials. We report the regioselective synthesis of eight π-expanded diarenoindacene analogues based on the indeno­[1,2-<i>b</i>]­fluorene framework along with the computational investigation of an array of diareno-fused antiaromatic compounds possessing <i>s</i>-indacene, pentalene, or cyclobutadiene cores. Analysis of the experimental and computationally derived optoelectronic properties uncovered a linear correlation between the bond order of the fused arene bond and the paratropicity strength of the antiaromatic unit. The <i>E</i>_red¹ for the pentalene and indacene core molecules correlates well with their calculated NICS_πZZ values. The findings of this study can be used to predict the properties of, and thus rationally design, new diareno-fused antiaromatic molecules for use as organic semiconductors

Bifunctional Adsorbent-Catalytic Nanoparticles for the Refining of Renewable Feedstocks

A hybrid adsorbent-catalytic nanostructured material consisting of aminopropyl groups and nickel nanoparticles immobilized in mesoporous silica nanoparticles (AP-Ni-MSN) was employed to selectively capture free fatty acids (FFAs) and convert them into saturated hydrocarbons. The working principle of these sorbent-catalytic particles was initially tested in the hydrogenation of oleic acid. Besides providing selectivity for the capture of FFAs, the adsorbent groups also affected the selectivity of the hydrogenation reaction, shifting the chemistry from hydrocracking-based (Ni) to hydrotreating-based and improving the carbon economy of the process. This approach was ultimately evaluated by the selective sequestration of FFAs from crude microalgal oil and their subsequent conversion into liquid hydrocarbons, demonstrating the suitability of this design for the refinery of renewable feedstocks.Reprinted (adapted) with permission from ACS Catalysis 3 (2013): 2750, doi:10.1021/cs4008039. Copyright 2013 American Chemical Society.</p

Bifunctional Adsorbent-Catalytic Nanoparticles for the Refining of Renewable Feedstocks

A hybrid adsorbent-catalytic nanostructured material consisting of aminopropyl groups and nickel nanoparticles immobilized in mesoporous silica nanoparticles (AP-Ni-MSN) was employed to selectively capture free fatty acids (FFAs) and convert them into saturated hydrocarbons. The working principle of these sorbent-catalytic particles was initially tested in the hydrogenation of oleic acid. Besides providing selectivity for the capture of FFAs, the adsorbent groups also affected the selectivity of the hydrogenation reaction, shifting the chemistry from hydrocracking-based (Ni) to hydrotreating-based and improving the carbon economy of the process. This approach was ultimately evaluated by the selective sequestration of FFAs from crude microalgal oil and their subsequent conversion into liquid hydrocarbons, demonstrating the suitability of this design for the refinery of renewable feedstocks

Synthesis and Properties of Indeno[2,1-c]fluorenes and Benzo- Fused Analogues

International audienceA new set of fully-conjugated indenofluorenes has been synthesized and confirmed by solid-state structure analysis. The indeno[2,1-c]fluorenes and their benzo-fused analogues all contain the antiaromatic as-indacene core. The molecules possess high electron affinities and show a broad absorption that reaches into the near-IR region of the electromagnetic spectrum. All of the featured compounds reversibly accept up to two electrons as revealed by cyclic voltammetry. Analysis of molecule tropicity using NICS-XY scan calculations show that, while the as-indacene core is less paratropic than s-indacene, benz[a]-annulation further reduces the antiaromaticity of the core. Antiaromatic strength of the as-indacene core can also be tuned by the position of fusion of additional arenes on the outer rings

Synthesis and Properties of Quinoidal Fluorenofluorenes

The synthesis and optoelectronic properties of 24 π-electron, formally antiaromatic fluoreno­[3,2-<i>b</i>]­fluorene and fluoreno­[4,3-<i>c</i>]­fluorene (FF), are presented. The solid-state structure of [4,3-<i>c</i>]­FF along with computationally analogous molecules shows that the outer rings are aromatic while the central four rings possess a bond-localized 2,6-naphthoquinodimethane motif. The antiaromaticity and biradical character of the FFs is assessed computationally, the results of which indicate the dominance of the closed-shell ground state for these molecules

Serendipitous Rediscovery of the Facile Cyclization of Z,Z‐3,5‐Octadiene‐1,7‐diyne Derivatives to Afford Stable, Substituted Naphthocyclobutadienes

International audienceThe serendipitous isolation of very small amounts of two naphthocyclobutadiene (NCB) derivatives has led to the computational re-examination of the electrocyclization of Z,Z-3,5-octadiene-1,7-diyne as well as the experimental and computational study of diethynylindeno[2,1-a]fluorene derivatives that contain the 3,5-octadiene-1,7-diyne motif as part of a larger π-framework. In both cases the calculated potential energy surface strongly implicates two successive electrocyclic reactions to afford the antiaromatic products. With the octadienediyne fragment locked in the reactive conformation, the postulated diethynylindeno[2,1-a]fluorene intermediates afford the NCBs in modest to good yields. X-ray crystallography of four NCBs as well as NICS-XY scan calculations show that the paratropic motif is located primarily in the benzocyclobutadiene fragment within the larger π-scaffold