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S. Holger Eichhorn


Dr. S. Holger Eichhorn
Materials/Organic/Polymer Chemistry
Ph.D. (Bremen Germany)
Associate Professor
253-3000 Ext. 3990
364 Essex Hall
Personal Homepage

Organic / Materials / Polymer Chemistry, Liquid Crystals, Organic Semiconductors, and Metal Nanoparticles

Our general area of research is best categorized as synthetic materials chemistry, which encompasses molecular design, synthesis, and materials characterization. Synthesis clearly dominates our efforts and we cover a wide range of synthetic methodology including modern and environmentally more benign methods, such as solvent-free and microwave assisted reactions. We are specialized in the synthesis of heterocycles and dyes, polyurethanes and their (nano)-composites, and monolayer protected metal nanoparticles.

Synthesis is often preceded by molecular design and the prediction of properties that heavily rely on computational studies at the DFT level of theory (Gaussian 09, SHARCNET). Synthesis is followed by the characterization of molecular and supramolecular structures and properties of the prepared compounds/materials. We are particularly well equipped for temperature dependent (polarized) spectroscopy (UV-Vis, IR, Raman, and CD) and 2D X-ray diffraction of anisotropic materials as well as their thermal analysis (DSC and TGA/DTA-MS). Please visit our separated websites for more information on powder X-ray diffraction and thermal analysis. Investigations of electronic properties of our compounds and their performance in devices are conducted in collaboration with other groups in North America and worldwide.

Present areas of interest include:

Columnar mesophases as organic semiconductors for organic electronics

Columnar mesomorphism of fluorescent board‒shaped quinoxalinophenanthrophenazine derivatives with donor‒acceptor structure. Shuai Chen, M. Ahmida, F. S. Raad, B. R. Kaafarani and S. H. Eichhorn, Org. Lett. 2013 (15,3) 558-61, DOI: 10.1021/ol303375x.

Quasi Temperature Independent Electron Mobility in Hexagonal Columnar Mesophases of an H-Bonded Benzotristhiophene Derivative. A. Demenev, S. H. Eichhorn, T. Taerum, D. F. Perepichka, S. Patwardhan, F. C. Grozema, L. D. A. Siebbeles and R. Klenkler, Chem. Mater. 2010 (22,4) 1420-28, DOI: 10.1021/cm902453z.

Halide effect in electron rich and deficient discotic Phthalocyanines. M. M. Ahmida, R. Larocque, M. S. Ahmed, A. Vacaru, B. Donnio, D. Guillon and S. H. Eichhorn, J. Mater. Chem. 2010 (20,7) 1292–303, DOI: 10.1039/b917169j. Invited Contribution to Emerging Investigators Themed Issue.

Monolayers and thin films of organic dyes

Face- and edge-on orientations of octa-acid and -alcohol substituted tetraazaporphyrins in langmuir and Langmuir-Blodgett monolayers. M. M. Ahmida, S. Dufour, Hui–Sheng Li, H. Kayal, R. Schmidt, C. E. DeWolf and S. H. Eichhorn, Soft Matter 2013 (9,3) 811-9, DOI:10.1039/c2sm27064a.

Cross-linking of discotic tetraazaporphyrin dyes in 2 and 3 dimensions by clickchemistry. H. Kayal, M. M. Ahmida, S. Dufour, H. Taing, S. H. Eichhorn, J. Mater. Chem. C 2013 (1,42), 7064-7072, DOI: 10.1039/C3TC31588F

Exotic liquid crystals

Mesomorphic [2]rotaxanes: Sheltering ionic cores with interlocking components. N. D. Suhan, S. J. Loeb and S. H. Eichhorn, J. Am. Chem. Soc. 2013 (135,1) 400–8, DOI: 10.1021/ja309558p. Featured in JACS Spotlights!

Hollow Six-Stranded Helical Columns of a Helicene. M. A. Shcherbina, X. Zeng, T. Tadjiev, G. Ungar, S. H. Eichhorn, K. E. S.Phillips, T.J. Katz, Angew. Chem. Int. Ed. 2009 (48,42) 7837–40, DOI: 10.1002/anie.200903658.

Ligand design for mono-layer protected metal nanoparticles

Thiolate Ligands Affect Size and Purity of Gold Nanoparticles Generated by a Single Phase Solution Method. W. Jia, J. McLachlan, J. Xu, and S. H. Eichhorn, J. Therm. Anal. Calorim. 2010 (100,3) 839-45, DOI 10.1007/s10973-010-0711-2.

Ligand Effects on the Size and Purity of Pd Nanoparticles. M. Iqbal, J. McLachlan, W. Jia, N. Braidy, G. Botton and S. H. Eichhorn, J. Therm. Anal. Calorim. 2009 (96) 15–20, DOI: 10.1007/s10973-008-9832-2.

Electrically and thermally conductive polymer composites

Thermal conductivity of polyurethane composites containing nanometer and micrometer sized silver particles. M. Iqbal, M. McCullough, A. Harris and S. H. Eichhorn, J. Therm. Anal. Calorim. 2012 (108,3) 933-938, DOI: 10.1007/s10973-012-2412-5.