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Molecular Materials Development and application of materials with well defined molecular and bulk properties is becoming increasingly important for contemporary technologies. Our research addresses basic and applied problems and concentrates in three major areas of advanced organic materials. We design, synthesize, and characterize materials for optoelectronic applications, nanoscale construction, molecular electronics, and molecular magnetism. The desired electronic effects in organic molecules are engineered using main group elements such as B, Si, N, P, and S. Each project involves extensive computer-aided design of molecular systems, synthesis and study of the new materials, and comparison of the experimental results with theoretical predictions. One of our group's major strengths is our considerable expertise in organic synthesis and in the properties of liquid crystals. We have also developed a good level of understanding of semi-empirical and ab initio computational methods which allows us to predict molecular properties and also to choose synthetic targets for study. We are actively developing liquid crystalline materials for applications in flat panel displays. The centerpiece of our design of potentially magnetic radical liquid crystals is the thioaminyl radical fragment which can be easily incorporated into aromatic rings (e.g. Figure 2) and thus into the rigid cores of a variety of mesogenic molecules. The design is general and, in principle, allows for engineering of almost all types of liquid crystalline phases and the study of electronic and magnetic phenomena in semiordered media. Using these materials, we hope to test the theory that molecular organic magnetism may be achieved through partially oriented fluids. Nanotechnology and molecular electronics are rapidly growing interdisciplinary fields. However, there is a gap between the designs for nanodevices and available molecular building elements. Our goal is to fill this gap by providing rationally designed molecules, which would serve either as supportive elements, or as active components in molecular assembles. In our lab, we work on challenging ring systems with unique geometries and structures that can be used to make attractive spacers for the construction of a molecular diode, a molecular shift register, or for the study of electron transfer processes in general. Selected Publications Piecek W., Glab K.L., Januszko A., Perkowski P., Kaszynski P. Modification of electro-optical properties of an orthoconic chiral biphenyl smectogen with its isostructural carborane analogue. Journal of Materials Chemistry. 2009, 19 (8): 1173-1182. Kaszynski P., Pakhomov S., Gurskii M.E., Erdyakov S.Y., Starikova Z.A., Lyssenko K.A., Antipin M.Y., Mikhail Y., Young V.G., Bubnov Y.N. 1-Pyridine- and 1-Quinuclidine-1-boraadamantane as Models for Derivatives of 1-Borabicyclo[2.2.2]octane. Experimental and Theoretical Evaluation of the B-N Fragment as a Polar Isosteric Substitution for the C-C Group in Liquid Crystal Compounds. Journal of Organic Chemistry. 2009, 74 (4): 1709-1720. Johnson L., Ringstrand B., Kaszynski P. A convenient preparation of long chain 4-(4-n-alkylphenylazo)phenols and their 4-pentylbenzoate esters. Liquid Crystals. 2009, 36 (2): 179-185. Kaszynski P. Tautomerism and Regioselectivity of Acylation of 4-Hydroxy-2-mercaptopyridine-N-oxide and 2,4-Dimercaptopyridine-N-oxide: A Computational Study. Phosphorus Sulfur and the Related Elements. 2009, 184 (5): 1296-1306. Eccles W.; Jasinski M.; Kaszynski P.; Zienkiewicz K.; Stulgies B.; Jankowiak A. Reactivity of 13,13-dibromo-2,4,9,11-tetraoxadispiro[5.0.5.1]tridecane toward organolithiums: Remarkable resistance to the DMS rearrangement. Journal of Organic Chemistry. 2008, 73 (15): 5732-5744. Nagamine T.; Januszko A.; Ohta K.; Kaszynski P.; Endo Y. The effect of the linking group on mesogenic properties of three-ring derivatives of p-carborane and biphenyl. Liquid Crystals. 2008, 35 (7): 865-884. Januszko, A.; Kaszynski, P. A Comparison of Smectic Phase Induction in a Series of Isostructural Two-ring Esters by Tail Fluorination and Tail Elongation. Liquid Crystal. 2008, 35: 705-710. Januszko, A.; Glab, K. L.; Kaszynski, P. Induction of smectic behavior in a carborane-containing mesogen. Tail-fluorination of a three-ring nematogen and its miscibility with benzene analogues. Liquid Crystal. 2008, 35: 549-553. Pociecha, D.; Ohta, K.; Januszko, A.; Kaszynski, P.; Endo Y. Symmetric Bent-core Mesogens with m -Carborane and Adamantane as the Central Units. Journal of Materials Chemistry. 2008, 18: 2978-2982. Jasinski, M.; Jankowiak, A.; Januszko, A.; Bremer, M.; Pauluth, D.; Kaszynski, P. Evaluation of carborane-containing nematic liquid crystals for electro-optical applications. Liquid Crystal. 2008, 35: 343-350. Jankowiak, A.; Januszko, A.; Ringstrand, B.; Kaszynski, P. A New Series of Nematic and Smectic Liquid Crystals with Negative Dielectric Anisotropy: The effect of Terminal Chain Substitution on Thermal and Electro-optical Properties. Liquid Crystal. 2008, 35: 65-77. Jankowiak A.; Jakowiecki J.; Kaszynski P. Preparation of 4-Alkoxy-1-hydroxypyridine-2-thiones. Polish Journal of Chemistry. 2007, 81 (11): 1869-1877. Januszko A.; Kaszynski P.; Gruner B.R. Liquid crystalline derivatives of Bis(tricarbollide)Fe(II). Inorganic Chemistry. 2007, 46 (15): 6078-6082. Jankowiak A.; Jasinski M.; Kaszynski P. 1,1 '-bis(3-hydroxypropyl)ferrocene: Preparation and substitution with polyfluoroalkyl groups. Inorganica Chimica Acta. 2007, 360 (11): 3637-3641. Sienkowska M.J.; Farrar J.M.; Zhang F.; Kusuma S.; Heiney P.A.; Kaszynski P. Liquid crystalline behavior of tetraaryl derivatives of benzo[c]cinnoline, tetraazapyrene, phenanthrene, and pyrene: the effect of heteroatom and substitution pattern on phase stability. Journal of Materials Chemistry. 2007, 17 (14): 1399-1411. Sienkowska M.J.; Monobe H.; Kaszynski P.; Shimizu Y. Photoconductivity of liquid crystalline derivatives of pyrene and carbazole. Journal of Materials Chemistry. 2007, 17 (14): 1392-1398. Sienkowska M.J.; Farrar J.M.; Kaszynski P. Preparation of a discotic 2,4,7,9-tetraaryl-6H-dibenzo [c,e] [1,2] thiazine and generation of a persistent radical. Liquid Crystals. 2007, 34 (1): 19-24. Zienkiewicz J.; Fryszkowska A.; Zienkiewicz K.; Guo F.L.; Kaszynski P.; Januszko A.; Jones D. Synthesis of liquid crystalline 4H-benzo[1,2,4]thiadiazines and generation of persistent radicals. Journal of Organic Chemistry. 2007, 72 (9): 3510-3520. Nagamine T.; Januszko A.; Kaszynski P.; Ohta K.; Endo Y. Mesogenic, optical, and dielectric properties of 5-substituted 2-[12-(4-pentyloxyphenyl)-p-carboran-1-yl] [1,3]dioxanes. Journal of Materials Chemistry. 2006, 16 (39): 3836-3843. Januszko A.; Glab K.L.; Kaszynski P.; Patel K,.; Lewis R.A.; Mehl G.H.; Wand M.D. The effect of carborane, bicyclo[2.2.2] octane and benzene on mesogenic and dielectric properties of laterally fluorinated three-ring mesogens. Journal of Materials Chemistry. 2006, 16 (31): 3183-3192. Januszko A.; Kaszynski P.; Drzewinski W. Ring effect on helical twisting power of optically active mesogenic esters derived from benzene, bicyclo[2.2.2] octane and p-carborane carboxylic acids. Journal of Materials Chemistry. 2006, 16 (5): 452-461. Ringstrand B.; Vroman J.; Jensen D.; Januszko A.; Kaszynski P.; Dziaduszek J.; Drzewinski W. Comparative studies of three- and four-ring mesogenic esters containing p-carborane, bicyclo[2.2.2] octane, cyclohexane, and benzene. Liquid Crystals. 2005, 32 (8): 1061-1070. Stulgies B.; Pigg D.P.; Kaszynski P.; et al. 9,9-dimethyl-8,10 dioxapentacyclo[5.3.0.0(2,5).0(3,5).0(3,6)]Decane and Naphthotetracyclo[5.1.0.0(1,6).0(2,7)]oct-3-ene: New Substituted [1.1.1]Propellanes as Precursors to 1,2,3,4-Tetrafunctionalized Bicyclo[1.1.1]Pentanes. Tetrahedron. 2005, 61 (1): 89-95. Endo Y.; Songkram C.; Ohta K.; Kaszynski P. Distorted Benzene Bearing Two Bulky Substituents on Ajacent Positions: Structure of 1,2-bis(1,2-dicarba-closo-dodecaboran-1-yl)Benzene. Tetrahedron Letters. 2005, 46 (4): 699-702. Fryszkowska A.; Tilford R.W.; Guo F.; Kaszynski P. Activation of Chlorine and Fluorine by a Phenylazo Group Towards Nucleophilic Aromatic Substitution. Regioselective Preparation of Polysubstituted Anilines. Tetrahedron. 2005, 61 (9): 2327-2333. Specialties
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Vanderbilt University Department of Chemistry |
Associate Professor of Chemistry
The dielectric anisotropy is related to the distribution of dipole moments within the molecule and is essential for the electrooptical effect in liquid crystal displays in calculators, laptop computers, etc. An electron deficient boron atom and its polar bonds in tetra- and higher-coordinated boron compounds are at the heart of our design. We are exploring boron closo-clusters, such as p-carborane, as novel structural elements of liquid crystalline molecules as shown in Figure 1.We also pursue a novel class of ionic liquid crystals based on the [CB9H10]- inorganic boron cluster.