• UNL
• NCMN
• Faculty
• Andrzej Rajca

Nebraska Center for Materials and Nanoscience

Faculty Rajca

Current Research

Professor Rajca’s research area of interest is organic chemistry with emphasis on novel materials with magnetic, conducting, and optical properties. Understanding of fundamental aspects of electronic structure and its dependence on the size ranging from fraction of nanometer to several nanometers is the underlying theme of many projects in this research group.

Currently, their focus is on the design and synthesis of stable high-spin polyradicals. Following the design principles developed for the polyarylmethyls, they are working on syntheses of high-spin polynitroxides and other polyradicals stable at ambient condition. They are in search for macrocyclic cores and linkers that are promising building blocks for preparation of organic polymer magnets with improved ordering temperature and stability at ambient conditions (“plastic magnets”).

Their efforts are aimed at the synthesis and study of chiral π-conjugated molecules and polymers, precursors to organic chiral semiconductors/conductors and materials for chiral waveguides. The target molecules include molecules related to a hypothetical allotrope of carbon (3-dimensional graphite) and sulfocarbons (C_nS_m). A number of chiral organic molecules with interesting molecular structure and properties are being prepared in this research group.

Recent Publications

Rajca, A (Rajca, Andrzej); Vale, M (Vale, Matthew); Rajca, S (Rajca, Suchada), Diarylnitroxide diradicals: Low-temperature oxidation of diarylamines to nitroxides, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 130 (28): 9099-9105 JUL 16 2008

Sato, H (Sato, Hideo); Kathirvelu, V (Kathirvelu, Velavan); Spagnol, G (Spagnol, Gaelle); Rajca, S (Rajca, Suchada); Rajca, A (Rajca, Andrzej); Eaton, SS (Eaton, Sandra S.); Eaton, GR (Eaton, Gareth R.), Impact of electron-electron spin interaction on electron spin relaxation of nitroxide diradicals and tetraradical in glassy solvents between 10 and 300 K, JOURNAL OF PHYSICAL CHEMISTRY B, 112 (10): 2818-2828 Mar 13 2008

Vale, M (Vale, Matthew); Pink, M (Pink, Maren); Rajca, S (Rajca, Suchada); Rajca, A (Rajca, Andrzej), Synthesis, structure, and conformation of aza[1(n)]metacyclophanes, JOURNAL OF ORGANIC CHEMISTRY, 73 (1): 27-35 Jan 4 2008

Rajca, A (Rajca, Andrzej); Pink, M (Pink, Maren); Mukherjee, S (Mukherjee, Surnit); Rajca, S (Rajca, Suchada); Das, K (Das, Kausik), ,3-alternate calix[4]arene nitronyl nitroxide tetraradical and diradical: synthesis, X-ray crystallography, paramagnetic NMR spectroscopy, EPR spectroscopy, and magnetic studies, TETRAHEDRON, 63 (44): 10731-10742 Oct 29 2007

Rajca, A (Rajca, Andrzej); Rajca, S (Rajca, Suchada); Pink, M (Pink, Maren); Miyasaka, M (Miyasaka, Makoto), Annelated, chiral pi-conjugated systems: Tetraphenylenes and helical beta-oligothiophenes, SYNLETT, (12): 1799-1822 Jul 24 2007

Rajca, A (Rajca, Andrzej); Takahashi, M (Takahashi, Masahiro); Pink, M (Pink, Maren); Spagnol, G (Spagnol, Gaelle); Rajca, S (Rajca, Suchada), Conformationally constrained, stable, triplet ground state (S=1) nitroxide diradicals. Antiferromagnetic chains of S=1 diradicals, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 129 (33): 10159-10170 Aug 22 2007

M. Miyasaka, A. Rajca, “Synthesis of a Short Carbon-Sulfur Helicene: Pd-Catalyzed Cross-Coupling at the β-Positions of Thiophenes,” Synlett 177–182 (2004).

A. Rajca, M. Pink, T. Rojsajjakul, K. Lu, Hua Wang, and S. Rajca, “X-ray Crystallography and Magnetic Studies of a Stable Macrocyclic Tetranitroxide. Intramolecular Dimer of Nitroxides in a Constrained Geometry of the Upper Rim of Calix[4]arene”, J. Am. Chem. Soc. 125, 8534-8538 (2003).

A. Rajca, “From High-Spin Organic Molecules to Organic Polymers with Magnetic Ordering”, Chem. Eur. J. 8, 4834-4841 (2002) (Concept Article).

Recent Graduates

• Kausik Das PhD 2007 Streck Laboratories, Omaha, Nebraska
• Sumit Mukherjee PhD 2006 University of Wisconsin-Madison
• Kan Lu, M.S., 1995, now with Norchem (Chicago, IL)