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Chemistry & Chemical Biology / New Brunswick |
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Karsten Krogh-Jespersen Professor M.S. 1974, Ph.D. 1976, New York University |
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Research
Summary
My research efforts focus on computational investigations of molecular electronic structure using ab initio and semiempirical molecular orbital techniques.Ab initio calculation of the catalytic activation of C-H and C-F bonds by transition metals
In a DOE-funded collaboration with Professor Alan Goldman and his research group, we are using ab initio electronic structure methods to calculate thermodynamic and kinetic parameters pertaining to a number of fundamental catalytic reactions involving transition metal complexes and small molecule substrates. We are especially interested in C-X (X = H, F) bond breaking processes and in the study of oxygen atom transfer reactions. Also of interest is the accurate computation of kinetic and thermodynamic isotope effects for organometallic reactions. We hope to make such calculations into almost a "routine" tool and to provide detailed mechanistic interpretations of isotope effects for a number of prototypical - and some perhaps not so prototypical - reactions.Semiempirical electronic structure calculations on large systems
We use semiempirical all-valence electron methods for studies of electronically excited states of large molecules. We are currently investigating a number of dimeric systems related to photosynthetic reaction centers and also some small molecular aggregates of potential interest to photovoltaic cell design. Finally, the merger of molecular orbital techniques with classical molecular mechanics/dynamics techniques for the purpose of investigating the ground and excited state properties of molecules imbedded in a condensed phase such as water or protein continue to be of interest.Chemical Education
I have, for a number of years, mostly been involved in the teaching of General Chemistry. However, I have just returned to delivering one of my favorite courses, the introductory course in quantum chemistry for graduate students (and senior undergraduates). I am having particular fun with a number of computational assignments in this course — for additional details about this project, look at: Atomic and Molecular Structure: Chemistry 421/521Representative Publications
R. A. Moss, J. Tian, R. R. Sauers, and K. Krogh-Jespersen, "Tracking ‘Invisible’ Alkylchlorocarbenes by their σ --> p Absorptions: Dynamics and Solvent Interactions", J. Am. Chem. Soc., 129, 10019-10028 (2007).
R. A. Moss, J. Tian, R. R. Sauers, D. H. Ess, K. N. Houk, and K. Krogh-Jespersen, "The Synthesis of Dichlorodiazirine and the Generation of Dichlorocarbene: Spectroscopy and Structure of Dichlorocarbene-Ylides", J. Am. Chem. Soc., 129, 5167-5174 (2007).
R. A. Moss, J. Tian, G. Chu, R. R. Sauers, and K. Krogh-Jespersen, "New Mechanisms Centered on Reactive Intermediates: Examples from Diazirine and Carbene Chemistry", Pure Appl. Chem., 79, 993-1001 (2007).
R. Ghosh, X. Zhang, P. Achord, T. J. Emge, K. Krogh Jespersen, and A. S. Goldman, "Dimerization of Alkynes Promoted by a Pincer-Ligated Iridium Complex. C-C Reductive Elimination Inhibited by Steric Crowding", J. Am. Chem. Soc., 129, 853-866 (2007).
D. M. Himmel, S. G. Sarafianos, S. Dharmasena, M. M. Hossain, K. McCoy-Simandle, T. Ilina, A. D. Clark, Jr., J. L. Knight, J. G. Julias, P. K. Clark, K. Krogh-Jespersen, R. M. Levy, S. H. Hughes, M. A. Parniak, and E. Arnold, "HIV-1 Reverse Transcriptase Structure with RNase H Inhibitor Dihydroxy Benzoyl Naphtyl Hydrazone Bound at a Novel Site", ACS Chem. Biol., 1, 702-712 (2006).
X. Zhang, T. J. Emge, K. Krogh-Jespersen, and A. S. Goldman, "Reaction of Nitromethane with an Iridium Pincer Complex. Multiple Binding Modes of the Nitromethanate Anion", Organometallics, 25, 1303-1309 (2006).
K. Zhu, P. D. Achord, X. Zhang, K. Krogh-Jespersen, and A. S. Goldman, "Highly Effective Pincer-Ligated Iridium Catalysts for Alkane Dehydrogenation: DFT Calculations of Relevant Thermodynamic, Kinetic, and Spectroscopic Properties", J. Am. Chem. Soc., 126, 13044-13053 (2004).
A. S. Goldman, K. B. Renkema, M. Czerw, and K. Krogh-Jespersen, "Alkane Transfer-Dehydrogenation Catalyzed by a Pincer-Ligated Iridium Complex", pp. 198-215 in ACS Symposium Series No. 885, "Activation and Functionalization of C-H Bonds", K. I. Goldberg and A. S. Goldman, Ed(s); 2004.
K. Krogh-Jespersen, M. Czerw, and A. S. Goldman, "DFT Calculations on the Mechanism of (PCP)Ir-Catalyzed Acceptorless Dehydrogenation of Alkanes: Realistic Computational Models and Free Energy Considerations", pp. 216-233 in ACS Symposium Series No. 885, "Activation and Functionalization of C-H Bonds", K. I. Goldberg and A. S. Goldman, Ed(s); 2004.
K. Krogh-Jespersen, M. Czerw, and A. S. Goldman, "Computational and Experimental Studies of the Mechanism of (PCP)Ir-catalyzed Acceptorless Dehydrogenation of Alkanes", Special Issue: "Progress Towards the Development of Catalytic Systems for Selective C-H and C-C Bond Activation", J. Mol Cat. A: Chemical, 189, 95-110, (2002).
K. Krogh-Jespersen, M. Czerw, N. Summa, K. B. Renkema, P. Achord, and A. S. Goldman, "On the Mechanism of (PCP)Ir-catalyzed Acceptorless Dehydrogenation of Alkanes: a Combined Computational and Experimental Study", J. Am. Chem. Soc., 124, 11404-11416 (2002).
K. Krogh-Jespersen, M. Czerw, K. Zhu, B. Singh, M. Kanzelberger, N. Darji, P. Achord, K. B. Renkema, and A. S. Goldman, "Combined Computational and Experimental Study of Substituent Effects on the Thermodynamics of H2, CO, Arene, and Alkane Addition to Iridium", J. Am. Chem. Soc., 124, 10797-10809 (2002).
R. A. Moss, F. Zheng, and K. Krogh-Jespersen, "Rearrangement Kinetics of Spiropentylchlorocarbene, [3]Triangulylchlorocarbene, and Related Species", Organic Letters, 3, 1439-1442 (2001).
M. Czerw, T. K. Whittingham, and K. Krogh-Jespersen, "Oxidative Addition of Dihydrogen to M(PH3)2Cl, M = Rh and Ir: A Computational Study Using DFT and MO Methods" in Computational Metalloorganic Chemistry, T. Cundari, Ed., Marcel Dekker, Inc., Chpt 13, pp 323-344 (2001) (invited).
K. Krogh-Jespersen, M. Czerw, M. Kanzelberger, and A. S. Goldman, "DFT/ECP Study of C-H Activation by (PCP)Ir and (PCP)Ir(H)2 (PCP = ?3-1,3-C6H3(CH2PR2)2). Enthalpies and Free Energies of Associative and Dissociative Pathways", J. Chem. Inf. Comp. Sci., 41, 56-63 (2001) (invited; ECP 2000 Symposium Issue).
M. Kanzelberger, B. Singh, M. Czerw, K. Krogh-Jespersen, and A. S. Goldman, "Addition of C-H Bonds to the Catalytically Active Complex (PCP)Ir (PCP = ?3-2,6-(R2PCH2)2C6H3)", J. Am. Chem. Soc., 122, 11017-11018 (2000).
L. A. Burke and K. Krogh-Jespersen, "Alternating Planarity/Nonplanarity in n-Doped Odd-Numbered, All-Trans Polyenes: Molecular Structures of NaCnHn+2 (n = 3, 5, 7, and 9)", J. Mol. Modeling, 6, 248-256 (2000) (invited; P. v. R. Schleyer 70'th Birthday Festschrift).
M. Czerw, A. S. Goldman, and K. Krogh-Jespersen, "Addition of Ammonia to AlH3 and BH3. Why Does Only Aluminum Form 2:1 Adducts?", Inorg. Chem., 39, 363-369 (2000).