Scientific Career

Thesis Title	Characterization of Lithium Ion Pair Structures in Solution. Effects of Ion Pair Separation on the Configurational Stability and Geometry of Sulfur- and Silicon-stabilized Organolithium Reagents.
Research Summary	Bob spent the first year or two years of his thesis work making substrates for asymmetric selenation of olefins, but then decided to join the lithium reagent folks and eventually coauthored 10 papers in the area. He followed up the work of Joe Borst on the behavior of organolithium reagents with HMPA as cosolvent, and perfected the NMR "HMPA titration" technique which has since become a standard experiment whenever a new lithium reagent is investigated in the group. Bob was among the first to detect triple ions and the unusual "sesquidimers" in ether-HMPA solutions, and performed an important stereochemical study on lithiated sulfides and selenides. During this work Bob made the astounding observation counter to chemist intuition and all previous experiments that some lithium reagents have a higher barrier to configurational inversion as a separated ion pair (lithium not connected to carbon) than as a contact ion pair.
Papers	"The First Organoselenium Ate Complex," Hans J. Reich, Birgir Ö. Gudmundsson and Robert R. Dykstra, J. Am. Chem. Soc. 1992, 114, 7937. (Communication). PDF "Structure Effects of Ion Pair Separation: Planar and Pyramidal Sulfur and Silicon Substituted Carbanions," H. J. Reich, R. R. Dykstra, J. Am. Chem. Soc. 1993, 115, 7041. (Communication). PDF "A Nuclear Magnetic Resonance Spectroscopic Technique for the Characterization of Lithium Ion Pair Structures in THF and THF/HMPA Solution," H. J. Reich, J. P. Borst, R. R. Dykstra, D. P. Green J. Am. Chem. Soc. 1993, 115, 8728-41. (Article). PDF "Effect of Ion Pair Separation on Inversion and Rotation of Sulfur, Selenium, and Silicon Stabilized Organolithium Reagents," Hans J. Reich, Robert R. Dykstra Angew. Chem., Int. Ed. Engl. 1993, 32, 1469-70. (Communication).PDF "Trimethylstannyl- and Tributylstannyllithium: Solution Structure in Ether, THF and HMPA," Hans J. Reich, Joseph P. Borst, Robert R. Dykstra, Organometallics 1994, 13, 1. (Communication). PDF "Solution Ion Pair Structure of 2-Lithio-1,3-Dithianes in THF and THF-HMPA," Hans J. Reich, Joseph P. Borst, Robert R. Dykstra, Tetrahedron 1994, 50, 5869. (Article). PDF "Solution Structure of Lithium Benzeneselenolate and Lithium Diphenylphosphide: NMR Identification of Cyclic Dimers and Mixed Dimers," Hans J. Reich and Robert R. Dykstra, Organometallics 1994, 13, 4578. (Article) PDF "Triple Ion Formation in Localized Organolithium Reagents," Hans J. Reich, William H. Sikorski, Birgir Ö. Gudmundsson and Robert R. Dykstra, J. Am. Chem. Soc. 1998, 120, 4035-4036. (Communication) PDF "Aggregation and Reactivity of Phenyllithium Solutions," Hans J. Reich, D. Patrick Green, Marco A. Medina, Wayne S. Goldenberg, Birgir Ö. Gudmundsson, Robert R. Dykstra, and Nancy H. Phillips, J. Am. Chem. Soc. 1998, 120, 7201-7210. (Article) PDF Suppl. "Identification and Mechanistic Consequences of Contact and Solvent-Separated Ion Pair Structures in Organolithium Chemistry." Hans J. Reich, Aaron W. Sanders, Martin J. Bevan, Wiliam H. Sikorski, and Robert R. Dykstra Latvian J. Chem. 2002, 93-103.(Article) PDF
Current Position	Proctor and Gamble Company