Publications, Grants,Presentations & Workshops



Properties and Reactivities of Transition Metal Polyhydridometallate Complexes

This project has sought to expandt the current knowledge in synthetic methods and reactivity patterns of less common  complex transition metal hydride systems, [MHn]z-.  The current metal systems under investigation are where M = Fe and Ru.  Solution synthesis of the complex hydride,[FeH6]4-, is accomplished by an improved benchtop procedure starting from FeX2 and PhMgX (X=Cl and Br) in THF. 1
 The product [FeH6][Mg(THF) 2X]4, (see below), reacts with alkoxide to form the hydrocarbon soluble species,

   

 

This complex displays spectroscopic behavior typical of charge-transfer behavior displayed by organic ion pairs.  Further, 13C NMR shows that the alkoxide ions are positioned around the Mg2+ ion according to the 1/r6 distance dependence from the Van Vleck paramagnetic iron center.  Work has shown these compounds as aids in elucidating Fe-H vibrations buried deep within metalloproteins.3

Current work has focused on use of these novel reagents as precursor catalysts in the preparation of organics and novel ferromagnetic materials.

1.  Linn, D. E., Jr.; Skidd, G. M.; Tippmann, E. M.  Inorg. Chim. Acta 1999, 291, 142.
2.  Linn, D. E., Jr.; Gibbins, S. G.  J. Organomet. Chem. 1998, 554, 171.
3.  Bergmann, Uwe; Sturhahn, Wolfgang; Linn, Donald E., Jr.;  Jenny, Francis E., Jr.; Adams, Michael, W. W.; Rupnik, Kressmir; Hales, Brian J.; Apl, Ercan E.; Mayse, Aaron; Cramer, Stephen P., “Observation of Fe–H(D) Modes by Nuclear Resonant Vibrational Spectroscopy”,  J. Am. Chem. Soc. 2003, 125(14), 4016.




 

NSF-CCLI  Adaptation and Implementation #9980968
CollaborativeUndergraduate Education Using Enhanced NMR Technology in NE Indiana

Undergraduate education in NMR theory and operation, from the freshman to upper level courses, presents the challenge which is now being addressed by this proposal.  (A)  Restructuring will begin at the general chemistry laboratory level in which a number average molecular weight will be collected on samples of industrially important organic polymers using NMR.  (B)  Sophomore organic chemistry laboratory will be enhanced by beginning instruction in 1D 13C{1 H}and DEPT NMR spectroscopy.  (C)  Additional biochemistry andorganic laboratories will introduce the use of NMR to make stereochemical assignments of natural products and resolve stereoisomers using chirotropic reagents.  (D)  Inorganic synthesis laboratory will be introduced to the use of 2DNMR (HETCOR and 1H NOESY) spectra to probe both molecular structure and dynamics of transition metal complexes. (E)  A dual level undergraduate/graduate course entitled "NMR Theory and Practice" is proposed which is to be offered as a one hour lecture and three hour laboratory package to engage students who which to pursue the subject in more depth.  This course will discuss some pitfalls in NMR spectroscopy such as sample preparation, instrumental issues, optimizing signal-to-noise and resolution, decoupling, relaxation, the nuclear Overhauser effect, mathematics of the Fourier transform, quadrature phase detection and instrumental artifacts.  (F)  Students enrolled in both teaching and CHM 499 (undergraduate research) courses will further benefit from enhanced instrument availability and new computer networked pedagogical and analytical NMR software.  One or two new experiments will be presented in a peer reviewed chemical education journal [(A) and (D)].



Ongoing Goals in UndergraduateTeaching and Research

Two or three undergraduate scholars in their second or third years would be employed on a part-time to full-time basis.  These students must learn how to use research publications and databases, how to follow published directions carefully, and how to extend literature methods.  Other aspects include the treatment of numerical data, appreciating artifacts, and the use of computers (PC, Mac and UNIX), helping students with written and oral presentations, how to seek research support, how to cope with hazardous experimental situations and how to assume responsibility in the maintenance of laboratory equipment. Students supported by this research have thus far contributed to eight presentations at campus and regional undergraduate conferences in addition to the PI’s contributions at national and international conferences