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Assistant Professor, Inorganic Chemistry
A.B. 1996, Harvard University
Ph.D. 2000, Northwestern University
Postdoctoral: 2000-2002, Harvard University
Email: ccmclau@ilstu.edu
Phone: (309)438-7019
Office: 206 Science Laboratory Building
Currently, my research
interests lie with vanadium coordination chemistry, with one
conceived project focused on materials and catalysis and another
involving bio-mimetic activity of V complexes. These topics have
been chosen with student interests and education in mind in that
they each expose students to a variety of synthetic and
characterization techniques while pursuing some intriguing
chemical problems. A brief summary of each project follows.
Characterization techniques and required instrumentation as well
as a brief summary follow the research plans.
Open Framework Vanadium-Phosphonates as Catalysts
Vanadium is used quite extensively for oxidation
catalysis-- specifically for sulfuric acid production. Recently,
it has been demonstrated that a vanadyl phosphate catalyst
transforms C4H10 to maleic anhydride. Can
simple reactions be used to make vanadium phosphates and
phosphonates for catalytic use?
It has been shown that reactions of
phosphonic acids with metal alkyl reagents leads to the
formation of cage structures. Metal -oxy and -amino complexes
have also been reacted with phosphonic acids to create these
open frameworks. The work in this area has, thus far, been
limited to gallium and aluminum alkyl species. Other metal
systems could be explored and, perhaps, expose new structures
with unusual properties. With an open framework like a zeolite,
vanadium species such as these could possess high surface areas
conducive to effective catalysis. It is the goal of this work to
produce new vanadium phosphate or -phosphonate complexes that
possess open frameworks and to study their catalytic properties.
Biomimetic Uses of Vanadium: Insulin-Enhancing V Complexes
Over the past 25 years, a number of vanadium complexes
have been shown to be "insulin mimetic", that is, to
diminish blood glucose levels, when administered as therapeutic
agents. More recent studies have shown that these
complexes do not actually mimic insulin, but merely enhance the
effects of the small quantities of insulin that are present. A
variety of coordination complexes containing combinations of
N/S/O donor sets all seem effective in reducing blood glucose
levels regardless of which donor set is employed. Complexes with
ligand systems including dithiolenes (S/S), cysteine-amines
(S/N), picolinates (N/O), catecholates (O/O), salen (N/O), and
guanidine (N/N) have all been employed, all almost exclusively
with V(IV) and V(V) systems. The disparate nature of the ligands
suggests that it is the metal center and not the ligand that is
playing the dominant role in therapy. To date,
bis(picolinato)oxovanadium(IV) (VO(pico)2) is one of
the most effective coordination complex being investigated for
use in diabetic therapy.
Although initial studies were with VO43-, a V(V) complex, subsequent
studies have shown that V complexes, whether administered as
V(III), V(IV), or V(V) complexes, all seem to be effective in
reducing blood glucose levels. Although V(III) is believed to
oxidize to V(IV) or V(V) under physiological conditions, these
transformations are not well studied and the end products of
these oxidations are only hinted at, save for the V(OH2)63+/SO42-system.
One of the dangers of using V complexes for diabetic therapies is the accumulation of V in the
body, especially in the bone with, as yet, unknown physiological
consequences. With appropriate ligand choice, the required dose
may be minimized. It is the goal of this work
to gain an understanding of the oxidation under physiological
conditions of a series of V(III) species with well-understood
ligands and then implement the acquired knowledge in the
synthesis of vanadium coordination complexes to be studied for
bio-mimetic insulin-enhancing properties.
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SELECTED PUBLICATIONS
Weberski, M. P., Jr.; McLauchlan, C. C. Synthesis, Reactivity, and X-ray Structural Characterization of a Vanadium(III) Oxidation Pre-Catalyst, (CpPOEtCo)VCl2(DMF), Inorg. Chem. Commun. 2007, 10, 906-909. [doi:10.1016/j.inoche.2007.04.016]
Greiner, B. A.; Marshall, N. M.; Sarjeant, A. A. N.; McLauchlan, C. C., Synthesis and Characterization of a Series of [M(2-MeTIC)2]2+ and [M(2-TIC)2]2+ Complexes (M= Co, Ni). Inorg. Chim. Acta 2007, 360, 3132-3140. [doi:10.1016/j.ica.2007.03.007]
Weberski, M.P., Jr.; McLauchlan, C. C. "Bis[η5-cyclopentadienyltris(diethylphosphito- κ3-P,P',P") cobaltate(III)-κ3-O,O',O"]cobalt(II)" Acta Crystallogr., Sect. E.: Struct. Rep. Online. 2007, 63, m1171-m1172. [doi:10.1107/S1600536807013001]
McLauchlan, C. C.; McDonald, K. J. "Cocrystallization of dichloro-(N,N-dimethylformamide)[hydrotris(pyrazol-1-yl)borato]vanadium(III) with its partially oxidized analog chloro(N,N-dimethylformamide)[hydrotris(pyrazol-1-yl)borato]oxovanadium(IV)," Acta Crystallogr., Sect. E.: Struct. Rep. Online 2006, 62, m588-m590. [doi:10.1107/S1600536806005423]
Weberski, M. P., Jr.; McLauchlan, C. C.; Hamaker, C. G. "Synthesis and X-ray Structural Characterization of M(3,5-tBu2-salophen) (M = Cu, V=O)," Polyhedron 2006, 25, 119-123.
McLauchlan, C. C.; McDonald, K. J. "Chlorohydrotris(pyrazol-1-yl)boratooxo(pyrazole)vanadium(IV)," Acta Crystallogr., Sect. E.: Struct. Rep. Online 2005, 61, m2379-m2381. [doi:10.1107/S1600536805033568]
McLauchlan, C. C.; Ziegler, A. J.; Herlinger, A. W. "Pentane-1,5-bisphosphonic Acid," Acta Crystallogr., Sect. E.: Struct. Rep. Online 2005, 61, o1359-o1361. [doi:10.1107/S1600536805011207]
Fomitchev, D. V.; McLauchlan, C. C.; Holm, R. H. "Heterometal Cubane-Type MFe3S4 Clusters (M = Mo, V) Trigonally Symmetrized with Hydrotris(pyrazolyl)borate(1-) and Tris(pyrazolyl)methanesulfonate(1-) Capping Ligands," Inorg. Chem., 2002, 41, 958-966.
McLauchlan, C. C.; Robowski, S. D.; Ibers, J. A. "Synthesis and Characterization of the Metal Maleonitrilediselenolates [K([2.2.2]-cryptand)]2[M(Se2C2(CN)2)2] (M = Ni, Pd, Pt) and [Ni(dmf)5Cl]2[Ni(Se2C2(CN)2)2]," Inorg. Chem., 2001, 40, 1372-1375.
Complete List
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