Dominic V Mcgrath

Professor, Chemistry and Biochemistry-Sci

Professor, BIO5 Institute

Primary Department

Chemistry & Biochemistry

Department Affiliations

Chemistry & Biochemistry

BIO5 Institute

Contact

(520) 626-4690

mcgrath@u.arizona.edu

Research Interest

Dominic Mcgrath, PhD, set forth a program which involves the use of organic synthesis for the design, development, and application of new concepts in macromolecular, supramolecular, and materials chemistry. Research efforts span a number of areas in the chemical sciences and include studies of: 1) chiral dendritic macromolecules and the effect of chiral subunits on dendrimer conformation, 2) photochromic dendrimers and linear polymers which undergo structural changes in response to visible light, 3) liquid crystalline materials based on dendritic and photochromic mesogens, and 4) synthesis of new ligands based on saturated nitrogen heterocycles.A continuing interest remains in the effect of structural perturbations on the properties and functional of dendritic macromolecules. Part of this research addresses the design, synthesis, and study of dendrimeric materials containing chiral moieties in the interior for influencing the conformational order of these 3-dimensional macromolecules. An ultimate goal is to develop materials active for the selective clathration of small guest molecules. Potential applications include chemical separations, sensor technology, environmental remediation, and asymmetric catalysis.Dr. Mcgrath and his lab team recently developed several new classes of dendritic materials containing photochromic subunits. As nature uses light energy to alter function in photoresponsive systems such as photosynthesis, vision, phototropism, and phototaxis, they use light energy to drive gross topological or constitutional changes in fundamentally new dendritic architectures with precisely placed photoresponsive subunits. In short, they can drive dendrimer properties with light stimuli. Two entirely new classes of photoresponsive dendritic macromolecules have been developed and include: 1) photochromic dendrimers and 2) photolabile dendrimers. Dr. Mcgrath anticipates that switchable and degradable dendrimers of this type will have application in small molecule transport systems based on their ability to reversibly encapsulate guest molecules. He continues to develop these materials as potential transport hosts and photoresponsive supramolecular assemblies.

Publications

Synthesis of optically active chiral dendrimers with 1,2-diol linkages

McElhanon, J., Wu, M., Escobar, M., & McGrath, D. V. (1996). Synthesis of optically active chiral dendrimers with 1,2-diol linkages. American Chemical Society, Polymer Preprints, Division of Polymer Chemistry, 37(2), 495-496.

Molecular packing of amphiphiles with crown polar heads at the air-water interface

Larson, K., Vaknin, D., Villavicencio, O., McGrath, D., & Tsukruk, V. V. (2002). Molecular packing of amphiphiles with crown polar heads at the air-water interface. Journal of Physical Chemistry B, 106(29), 7246-7251.

Abstract:

An amphiphilic compound containing a benzyl-15-crown-5 focal point, azobenzene spacer, and a dodecyl tail as a peripheral group has been investigated at the air-water interface. X-ray reflectivity and grazing incident diffraction (XGID) were performed on the Langmuir monolayers to elucidate molecular packing and orientation of molecular fragments for the compound with mismatch between cross-sectional areas of hydrophobic and hydrophilic segments. At high surface pressure, we observed intralayer packing of the alkyl tails with doubling parameters of the conventional orthorhombic unit cell (supercell) and long-range positional ordering. High tilt of the alkyl tails of 58° from the surface normal was a signature of molecular packing caused by a large mismatch between the cross-sectional areas of the polar head (45 Å²) and the alkyl tail (20 Å²).

Thermally reversible dendronized linear ab step-polymers via "click" chemistry

Polaske, N. W., McGrath, D. V., & McElhanon, J. R. (2011). Thermally reversible dendronized linear ab step-polymers via "click" chemistry. Macromolecules, 44(9), 3203-3210. doi:http://doi.org/10.1021/ma200296t

Abstract:

The synthesis and characterization of thermally labile dendronized linear AB step-polymers is described. First through third generation dendritic AB monomers 14a-c containing both a furan and furan-protected maleimide functionality were prepared by the Cu(I)-catalyzed azide-alkyne cycloaddition reaction followed by polymerization via the thermally reversible furan-maleimide Diels-Alder reaction. The assembly, disassembly, and reassembly behavior of linear dendronized step-polymers 16a-c was studied by GPC. © 2011 American Chemical Society.

Geometric Disassembly of Dendrimers: Dendritic Amplification

Szalai, M. L., Kevwitch, R. M., & McGrath, D. V. (2003). Geometric Disassembly of Dendrimers: Dendritic Amplification. Journal of the American Chemical Society, 125(51), 15688-15689. doi:http://doi.org/10.1021/ja0386694

Synthesis and degradation of photolabile dendrimers based on o-nitrobenzyl ether photolabile cores

Kevwitch, R. M., & McGrath, D. V. (2007). Synthesis and degradation of photolabile dendrimers based on o-nitrobenzyl ether photolabile cores. New Journal of Chemistry, 31(7), 1332-1336. doi:http://doi.org/10.1039/b617289j

Abstract:

Two dendrimer cores, 1a and 2a, that contain o-nitrobenzyl photolabile moieties, lack hydrolytically sensitive ester linkages and possess three and six sites for dendron attachment, respectively, have been alkylated to provide methylated core analogs 1b and 2b as well as second-generation benzylaryl ether dendrimer 1c and third-generation dendrimer 2c. These dendrimers undergo clean photocleavage as indicated by the evolution of isosbestic points in the UV spectra during photolysis. In addition, the nature of the photodegradation products was confirmed by observing the photolyses by both ¹H NMR and GPC. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Dominic V Mcgrath