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

Asymmetric ZnPc–rhodamine B conjugates for mitochondrial targeted photodynamic therapy

Muli, D. K., Rajaputra, P., You, Y., & McGrath, D. V. (2014). Asymmetric ZnPc–rhodamine B conjugates for mitochondrial targeted photodynamic therapy. Bioorganic & Medicinal Chemistry Letters, 24(18), 4496-4500. doi:http://dx.doi.org/10.1016/j.bmcl.2014.07.082

Design, synthesis, characterization, and photodynamic activity of mitochondria specific asymmetric ZnPc–Rh B conjugates are described. Conjugation of asymmetric ZnPc–OH chromophores 3a and 3b with rhodamine B via the corresponding DIC-activated ester gave the desired near IR-absorbing asymmetric ZnPc–Rh B conjugates 1a and 1b. Conjugates 1a and 1b were shown to produce singlet oxygen upon illumination in DMSO, MeOH and THF. Fluorescence aggregation studies of the dyes 1a, 1b, 3a and 3b in DMSO and phosphate buffered saline (PBS) solution showed that conjugates 1a and 1b were less aggregated compared to the corresponding non-conjugates 3a and 3b suggesting that incorporation of Rh B lowered aggregation of the conjugates in the PBS solution. The four dyes studied have log D7.4 values between 2.31 and 2.48, with the sulfur-containing conjugate 1b being the most hydrophobic. All the dyes showed negligible dark toxicity when colon 26 cells were treated with 5 μM of the dyes while 10–15% cell death was observed for dye concentrations of 15 μM. Illumination (700 ± 40 nm, 45 J/cm2, 15 min) of the cells ([dye] = 15 μM) gave 70% cell death for ZnPc–Rh B conjugates 1a and 1b while no killing for non-conjugates 3a and 3b suggesting that the incorporation of the Rh B in the photosensitizer lowered the aggregation and subsequently improved cellular uptake and phototoxicity.

Langmuir monolayers from azobenzene-containing dendrons

Sidorenko, A., Houphouet-Boigny, C., Greco, A. C., Villavicencio, O., Hashemzadeh, M., McGrath, D. V., & Tsukruk, V. V. (2000). Langmuir monolayers from azobenzene-containing dendrons. American Chemical Society, Polymer Preprints, Division of Polymer Chemistry, 41(2), 1487-1488.

Abstract:

Monolayer films were fabricated from photochromic monodendrons with amphiphilic character. Amphiphilicity was established by a hydrophilic focal point (crown-ether) and hydrophilic tails (alkyl chains) that flank a photochromic azobenzene moiety. The monolayer forming properties of four generations of dendrons along with both stearic acid and a reference azobenzene compound with a carboxylic acid focal point group were determined.

Synthesis, Spectroscopic Studies, and Computational Analysis of a Solvatochromic Phthalocyanine Derivative

Roberts, J. M., Mayukh, M., Lichtenberger, D. L., Mcgrath, D. V., Mcgrath, D. V., Lichtenberger, D. L., Mayukh, M., & Roberts, J. M. (2018). Synthesis, Spectroscopic Studies, and Computational Analysis of a Solvatochromic Phthalocyanine Derivative. Chemical Communications.

Intralayer reorganization of photochromic molecular films

Tsukruk, V. V., Luzinov, I., Larson, K., Li, S., & McGrath, D. V. (2001). Intralayer reorganization of photochromic molecular films. Journal of Materials Science Letters, 20(9), 873-876.

Abstract:

Azobenzene-containing amphiphilic dendrimer was used to fabricate a photosensitive monolayer. A crown-ether moiety served as a polar head and a polyether fragment with long-chain alkyl tails providing hydrophobicity for an overall amphiphilic character. The architecture exhibited two dissimilar bulky terminal fragments.

Synthesis of spiropyran based photoresponsive dendrimers

Radhakrishnan, U., & McGrath, D. V. (2000). Synthesis of spiropyran based photoresponsive dendrimers. American Chemical Society, Polymer Preprints, Division of Polymer Chemistry, 41(1), 883-884.

Abstract:

The polarity of the open form of spiropyrans is suitable for use as surfactants and for controlling the hydrophilicity of the dendrimer surface with the use of light. Spiropyrans as a peripheral unit of dendrimer with a non-polar inner core will lead to the formation of macromolecules with photolytically-controlled amphiphilic character. In this connection, spiropyran subunits were introduced on the surface of dendrimers prepared using the convergent synthetic strategy to modify the dendrimers' properties.

Dominic V Mcgrath