Ojala Group Researchers

Students gain experience not widely available to undergrads

Benzonitrile Oxides and their Dimers

We investigate how crystal structures influence dimerization

Bridge-Flipped Isomers

We study dimers with similar sterics but different chemistry

Monosaccharide Derivatives

Crystal structures serve as models for biomolecules

Crystal Structures of "Strict Isosteres"

We study the packing arrangement of similar molecules

The Ojala Group

Research Interests:  X-ray crystallography; solid-state structures of reactive benzonitrile oxides and their dimers; crystal structures of biomedically significant molecules including carbohydrate derivatives, small peptides, and potential antiviral agents; solid-state molecular packing arrangements of bridge-flipped isomers and strict isosteres.

 Bridge-flipped isomers is our designation for pairs of molecules differing only in the orientation of a bridge of atoms joining two major portions of the molecules.  Bridge-flipped isomers that are isomorphous (that assume the same solid-state molecular packing arrangement) may be capable of co-crystallization to form new solid materials, while those that are not isomorphous may serve as seed crystals for preparing new polymorphs of their isomer.  Examining these isomers as pairs gives helpful context to our examination of the features of solid-state molecular geometry and intermolecular interactions that differentiate these isomers from each other.

 Strict isosteres is our designation for chemically different molecules that possess closely similar space-filling properties due to closely corresponding atomic coordinates and van der Waals radii.  Examples include isocyanates/cyanates/azides, acyl fluorides/nitro compounds, and nitrile oxides/fluoroalkynes.  We are examining these compounds for isomorphism and for their potential, on incorporation into the same crystal, to affect the course of solid-state phase transitions occurring within that crystal.   

 Crystal structures of selected compounds are determined with the assistance of the X-ray Crystallographic Laboratory (XCL) of the Department of Chemistry of the University of Minnesota—Twin Cities.  Data sets collected at the XCL are transmitted to our laboratory, where our students solve, refine, and analyze the crystal structures using software including SHELXOlex2PLATON, and Mercury.  The Chemistry Department provides access to the Cambridge Structural Database for students throughout the Department in support of their research projects.   

If you are interested in joining the research group, contact Dr. Ojala at whojala@stthomas.edu

 

Recent Publications

  1. Beard, L. E.; Ojala, C. R.; Kassekert, K. J.; Ojala, W. H.  “Molecular Packing Preferences in ‘Bridge-flipped’ Isomeric Aryl-2-pyridylhydrazones and 2-Pyridinecarboxaldehyde Arylhydrazones,” CrystEngComm 2016, 18, 7036-7048.

  2. Ojala, W. H.  “Peggy Etter and Polymorphism:  Highlights of an Enduring Scientific Legacy,” Cryst. Growth Des. 2016, 16, 1144-1148. 

  3. Ojala, W. H.; Balidemaj, B.; Johnson, J. A.; Larson, S. N.; Ojala, C. R. “Molecular Symmetry and Fluorine-Containing Supramolecular Synthons as Structure-Differentiating Agents in Some ‘Bridge-Flipped’ Isomeric bis-Benzylideneanilines,” CrystEngComm, 2014, 16, 7226-7235.

  4. William H. Ojala, Trina M. Arola, Ann M. Brigino, Jeremy D. Leavell, and Charles R. Ojala (2012) Competing Intermolecular Interactions in Some ‘Bridge-Flipped’ Isomeric Phenylhydrazones,; Acta Crystallographica, Section C:  Crystal Structure Communications 68,o270-o278.

Recent Presentations

William H. Ojala, Jaya K. Dhami, Michael J. Stodolka, Samantha R. Whitcomb, and Ryan B. Johnson, “Molecular Packing Properties of Some Symmetrically Substituted Diaryl Furoxans,” (poster) American Crystallographic Association 2017 Annual Meeting, May 26-30, 2017, New Orleans, Louisiana.

Kiersten M. Idzorek and William H. Ojala, “Solid-State Chemistry of Dimers of a Sterically Hindered Benzonitrile Oxide,” (oral presentation) Winchell Undergraduate Research Symposium of the Minnesota Academy of Science, April 22, 2017, Macalester College, St. Paul, Minnesota.

Maria K. Neuzil and William H. Ojala, “Solid-State Studies of Benzonitrile Oxides and their Dimers:  Crystal Structure of a 1,2,4-Oxadiazole,” (poster) Winchell Undergraduate Research Symposium of the Minnesota Academy of Science, April 22, 2017, Macalester College, St. Paul, Minnesota.

Michael J. Stodolka and William H. Ojala, “Solid-State Structures and Reactivity of Halogenated Benzonitrile Oxides:  Crystal Structure of bis(3-Chlorophenyl)furoxan,” (poster) Winchell Undergraduate Research Symposium of the Minnesota Academy of Science, April 22, 2017, Macalester College, St. Paul, Minnesota.

Ryan B. Johnson and William H. Ojala, “Solid-State Nitrile Oxide Dimerization:  Crystal Structures of 2,3-Dichlorobenzonitrile Oxide and its Solution Dimer,”(poster) Winchell Undergraduate Research Symposium of the Minnesota Academy of Science, April 22, 2017, Macalester College, St. Paul, Minnesota.

Samantha R. Whitcomb and William H. Ojala, “Solid-State Chemistry of Dimers of Reactive Nitrile Oxides,” (poster) 253rd American Chemical Society National Meeting and Exposition, San Francisco, California, April 2-6, 2017.

Maria K. Neuzil and William H. Ojala, “Solid-State Studies of Benzonitrile Oxides and their Dimers:  Crystal Structure of a 1,2,4-Oxadiazole,” (poster) 253rd American Chemical Society National Meeting and Exposition, San Francisco, California, April 2-6, 2017.

Michael J. Stodolka and William H. Ojala, “Solid-State Structures and Reactivity of Halogenated Benzonitrile Oxides:  Crystal Structure of bis(3-Chlorophenyl)furoxan,” (poster) 253rd American Chemical Society National Meeting and Exposition, San Francisco, California, April 2-6, 2017.

Kiersten M. Idzorek and William H. Ojala, “Solid-State Chemistry of Dimers of a Sterically Hindered Benzonitrile Oxide,” (poster) 253rd American Chemical Society National Meeting and Exposition, San Francisco, California, April 2-6, 2017.

 

Current and Past Funding

Dr. Ojala and his students gratefully acknowledge the American Chemical Society Petroleum Research Fund for financial support of their work.