Dan O'Leary

I worked with this program for 20 years. It only funded students interested in chemistry and chemical engineering careers. I'm saddened to see it terminated.

The animation pairs with this slide:

Fischer's discovery of the configuration of (+)-glucose, described differently in organic textbooks, remains for me a must tell story as the semester winds down. Symmetry tests are timeless. This animation illustrates the end group interchange for sorting glucose (3) and mannose (4). #chemsky 🧪🎉

A chemistry professor and Cecil the Sagehen, mascot of Pomona College.

Dan and Cecil the Sagehen.

The final 3D orbital print of the semester is a sweet one! Organic chemistry students @pomonacollege.bsky.social received a model illustrating the anomeric effect. An unexpected bonus (scroll down) was a visit by Cecil the Sagehen! ##chemsky #compchemsky #3dp 🧪

Thanks! We've been approaching this from a DIY point of view, with hopes of enabling others to do the same. That said, it would be interesting to learn more about marketability. HGS Maruzen remains my favorite molecular model company.

Multicolor 3D-Printed Molecular Orbital Models for a First-Semester Organic Chemistry Course We have developed a set of multicolor 3D-printed structural and molecular orbital models for use in a first-semester organic chemistry course. These models provide visual and tactile insights regarding aspects of organic structure, reactivity, and mechanistic “arrow pushing”. The set includes: 1. orbital models of σ and π bonding in methane and ethylene, 2. σCH–σ*CH hyperconjugation in staggered and eclipsed ethane conformations, 3. LUMO accessibility in SN2 electrophiles and HOMO–LUMO orbital interactions in SN2 transition states, 4. E2 transition state structure and orbital interactions in β-hydrogen removal and π bond formation, 5. σCH–pC hyperconjugation in the ethyl cation, 6. transition state structure and σCH–pC orbital interactions in a carbocation 1,2-hydride shift, 7. late and early, respectively, Br• and Cl• H atom radical abstraction transition state structures and SOMO orbitals, 8. bromonium ion structure and LUMO orbital, 9. protonated epoxide ion and neutral epoxide structures and LUMO orbitals, 10. transition state structure and orbital interactions in a hydroboration reaction, 11. transition state structure and orbital interactions in the lithium aluminum hydride reduction of formaldehyde, and 12. π molecular orbitals in 1,3-butadiene. The prints are made with hobby-grade 5-color 3D fused deposition modeling (FDM) printers and sized to provide compact take-home class handouts for each student or projected in-class with a document camera. Models are fabricated with orbital or electron density surface bisections and text annotations to enhance information content. Student perceptions of this set of 3D-printed molecular models are generally favorable and have improved their understanding of course materials.

Workflow for models previously used in the classroom:
pubs.acs.org/doi/10.1021/...

3D print of an alanine derived alpha helix showing a hydrogen bond orbital interaction between two amino acids at the i and i+4 positions.

Biomolecular 3D orbital prints were featured this week in organic chemistry @pomonacollege.bsky.social! Class members went home with a student-designed alpha helix model showing i, i+4 N-H---O=C hydrogen bond orbital overlap. #chemsky #compchemsky #3dp 🧪

Monday's 3D print for my organic chemistry class @pomonacollege.bsky.social: an orbital interaction that partly defines the water dimer hydrogen bond. Orbital phases displayed in Pomona-Pitzer colors, appropriate for admitted students day! ELO warming the space. #chemsky #compchemsky #3dp 🧪⚗️🧪

Thank you! I'll share this link with students tomorrow.

Do-It-Yourself 5-Color 3D Printing of Molecular Orbitals and Electron Density Surfaces This report outlines an approach for preparing 5-color 3D printed plastic models of molecular orbitals and electron density surfaces using a hobby-grade 3D printer. Instructions are provided for preparing 3D orbital and electron density surface (EDS) models using solid or mesh representations in ground state and transition state structures. We show that the information content of 3D orbital and surface models can be enhanced with text annotation, bisection, strut and dashed bond placement, and composite orbital-EDS model constructions. Example prints illustrate orbital concepts in organic and inorganic chemistry, such as the ethyl cation (σ–p hyperconjugation), methane (hybridization and C–H bonding), ethane (σ–σ* hyperconjugation in the staggered and eclipsed conformations), 2-hydroxytetrahydropyran (the anomeric effect/n−σ* hyperconjugation), the water dimer (hydrogen bonding/n−σ* overlap), ethylene, 1,3-butadiene, and benzene (π molecular orbitals), Re2Cl82–, and U2(COT)2 (metal–metal quadruple bonds). Transition state models illustrate orbital interactions in the SN2 reaction of cyanide with methyl, ethyl, and isopropyl chloride and in a hydroboration reaction of BH3 with propene. Composite EDS models of methyl and isopropyl chloride (for exploring their relative reactivities as SN2 electrophiles) and methylcyclohexane (visualizing 1,3-diaxial interactions) are described. Student perceptions of a multicolor 3D orbital print used in an introductory organic chemistry laboratory course are reported.

Workflow:
pubs.acs.org/doi/10.1021/...

3D printed d-orbital models.

3D printed d-orbital models.

These 3D-printed d-orbital models are ready to parachute into an active learning-based general chemistry class @pomonacollege.bsky.social. Some assembly required! #3dp #chemsky #compchemsky 🧪⚗️🧪

Very cool!

Thank you for sharing! In some years, a friend on the music faculty will provide students with a brief synopsis of Borodin's musical contributions. One year, he even collaborated with a student in the class and performed a piano piece written by a very young Borodin. That was a fun class!

Thanks! We have some peptide systems coming up that you might like too.

All set to the music of Georgian-Russian composer and chemist Alexander Borodin, an early investigator of the aldol reaction. 🎶🎵🧪🧬⚗️

The aldol reaction was front and center in today's organic class! The orbital prints are a Houk group transition state for a lithium enolate + aldehyde reaction and a @pomonacollege.bsky.social student-designed Burgi-Dunitz print. #chemsky #3dp #compchemsky

Multicolor 3D-Printed Molecular Orbital Models for a First-Semester Organic Chemistry Course We have developed a set of multicolor 3D-printed structural and molecular orbital models for use in a first-semester organic chemistry course. These models provide visual and tactile insights regardin...

Workflow and 3mf files: pubs.acs.org/doi/10.1021/...

Poster: Hiwot Endeshaw and Jaylyn Gonzalez, "Development of 3D-Printed Molecular Orbital Teaching Models for Advanced Topics in Chemistry and Biologically Relevant Systems", Monday 3/24, 12:00 PM - 2:00 PM, Hall B2/C SD Convention Center, Poster Board #441.

Talk: Daniel O'Leary, "3D-Printed Molecular Orbitals and Transition State Structures for a First-Semester Organic Chemistry Course", Sunday 3/23, 8:25-8:45 AM, Hall B-1, Room 2, SD Convention Center.

A chemical reaction between cyanide and formaldehyde and molecular models showing the angle of attack (Burgi-Dunitz) of the nucleophile in the reaction transition state.

Happy to be participating in the "3D Printing in Chem Ed" symposium at #ACSSpring2025! Attendees will receive a Burgi-Dunitz orbital model designed by a @pomonacollege.bsky.social student. If you miss the talk, visit their poster and pick one up! Details are below. #ChemSky #CompChemSky #3DP 🧪

Multicolor 3D-Printed Molecular Orbital Models for a First-Semester Organic Chemistry Course We have developed a set of multicolor 3D-printed structural and molecular orbital models for use in a first-semester organic chemistry course. These models provide visual and tactile insights regardin...

Our workflow is outlined here: pubs.acs.org/doi/10.1021/...

Plastic 3D prints of a transition state for an enolate alkylation reaction.

Plastic 3D prints of the pi molecular orbitals for the enolate of acetaldehyde.

Plastic 3D prints of a transition state for an enolate alkylation reaction.

Plastic 3D prints of the pi molecular orbitals for the enolate of acetaldehyde.

A few 3D prints from this week's organic chemistry class: an NBO enolate alkylation transition state and a pi MO model for the enolate of acetaldehyde. We reviewed the SN2 reaction and noted the larger "on-C" orbital of the nucleophilic pi2 MO! #ChemSky #CompChemSky #3DP #3Dprint #3DModels #prusa 🧪

If you are attending the Spring ACS Meeting in San Diego, please come and join us on Monday night for a showcase of UCLA research and to meet UCLA students, postdocs, faculty, alumni, and friends! All ACS attendees are welcome! #ChemSky

from microagae to a 3D printed design

starting from microalgae oil, we performed two reactions, mix the resulting product with more components and the print and mechanical test the objects.

3D printed tests, the classical rook and one hexagon with the name of the group (BNT)

We're back!!!
First preprint of the year (3 more on the way).
Here, we used microalgae to produce a 3D printable resin:
Squeeze the oil from the microalgae, a couple of simple reactions (#chemsky), mixy mixy and there you have a strong bioresin.

chemrxiv.org/engage/chemr...

We made these enantiomer keychains for students last spring, and a co-worker converted smaller prints into earrings. I like your CPK earrings!