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Group News

January 21, 2014: There is a new Doctor in the group! Today we celebrate the successful defense of Kady's doctoral thesis. In addition to her excellent work helping maintain the high quality of the Journal of the American Chemical Society, Kady has been working on her Ed.D in Organizational Leadership at the University of La Verne. We are lucky to have Kady be part of our group. Congratulations Kady!

July 2, 2012: Today we welcome Mr. Xizhen Lian from Nankai University. He will be spending the summer in our group working on ferroic molecular rotors as part of the Cross-disciplinary Scholars in Science and Technology (CSST) program. Welcome Xizhen!

July 1, 2012: As of this date, Miguel will be serving as the Chair of our Department. He will be joined by Profs. Neil Garg, Ben Schwartz and Jim Bowie as Vice Chairs. Best Wishes!

June 27, 2012: Congratulations to Cortnie Vogelsberg for winning the Thomas L. and Ruth F. Jacobs Dissertation Award for excellence in organic chemistry research! What a great accomplishment!

September 22, 2011: Kudos to Mexican Science!  In addition to group members Dr. Denisse de Loera (Univ. Autonoma de San Luis Potosi) and Dr. Braulio Rodriguez Molina (Estudios Avanzados del IPN), our group recently welcomed visiting student Aaron Torres Huerta (Univ. Autonoma de Morelos), Dr. Salvador Perez (Ciencias Biologicas del IPN), and Prof.  Eduardo Gonzalez Zamora (Univ. Autonoma Metropolitana).  Dr. Edgar Escalante (UNAM) will start his second Postdoctoral year in October.

June 27, 2011:  Braulio Molina's JACS communication on the anisochronous dynamics of a 1D rotor chain was highlighted on the "Noteworthy Chemistry" Web site of the American Chemical Society. Nice job Braulio!

Saori-2.jpg June 20, 2011: Tasty cupcakes and red wine were involved in our recent celebration of new Drs. Saori Shiraki (picture) and Greg Kuzmanich.  Their dissertations on  "Synthesis and Solid-State Photochemical Studies of Hexasubstituted Ketones and 1-Pyrazolines" and "Steady-State and Transient Absorption Spectroscopic Studies of Photochemical Mechanisms in Crystalline Solids Utilizing Nanocrystalline Suspensions," respectively, have advanced the field of solid state photochemistry considerably!

June 13, 2011:  We welcome new Mexican group members Regina Balderas and Braulio Rodriguez Molina.  Regina is a summer student from the University of San Luis Potosi, and Braulio is a CoNaCyT Postdoc that joins us from CINVESTAV in Mexico City. 

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Greg.jpgJune 11, 2011:  Congratulations to Greg Kuzmanich for being awarded the THOMAS L. AND RUTH F. JACOBS AWARD for excellence in organic chemistry research.  His award was announced during the 2011 graduation ceremony. 

June 10, 2011:  Just a month from now, on July 10-15, Miguel will be giving a presentation on "Signal Amplification with a Gain by Quantum-Chain Reactions in Crystalline Solids" at the Photochemistry Gordon Conference at Stonehill College in Easton, MA.

 

 

 

May 20, 2011:  Cortnie Vogelsberg was awarded a Travel Grant from the American Crystallographic Association to present her recent work on halogen-bonded molecular rotors at their 2011 annual meeting in New Orleans, LA. She is scheduled to give her talk at the Small Molecule Molecular Machines session on June 2, 2011. 


The 2011 Organic Symposium coming up this June 4 will celebrate the accomplishments of the UCLA organic graduate students earning their PhD degrees in Chemistry this year. Our group will be represented by Saori Shiraki, Zach O'Brien, and Greg Kuzmanich. We are looking forward to thier research talks.

April 8, 2011: Jiang Xing finished his cumes in record time! Congrats Xing!

April 1, 2011: After a year in our group, Dr. Brianda Barrios accepted a position at the University of Helsinki. Good luck Brianda!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Our research, education, and outreach activities are made possible by generous grants from the National Science Foundation.

Research Highlights

October 21, 2013: Isomorphic polymorphs found! While polymorphism is the ability of a given structure to crystallize in different forms, isomorphism is the ability of two or more distinct structures to adopt the same crystal packing.  As described in our recent paper in Crystal Growth and Design, the systematic replacement of hydrogen by fluorine atoms in the phenylene rotator of a series of steroidal molecular rotors leads to the formation of several sets of isomorphic polymorphs.  Some of their structures are related by loss of solvent and/or by thermal phase transitions. 

July 18, 2013: Rotation in crystals is determined by the size and symmetry of the rotator - Smaller rotators have smaller moments of inertia and fewer van der Waas contacts to hinder their motion, which makes them faster.  It is therefore remarkable that a relatively large bicyclo[2.2.2]octane, with an activation energy of only Ea = 1.15 kcal mol−1, has faster rotational motion than smaller methyl and methoxy groups in the same steroidal structure. In our most recent JACS article, we describe how to sort out the dynamics of the three different groups and we explain how the misalignment between crystallographic and BCO symmetry axes creates an advantageous 6-fold axial symmetry order that more than makes up for its larger size.  

April 10, 2013: Large differences in size and shape between the triazoline reactants and aziridine products provide the means to document solid-to-solid reactions that follow different phase transformation mechanisms. Denisse de Loera’s JACS article documents the quantitative thermal and photochemical formation of aziridines with bulky substituents.

 

October 29, 2012: Just published in The Journal of Organic Chemistry as a Feature Article, work carried out with the groups of Profs. J. Morzycki in Poland and R. Santillan in Mexico describes an efficient seven-step synthetic route and the internal dynamics of two beautiful crystalline macrocyclic molecular rotors.

July 19, 2012: Aziridines crystals are “born” in a metastable form - The photodenitrogenation of crystalline triazolines generates the corresponding aziridines in nearly quantitative yields. Using powder X ray diffraction to monitor the photoreaction progress, it was shown that the packing structure of the starting material remains in the product obtained. The study is detailed in Denisse de Loera’s just published Organic Letters paper.

February 16, 2012: 2D Glasses!!! - Molecular rotors confined in two dimensions form rotational glasses and rotational liquids. Cortnie Vogelsberg's recent Journal of Physical Chemistry B article describes this phenomenon with p-divinylphenylene rotators in a hierarchically ordered periodic mesoporous organosilica. The study reveals non-Arrhenius dynamics and an increase in heat capacity characteristic of a phase transition. This unprecedented discovery is an exceptional platform for the development of hypersensitive thermally activated molecular machines. Congrats, Cortnie!

October 24, 2011: Cortnie Vogelsberg’s Chem. Soc. Rev. article “Crystalline molecular machines: function, phase order, dimensionality, and composition” is now available as an Advance Article here!  This thought provoking critical review is a great introduction to the developing field of amphidynamic molecular machines and their potential.  It is also a great read to catch up on the latest progress in the field.  Congrats, Cortnie!

September 23, 2011: How to cross three bridges in one step - A very nice synthetic strategy wresearch highlight picture.tiffas devised to construct molecular gyroscopes with three bridges (shown in green) in only one step.  Their single crystal X-ray structures reveal that the molecular gyroscopes pack in ordered sheets, which will be ideal for structures with interacting polar rotators.  Read Patrick Commins’ and Jose Nunez’s synthetic strategy in the Journal of Organic Chemistry.

September 22, 2011:  The Case of the Short-Lived Triplets - Using transient spectroscopy to determine the excited lifetimes of nanocrystalline benzophenones, we determined why certain triplet states are extremely short lived in solids but not in solution.  The triplet excited states of the substituted benzophenones are quenched by an adjacent molecule in the ground state via a reductive charge transfer (CT) mechanism.  Hot off of the press, see the “just accepted” JACS full article describing Greg Kuzmanich and Matt Gard’s work in collaboration with the group of Prof. Guldi.

May 23, 2011:  Challenging Reactions Gone Green - Crystals of hexasubstituted ketones exposed to light, without solvents or any other reagents, give quantitative yields of products with all-carbon adjacent quaternary stereogenic centers, which are very difficult to obtain otherwise.  Crystalline ketones were easily generated by trapping tertiary carbanions with a carbonyl source and the subsequent solid-state reaction gave the product with complete diastereoselectivity.  The method developed by Saori Shiraki just appeared in Photochemical and Photobiological Sciences.

May 20, 2011: Life in the Fast Lane - Using ultrafast pulses to determine the excited kinetics of a nanocrystalline indanone, we discovered that the reaction in crystals can be very fast; starting with a singlet biradical, visting the triplet state, and then going on to the product in less than 10 nanoseconds. See the Chemical Science edge article describing Greg Kuzmanich's work in collaboration with Profs. Tito Scaiano, JosÚ-Carlos Netto-Ferrerria, and Matt Platz.






May 18, 2011:  First 1D rotor chain! - Collaborative studies bridged by Braulio Rodriguez-Molina between our group at UCLA and the Santillan group in CINVESTAV, Mexico, led to the discovery of the first crystalline array of molecular rotors that undergo correlated motions in a 1D chain.   Read this work in: J. Am. Chem. Soc., 2011, 133, 7280.







April 21, 2011: Towards Exploded Stators - Zach O'Brien's design and solid state NMR study of a new molecular gyroscope with "exploded" tri-(meta-terphenyl)methyl stators shows that steric bulk and rigidity yields robust yet low-density crystals capable of accommodating phenylene rotation in excess of 100 MHz at room temperature.








April 11, 2011: Add halogen-bonding to the toolbox of crystal engineering techniques for amphidynamic molecular machines. Cortnie Vogelsberg's solid-state NMR analysis of crystalline 1,4-bis(iodoethynyl)bicyclo[2.2.2]octane showed that halogen-bonded molecular rotors sustain ultra-fast rotation. This study, in collaboration with Prof. Stuart Brown and the group of Prof. Patrick Batail, validates an unprecedented approach to the construction of amphidynamic molecular machines where the extended framework itself provides the template to sustain engineered rotation to very low temperatures. See the ASAP JACS article here!





February 8, 2011: Oxyallyl is Blue! Even though oxyallyl is a ubiquitous reaction intermediate involved in many organic reactions, until now, it had resisted all attempts at direct detection, isolation, and characterization. See here the JACS communication describing Greg Kuzmanich's work in collaboration with the groups of Profs. Dirk M. Guldi and Kendall Houk.


See also...


Research

Solid state organic chemistry: Structure-reactivity correlations; supramolecular organic photochemistry and absolute asymmetric synthesis; chemical dynamics in organic crystals; X-ray diffraction and solid state NMR; crystal engineering and organic materials science.

Contact

University of California, Los Angeles
Department of Chemistry & Biochemistry
607 Charles E. Young Drive East
Los Angeles, CA 90095
mgg@chem.ucla.edu

Office:
Molecular Sciences Building, Room 4505-C
Phone: 310-825-3159

Labs:
MSB 4240, MSB 4241, MSB 4235, MSB 4210

Links:
California NanoSystems Institute (CNSI)
Materials Creation Training Program (MCTP)
Organization for Cultural Diversity in Chemistry
ICCOSS XVII (2005, UCLA)