{"id":177,"date":"2019-03-27T11:31:25","date_gmt":"2019-03-27T11:31:25","guid":{"rendered":"http:\/\/mgg.chem.ucla.edu\/?page_id=177"},"modified":"2026-06-10T21:38:04","modified_gmt":"2026-06-10T21:38:04","slug":"publications","status":"publish","type":"page","link":"https:\/\/mgg.chem.ucla.edu\/index.php\/publications\/","title":{"rendered":"Publications"},"content":{"rendered":"\n<h2 id=\"mce_0\" class=\"wp-block-heading\">Most Recent Publications<\/h2>\n\n\n\n<p class=\"has-text-align-left has-medium-font-size wp-block-paragraph\"><strong>Engineering Ultrafast Molecular Rotors via Chalcogen bond<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Chalcogen bonds are emerging \u03c3-hole interactions with untapped potential in amphidynamic materials. We report the first crystalline molecular rotors held by chalcogen bonds and their ultrafast rotational dynamics. The rotator component 1,4-diazabicyclo[2.2.2]octane and phenylselenocyanate-based stators assemble via exceptionally short and highly directional Se\u00b7\u00b7\u00b7N contacts (Nc = 0.76\u20130.81; \u2220NC\u2013Se\u00b7\u00b7\u00b7N = 174\u2013175 \u00b0). Solid-state\u00a0<sup>1<\/sup>H NMR T<sub>1<\/sub>\u00a0spin\u2013lattice relaxation measurements reveal rotation at hundreds of MHz with low activation barriers (<em>E<\/em><sub><em>a<\/em><\/sub>\u00a0= 1.22\u20132.78 kcal mol<sup>\u20131<\/sup>), in agreement with the packing coefficient and computational analysis. These findings highlight chalcogen bonds as a powerful tool for designing robust, crystalline molecular machines.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img decoding=\"async\" src=\"https:\/\/pubs.acs.org\/cms\/10.1021\/jacs.6c02463\/asset\/images\/medium\/ja6c02463_0006.gif\" alt=\"\"\/><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><a href=\"https:\/\/doi.org\/10.1021\/jacs.6c02463\"><em>J. Am. Chem. Soc.<\/em>\u00a02026, 148, 18, 18591\u201318596<\/a><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>Three-dimensional imaging via quantum chain amplification in a crystalline two-photon adiabatic photocage<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">We report here a Dewar-benzene-1,2-dicarboxylic-acid monoester with a 7-hydroxycoumarin (7H) fluorescent cage (DB-7HC) that leverages two-photon excitation (TPE) to trigger an adiabatic triplet-state reaction that initiates a quantum chain capable of releasing up to 400 molecules of 7HC per excitation event. The chemical enhancement afforded by a TPE microscope enables precise, chemically amplified uncaging, which together with sensitive fluorescence detection results in high three-dimensional (3D) spatial resolution. Using a femtosecond pulse laser operating in the 690- to 770-nm range, this system allows for deep bulk activation with minimal scattering, with 7HC acting as a TPE antenna and triplet sensitizer and, once released, as a fluorescent reporter for real-time imaging. The high quantum yield and solid-state reactivity of the Dewar-benzene-1,2-dicarboxylic-acid monoester motif make it a promising probe for 3D microfabrication, patterning, optogenetics, and targeted drug delivery, with a demonstrated 1- to 5-\u03bcm spatial resolution.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img decoding=\"async\" src=\"https:\/\/www.cell.com\/cms\/10.1016\/j.chempr.2026.102957\/asset\/d985550c-f8a8-4a17-9b2e-79905f826d4c\/main.assets\/fx1_lrg.jpg\" alt=\"\" style=\"width:660px;height:316px\"\/><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><a href=\"https:\/\/www.cell.com\/chem\/fulltext\/S2451-9294(26)00023-9\">Chem, 2026; 0.<\/a><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-default\"\/>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>Crystalline Thymine Dimers Splitting by an Interfacial Photomechanochemical Single Electron Transfer Chain Reaction<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Splitting of the\u00a0<em>cis, syn<\/em>\u00a0thymine dimer (<strong>TD<\/strong>) into thymine (<strong>T<\/strong>) can be achieved in the solid state via an interfacial SET photomechanochemical reaction with\u00a0<em>N<\/em>,<em>N<\/em>,<em>N<\/em>,<em>N<\/em>-tetramethyl-1,4-phenylenediamine (TMPD) as the photochemical reductant. Mechanical grinding enabled the uniform deposition of the TMPD sensitizer on the dimer surface, and photoirradiation of this solid\u2013solid mixture (<strong>TD<\/strong>+TMPD) triggered electron transfer at the solid\u2013solid interface that was propagated into the bulk of the crystal as a chain reaction. Variables explored included sensitizer loading and preparation strategies that included solid\u2013solid mixing and the deposition of the photosensitizer onto the\u00a0<strong>TD<\/strong>\u00a0surface from solution. Clean solid-to-solid transformations were observed with product yields as high as \u223c95%.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large\"><img decoding=\"async\" src=\"https:\/\/pubs.acs.org\/cms\/10.1021\/jacs.5c17553\/asset\/images\/medium\/ja5c17553_0008.gif\" alt=\"\"\/><\/figure>\n<\/div>\n\n\n<p class=\"has-text-align-center wp-block-paragraph\"><a href=\"https:\/\/doi.org\/10.1021\/jacs.5c17553\"><em>J. Am. Chem. Soc.<\/em>\u00a02026, 148, 2, 2103\u20132107<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Most Recent Publications Engineering Ultrafast Molecular Rotors via Chalcogen bond Chalcogen bonds are emerging \u03c3-hole interactions with untapped potential in amphidynamic materials. We report the first crystalline molecular rotors held by chalcogen bonds and their ultrafast rotational dynamics. The rotator component 1,4-diazabicyclo[2.2.2]octane and phenylselenocyanate-based stators assemble via exceptionally short and highly directional Se\u00b7\u00b7\u00b7N contacts (Nc [&hellip;]<\/p>\n","protected":false},"author":8,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-177","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/pages\/177","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/comments?post=177"}],"version-history":[{"count":65,"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/pages\/177\/revisions"}],"predecessor-version":[{"id":2169,"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/pages\/177\/revisions\/2169"}],"wp:attachment":[{"href":"https:\/\/mgg.chem.ucla.edu\/index.php\/wp-json\/wp\/v2\/media?parent=177"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}