{"id":574,"date":"2025-07-28T11:59:00","date_gmt":"2025-07-28T10:59:00","guid":{"rendered":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/?p=574"},"modified":"2026-09-21T12:01:31","modified_gmt":"2026-09-21T11:01:31","slug":"coordination-of-deprotonated-ferrous-heme-with-co-and-o2-in-the-gas-phase-influence-of-spin-orbit-splitting-and-charge","status":"publish","type":"post","link":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/?p=574","title":{"rendered":"Coordination of Deprotonated Ferrous Heme with CO and O2 in the Gas Phase: Influence of Spin-Orbit Splitting and Charge"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\">A Muhieddine, S Soorkia, J Attard, A de La Lande, Niloufar Shafizadeh, B Soep. <em>J. Phys. Chem. A<\/em>, <strong>2025<\/strong>, 129, 7087\u20137093. DOI: <a href=\"https:\/\/doi.org\/10.1021\/acs.jpca.5c02554\" target=\"_blank\" rel=\"noopener\">doi.org\/10.1021\/acs.jpca.5c02554<\/a><\/h3>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/wp-content\/uploads\/2026\/09\/m_jp5c02554_0007.png\"><img loading=\"lazy\" decoding=\"async\" width=\"492\" height=\"311\" src=\"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/wp-content\/uploads\/2026\/09\/m_jp5c02554_0007.png\" alt=\"\" class=\"wp-image-575\" srcset=\"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/wp-content\/uploads\/2026\/09\/m_jp5c02554_0007.png 492w, https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/wp-content\/uploads\/2026\/09\/m_jp5c02554_0007-300x190.png 300w\" sizes=\"auto, (max-width: 492px) 100vw, 492px\" \/><\/a><\/figure>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\">The ligation of 4-coordinated ferrous heme has been investigated in the gas phase using singly deprotonated heme anions to act as a model for neutral heme. The equilibrium of dioxygen and carbon monoxide ligated to deprotonated heme was observed in the 250\u2013150 K temperature range in a Paul ion trap. The van\u2019t Hoff equation was used for the determination of ligand binding energies with CO or O<sub>2<\/sub>. Density functional theory calculations have been undertaken to analyze the mechanism of bonding that evolves through spin-orbit crossing between the triplet heme reactant and the singlet carbon monoxide-ligated product. The deprotonated heme anion is a good model for neutral heme, since the negative charge on the carboxylate end of the propionate group of heme is shown to have little influence. Deprotonated heme anions yield a ligation enthalpy of 4-coordinated heme with O<sub>2<\/sub> or CO, which is surprisingly low (respectively, \u0394<em>H<\/em> = 20.6 \u00b1 1.7 and 37.9 \u00b1 1.6 kJ mol<sup>1<\/sup>).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A Muhieddine, S Soorkia, J Attard, A de La Lande, Niloufar Shafizadeh, B Soep. J. Phys. Chem. A, 2025, 129, 7087\u20137093. DOI: doi.org\/10.1021\/acs.jpca.5c02554 The ligation of 4-coordinated ferrous heme has been investigated in the gas phase using singly deprotonated heme anions to act as a model for neutral heme. The equilibrium of dioxygen and carbon &hellip; <a href=\"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/?p=574\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Coordination of Deprotonated Ferrous Heme with CO and O2 in the Gas Phase: Influence of Spin-Orbit Splitting and Charge<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,8],"tags":[],"class_list":["post-574","post","type-post","status-publish","format-standard","hentry","category-density-functional-theory","category-hemes-and-chlorophylls"],"_links":{"self":[{"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/posts\/574","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=574"}],"version-history":[{"count":2,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/posts\/574\/revisions"}],"predecessor-version":[{"id":577,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=\/wp\/v2\/posts\/574\/revisions\/577"}],"wp:attachment":[{"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=574"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=574"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.adelalandecnrs.universite-paris-saclay.fr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=574"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}