{"id":3736,"date":"2011-04-04T14:30:10","date_gmt":"2011-04-04T14:30:10","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=3736"},"modified":"2011-06-12T09:11:18","modified_gmt":"2011-06-12T09:11:18","slug":"the-colour-of-monastral-blue-part-2","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736","title":{"rendered":"The colour of Monastral blue (part 2)."},"content":{"rendered":"
\n

Andy Mclean posted a comment<\/a> to my story<\/a> of copper phthalocyanine (Monastral blue). The issue was its colour, and more specifically why this pigment has two peaks \u03bbmax<\/sub> 610 and 710nm making it blue. The first was accurately reproduced by calculation on the monomer, but the second was absent with such a model. Andy suggested this latter was due to stacking. Here, the calculated spectrum of a stacked dimer is explored.<\/p>\n

\"\"

Copper phthalocyanine, showing herring-bone stacking. Click for 3D.<\/p><\/div>The X-ray structure (above) shows layers of the phthalocyanine, dislocated so that the Cu of one unit aligns perfectly with a N of the units above and below the first one (Cu-N 3.28\u00c5). This corresponds to the di-axially solvated system I explored<\/a> in a comment appended to the original post. The TD-DFT calculated<\/a> (since each unit is a doublet radical, the dimer was treated as a triplet state, this being much lower in energy than a singlet closed shell state) \u00a0electronic spectrum for two units, stacked above each other as shown above reveals two transitions at ~ 600 and \u00a0620 nm. This is still some way away from reproducing the measured \u00a0(solid state or solution spectra).<\/p>\n

\"\"<\/a>The hypothesis must now be that the effect of such \u03c0-\u03c0 stacking on the electronic spectrum converges only slowly with the degree of stacking (if indeed it is that that is the root cause of the 710nm transition). A calculation on a triple-layered model is currently under way (this being the absolute limit of what can be done without a periodic boundary model). The spectrum will be appended to this post in a week or so (see below). There is little sign of the spectrum evolving a quite separate band at 710nm. The model is still incomplete!
\n\"\"<\/a><\/p>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

Andy Mclean posted a comment to my story of copper phthalocyanine (Monastral blue). The issue was its colour, and more specifically why this pigment has two peaks \u03bbmax 610 and 710nm making it blue. The first was accurately reproduced by calculation on the monomer, but the second was absent with such a model. Andy suggested […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[4],"tags":[500,496,24,2651,495,42],"ppma_author":[2661],"class_list":["post-3736","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-andy-mclean","tag-copper-phthalocyanine","tag-energy","tag-historical","tag-td-dft","tag-x-ray"],"yoast_head":"\nThe colour of Monastral blue (part 2). - Henry Rzepa's Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The colour of Monastral blue (part 2). - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"Andy Mclean posted a comment to my story of copper phthalocyanine (Monastral blue). The issue was its colour, and more specifically why this pigment has two peaks \u03bbmax 610 and 710nm making it blue. The first was accurately reproduced by calculation on the monomer, but the second was absent with such a model. Andy suggested […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2011-04-04T14:30:10+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2011-06-12T09:11:18+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/04\/stacked-mb.jpg\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"The colour of Monastral blue (part 2). - Henry Rzepa's Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736","og_locale":"en_GB","og_type":"article","og_title":"The colour of Monastral blue (part 2). - Henry Rzepa's Blog","og_description":"Andy Mclean posted a comment to my story of copper phthalocyanine (Monastral blue). The issue was its colour, and more specifically why this pigment has two peaks \u03bbmax 610 and 710nm making it blue. The first was accurately reproduced by calculation on the monomer, but the second was absent with such a model. Andy suggested […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736","og_site_name":"Henry Rzepa's Blog","article_published_time":"2011-04-04T14:30:10+00:00","article_modified_time":"2011-06-12T09:11:18+00:00","og_image":[{"url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/04\/stacked-mb.jpg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"The colour of Monastral blue (part 2).","datePublished":"2011-04-04T14:30:10+00:00","dateModified":"2011-06-12T09:11:18+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736"},"wordCount":301,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/04\/stacked-mb.jpg","keywords":["Andy Mclean","copper phthalocyanine","energy","Historical","TD-DFT","X-ray"],"articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3736","name":"The colour of Monastral blue (part 2). - 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Fortunately, much of that story is actually recorded on film (itself a unique archive dating from 1933 and being\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/03\/phthalocyanine.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":3670,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3670","url_meta":{"origin":3736,"position":1},"title":"From the colour blue to molecular wires","author":"Henry Rzepa","date":"March 9, 2011","format":false,"excerpt":"In the previous post I pondered the colour of Monastral blue (copper phthalocyanine). Something did not quite fit, and so I speculated that perhaps some oxidation of the pigment might give a new species. This species (Cambridge code FEGJOQ) comprises two parts of copper phthalocyanine, 1 part of the corresponding\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/03\/FEGJOQ2.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":3723,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3723","url_meta":{"origin":3736,"position":2},"title":"Chemicalizing a blog.","author":"Henry Rzepa","date":"March 30, 2011","format":false,"excerpt":"I am at the ACS meeting, attending a session on chemistry and the Internet. This post was inspired by Chemicalize, a service offered by ChemAxon, which scans a post like this one, and identifies molecules named. I had previously used generic post taggers, which frankly did not work well in\u2026","rel":"","context":"In "Chemical IT"","block_context":{"text":"Chemical IT","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":26199,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=26199","url_meta":{"origin":3736,"position":3},"title":"Blue blood.","author":"Henry Rzepa","date":"August 7, 2023","format":false,"excerpt":"Respiratory pigments are metalloproteins that transport O2, the best known being the bright red\/crimson coloured hemoglobin in human blood. The colour derives from Fe2+ at the core of a tetraporphyrin ring. But less well known is blue blood, and here the colour derives from an oxyhemocyanin unit based on Cu1+\u2026","rel":"","context":"In "crystal_structure_mining"","block_context":{"text":"crystal_structure_mining","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1745"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2023\/08\/Screenshot57.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":20778,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=20778","url_meta":{"origin":3736,"position":4},"title":"Imaging normal vibrational modes of a single molecule of CoTPP: a mystery about the nature of the imaged species.","author":"Henry Rzepa","date":"April 25, 2019","format":false,"excerpt":"Previously, I explored (computationally) the normal vibrational modes of Co(II)-tetraphenylporphyrin (CoTPP) as a \"flattened\" species on copper or gold surfaces for comparison with those recently imaged. The initial intent was to estimate the \"flattening\" energy. There are six electronic possibilities for this molecule on a metal surface. Respectively positively, or\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":2230,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=2230","url_meta":{"origin":3736,"position":5},"title":"Non-covalent interactions (NCI): revisiting Pirkle","author":"Henry Rzepa","date":"July 15, 2010","format":false,"excerpt":"NCI (non-covalent interactions) is the name of a fascinating new technique for identifying exactly these. Published recently by Johnson, Keinan, Mori-Snchez, Contreras-Garca, Cohen and Yang, it came to my attention at a conference to celebrate the 20th birthday of ELF when Julia Contreras-Garcia talked about the procedure. It is one\u2026","rel":"","context":"In "Interesting chemistry"","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"The Pirkle reagent","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2009\/04\/pirkle.jpg?resize=350%2C200","width":350,"height":200},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/3736","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3736"}],"version-history":[{"count":0,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/3736\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3736"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3736"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3736"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=3736"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}