{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T22:16:25Z","timestamp":1780524985217,"version":"3.54.1"},"reference-count":40,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2019,10,31]],"date-time":"2019-10-31T00:00:00Z","timestamp":1572480000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001711","name":"Schweizerischer Nationalfonds zur F\u00f6rderung der Wissenschaftlichen Forschung","doi-asserted-by":"publisher","award":["200020_162631"],"award-info":[{"award-number":["200020_162631"]}],"id":[{"id":"10.13039\/501100001711","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Heteroleptic [Cu(BIPHEP)(N^N)][PF6] complexes (BIPHEP = 1,1\u2032-biphenyl-2,2\u2032-diylbis(diphenylphosphane)), in which N^N is 2,2\u2032-bipyridine (bpy), 6-methyl-2,2\u2032-bipyridine (6-Mebpy), 6-ethyl-2,2\u2032-bipyridine (6-Etbpy), or 5,5\u2032-dimethyl-2,2\u2032-bipyridine (5,5\u2032-Me2bpy), have been synthesized and characterized using multinuclear NMR spectroscopies and electrospray ionization mass spectrometry. The single crystal structures of [Cu(BIPHEP)(bpy)][PF6]\u2219CH2Cl2, [Cu(BIPHEP)(5,5\u2032-Me2bpy)][PF6]\u2219CH2Cl2, [Cu(BIPHEP)(6-Mebpy)][PF6]\u2219Et2O\u22190.5H2O and [Cu(BIPHEP)(6-Etbpy)][PF6] confirm distorted tetrahedral {Cu(P^P)(N^N)} coordination environments. Each compound shows a quasi-reversible Cu+\/Cu2+ process. In deaerated solution, the compounds are weak emitters. Powdered samples are yellow emitters (\u03bbemmax in the range 558\u2013583 nm) and [Cu(BIPHEP)(5,5\u2032-Me2bpy)][PF6] exhibits the highest photoluminescence quantum yield (PLQY = 14%). On cooling to 77 K (frozen 2-methyloxolane), the emission maxima are red-shifted and the excited state lifetimes increase from \u03c41\/2 &lt; 8 \u03bcs, to \u03c41\/2 values of up to 53 \u03bcs, consistent with the compounds with N^N = 6-Mebpy, 6-Etbpy and 5,5\u2032-Me2bpy exhibiting thermally activated delayed fluorescence (TADF).<\/jats:p>","DOI":"10.3390\/molecules24213934","type":"journal-article","created":{"date-parts":[[2019,10,31]],"date-time":"2019-10-31T06:33:29Z","timestamp":1572503609000},"page":"3934","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Hinged and Wide: A New P^P Ligand for Emissive [Cu(P^P)(N^N)][PF6] Complexes"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2667-9157","authenticated-orcid":false,"given":"Sarah","family":"Keller","sequence":"first","affiliation":[{"name":"Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland"},{"name":"Chimie ParisTech, PSL University CNRS, Institute of Chemistry for Life and Health Sciences, Laboratory for Inorganic Chemical Biology, 11 rue Pierre et Marie Curie, F-75005 Paris, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthias","family":"Bantle","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3631-5210","authenticated-orcid":false,"given":"Alessandro","family":"Prescimone","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4916-4041","authenticated-orcid":false,"given":"Edwin C.","family":"Constable","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8074-0089","authenticated-orcid":false,"given":"Catherine E.","family":"Housecroft","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 24a, CH-4058 Basel, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,31]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1016\/j.ccr.2017.09.011","article-title":"Sustainable metal complexes for organic light-emitting diodes (OLEDs)","volume":"373","author":"Bizzarri","year":"2018","journal-title":"Coord. 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