{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T12:27:23Z","timestamp":1780489643035,"version":"3.54.1"},"reference-count":38,"publisher":"MDPI AG","issue":"22","license":[{"start":{"date-parts":[[2020,11,13]],"date-time":"2020-11-13T00:00:00Z","timestamp":1605225600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003130","name":"Fonds Wetenschappelijk Onderzoek","doi-asserted-by":"publisher","award":["AUGE\/11\/029, AUGE\/09\/024 and 01N03217"],"award-info":[{"award-number":["AUGE\/11\/029, AUGE\/09\/024 and 01N03217"]}],"id":[{"id":"10.13039\/501100003130","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100007229","name":"Bijzonder Onderzoeksfonds UGent","doi-asserted-by":"publisher","award":["BOF15\/PDO\/091"],"award-info":[{"award-number":["BOF15\/PDO\/091"]}],"id":[{"id":"10.13039\/501100007229","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Erasmus Mundus Basileus V project","award":["na"],"award-info":[{"award-number":["na"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>In order to create near-infrared (NIR) luminescent lanthanide complexes suitable for DNA-interaction, novel lanthanide dppz complexes with general formula [Ln(NO3)3(dppz)2] (Ln = Nd3+, Er3+ and Yb3+; dppz = dipyrido[3,2-a:2\u2032,3\u2032-c]phenazine) were synthesized, characterized and their luminescence properties were investigated. In addition, analogous compounds with other lanthanide ions (Ln = Ce3+, Pr3+, Sm3+, Eu3+, Tb3+, Dy3+, Ho3+, Tm3+, Lu3+) were prepared. All complexes were characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray diffraction analysis of the complexes (Ln = La3+, Ce3+, Pr3+, Nd3+, Eu3+, Er3+, Yb3+, Lu3+) showed that the lanthanide\u2019s first coordination sphere can be described as a bicapped dodecahedron, made up of two bidentate dppz ligands and three bidentate-coordinating nitrate anions. Efficient energy transfer was observed from the dppz ligand to the lanthanide ion (Nd3+, Er3+ and Yb3+), while relatively high luminescence lifetimes were detected for these complexes. In their excitation spectra, the maximum of the strong broad band is located at around 385 nm and this wavelength was further used for excitation of the chosen complexes. In their emission spectra, the following characteristic NIR emission peaks were observed: for a) Nd3+: 4F3\/2 \u2192 4I9\/2 (870.8 nm), 4F3\/2 \u2192 4I11\/2 (1052.7 nm) and 4F3\/2 \u2192 4I13\/2 (1334.5 nm); b) Er3+: 4I13\/2 \u2192 4I15\/2 (1529.0 nm) c) Yb3+: 2F5\/2 \u2192 2F7\/2 (977.6 nm). While its low triplet energy level is ideally suited for efficient sensitization of Nd3+ and Er3+, the dppz ligand is considered not favorable as a sensitizer for most of the visible emitting lanthanide ions, due to its low-lying triplet level, which is too low for the accepting levels of most visible emitting lanthanides. Furthermore, the DNA intercalation ability of the [Nd(NO3)3(dppz)2] complex with calf thymus DNA (CT-DNA) was confirmed using fluorescence spectroscopy.<\/jats:p>","DOI":"10.3390\/molecules25225309","type":"journal-article","created":{"date-parts":[[2020,11,16]],"date-time":"2020-11-16T22:48:47Z","timestamp":1605566927000},"page":"5309","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["DNA Intercalating Near-Infrared Luminescent Lanthanide Complexes Containing Dipyrido[3,2-a:2\u2032,3\u2032-c]phenazine (dppz) Ligands: Synthesis, Crystal Structures, Stability, Luminescence Properties and CT-DNA Interaction"],"prefix":"10.3390","volume":"25","author":[{"given":"Aleksandar","family":"Savi\u0107","sequence":"first","affiliation":[{"name":"L<sup>3<\/sup>\u2013Luminescent Lanthanide Lab, Department of Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Ghent, Belgium"},{"name":"Chair of General and Inorganic Chemistry, Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5254-8762","authenticated-orcid":false,"given":"Anna M.","family":"Kaczmarek","sequence":"additional","affiliation":[{"name":"L<sup>3<\/sup>\u2013Luminescent Lanthanide Lab, Department of Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Ghent, Belgium"},{"name":"NanoSensing Group, Department of Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Ghent, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rik","family":"Van Deun","sequence":"additional","affiliation":[{"name":"L<sup>3<\/sup>\u2013Luminescent Lanthanide Lab, Department of Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Ghent, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2455-8856","authenticated-orcid":false,"given":"Kristof","family":"Van Hecke","sequence":"additional","affiliation":[{"name":"XStruct, Department of Chemistry, Ghent University, Krijgslaan 281-S3, B-9000 Ghent, Belgium"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,11,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1039\/B905604C","article-title":"Lanthanide luminescence for functional materials and bio-sciences","volume":"39","author":"Eliseeva","year":"2010","journal-title":"Chem. 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