Phosphorescence at Low Temperature by External Heavy‐Atom Effect in Zinc(II) Clusters. Issue 23 (12th March 2019)

• Record Type: Journal Article
• Authors: Kobayashi, Fumiya; Ohtani, Ryo; Teraoka, Saki; Yoshida, Masaki; Kato, Masako; Zhang, Yingjie; Lindoy, Leonard F.; Hayami, Shinya; Nakamura, Masaaki
• Is Part Of: Chemistry. Volume 25:Issue 23(2019)
• Page Start: 5875
• Page End: 5879
• Publication Date: 2019-03-12
• Subjects: external heavy-atom effect -- long emission lifetime -- luminescence -- phosphorescence -- zinc; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201900343
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Luminescent Zn II clusters [Zn4 L4 (μ3 ‐OMe)2 X2 ] (X=SCN (1 ), Cl (2 ), Br (3 )) and [Zn7 L6 (μ3 ‐OMe)2 (μ3 ‐OH)4 ]Y2 (Y=I − (4 ), ClO4 − (5 )), HL=methyl‐3‐methoxysalicylate, exhibiting blue fluorescence at room temperature ( λ max =416≈429 nm, Φ em =0.09–0.36) have been synthesised and investigated in detail. In one case the external heavy‐atom effect (EHE) arising the presence of iodide counter anions yielded phosphorescence with a long emission lifetime ( λ max =520 nm, τ =95.3 ms) at 77 K. Single‐crystal X‐ray structural analysis and time‐dependent density‐functional theory (TD‐DFT) calculations revealed that their emission origin was attributed to the fluorescence from the singlet ligand‐centred ( 1 LC) excited state, and the phosphorescence observed in4 was caused by the EHE of counter anions having strong CH−I interactions. Abstract : Luminescent Zn II clusters [Zn4 L4 (μ3 ‐OMe)2 X2 ] (X=SCN, Cl, Br) and [Zn7 L6 (μ3 ‐OMe)2 (μ3 ‐OH)4 ]Y2 (Y=I −, ClO4 − ), HL=methyl‐3‐methoxysalicylate, exhibiting blue fluorescence at room temperature ( λ max =416≈429 nm, Φ em =0.09–0.36) have been synthesized and investigated in detail (see figure).