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Silver(I) Clusters with Carba‐ closo ‐dodecaboranylethynyl Ligands: Synthesis, Structure, and Phosphorescence
Author(s) -
Hailmann Michael,
Wolf Natalia,
Renner Rebecca,
Hupp Benjamin,
Steffen Andreas,
Finze Maik
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201702515
Subject(s) - intersystem crossing , pentagonal bipyramidal molecular geometry , chemistry , octahedron , pyridine , crystallography , phosphorescence , crystal structure , ligand (biochemistry) , cluster (spacecraft) , bipyramid , stereochemistry , fluorescence , medicinal chemistry , physics , biochemistry , receptor , quantum mechanics , computer science , nuclear physics , singlet state , programming language , excited state
Salts of anionic silver(I) clusters with the carba‐ closo ‐dodecaboranylethynyl ligand were obtained from {Ag 2 (12‐C≡C‐ closo ‐1‐CB 11 H 11 )} n , selected pyridines, and [Et 4 N]Cl or [Ph 4 P]Br. Salts of octahedral silver(I) clusters [Et 4 N] 2 [Ag 6 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (4‐X‐C 5 H 5 N) x ] were formed with pyridine (X=H, x= 8), 4‐methylpyridine (X=Me, x= 8), and 4‐cyanopyridine (X=CN, x= 10). In contrast, 3,5‐lutidine (3,5‐Me 2 Py) did not result in salts of dianionic clusters, even in the presence of excess of [Et 4 N]Cl or [Ph 4 P]Br; instead salts of monoanionic Ag I 7 clusters, [Et 4 N][Ag 7 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (3,5‐Me 2 Py) 9 ] and [Ph 4 P][Ag 7 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (3,5‐Me 2 Py) 13 ] were obtained. The Ag I 7 cluster is pentagonal bipyramidal in the former, but is an edge‐capped octahedron in the latter. The 4‐methylpyridine and 3,5‐lutidine complexes show green phosphorescence at room temperature. Although argentophilic interactions give rise to sufficient spin–orbit coupling for intersystem crossing S 1 →T n and moderate‐to‐high radiative rate constants, time‐resolved measurements indicate that the quantum yields are greatly influenced by the pyridine ligands, which mainly determine the non‐radiative rate constants. In addition, the crystal structures of [Ag 16 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 8 (Py) 9.25 (CH 3 CN) 2 (CH 2 Cl 2 ) 0.75 ] ⋅ CH 2 Cl 2 , [Ag 8 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (Py) 12 ], [Ag 10 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (4‐MePy) 10 Br 2 ], [Ag 7 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 3 (4‐ t BuPy) 11 Cl] ⋅ (4‐ t BuPy), and [Ag 9 (12‐C≡C‐ closo ‐1‐CB 11 H 11 ) 4 (3,5‐Me 2 Py) 11 Cl] were elucidated.