Silver Alkynyl-Phosphine Clusters: An Electronic Effect of the Alkynes Defines Structural Diversity

Yi Ting Chen, Ilya S. Krytchankou, Antti J. Karttunen*, Elena V. Grachova, Sergey P. Tunik, Pi-Tai Chou, Igor O. Koshevoy

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)

Abstract

The face-capping triphosphine, 1,1,1-tris(diphenylphosphino)methane (tppm), together with bridging alkynyl ligands and the counterions, facilitates the formation of a family of silver complexes, which adopt cluster frameworks of variable nuclearity. The hexanuclear compounds [Ag6(C2C6H4-4-X)3(tppm)2(An-)3] (X = H (1), CF3 (2), OMe (3), An- = CF3SO3 - X = OMe (4), An- = CF3COO-) are produced for the electron-accepting to moderately electron-donating alkynes and the appropriate stoichiometry of the reagents. 1 and 3 undergo an expansion of the metal core when treated with 1 equiv of Ag+ to give the species [Ag7(C2C6H4-4-X)3(tppm)2(CF3SO3)3](CF3SO3) (X = H (5), OMe (6)). The electron-donating substituent (X = NMe2) particularly favors this Ag7 arrangement (7) that undergoes geometry changes upon alkynylation, resulting in the capped prismatic cluster [Ag7(C2C6H4-4-NMe2)4(tppm)2(CF3SO3)](CF3SO3)2 (8). Alternatively, for the aliphatic tBu-alkyne, only the octanuclear complex [Ag8(C2But)4{(PPh2)3CH}2(CF3SO3)2](CF3SO3)2 (9) is observed. The structures of 1-4 and 6-9 were determined by X-ray diffraction analysis. In solution, all the studied compounds were found to be stereochemically nonrigid that prevented their investigation in the fluid medium. In the solid state, clusters 2, 3, 5-8 exhibit room temperature luminescence of triplet origin (maximum φem = 27%, λem = 485-725 nm). The observed emission is assigned mainly to [d(Ag) → π∗(alkyne)] electronic transitions on the basis of TD-DFT computational analysis.

Original languageEnglish
Pages (from-to)480-489
Number of pages10
JournalORGANOMETALLICS
Volume36
Issue number2
DOIs
Publication statusPublished - 23 Jan 2017
MoE publication typeA1 Journal article-refereed

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