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Interpreting the different emissive properties of cyclic triimidazole‐based Cu I and Ag I coordination polymers: a QTAIM and IQA study
Author(s) -
Forni Alessandra,
Cariati Elena,
Carlucci Lucia,
Lucenti Elena,
Marinotto Daniele,
Pieraccini Stefano,
Sironi Maurizio
Publication year - 2021
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520621009707
Subject(s) - isostructural , ligand (biochemistry) , covalent bond , crystallography , delocalized electron , chemistry , metal , electron localization function , non covalent interactions , halogen , molecule , hydrogen bond , crystal structure , electron , organic chemistry , physics , receptor , quantum mechanics , alkyl , biochemistry
A QTAIM and IQA investigation on model compounds of two isostructural Ag I and Cu I coordination polymers (CPs) based on cyclic triimidazole ( L ), i.e. the [ M I L ] n 1D double‐stranded stair chain and the [ M Cl L ] n 3D network ( M = Cu, Ag), has allowed light to be shed on the different emissive behaviour associated with the two metal ions. According to a previously reported investigation [Malpicci et al. (2021). Inorg. Chem. Front. 8 , 1312–1323], Ag I CPs showed both fluorescence and multiple ligand‐centred room‐temperature phosphorescences, whereas Cu I CPs displayed non‐thermally equilibrated halogen and metal‐to‐ligand charge transfer and two ligand‐centred phosphorescences, the latter observed only by their selective activation. Analysis of both local and integral QTAIM descriptors, including delocalization indices and source function, of the Ag—N and Cu—N bonds reveals a higher covalent and local character for the latter, explaining the greater metal–ligand electronic communication observed for the Cu compounds. Moreover, IQA investigation shows that the Cu—N bond is characterized by higher interaction energy, due to both higher electrostatic and exchange‐correlation contributions. Analysis on the M — X ( M = Ag, Cu; X = I, Cl) bonds, also present in these structures, highlights a much higher covalent and local character with respect to the M —N bonds.