Silver(I) Complexes with Nopinane-Annelated 4-Aza- and 4,5-Diazafluorene Derivatives

Abstract

Complexes [AgL(NO₃)] (I), [AgL¹(NO₃)] (II) and [Ag(μ-NO₃)L²]_n (III), (L, L¹, L² are nopinane-annelated 4-aza- and 4,5-diazafluorene derivatives) are prepared. The molecular structures of I, II, and that of the [Ag(μ-NO₃)L²]_n·0.5Et₂O (IV) solvate are established by single crystal X-ray diffraction (CCDC No. 2546650, 2546708, 2546710). The crystal structures of I and II are built of supramolecular dimeric ensembles formed by molecules of two-coordinate and three-coordinate silver(I) complexes, respectively. The dimeric ensembles in II are additionally stabilized by argentophilic interactions (Ag⋯Ag 2.92 Å). Compound IV contains a polynuclear complex III and diethyl ether molecules. Ligand L is monodentate, whereas L¹ and L² are bidentate cyclic ligands. The compounds are characterized by elemental analysis, X-ray powder diffraction, and NMR spectroscopy. The cytotoxic properties of the free ligands L¹, L², complexes II and III, and the previously obtained nopinane-annelated 4,5-diazafluorenone L³ and \([\text{Ag}{{(\text{L}_{\text{N}\text{,N}}^{ 3})}_{2}}]\text{N}{{\text{O}}_{3}}\cdot \text{EtOH}\cdot {{\text{H}}_{2}}\text{O}\) (V) are investigated against the breast adenocarcinoma cell line MCF-7 and the non‑tumor human lung fibroblast cell line MRC-5.