Inorganic Chemistry, Vol.52, No.14, 7862-7872, 2013
Self-Assembled Supramolecular Clusters Based on Phosphines and Coinage Metals: Tetrahedra, Helicates, and Mesocates
An array of coordination-driven supramolecular metal-ligand clusters has been synthesized using polytopic phosphine ligands and coinage metals (Cu+, Ag+, Au+). Rigid 3-fold or 2-fold symmetric phosphine ligands have been prepared: 1,3,5-tris((4-(diphenylphosphino)ethynyl)phenyl)benzene) (tppepb, L-1), 1,4-bis((diphenylphosphino)ethynyl)benzene (1,4-dppeb, L-2), 1,3-bis((diphenylphosphino)ethynyl)benzene (1,3-dppeb, L-3), 2,6-bis((diphenylphosphino)ethynyl)pyridine (2,6-dppep, L-4), and 1,5-bis-((diphenylphosphino)ethynyl)naphthalene (1,5-dppen, L-8). Self-assembly of these ligands with coinage metals produces four different types of metal-ligand clusters, or in some cases coordination polymers, depending on number and relative geometry of the phosphine donor atoms. Supramolecular tetrahedral clusters of the formula M-4(L-1)(4)I-4 (M = Cu+, Ag+, Au+) were obtained with the tppepb ligand, encapsulating solvent molecules (either CH2Cl2 or DMF) as guests within the central cavity of the clusters. The ligands 1,3-dppeb (L-3) and 2,6-dppep (L-4) give achiral, triple-stranded, dinuclear mesocates with the formula M-2(L)(3)I-2 (M = Cu+ or Au+). In contrast, the ligand 1,4-dppeb (L-2) generates a triple-stranded, dinuclear helicate with Cu+, but a coordination polymer with Au+ (both with the empirical formula M-2(L-2)(3)I-2). Finally, coordination polymers were obtained from 1,5-dppen (L-5) with Cu+. The clusters have been fully characterized by single crystal X-ray crystallography, high-resolution mass spectrometry, H-1 NMR, and P-31 NMR.