Same head, different scaffold: a plethora of structural motifs assembled from silver(i) and ditopic 2,2′-bipyridine ligands

Bis(aryl)acenaphthenequinonediimine Substituent Effect on the Properties and Coordination Environment of Ligands and Their Bis‐Chelate AgI Complexes

“…Coordination numbers higher than four are not uncommon for silver, and there exist several examples of such coordination geometries realized for silver complexes with heterocyclic nitrogen donors, mainly polypyridines. These compounds are usually dimeric in nature, that is, [Ag 2 L n ] 2+ and the chromophores formed are of the formula AgN 5 ,29 although higher nuclearities have been reported 30. Of special interest in this type of compounds is the nature of the counteranions that participate in the determination of the overall structure through their interaction with the cationic complexes or solvent molecules.…”

From Mesocates to Helicates: Structural, Magnetic and Chiro‐Optical Studies on Nickel(II) Supramolecular Assemblies Derived from Tetradentate Schiff Bases

“…In this case, the main axis of the molecule is placed on the center of opposite triangular faces of the octahedra and NCCN torsions around 60° are enough to satisfy the helicate requirements. A large number of M 2 L 2 (M=tetrahedral Cu I , Cu II , Ag I ) helicates have been reported for ligands with a two‐C spacer like those employed in the present work, with NCCN torsion angles also around 60° . In contrast, for the less common ML 2 X 2 double helicates with monoatomic or small double M‐X‐M bridges, the symmetry is reduced to C 2 , with the main molecular axis along the center of opposite edges of the octahedra (Figure , right).…”

“…When pyridyl/imine Schiff bases with an ethylene spacer are employed as ligands, systematic characterization of [M 2 L 2 ] n + helicates have been reported and, in both cases, the bidentate or tridentate units around the same cation have an ideal 90° angle between them. Furthermore, in both cases, the torsion angle subtended by the NCCN atoms of the flexible spacer typically lies around 60°, as shown in the analysis of the 30 reported structures with pyridyl/imine ligands and tetrahedral Cu I , Ag I , or with bipyridyl/imine ligands and octahedral Zn II , Cu II or Fe III cations, Scheme (a) and (b). Double Ni II helicates with the cations in octahedral environment and with two coordination sites occupied by one bidentate ligand and employing the L2 Schiff base (Scheme ), exhibit similar coordination sites for the N ‐donors and NCCN torsion angles in the same range (Scheme c) …”

“…[16] Ligands must be chosen carefully to preparec ompounds of this kind because they must have the ability to link different metal centers in spite of chelating asingle cation. [17] Usually,a ll the coordination sites around the metal are filled by the ligands, resulting in double helicates ([M 2 L 2 ] n + )w hen the bis-bidentate ligands react with cations that prefer at etrahedral environment, or when the bis-tridentate ligands reactwith cations that prefer aoctahedral environment.W hen pyridyl/imine Schiff bases with an ethylene spacer are employed as ligands, systematic characterization of [M 2 L 2 ] n + helicates have been reported and, in both cases, the bidentate or tridentate units around the same cation have an ideal 908 angle between them.F urthermore, in both cases, the torsion angle subtended by the NCCN atoms of the flexible spacer typically lies around6 0 8,a ss hown in the analysiso ft he 30 reported structures with pyridyl/imine ligands and tetrahedral Cu I , [18][19][20][21][22][23][24][25][26][27][28][29] Ag I , [24,25,[30][31][32][33][34][35] or with bipyridyl/imine ligandsa nd octahedral Zn II ,C u II or Fe III cations, [28,36,37] Scheme 1(a) and (b). In this sense, the first-rowt ransition metals have been speciallys tudied, although structures with other transition metals or even quadruple helicates with rare earths have also been reported.…”

Electrospray mass spectrometry and molecular modeling study of formation and stability of silver complexes with diazaperylene and bisisoquinoline

“…Figure S2) are shown (see Supporting Information). Other dinuclear complex types [Ag 2 (L) 2 BF 4 ] + were assigned earlier in ESI-mass spectra in a study of interactions of silver(1) with different ditopic 2,2′-bipyridine ligands reported by Constable et al54,55 The bisisoquinoline ligand 2 promotes weak Ag…Ag interaction in some cases 24. Bardaji et al reported that the silver coordination sphere is completed by the anion and in some cases by solvent (acetone and water).…”