Roles of Anion and Solvent in the Self-Assembly of Silver(I) Complexes Containing 2,3-Diphenylquinoxaline

Abstract

A series of Ag(I) complexes with zero-, one-and two-dimensional structures have been successfully prepared by the reactions of 2,3-diphenylquinoxaline, L, with corresponding Ag(I) salts in various solvents, which were characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Complexes of the type [Ag(L) 2 ](X) (X ) ClO 4 , 1; X ) PF 6 , 2; and X ) SbF 6 , 3) are monomeric, while the complexes {5CH 2 Cl 2 , show 1-D polymeric infinite chains. The ClO 4 anions in complex 6 interact with the rings in a tridentate bonding mode forming the rare [ClO 4 -π] n zigzag chain. The molecules of the complex Ag 2 (L)(NO 3 ) 2 (DMF) 2 , 9, are dinuclear, while complexes of the type [Ag 2 (L)(NO 3 ) 2 (L′) 2 ] ∞ (L′ ) H 2 O, 10, and L′ ) CH 3 CN, 11) show 1-D ladderlike chain structures, and the [Ag 2 (L)] 2+ units are interlinked by H 2 O molecules and/or NO 3 anions. The complexes [Ag 2 (L)(NO 3 ) 2 ] ∞ , 12, and [Ag(L)(p-TsO)] ∞ (p-TsO ) p-toluenesulfonate), 13, show 2-D distorted hexagonal net and 2-D pleated rectangular grids, respectively. For complexes 1-8 with noncoordinating anions, those with coordinated or packed solvent molecules show the polymeric structures, whereas those without solvent molecule are mononuclear. For complexes 9-13, the nitrate and p-toluenesulfonate ions are found to be coordinating and the bonding modes of nitrate anions are dependent on the nature of the solvents. All the complexes exhibit emissions which may be tentatively assigned as intraligand (IL) π f π* transitions.

Molecular and electronic structure of several 2,3-dithienylquinoxalines and their 2:1 complexes with silver(I) nitrate

“…The nitrates involved in the metal bonding in these complexes show three variations: the nitrate may bind one oxygen to one silver [8], two oxygen to one silver [9,13], or two oxygen on one nitrate group may bridge two silvers on separate molecules [7]. The silver geometry is either linear or bent with the perturbation to non-linear geometries caused by the cation-anion interaction.…”

“…Preliminary observations have shown that weakly coordinating anions such as tend to be located near the silver [6,10]. However, several structures have seen nitrate-silver interactions that lead to: monodentate O-Ag bonding [8]; bidentate nonbridging O-Ag bonding [9,13]; and bidentate bridging bonding [7]. In Ag(1) 2 NO 3 , one nitrito group oxygen is within bonding distance to the silver at a distance of 2.461 (5) Å with the other at a distance of over 3 Å.…”

“…Molecular solids having Ag(L) + and ( ) 2 Ag L + structural units have shown a wide range of structural variation that is guided by a few basic principles. For example, mono-or bis-quinoxaline silver complexes tend to have linear geometries about Ag [6,7]; such complexes with heterocyclic aromatic ligands, tend to interact via π-π stacking interactions building higher dimensional structural networks [8,9]; their counteranions tend to direct extended structures through weak associations with the silver in the complex (e.g. 1 6 PF − , 1 4 BF − ) [6,10] or through direct coordination (e.g.…”

“…1 6 PF − , 1 4 BF − ) [6,10] or through direct coordination (e.g. 3 2 3 CF CO , NO − − ) [11][12][13][14]; and solvent from which crystals are grown tends to influence packing [7].…”

Syntheses, Structures and Luminescent Properties of Metal Halide Complexes Containing 2,3‐Diphenylquinoxaline

“…[7][8][9][10] This ligand can coordinate to the metal centers through their quinoxailne nitrogen atoms and interact with each other through p-p stacking and hydrogen bonds which are important for molecular recognition and constructing supramolecular arrays. In our previous report, 9 we have found that metal-to-ligand molar ratio and nature of the solvents involved in the reactions play important roles in determining the structural type of the Ag(I)-L complexes containing coordinating or non-coordinating anion. For complexes with non-coordinating anions, coordinated or packed solvent molecules show the polymeric structures, while those without solvent molecule are mononuclear.…”