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.

The reactions of N,N′-di(3-pyridyl)adipoamide (L) with the corresponding silver(I) salts afforded the complexes {[Ag(L)](PF 6 )·2CH 3 CN} ∞ , 1, {[Ag(L)](BF 4 )· CH 3 CN} ∞ , 2, {[Ag(L)](NO 3 )·CH 3 CN} ∞ , 3, {[Ag(L)](PF 6 )· 4DMF} ∞ , 4, {[Ag(L)](BF 4 )·4DMF} ∞ , 5, {[Ag(L)](CF 3 SO 3 )· DMF} ∞ , 6, {[Ag(L)](ClO 4, 9, and [Ag(L)(p-TsO)] ∞ , 10. Complex 1 forms a one-dimensional (1D) concavo-convex chain, and complexes 2, 3, 6, and 7 show 1D polymeric pairs of zigzag chains supported by the Ag---Ag and π−π interactions, whereas complexes 4, 5, and 8 adopt zigzag chains. Complex 9 forms a zero-dimensional (0D) dinuclear metallocycle, and complex 10 shows a two-dimensional (2D) pleated grid with a {4,8 2 } topology, respectively. The L ligands in these complexes adopt various ligand conformations, which are subjected to the changes of the counteranions and solvents, resulting in the different structural types. Reversible crystal-to-crystal transformation was observed in 7 and 8 upon removal and uptake of the acetonitrile molecules, while the process was irreversible in 9 and 10, which is concomitant with changes in supramolecular structures, ligand conformations, and luminescent properties. The main driving forces for the structural transformations are the Ag---N and Ag---O interactions. ■ INTRODUCTIONThe rational design and synthesis of novel coordination polymers continue to be an active area of investigation because it expands the range of new complexes with preselected physical and chemical properties. 1 The range and variety of the selfassembling structures that can be constructed rely on the presence of suitable metal−ligand interactions and supramolecular contacts, that is, hydrogen bonding and other weak interactions. 2 Additionally, the structural types of the resulting coordination polymers are also affected by factors such as counterion, 3 metal-to-ligand ratio, 4 and solvent. 5 The networks of coordination polymers containing flexible bidentate ligands are less predictable due to the possible occurrence of supramolecular isomerism involving the adoption of different ligand conformations. 6 It has been shown that 1,2-bis(4-pyridyl)ethane can adopt either a gauche or anti geometry, and 1,3-bis(4-pyridyl)propane can exist in anti-anti, gauche-anti, and gauche− gauche conformations. However, the use of conformationally flexible ligands may provide unique opportunities to construct novel crystalline architectures with desirable characteristics. 6f We have recently investigated the roles of ligand conformations of the flexible dipyridyl ligands bearing amide groups in the structural diversity, 7 and reported a series of one-dimensional (1D) silver(I) coordination polymers containing the flexible ligand N,N′-di(2-pyridyl)adipoamide (L′), 7a involving the zigzag chains [Ag(L′)(NO 3 )] ∞ , [Ag(L′)(PF 6 )] ∞ , [Ag(L′)(BF 4 )-(CH 3 CN)(H 2 O) 0.5 ] ∞ , and [Ag(L′)(ClO 4 )(CH 3 CN)] ∞ , the helical chain [Ag(L′)(ClO 4 )(H 2 O) 0.67 ] ∞ , and the sinusoidal chain [Ag 2 (L′) 2.5 SO 4 ] ∞ , which demonstrates an un...

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