Flexible Bis(imidazole) Mediated Assembly of Silver(I)–Organic Frameworks with Ethynide and Trifluoroacetate Ligands

A new family of 10 organosilver­(I)
complexes, namely, [(AgCCPh)2­(AgO2­CCF3)4­(cis-1,2-bix)­(CH3OH)]·2CH3OH (1,2-bix = 1,2-bis­(imidazol-1-ylmethyl)­benzene, 1A), [(AgCC­C6H4­Me-2)2­(AgO2­CCF3)4­(cis-1,3-bix)]·5.25H2O (1,3-bix = 1,3-bis­(imidazol-1-ylmethyl)­benzene, 1B), [(AgCCPh)3­(AgO2­CCF3)6­(trans-1,4-bix)­(CH3OH)3]·2CH3OH (1,4-bix = 1,4-bis­(imidazol-1-ylmethyl)­benzene, 2A), [(AgCC­C6H4­Me-4)3­(AgO2­CCF3)6­(trans-1,4-bix)­(CH3OH)3]·2CH3OH (2B), [(AgCCPh)­(AgO2­CCF3)3­(trans-1,3-bix)­(H2O)]·0.5H2O (3A), [(AgCC­C6H4­Me-4)­(AgO2­CCF3)3­(trans-1,3-bix)­(H2O)] (3B), [(AgCC­C6H4­Me-4)­(AgO2­CCF3)3­(bbi)­(H2O)] (bbi = 1,1′-(1,4-butanediyl)­bis­(imidazole), 3C), [(AgCC­C6H4­tBu-4)­(AgO2­CCF3)3­(trans-1,4-bix)] (3D), [(AgCCPh)2­(AgO2­CCF3)4­(bbi)­(H2O)]·2H2O (4), and [(AgCCtBu)2­(AgO2­CCF3)4­(bbi)] (5), have been synthesized employing
a variable combination of ethynide, trifluoroacetate, and bridging
bis­(imidazole) ligands. In both 1A and 1B, the flexible 1,2-bix or 1,3-bix ligands in cis-conformations are alternatively attached on both sides of an infinite
cationic silver­(I) chain, and neighboring organosilver­(I) chains are
further interconnected by intermolecular hydrogen bonds to generate
a three-dimensional supramolecular architecture. In structural analogues 2A and 2B, pairs of silver­(I) chains are linked
via the trans-1,4-bix ligands to yield infinite ladders,
which are further joined together by hydrogen bonds to afford a three-dimensional
supramolecular network. In the isostructural series 3A–3D, centrosymmetric (PhC2)2­Ag8 aggregates are connected by trifluoroacetate
groups to give an infinite chain, and such chains are then bridged
by bis­(imida­zole) ligands to generate a coordination layer.
Furthermore, adjacent layers are linked by hydrogen bonds to form
a three-dimensional supramolecular network. In 4, infinite
silver­(I)–phenylethynide chains constructed by Ag6 aggregates are bridged by bbi ligands in a gauche–trans–gauche conformation
to yield a three-dimensional coordination framework. In contrast,
infinite silver­(I)-tert-butylethynide chains based
on Ag8 and Ag6 aggregates in 5 are
linked by bbi ligands exhibiting different trans–trans–trans and gauche–trans–gauche conformations
to generate a three-dimensional coordination network. Finally, the
roles played by various bis­(imida­zole) ligands and ethynides
bearing different substituents in the framework assembly are discussed
in detail.