Polyatomic anion versus acetonitrile in coordinating ability: Structural properties of AgX-bearing 1,4-bis(2-isonicotinoyloxyethyl)piperazine (X ^- = NO₃ ^-, CF₃SO₃ ^-, ClO₄ ^-, BF₄ ^-, and PF₆ ^-)

Type studies on competitive polyatomic anion versus acetonitrile coordination in the self-assembly of a series of [Ag₂(X) _m (bip)(NCCH₃) _n ](X)_2-m (X^- = NO₃ ^-, CF₃SO₃ ^-, ClO ₄ ^-, BF₄ ^-, and PF₆ ^-; m = 0, 2; n = 0, 2, 4; bip = 1,4-bis(2-isonicotinoyloxyethyl) piperazine) were carried out. Each bip spacer acts as an N₄ tetradentate ligand and is linked to four silver(I) centers through two pyridine and two piperazine moieties, producing a double strand consisting of two 20-membered ring units. The coordinating environment around the silver(I) center is subtly determined by the competition of the polyatomic anions with acetonitrile, that is, by the Ag•••NCCH₃ versus Ag•••X interactions. The coordinating ability of acetonitrile is inversely proportional to the order of the coordination ability of the Hoffmeister series of polyatomic anions, NO₃ ^- ≫ CF₃SO₃ ^- > ClO₄ ^- > BF₄ ^- ≫ PF₆ ^-.