Synthesis and Structure of a Novel Silver(I) Perchlorate 2,2′:6′,2″-Terpyridine Adduct Solvated With Acetonitrile

Abstract

Recrystallization of an equimolar mixture of silver(I) perchlorate and 2,2′:6′,2″-terpyridine ( terpy ) from acetonitrile solution yields the golden yellow crystalline adduct shown by a room-temperature single-crystal X-ray study to be [Ag₃( terpy )₄][( MeCN )Ag( terpy )](ClO₄)₄. Crystals are triclinic, Pī , a 21.48(1), b 14.525(7), c 13.506(8) Ǻ, α 68.50(4), β 80.71(4), γ 81.66(4)°, Z 2 formula units; R was 0.045 for 9681 'observed' reflections. The complex helical cation is quasi- centrosymmetric with a collinear Ag₃ array. The environment of the central silver atom is planar four-coordinate, two short Ag-N distances [(2.198(5), 2.188(5)Ǻ] arising from the nitrogen atoms of outer rings of a pair of twisted terpy ligands ; the other two sites are occupied by the nitrogen atoms of the central terpy rings which bifurcate to the other silver atoms [Ag(central)-N(central) 2.624(5), 2.818(5)Ǻ; Ag(outer)-N(central) 2.704(4), 2.640(4)Ǻ], which are also coordinated by the outer ring nitrogen of the two ligands [Ag-N, 2.266(5), 2.304(4) Ǻ]. Coplanar with the latter, each outer silver atom has a further tridentate terpy coordinated [Ag-N(central) 2.362(4), 2.381(4)Ǻ; Ag-N(outer) 2.403(6)-2.573(5)Ǻ]. The [( MeCN )Ag( terpy )]⁺ species is also quasi-planar, Ag- NCMe being 2.174(7)Ǻ, opposed to the central ring nitrogen [2.331(5)Ǻ; Ag-N(outer) being 2.399(7), 2.433(7)Ǻ].