4-Substituted 3,6-Bis(2-pyridyl)pyridazines: Silver(i) Complexes of 4-Cyano- and 4-(4-Bromophenyl)-3,6-bis(2-pyridyl)pyridazine and Pseudopolymorphs of 1,3,5-Tris{3,6-bis(2-pyridyl)pyridazin-4-yl}benzene

Metal:ligand complexes are crystallized from reaction mixtures of equimolar amounts of 4-cyano-3,6-bis(2-pyridyl)pyridazine 2 or 4-(4-bromophenyl)-3,6-bis(2-pyridyl)pyridazine 3 and silver(i) triflate. In [Ag2(2)2]2+, the two ligands adopt a head-to-tail arrangement, while a head-to-head motif is confirmed for the solid state structure of [Ag2(3)2]2+. In solution, one ligand environment is observed in each case. Silver(i) reacts with 1,3,5-tris{3,6-bis(2-pyridyl)pyridazin-4-yl}benzene 4 to give highly insoluble powders. The single crystal structures of the pseudopolymorphs (4)·Et2O and 2(4)·2MeCN·H2O are reported; in each structure, the ligand adopts the same conformation, derived from a Cs rather than C3v model structure.