Crystal retro-engineering: structural impact on silver(I) complexes with changing complexity of tris(pyrazolyl)methane ligands

The preparation and structures of seven new silver(I) complexes involving the parent tris(pyrazolyl)methane unit, C(pz)(3)], as the donor set, {C6H5CH2OCH2C(pz)3]Ag}(BF4), {C6H5CH2OCH2C(pz)3]2Ag3}(CF3SO3)3, {HOCH2C(pz)3]Ag}(BF4), {HOCH2C(pz)3]Ag}(CF3SO3), {HC(pz)3]2Ag2(CH3CN)}(BF4)2, {HC(pz)3]Ag}(PF6), and {HC(pz)3]Ag}(CF3SO3), are reported. This project is based on a retro-design of our multitopic C6H(6-n)CH2OCH2C(pz)3]n (pz = pyrazolyl ring, n = 2, 3, 4, and 6) family of ligands in such a way that each new ligand has one fewer organizational feature. The kappa2-kappa1 bonding mode of the C(pz)3] units to two silvers, also observed with the multitopic ligands, is the dominant structural feature in all cases. Changing the counterion has important effects on the local structures and on crystal packing. When these structures are compared to similar ones based on the multitopic C6H(6-n)CH2OCH2C(pz)3]n ligands, it has been shown that the presence of the rigid parts (central arene core and the C(pz)3] units) are important in order to observe highly organized supramolecular structures. The presence of the flexible ether linkage is also crucial, allowing all noncovalent forces to manifest themselves in a cumulative and complementary manner.