Silver(I) Complexes of Fixed,Polytopic Bis(pyrazolyl)methane Ligands:Influence of Ligand Geometry on the Formation of Discrete Metallacycles and Coordination Polymers

摘要

Reactions of the arene-linked bis(pyrazolyl)methane ligands m-bis[bis(1-pyrazolyl)methyl]benzene,(m-[CH(pz)_2]_2C_6H_4,L_m),p-bis[bis(1-pyrazolyl)methyl]benzene,(p-[CH(pz)_2]_2C_6H_4,L_p),and 1,3,5-tris[bis(1-pyrazolyl)methyl]benzene (1,3,5-[CH(pz)_2]_3C_6H_3,L~3) with AgX salts (pz = 1-pyrazolyl;X = BF_4~- or PF_6~-) yield two types of molecular motifs depending on the arrangement of the ligating sites about the central arene ring.Reactions of the m-phenylene-linked L_m with AgBF_4 and AgPF_6 afford complexes consisting of discrete,metallacyclic dications:[Ag_2(mu-L_m)_2]-(BF_4)_2 (1) and [Ag_2(mu-L_m)_2](PF_6)_2 (2).When the p-phenylene-linked L_p is treated with AgBF_4 and AgPF_6,acyclic,cationic coordination polymers are obtained:{[Ag(mu-L_p)]BF_}_(infinity) (3) and {[Ag(mu-L_p)]PF_6}_(infinity) (4).Reaction of the ligand L~3,containing three bis(pyrazolyl)methane units in a meta arrangement,with an equimolar amount of AgBF_4 again yields discrete metallacyclic dications in which one bis(pyrazolyl)methane unit on each ligand remains unbound:[Ag_2(mu-L~3)_2](BF_4)_2 (5).Treatment of L~3 with an excess of AgBF_4 affords a polymer of metallacycles,{[Ag_3(mu-L~3)_2]-(BF_4)_3}_(infinity) (6),with one of the bis(pyrazolyl)methane units on each ligand bound to a silver cation bridging two metallacycles.The supramolecular structures of the silver(l) complexes 1-6 are organized by noncovalent interactions,including weak hydrogen bonding,pi-pi,and anion-pi interactions.