Supramolecular networks of silver(I) and iron(II) complexes of the third generation tris(pyrazolyl)methane ligand Ph2(O)POCH2C(pz)3 (pz = pyrazolyl ring)

摘要

The new ligand Ph2(O)POCH2C(pz)3 (pz = pyrazolyl ring), prepared from the reaction of HOCH2C(pz)3 and Ph2P(O)Cl in the presence of base, reacts with either AgBF4 or Fe(BF4)2·6H2O in a 2/1 molar ratio to yield {[Ph2(O)POCH2C(pz)3]2Ag}(BF4) (1) and {[Ph2(O)POCH2C(pz)3]2Fe}(BF4)2 (4), respectively. In the structure of 1, the silver is in an unusual planar geometry with each of the ligands in a k~2-k~0 coordination mode. Slow evaporation of a thf solution of 1 yields crystalline [Ph2(O)POCH2C(pz)3Ag]2(thf)2}(BF4)2 (2). In each cationic unit of 2, the two Ph2(O)POCH2C(pz)3 ligands coordinate to the same two silver(I) centers in a k~2-k~1 bonding mode, with a silver atom separation of 3.36 A. The supramolecular structure of both 1 and 2 is dominated by a pair of cooperative hydrogen bonding interactions between the Ph2P(O) secondary tecton and a hydrogen at6m from a methylene group situated on a neighboring building block, which arranges the cations in chains. The reaction of HC(pz)3 and AgO3SCF3 (AgOTf) yields {[HC(pz)3]2Ag2}(OTf)2 (3). The cationic unit in 3 has a structure very similar to that of 2, but with a much shorter distance between the silver atoms at 2.86 A. The supramolecular structure of 3 is dominated by an unusual pyrazolyl embrace interaction where the acceptor ring in the C-H ··· π interaction is the pyrazolyl ring k~1 -bonded to silver in the adjacent dimeric unit rather than the other ring in a k~2-bonded Cpz2 unit. This interaction arranges the cations in chains which are further organized into sheets by the triflate anions that link the chains via combined Ag··· O/CH ··· O interactions. The iron in 4 is octahedral with each tris(pyrazolyl)methane unit in the k~3-tripodal coordination mode. The supramolecular structure is sheets formed by hydrogen bonding between the Ph2P(O) oxygen and a meta-position hydrogen on one of the diphenylphosphine rings from an adjacent cation.