Synthesis of a tritopic, third-generation bis(1-pyrazolyl)methane ligand and its silver(I) complex: Unexpected structure with high coordination numbers

Multiple coordination modes of a new ditopic bis(pyrazolyl)methane-based ligand

A new ditopic ligand, N-(2,2-bis(pyrazolyl)ethyl)-2,2-bis(pyrazolyl)acetamide ((pz)₂CH-C(O)-NH-CH₂-CH(pz)₂, L4Pz, pz = pyrazolyl ring), comprising two bis(pyrazolyl)methane donor groups linked via an amide bridge, has been prepared from the reaction of HOOCCH(pz)₂ and H₂NCH₂CH(pz)₂. The ligand coordinates to various metallic salts (i.e. AgO₃SCF₃, PdCl₂, Re(CO)₅Br, and Fe(BF₄)₂), in either a κ²-μ-κ² or a κ³-μ-κ² fashion, depending on the coordination preferences of the metallic center. These compounds were characterized by NMR, UV-Vis and IR spectroscopy, and in solid state by single crystal X-ray diffraction. In the case of silver(i), a mono-dimensional coordination polymer was obtained, while the others were found to be discrete complexes. The synthesis and characterization of a heterobimetallic complex is also described. In solid state, all compounds are associated into supramolecular architectures via hydrogen bonding and pyrazolyl embrace interactions.

1,1'-[(5-Hy-droxy-methyl-1,3-phenyl-ene)bis-(methyl-ene)]dipyridin-4(1H)-one monohydrate

The asymmetric unit of the title compound, C(19)H(18)N(2)O(3), comprises a whole organic dipyridinone mol-ecule plus a water mol-ecule of crystallization. The planes of the pyridinone rings are approximately perpendicular with the plane of the central aromatic ring [dihedral angles = 80.68 (8) and 83.65 (8)°]. The C-O bond of the hy-droxy group subtends an angle of 31.71 (10)° with the plane through the central aromatic ring. The crystal packing is mediated by the presence of several O-H⋯O hydrogen-bonding inter-actions and while the water mol-ecules form a C(2) (1)(4) chain parallel to the c axis of the unit cell, the pendant hy-droxy groups are engaged in O-H⋯O=C hydrogen bonds described by a C(1) (1)(12) graph-set motif which runs parallel to the a axis.