RuCl₂(PPh₃)₂(N‐ppa) – A Hydrogen‐Bridged Ruthenium(II) Complex of N‐Pyrazolylpropanamide

Abstract

The reaction of RuCl2(PPh3)3 with N‐pyrazolylpropanamide (N‐ppa) displaces a single PPh3 producing the six‐coordinate complex RuCl2(PPh3)2(N‐ppa) (1). A crystal structure determination of the dichloromethane solvate RuCl2(PPh3)2(N‐ppa)·2CH2Cl2 (1·2CH2Cl2) revealed that the geometry about the central Ru atom is distorted octahedral with the chloride ligands in trans‐position and the N‐ppa acting as N,O‐chelating ligand. In the solid state, RuCl2(PPh3)2(N‐ppa) molecules are dimerized via N–H···Cl hydrogen bonds. The dimers pack as chains in the c direction and form voids that are occupied by dichloromethane solvent molecules.

Pyrazolylpropanoate Complexes of Palladium(II) Chloride

“…The crystal structure shows the existence of supramolecular dimers formed by NÀ H•••Cl bonds, but not an extensive hydrogen-bonded network. [19] In contrast, silver(I) forms the di-coordinate complex [Ag(PPA) 2 ]NO 3 . H 2 O, in which the PPA ligand is kN-monodentate, and participates in a complex hydrogen-bonded framework.…”

“…[20] The present study extends the ligand type from amide to ester functionalities and concentrates on the synthesis and structural characterization of PdCl 2 complexes with 3-(pyrazol-1yl)methylpropanoate (L1 = PPE) and 3-(2,4-dimethylpyrazol-1yl)methylpropanoate (L2 = Me 2 PPE), two ligands depicted in Scheme 2. We were interested in determining if the ligands would chelate as observed with e. g. ruthenium(II), [19] whether a monodentate mode as seen with silver(I), [13] or other modes of coordination would occur. We were drawn to these ligands as they do not offer the hydrogen bonding possibilities of the PPA and related amide derivatives.…”

“…The reaction of RuCl 2 (PPh 3 ) 3 with 1 forms RuCl 2 (PPA)(PPh 3 ) 2 , which also contains a κ N ,κ O ‐chelating ligand. The crystal structure shows the existence of supramolecular dimers formed by N−H⋅⋅⋅Cl bonds, but not an extensive hydrogen‐bonded network [19] . In contrast, silver(I) forms the di‐coordinate complex [Ag(PPA) 2 ]NO 3 ⋅ H 2 O, in which the PPA ligand is κ N ‐monodentate, and participates in a complex hydrogen‐bonded framework [13] .…”