Amalina Mohd Tajuddin

Synthesis and Characterization of Palladium(II) Schiff Base and their Catalytic Activities for Heck Reaction

The syntheses, physico-chemical and spectroscopic characterization of ovan-type Schiff-base ligands (L1, L2) and their novel mononuclear Pd(II) complexes (PdL1, PdL2) are reported herein. Elemental analysis, FT-IR, 1H NMR as well as magnetic susceptibility measurements characterised the compounds. The catalytic potential of the Pd(II) complexes for Heck coupling reaction were investigated and monitored using GC. It was observed that both Pd(II) complexes displayed properties of good catalysts for the reaction, indicated by 100% conversion of the starting materials to the subtituted alkene product after 6 hours of reaction time at 100°C in inert conditions. The catalytic activity was compared with the reaction without Pd(II) complexes.

Bis{2-[(E)-(4-fluoro-benz-yl)imino-meth-yl]-6-meth-oxy-phenolato}palladium(II).

In the title compound, [Pd(C15H13FNO2)2], the PdII atom is tetracoordinated by two N atoms and two O atoms from the two 2-[(4-fluorobenzyl)iminomethyl]-6-methoxyphenoxy ligands, forming a square-planar geometry. The two N atoms and the two O atoms around the PdII atom are trans to each other. The dihedral angle between the two fluoro-substituted benzene rings is 39.03 (6)°. The molecular structure is stabilized by an intramolecular C—H⋯O hydrogen bond. In the crystal, weak intermolecular C—H⋯π interactions occur.

Bis{2-[1-(benzyl-imino)-eth-yl]phenolato}palladium(II).

In the title compound, [Pd(C15H14NO)2], the Pd atom lies on an inversion center and is coordinated by two ligand molecules through the O and N atoms in a bidentate manner, forming a slightly distorted square-planar geometry. The dihedral angle between the two benzene rings in the ligand is 76.53 (19)°. The molecular packing is stablized by C—H⋯O and C—H⋯π interactions.

Bis{2-meth-oxy-6-[(E)-(4-methyl-benz-yl)imino-meth-yl]phenolato}palladium(II) chloro-form monosolvate.

In the title complex, [Pd(C16H16NO2)2]·CHCl3, the PdII cation lies on an inversion center. One Cl atom of the CHCl3 solvent molecule lies on a twofold axis and the C—H group is disordered with equal occupancies about this axis with the other Cl atom in a general position with full occupancy. The PdII cation is four-coordinate and adopts a square-planar geometry via coordination of the imine N and phenolic O atoms of the two bidentate Schiff base anions. The N and O atoms of these ligands are mutually trans. The plane of the benzene ring makes a dihedral angle of 73.52 (10)° with that of the methoxyphenolate ring. In the crystal, molecules of the PdII complex are arranged into sheets parallel to the ac plane, and the chloroform solvent molecules are located in the interstitial areas between the complex molecules. Weak intermolecular C—H⋯O and C—H⋯π interactions stabilize the packing.

Bis{2-[(E)-(4-fluoro-benz-yl)imino-meth-yl]-6-meth-oxy-phenolato-κN,O}nickel(II).

In the title compound, [Ni(C15H13FNO2)2], the NiII atom is tetracoordinated by two N atoms and two O atoms from two 2-[(4-fluorobenzyl)iminomethyl]-6-methoxyphenolate ligands in a square-planar geometry. The two N atoms and two O atoms around the NiII atom are trans to each other, as the NiII atom lies on an inversion centre. In the fluorophenyl group, five C atoms and an F atom are disordered over two sets of positions of equal occupancy. In the crystal, the complex molecules are linked via intermolecular C—H⋯F hydrogen bonds, forming chains along [001].

Crystal structure of bis­{2-[(E)-(4-meth­oxy­lbenz­yl)imino­meth­yl]phenolato-κ2N,O1}nickel(II)

In the square-planar [Ni(C14H11FNO)2] complex, weak C—H⋯F and C—H⋯π interactions play an important role in the molecular self-assembly, resulting in the formation of 2D molecular sheets which are stacked along the b axis.

Crystal structure of bis­(2-{1-[(E)-(4-fluoro­benz­yl)imino]­eth­yl}phenolato-κ2N,O)palladium(II)

In the square planar [Pd(C15H13FNO)2] complex, weak C—H⋯O and π–π interactions play important roles in the molecular self-assembly, resulting in the formation of two-dimensional molecular sheets which are further stacked along the b axis.