Synthesis, characterization and thermal properties of palladium(II) complexes containing phenyltetrazole. Crystal structure of trans-[C40H64N8 O2PdCl2]

Abstract

Neste trabalho, descreve-se a síntese de novos ligantes e dos seus complexos de Pd(II) com os ligantes 5-(n-alcoxifenil)-2-n-alquiltetrazol (L 1 ) e α,ω-bis-[5-(4-pentoxifenil)-2-alcanotetrazois] (L 2 ). A determinação estrutural através de difração de raios-X do complexo de paládio contendo L 1 revela uma estrutura mononuclear na qual a geometria do cromóforo Pd(L 1 ) 2 Cl 2 é plana e possui um centro de inversão sobre o átomo de paládio. As moléculas de feniltetrazol estão ligadas ao íon metálico de forma monodentada e trans entre si, através de uma ligação σ, Pd-N1. Para o complexo de paládio contendo L 2 , propõe-se uma estrutura dinuclear, ([Pd 2 (L 2 ) 2 Cl 4 ]), com base em dados de espectroscopia de RMN e IV.The new 5-(n-alkoxyphenyl)-2-n-alkyltetrazole (L 1 ) and α,ω-bis-[5-(4-pentoxyphenyl)-2-alkanetetrazoles] (L 2 ) ligands and their Pd(II) complexes have been synthesized. The X-ray diffraction study of the palladium complex with L 1 reveals a mononuclear structure in which the geometry of the Pd(L 1 ) 2 Cl 2 chromophore is planar as required by the inversion center at the palladium atom, where each molecule of phenyltetrazole binds to the metal ion in a monodentate fashion via a Pd-N1 σ-bond. For the palladium complex with L 2 , a dinuclear structure ([Pd 2 (L 2 ) 2 Cl 4 ]) has been proposed on the basis of NMR and IR spectroscopy.

Metal derivatives of tetrazoles

“…It is noteworthy that analogous ligands containing no pyridine rings are coordinated through the tetrazole N(4) atom and form palladium(II) complexes giving no liquid-crystalline phases. 283 According to X-ray diffraction data, 284,285 in copper(II) complexes 151 ± 153, the exocyclic oxygen atom also participates in the coordination of the metal ion to binuclear tetrazoles. Note that 1,5-bis(1-methyltetrazol-5-yl)-3-oxapentane isolated as perchlorate reacts with copper(II) chloride to yield complex 151 or 153, On the basis of IR spectra of disulfide 154 and the complexes MO 2 L 2 Cl 2 (M = Mo, W; L is compound 154), it was concluded that the ligands are coordinated through one of the sulfur atoms.…”

Synthesis and characterization of some novel tetrazole liquid crystals

“…In recent years, tetrazole heterocyclics have got much signicance in coordination chemistry 13,14 due to their ability to act as a ligand. Tetrazole derivatives have been signicant in material applications such as speciality explosives, information recording systems, rocket propellants and in agrichemical applications.…”