5-Cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinane, its phosphine oxide, and its [NiCl₂ L ₂] complex

Area of Science:

• Coordination Chemistry
• Crystallography
• Organophosphorus Chemistry

Background:

• Di-aza-phosphinane ligands are versatile in coordination chemistry.
• Understanding ligand structure influences metal complex geometry.
• Cyclohexyl substituents can impact steric and electronic properties.

Purpose of the Study:

• To elucidate the crystal structures of a di-aza-phosphinane ligand and its oxidized form.
• To characterize the coordination behavior of the di-aza-phosphinane ligand with nickel(II).
• To determine the geometry and steric arrangement within the resulting nickel(II) complex.

Main Methods:

• Single-crystal X-ray diffraction was employed to determine the crystal structures.
• The ligand and its phosphine oxide were synthesized and characterized.
• The nickel(II) complex was synthesized and its crystal structure analyzed.

Main Results:

• The crystal structures of 5-cyclo-hexyl-1,3-diphenyl-1,3,5-di-aza-phosphinane and its phosphine oxide were solved, revealing primitive monoclinic symmetry.
• The nickel(II) complex, [NiCl2(C21H27N2P)2], adopts a four-coordinate square-planar geometry.
• Bulky cyclohexyl groups on the ligand are positioned axially and adopt an anti-configuration relative to the square plane.

Conclusions:

• The study provides detailed structural insights into a novel di-aza-phosphinane ligand and its coordination complex.
• The steric bulk of the cyclohexyl groups influences the ligand's conformation and the complex's geometry.
• The findings contribute to the understanding of ligand design in coordination chemistry.