Ligand substituents effect on 10Dq

Area of Science:

• Coordination Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• 1,10-phenanthroline derivatives are important ligands in coordination chemistry.
• Epoxy-functionalized ligands offer unique reactivity for complex synthesis.
• Nickel(II) complexes exhibit diverse electronic and structural properties.

Purpose of the Study:

• To synthesize novel Nickel(II) complexes using an epoxy-functionalized 1,10-phenanthroline ligand.
• To investigate the structural and electronic properties of the resulting complexes.
• To explore the relationship between ligand substituents and the electronic properties of Nickel(II) complexes.

Main Methods:

• Synthesis of [NiL(3)](ClO(4))(2)·2H(2)O from 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) and Ni(ClO(4))(2)·6H(2)O.
• X-ray crystal structure determination of the [NiL(3)](2+) cation.
• Aminolysis of epoxide rings with 4-substituted anilines to form Ni(II) complexes.
• Spectroscopic characterization including UV-Vis spectroscopy to determine crystal field splitting (10Dq).

Main Results:

• The crystal structure of [NiL(3)](2+) revealed an octahedral coordination geometry.
• A series of Ni(II) complexes with an octahedral NiL(6)(2+) core were successfully synthesized via aminolysis.
• Crystal field splitting (10Dq) values ranged from 11601 to 15798 cm(-1) in acetonitrile.
• A linear correlation (r(2)=0.951) was observed between 10Dq and the Hammett σ(R) parameter.
• 10Dq increased with enhanced electron-donating ability of the substituent on the anilino fragment.

Conclusions:

• The study successfully synthesized and characterized novel Nickel(II) complexes.
• The electronic properties (10Dq) of these complexes are tunable via substituents on the ligand.
• A clear structure-property relationship was established, linking ligand electronic effects to the crystal field splitting in Nickel(II) complexes.