Ruthenium Complexes of a Simple Tridentate Ligand Bearing Two "Distal" Pyridine Bases

Area of Science:

• Coordination Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• The synthesis of novel metal complexes is crucial for developing new catalytic and functional materials.
• Ruthenium complexes, in particular, have shown diverse applications due to their unique electronic and steric properties.
• Ligand design plays a pivotal role in tuning the reactivity and stability of metal complexes.

Purpose of the Study:

• To synthesize and characterize a new ruthenium complex using N,N′-bis(6-methyl-2-pyridinyl)-2,6-pyridinedicarboxamide (H(2)LMe(2)).
• To investigate the reactivity of the ruthenium complex towards anion metathesis reactions.
• To explore the formation of a nitrosyl-containing ruthenium complex and elucidate its structure.

Main Methods:

• Synthesis of the ruthenium complex RuCl(2)(PPh(3))(LMe(2){H}(2)) (2) from H(2)LMe(2) and RuCl(2)(PPh(3))(3).
• Anion exchange reactions of complex 2 with SCN(-), CH(3)CO(2)(-), and NO(2)(-) to form new complexes.
• Single-crystal X-ray diffraction for structural determination of key compounds (1, 2, and 5).

Main Results:

• The ruthenium complex 2 was successfully synthesized, featuring coordination to deprotonated amides and the central pyridine, with protonated pendant pyridines and hydrogen-bonded chlorides.
• Anion metathesis reactions with SCN(-) and CH(3)CO(2)(-) yielded complexes 3 and 4, respectively.
• Reaction with NO(2)(-) led to the formation of a nitrosyl complex Ru(NO(2))(NO)(PPh(3))(LMe(2)) (5), involving deprotonation of pendant pyridines.

Conclusions:

• The study demonstrates the versatility of the H(2)LMe(2) ligand in forming stable ruthenium complexes.
• The facile anion exchange and the formation of the nitrosyl complex highlight the tunable reactivity of these ruthenium systems.
• The structural insights gained from X-ray diffraction are crucial for understanding the coordination chemistry and potential applications.