Axial functionalization of sterically hindered titanium phthalocyanines

Area of Science:

• Materials Chemistry
• Organometallic Chemistry
• Coordination Chemistry

Background:

• Titanium phthalocyanines (Pc) are known for their unique electronic and optical properties.
• Axial functionalization offers a route to tune the properties and reactivity of Pc complexes.
• Weakly aggregating systems are desirable for solution-based applications.

Purpose of the Study:

• To synthesize and characterize novel axially functionalized, weakly aggregating titanium phthalocyanines.
• To explore the reactivity of these titanium complexes in catalytic applications.
• To determine the crystal structures of key compounds.

Main Methods:

• Reductive cyclotetramerization of dinitrile precursors in the presence of TiCl(4).
• Synthesis of various axially functionalized titanium phthalocyanines.
• Crystallographic analysis (X-ray diffraction) for structural determination.
• Reactivity studies including atom group transfer reactions and ethene polymerization.

Main Results:

• Synthesis of soluble titanium dichlorido tetrakis-(1,1,4,4-tetramethyl-6,7-tetralino)-porphyrazine [Pc(#)TiCl(2)] and its oxido analog [Pc(#)TiO].
• Preparation of diverse axially functionalized titanium phthalocyanines (organoimido, alkoxido, aryloxido, peroxido, sulfido, disulfido, selenido, diselenido).
• Characterization of deprotonated ligand salts [Pc(#)M(2)] (M = Li, Na, K).
• Demonstrated reactivity in atom group transfer and ethene polymerization.
• Crystal structures of [Pc(#)TiCl(2)] (cubic, Im3, cis-chlorido ligands) and Pc(#)H(2) (trigonal, R3) were determined.

Conclusions:

• Novel, axially functionalized titanium phthalocyanines were successfully synthesized and characterized.
• These compounds serve as versatile precursors for a range of functionalized titanium Pc derivatives.
• The study provides insights into the structural and reactive properties of these titanium phthalocyanine systems, highlighting their potential in catalysis.