Theoretical study by DFT of organometallic complexes based on metallocenes active in NLO

Area of Science:

• Computational chemistry
• Materials science
• Quantum chemistry

Background:

• Organometallic molecules offer tunable electronic and optical properties.
• Understanding linear (LO) and nonlinear optical (NLO) behavior is crucial for materials design.
• Metallocene-based compounds are promising candidates for advanced optical applications.

Purpose of the Study:

• To investigate the linear and nonlinear optical (NLO) enhancement of five organometallic molecules.
• To compare the performance of various long-range and Minnesota functionals against the MP2 approach.
• To identify molecules with superior NLO properties.

Main Methods:

• Density Functional Theory (DFT) calculations using CAM-B3LYP, LC-BLYP, LC-wPBE, wB97X, M11, M06-2X, and M08-HX functionals.
• Comparison of calculated NLO properties with the reference MP2 method.
• Analysis of intramolecular charge transfers (ICTs) and solvatochromic effects.

Main Results:

• The CAM-B3LYP functional demonstrated the closest agreement with MP2 for NLO values.
• Molecule 3A, derived from nickelocene, exhibited the highest static first hyperpolarizability (β_tot) at 76.46 × 10^-30 esu and 4803.4 × 10^-30 esu at 532 nm.
• Intramolecular charge transfers were bidirectional in all studied molecules.
• Maximum absorption wavelengths for molecules 2A and 3A in acetonitrile were in the near-UV range (250-395 nm).

Conclusions:

• CAM-B3LYP is a reliable functional for predicting NLO properties of these metallocene derivatives.
• Molecule 3A shows significant potential for NLO applications.
• The studied molecules exhibit interesting charge transfer characteristics and solvatochromic behavior.