1D Cobalt-Cytidine Monophosphate Coordination Polymer Exhibiting Efficient Ultraviolet Second-Harmonic Generation

Area of Science:

• Materials Science
• Inorganic Chemistry
• Crystallography

Background:

• Development of novel ultraviolet (UV) nonlinear optical (NLO) materials is crucial for advanced optical applications.
• Coordination complexes offer tunable properties for NLO material design.

Purpose of the Study:

• To synthesize and characterize a novel cobalt-based hydrogen-bonded coordination complex for UV NLO applications.
• To investigate the structure-property relationships governing the NLO behavior of the synthesized complex.

Main Methods:

• Slow evaporation method for synthesis of the cobalt-based coordination complex.
• X-ray crystallography to determine the crystal structure and noncentrosymmetric (NCS) space group.
• Second-harmonic generation (SHG) measurements to quantify NLO response.
• Optical bandgap determination to assess UV transparency.

Main Results:

• A novel cobalt(II) coordination complex, [complex (1)], was successfully synthesized and crystallized in the NCS space group P2₁.
• [Complex (1)] exhibits a strong second-harmonic generation (SHG) response, approximately 7.4 times that of KDP.
• The material possesses an optical bandgap of 3.41 eV, indicating good UV transparency.
• Robust hydrogen-bonding interactions and a distorted, polarizable Co(II) coordination geometry contribute to the enhanced SHG activity.

Conclusions:

• The synthesized cobalt-based framework, [complex (1)], is a promising candidate for UV NLO applications.
• The study highlights the effectiveness of hydrogen-bonding and coordination geometry control in designing polar metal-organic systems with superior optical properties.