Synthesis, crystal structure, spectroscopic properties, thermal behavior and DFT studies of a new organic-inorganic hybrid [4FBzTPP]2[CoBr4]

Abstract

A new organic-inorganic hybrid [4FBzTPP]2[CoBr4](1) (4FBzTPP = 4-fluorobenzyltriphenylphosphonium) was synthesized and characterized by X-ray diffraction, DTA-TG measurement, FT-IR and Raman spectroscopies, Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and UV–vis diffuse reflectance spectrum. [4FBzTPP]2[CoBr4] crystallized in monoclinic system with P21/c space group, consisting of two [4FBzTPP]+ cations and one distorted tetrahedral [CoBr4]2− anion. Powder X-ray diffraction analysis confirmed the bulk phase purity and homogeneity of the material. The UV–vis-DRS result indicated that the energy gap value of the electron transition was 1.60 eV, which was quite distant from the calculated value of 1.64 eV. The material showed fluorescent emission at 389 nm, 414 nm, 448 nm, and 495 nm under the excitation of UV light at 380 nm. Theoretical calculations were performed using the density functional theory method to derive the dipole moment and first hyperpolarizability of the as-synthesized molecule. The first hyperpolarizability value (βtot) was more than 11,600 times higher than those of standard KDP crystals, indicating that [4FBzTPP]2[CoBr4] was an excellent material for applications.