Theoretical investigation on redox‐switchable second‐order nonlinear optical responses of push–pull Cp*CoEt₂C₂B₄H₃‐expanded (metallo)porphyrins

Abstract

The second-order nonlinear optical (NLO) properties of the Cp*Co(C(2)H(5))(2)C(2)B(4)H(3)-expanded (metallo)porphyrins (Cp* = C(5)Me(5)) have been investigated by using ab inito RHF and density functional theory (DFT) methods. The investigation shows that the compound with expand porphyrin possesses remarkable large molecular hyperpolarizability β(tot) value, ~414.1 × 10(-30) esu (at LC-ωPBE level), and might be an excellent second-order NLO material. From the character of charge transfer (CT) transition, it indicates that the -Cp*Co(C(2)H(5))(2)C(2)B(4)H(3) acts as an electron donor in this kind of systems. As a result of the redox behavior on expanded (metallo)porphyrin, the redox switching character of the NLO responses for the systems 2a-4a has also been studied. The results show that the β(tot) values of reduced forms are larger than that of neutral ones. Furthermore, the time-dependent DFT calculation illustrates that reduced forms have a significant difference on the CT patterns versus neutral ones. The present investigation provides insight into the comparison with DFT results on estimating first hyperpolarizability and the NLO properties of the series of push-pull compounds.

DFT Calculation of Static First Hyperpolarizabilities and Linear Optical Properties of Metal Alkynyl Complexes

“…Alongside the laboratory and spectroscopic techniques now accepted as suitable for the characterization of novel NLO materials, computational methods (including semiempirical methods and ab initio and density functional theory, DFT) − have become an increasingly powerful and versatile tool. DFT, in particular, appears very well suited to the modeling and exploration of large TM-containing systems, while electronic excitation spectra and response properties can be assessed using time-dependent DFT (TD-DFT).…”

Rational design of [Co(acacen)L2]+ inhibitors of protein function

“…24,25 This functional has been used for several studies of similar systems and shown to provide accurate results. [26][27][28][29][30] Optimization and frequency calculations of the lowest energy conformation of each structure were repeated using the same functional in conjunction with a correlation consistent, double zeta basis set (cc-pVDZ) to further validate results. Both basis sets produced structures that are in excellent agreement with X-ray crystal data, with Co-N and Co-O bond distances differing by less than 2 or 3% for calculations performed with 6-31G(d) and cc-pVDZ, respectively.…”

Mechanistic insight into the second-order nonlinear optical properties of Ru-coordinated DTE complexes: Photoisomerization, redox, and protonation switches

“…Interestingly, the topic of NLO responses for molecular switches ranges from the organic molecules to the organometallic molecules. Compared with the organic molecules, organometallic molecules associated with a metal center interacting with organic ligands have the unique structural and electronic characteristics [10].…”

“…Interestingly, the topic of NLO responses for molecular switches ranges from the organic molecules to the organometallic molecules. Compared with the organic molecules, organometallic molecules associated with a metal center interacting with organic ligands have the unique structural and electronic characteristics [10].Remarkably, switching of NLO responses [11e15] can be achieved by photoisomerization, redox, and protonation and so forth. The researches on photo-switchable NLO properties of photochromic compounds have received much attention [16,17].…”