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Organic compound-based nonlinear optical (NLO) materials have sparked a lot of attention due to their multitude of applications and shorter optical response times than those of inorganic NLO materials. In the present investigation, we designed exo-exo-tetracyclo[6.2.1.1 3,6 .0 2,7 ]dodecane (TCD) derivatives, which were obtained by replacing H atoms of methylene bridge carbon with alkali metals (Li, Na, and K). It was observed that upon the substitution of alkali metals at bridging CH 2 carbon, absorption within the visible region occurred. Moving from 1 to 7 derivatives, the maximum absorption wavelength of the complexes exhibited a red shift. The designed molecules showed a high degree of intramolecular charge transfer (ICT) and excess electrons in nature, which were responsible for rapid optical response time and significant large molecular (hyper)polarizability. Calculated trends also inferred that the crucial transition energy decreased in order that also played a key role in the higher nonlinear optical response. Furthermore, to examine the effect of the structure/property relationship on the nonlinear optical properties of these investigated compounds (1−7), we calculated the density of state (DOS), transition density matrix (TDM), and frontier molecular orbitals (FMOs). The largest first static hyperpolarizability (β tot ) of TCD derivative 7 was 72059 au, which was 43 times greater than that of the prototype p-nitroaniline (β tot = 1675 au).

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Manganese tricarbonyl complexes are one of the most promising compounds since they release carbon monoxide. CO-releasing molecules (CORMs) may supply a control amount of CO to the biological systems and therefore this area of research is a hot topic in medicine, especially for cancer treatment. The analysis of carbon monoxide-releasing compounds can be done using a variety of experimental and theoretical methods. To identify and scrutinize such molecules, we have performed density functional theory (DFT) calculations to investigate the ability of liberation of CO. In this report, we have taken Mn(Ⅰ) tricarbonyl complexes that bear bis(pyridin-2-ylmethyl) amine unit with different kinds of electron-withdrawing nature ligands. For optimization of different complexes, we have used density functional theory (DFT) with the B3LYP/LANL2DZ basis. DFT and time dependent density functional theory (TD-DFT) calculations infer that the taken carbonyl complexes will release CO efficiently. The calculated results also suggests that the transfer of electron density from the electron rich metal centres to π molecular orbitals of the ligand via strong metal to ligand charge transfer (MLCT) in the visible/near IR region. The strong MLCT results weaken the metal-CO back bonding and promote the speedy CO release.