RESUMO
We have designed a series of new conjugated donor-acceptor-based macrocyclic molecules using state-of-the-art computational methods. An alternating array of donors and acceptor moieties in these macrocycle molecules are considered to tune the electronic and optical properties. The geometrical, electronic, and optical properties of newly designed macrocyclic molecules are fully explored using various DFT methods. Five conjugated macrocycles of different sizes are designed considering various donor and acceptor units. The selected donor and acceptors, viz., thiophene (PT), benzodithiophene (BDT), dithienobenzodithiophene (DTBDT), diketopyrrolopyrrole (DPP), and benzothiazole (BT), are frequently found in high performing conjugated polymer for different organic electronic applications. To fully assess the potential of these designed macrocyclic derivatives, analyses of frontier molecular orbital energies, excited state energies, energy difference between singlet-triplet states, exciton binding energies, rate constants related to charge transfer at the donor-acceptor interfaces, and electron mobilities have been carried out. We found significant structural and electronic properties changes between cyclic compounds and their linear counterparts. Overall, the cyclic conjugated D-A macrocycles' promising electronic and optical properties suggest that these molecules can be used to replace linear polymer molecules with cyclic conjugated oligomers.
RESUMO
Metal nanoclusters (NCs) composed of the least number of atoms (a few to tens) have become very attractive for their emerging properties owing to their ultrasmall size. Preparing copper nanoclusters (Cu NCs) in an aqueous medium with high emission properties, strong colloidal stability, and low toxicity has been a long-standing challenge. Although Cu NCs are earth-abundant and inexpensive, they have been comparatively less explored due to their various limitations, such as ease of surface oxidation, poor colloidal stability, and high toxicity. To overcome these constraints, we established a facile synthetic route by optimizing the reaction parameters, especially altering the effective concentration of the reducing agent, to influence their optical characteristics. The improvement of the photoluminescence intensity and superior colloidal stability was modeled from a theoretical standpoint. Moreover, the as-synthesized Cu NCs showed a significant reduction of toxicity in both in vitro and in vivo models. The possibility of using such Cu NCs as a diagnostic probe toward C. elegans was explored. Also, the extension of our approach toward improving the photoluminescence intensity of the Cu NCs on other ligand systems was demonstrated.
RESUMO
HL1 and HL2 (HL1 = 5-diethylamino-2-({[4-(diethylamino)phenyl]imino}methyl)-phenol; HL2 = 5-diethylamino-2-({[4-(dimethylamino)phenyl]imino}methyl)-phenol) are new Schiff base ligands which were prepared along with their metal(II) complexes of [Cu(L1)2] (1), [Cu(L1)2] (2), [Ni(L2)2] (3) and [Ni(L2)2] (4) and characterized by different analytical as well as spectroscopic analyses. The single crystal XRD analysis confirms the proposed structure of ligands such as HL1 and HL2. EPR spectral analysis gives evidence about the tetrahedrally coordinated geometry of complexes 1 and 2. Density functional theory (DFT) analysis was executed using B3LYP/6-31G(d,p)âªLanL2DZ level. The DNA sequence (along with Dickerson's sequence) specificity of complexes 1-4 was evaluated and it has resulted that the complexes 1-4 primarily interact with double helix of DNA via groove mode of binding. From plasma protein docking results, we can say that complexes 2 and 4 showed more binding towards HSA and may have good bioavailability and are prone to act as drug candidates. The observed findings show that these metal(II) complexes 1-4 are better DNA probes, will act as anticancer agents and stimulate strong research focusing on the design of new chemical probes of DNA.