Macrocyclic Se₄N₂[7,7]ferrocenophane and Se₂N[10]ferrocenophane containing benzyl unit: synthesis, complexation, crystal structures, electrochemical and optical properties

Abstract

Two novel macrocyclic polyselena[n]ferrocenophanes containing a pendent benzyl unit, 20-membered Se4N2[7,7]ferrocenophane (L1) and 10-membered Se2N[10]ferrocenophane (L2), were designed and synthesized. The reaction of L1 with two molar amounts of metal salts (M = Cu(+), Cu(2+), Pd(2+) and Hg(2+)) led to six dimetallic complexes 1-6. A crystallographic study revealed that each metal center in 1-5 was tetracoordinated to two selenium atoms from different ferrocene units, one aliphatic nitrogen atom and one co-ligand. The structures of the complexes contain a two-fold axis perpendicular to the molecular plane with two pendant benzyl moieties in an anti-conformation. Macrocycle L1 gives significant electrochemical, linear and third-order nonlinear optical responses to Cu(2+) and Hg(2+). The DFT/B3LYP calculations of 4 demonstrated a small HOMO-LUMO energy gap and delocalization of the π-electron cloud in the frontier molecular orbitals, which led to the enhancement of molecular NLO properties after complexation. The results show that the oxidation state of the ferrocene unit is accompanied by significant differences in the corresponding absorption spectra and third-order NLO properties.

Oxidation-Induced Differentially Selective Turn-On Fluorescence via Photoinduced Electron Transfer Based on a Ferrocene-Appended Coumarin–Quinoline Platform: Application in Cascaded Molecular Logic

“…Therefore, the development of PET-based sensors and switches is becoming of great interest to scientists. Different design strategies are being employed in the development of PET-based sensor molecules, with the most commonly exploited approach of a “fluorophore–spacer–receptor” configuration in which donor (mostly nitrogen-containing groups) and acceptor units are present. − On the contrary, relatively fewer examples are known where the PET is triggered by the oxidation of a donor unit (ferrocene moiety), − and the process can be modulated between fluorescence “on” and “off” states by controlling the redox property of the donor unit.…”

Bioinspired Selenium‐Nitrogen Exchange (SeNEx) Click Chemistry Suitable for Nanomole‐Scale Medicinal Chemistry and Bioconjugation

“…Seleno‐macrocycles (SeMCs) play a critical role in multidisciplinary fields spanning from metal ligand, [44] self‐assembly [45] to functional materials [46] . However, the efficient preparation of SeMCs remains a severe challenge because of the limited selenylation methods, [47] especially for the underexplored selenylalkyne containing macrocycles because the intramolecular C(sp)‐Se bond formation reaction suitable for constructing macrocycles has not been reported yet.…”

Aggregation induced emission (AIE)‐active N‐arylated ferrocenyl pyrazole‐based push–pull chromophores: Structural, photophysical, theoretical and effect of substitution on second‐order non‐linear optical properties

“…[7] In general, the intramolecular charge transfer (ICT) in push-pull moiety in a conjugated system has large second-order NLO [8] response for an organic chromophore, which depends on planar arrangement and composition of the π-linker. [9] As an electron-donating unit, ferrocene has been covalently linked to π-acceptors like fullerene, [10] porphyrins and linear π-conjugated systems to boost up the molecular NLO properties. Ferrocene and its derivatives have attracted much attention due to their fulfilment in the field of non-linear optics (NLO) and electrochemistry.…”