A Cut-to-Link Strategy for Cubane-Based Heterometallic Sulfide Clusters with Giant Third-Order Nonlinear Optical Response

Abstract

Although the synthesis of low-dimensional metal sulfides by assembling cluster-based units is expected to promote the development of optical materials and models of enzyme active centers such as dinitrogenase, it is faced with limited assembly methodology. Herein we present a cut-to-link strategy to generate high-nuclearity assemblies, inspired by the formation of a Z-type dimer of the W−S−Cu analogues of P N cluster through in situ release of active linkers. Four new compounds with structures based on the same {Tp*WS 3 Cu 3 } incomplete cubane-like units were obtained using varied combinations of mild reagents. Open-aperture Z-scan measurements demonstrated the highest-nuclearity complex has the largest nonlinear optical absorption coefficient among discrete cluster-based materials reported to date. This approach enables building high-nuclearity metal sulfide clusters through cluster-based building blocks and opens a way to the design and exploration of materials based on well-identified building blocks.

Two solvent-dependent Al16 nanorings: design, synthesis and nonlinear optical limiting behavior

“…4e and Table S9 †). [51][52][53][54][55] The optical limiting properties of molecular rings are closely related to the supramolecular interactions in the structure. As shown in Table S8, † AlOC-135 has larger β and Im χ (3) (eqn ( 6) and ( 7)).…”

Significant Enhancement of Reverse Saturable Absorption Ability via Pt(II) Incorporation into the Conjugated Backbone of Benzo[1,2-b:4,5-b′]dithiophene-Based Donor–Acceptor Copolymers

“…Optical limiting (OL) materials based on nonlinear optical (NLO) responses, which show high transmittance for weak laser pulses and low transmittance for intense ones, have attracted increasing attention due to their potential application in laser protection. − In the past few decades, abundant excellent NLO materials have been elaborately designed and explored. ,− Representatively, the carbon-based materials (e.g., fullerene, graphene, carbon nanotubes) and organic materials (e.g., porphyrins, phthalocyanines, and related macrocycles), ,,,− , attributing to the extended π-conjugation, exhibit remarkable NLO performance. The main NLO mechanisms of carbon-based materials originate from the nonlinear scattering of the microbubbles and/or microplasmas, which are formed in their suspensions upon laser pulses. ,,, The dominant mechanism for organic NLO materials, on the other hand, is considered to originate from reverse saturable absorption (RSA), which mainly depends on the relative absorption section of the ground state and excited state and, more specifically, on the chemical structures as well as the molecular energy level of materials. ,,− , Therefore, the rational design of the π-conjugated molecular structure with suitable energy levels toward the functional wavelength of laser pulses is one of the effective strategies to explore outstanding organic NLO materials. ,,− Except for the construction of a π-conjugated backbone, (1) introducing an electron donor (D) and/or acceptor (A) into the conjugated backbone provides straightforward access toward remarkable NLO materials, attributing to the efficient intramolecular charge transfer (ICT) process from D to A (Figure a). − For example, Jia et al constructed D–A covalent organic frameworks with ultralow band gaps to improve the NLO property efficiently . (2) Incorporating a metallic atom into the π-conjugated backbone is another approach to facilitate the NLO response through the heavy-atom effect, which could lead to intersystem crossing (ISC) from the singlet excited state to the triplet excited state, attributing to the spin–orbital coupling (SOC; Figure b). ,−…”

Effects of bromine-containing counterion salts in directing the structures of medium-sized silver nanoclusters

“…In this context, how to control the size/structure of nanoclusters and regulate their chemical environment to obtain functional nanoclusters has aroused in-depth research interests of nanocluster scientists. 18–23…”