Tungsten(VI)–Copper(I)–Sulfur Cluster-Supported Metal–Organic Frameworks Bridged by in Situ Click-Formed Tetrazolate Ligands

Abstract

Six analogous two-dimensional (2D) [Tp*WSCu]-based (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) networks, namely, {[(Tp*WSCu)L](μ-N)} (2: L = 5-methyltetrazolate (Mtta); 3a: L = 5-ethyltetrazolate (Etta)) and {[(Tp*WSCu)L]BF} (3b: L = Etta; 4: L = 5-propyltetrazolate (Ptta); 5: L = 5-butyltetrazolate (Btta); 6: L = 5-pentyltetrazolate (Petta)) were synthesized by reactions of [EtN][Tp*WS] (1), [Cu(CHCN)]BF, NaN, and NHBF in different nitrile solvents (CH(CH)CN, n = 0, 1, 2, 3, and 4) under solvothermal conditions. In the structures of 2-6, each alkyl tetrazolate L as a bridging ligand was generated in situ from the "click" reaction between azide and nitrile. These 2D (6,3) networks support two types of voids wherein the pendant alkyl groups are accommodated. A tetrahedron cage-like cluster [Tp*W(μ-S)(μ-S')Cu] (7) was also formed in some of the above reactions and can be readily separated by solvent extraction. The proportion of 7 increased with the elongation of the alkyl chains and finally became the exclusive product when heptylnitrile was employed. Further use of CuCN as a surrogate for [Cu(CHCN)]BF with the aim of introducing additional CN bridges into the network led us to isolate a tetrazolate-free compound, {[EtN]{(Tp*WSCu)[Cu(CN)]}·2PhCHCN} (8·2PhCHCN), a unique 2D network that features {(Tp*WSCu)[Cu(CN)]}, {(Tp*WSCu)[Cu(CN)][Cu(CN)]}, and {(Tp*WSCu)[Cu(CN)]} ring subunits. Compounds 5-8 are soluble in DMF and exhibit a reverse saturable absorption and self-focusing third-order nonlinear optical (NLO) effect at 532 nm with hyperpolarizability γ values in the range of 4.43 × 10 to 5.40 × 10 esu, which are 400-500 times larger than that of their precursor 1. The results provide an interesting insight into the synergetic synthetic strategy related to the assembly of the [Tp*WSCu] cluster core, the "click" formation of the tetrazolate ligands, and the construction of the [Tp*WSCu] cluster-based 2D networks.

Butterfly and Nest‐Shaped Tp*‐W‐Cu‐S Cluster Monomers and Dimers with Hexamethylenetetramine as Ligand: Anion‐Dependent Structures and Nonlinear Optical Properties

“…Transition metal clusters of organo‐thiometallates such as [Cp*MS 3 ] − (Cp* = pentamethylcyclopentadienyl; M = Mo, W), [ 1 ] [TpMoS(S 4 )] − , [Tp*MoS(S 4 )] − , [TpWS 3 ] − and [Tp*WS 3 ] − (Tp = hydridotris(pyrazol‐1‐yl)borate; Tp* = hydridotris(3,5‐dimethylpyrazol‐ 1‐yl)borate) [ 2 ] have been extensively investigated in the last two decades because of their diverse structural characteristics, [ 3‐9 ] their revelation to biological systems, [ 10‐13 ] catalysis, [ 14‐15 ] and optoelectronic materials. [ 3,16‐24 ] In this regard, we and others have developed a keen interest in the development of molecular arrays from preformed Mo(W)‐Cu(Ag)‐S clusters. [ 25‐29 ] Some of these molecular entities are capable of gas adsorption, [ 30 ] sensing, [ 31 ] or exhibit nonlinear optical properties.…”

Auto-controlled fabrication of a metal-porphyrin framework thin film with tunable optical limiting effects

“…So far, various organic/inorganic and hybrid materials have been synthesized for third-order NLO response, including carbon nanodots, semiconductor quantum dots, conjugated organic molecules (porphyrins and phthalocyanines) or polymers, black phosphorus, metal-oxo clusters and so on. [6][7][8][9][10][11] As a kind of porous crystalline hybrid material, metalorganic frameworks (MOFs) [12][13][14][15] are constructed by the coordination of metal nodes (clusters) with organic linkers and are supposed to be promising candidates to exploit optical properties including NLO behaviour, upconversion luminescence, lasing and so on. [16][17][18][19][20] A few cases of powder MOFs have been realized to investigate the third-order NLO properties.…”

Highly Stable Copper(I)–Thiacalix[4]arene‐Based Frameworks for Highly Efficient Catalysis of Click Reactions in Water

“…Calix[4]arenes, as one type of excellent candidate ligand, have attracted considerable attention from researchers due to the ease of modifying their upper and lower edges . Particularly, calix[4]arenes substituted by coordination hybrid atoms, such as N and S, can improve the stability of the resulting Cu I MOFs as recycled catalysts …”