Reactions of a Tungsten Trisulfido Complex of Hydridotris(3,5-dimethylpyrazol-1-yl)borate (Tp*) [Et₄N][Tp*WS₃] with CuX (X = Cl, NCS, or CN): Isolation, Structures, and Third-Order NLO Properties

Reactions of a tungsten trisulfido complex of hydridotris(3,5-dimethylpyrazol-1-yl)borate (Tp*) [Et4N][Tp*WS3] (1) with 3 equiv of CuCl in CHCl3 afforded a tetranuclear anionic cluster [Et4N][Tp*W(μ3-S)3(CuCl)3] (2), while that of 1 with 3 equiv of CuNCS in MeCN produced a decanuclear neutral cluster (major product) [Tp*W(μ3-S)3Cu3(μ-NCS)3(CuMeCN)]2 (3) along with a binuclear anionic cluster (minor product) [Et4N][Tp*WO(μ-S)2(CuNCS)] (4). Solvothermal reactions of 1 with 3 equiv of CuCN in MeCN at 80 °C for 48 h followed by slowly cooling it to ambient temperature gave rise to a polymeric cluster [Tp*W(μ3-S)(μ-S)2Cu2(MeCN)(μ-CN)]n (5). Compounds 2−5 were characterized by elemental analysis, IR, UV−vis, 1H NMR, and single-crystal X-ray crystallography. The cluster anion of 2 has a [Tp*WS3Cu3] incomplete cube with one Cl atom coordinated at each Cu center. 3 is composed of an unprecedented centrosymmetric W2Cu8 cluster core in which each void of the two single incomplete cubane-like [Tp*W(μ3-S)3Cu3(μ-NCS)]+ cations is partially filled with an extra [Cu(MeCN)(μ-NCS)2]- anion via a pair of Cu−μ-NCS−Cu bridges. The cluster anion of 4 contains one WS2Cu core that is formed by an oxidized [Tp*WO(μ-S)2] species and one CuNCS fragment. 5 consists of butterfly shaped [Tp*W(μ3-S)(μ-S)2Cu2(MeCN)] fragments that are interconnected via cyanide bridges to form a 1D spiral chain extending along the c axis. The successful synthesis of 2−5 from 1 suggests that 1 may be an excellent synthon to the W/Cu/S clusters. In addition, the third-order nonlinear optical (NLO) properties of 1−3 in solution were also investigated by femtosecond degenerate four-wave mixing (DFWM) technique with a 80 fs pulse width at 800 nm. Although 2 was not detected to have NLO effects, 1 and 3 exhibited relatively good optical nonlinearities with the nonlinear refractive index n2 and the third-order nonlinear optical susceptibility χ(3) values being 0.79 × 10-13 and 0.38 × 10-14 esu (1) and 2.08 × 10-13 and 1.00 × 10-14 esu (3), respectively. The second-order hyperpolarizability γ value for 3 (5.46 × 10-32 esu) is ca. 5 times larger than that of its precursor 1.以氢化三(3,5-二甲基吡唑-1-基)硼酸盐（Tp*）合三硫化钨配合物[四乙基铵（Et4N）][Tp*WS3] (1) 与3当量氯化铜（CuCl）在三氯甲烷（CHCl3）中反应，得到四核阴离子簇[Et4N][Tp*W(μ3-S)3(CuCl)3] (2)；而1与3当量硫氰酸铜（CuNCS）在乙腈（MeCN）中反应，则以十核中性簇（主要产物）[Tp*W(μ3-S)3Cu3(μ-NCS)3(CuMeCN)]2 (3)为主，同时伴生双核阴离子簇（次要产物）[Et4N][Tp*WO(μ-S)2(CuNCS)] (4)。将1与3当量氰化铜（CuCN）在乙腈（MeCN）中于80℃进行溶剂热反应48小时后缓慢冷却至室温，得到聚合物簇[Tp*W(μ3-S)(μ-S)2Cu2(MeCN)(μ-CN)]n (5)。通过元素分析、红外光谱（IR）、紫外-可见光谱（UV−vis）、氢核磁共振谱（1H NMR）以及单晶X射线衍射对化合物2−5进行了表征。2的簇阴离子具有[Tp*WS3Cu3]不完全立方烷结构，每个铜中心均配位有一个Cl原子。3由前所未有的中心对称W2Cu8簇核构成：两个类单不完全立方烷结构的[Tp*W(μ3-S)3Cu3(μ-NCS)]+阳离子的空穴，通过一对Cu−μ-NCS−Cu桥键，分别被额外的[Cu(MeCN)(μ-NCS)2]−阴离子部分填充。4的簇阴离子包含一个WS2Cu核，该核由被氧化的[Tp*WO(μ-S)2]物种与一个CuNCS片段结合形成。5由蝶形[Tp*W(μ3-S)(μ-S)2Cu2(MeCN)]片段构成，这些片段通过氰桥相互连接，形成沿c轴延伸的一维螺旋链。从1出发成功合成2−5表明，1可作为构建W/Cu/S簇的优秀合成子。此外，还采用脉冲宽度为80 fs、波长800 nm的飞秒简并四波混频（DFWM）技术，研究了溶液中1−3的三阶非线性光学（NLO）性能。尽管未检测到2具有NLO效应，但1和3展现出较好的光学非线性性能，其非线性折射率n2与三阶非线性光学极化率χ(3)分别为0.79×10^-13和0.38×10^-14 esu（1），以及2.08×10^-13和1.00×10^-14 esu（3）。3的二阶超极化率γ值(5.46×10^-32 esu)约为其前驱体1的5倍。