Four new [AuBr2(CN)2]−-based coordination polymers, Zn(pyz)(NCMe)2[AuBr2(CN)2]2 (1; pyz = pyrazine), Co(pyz)[AuBr2(CN)2]2·H2O (2) and [M(bipy)2(AuBr2(CN)2)][nBu4N][AuBr2(CN)2]2 (bipy = 4,4′-bipyridine), where M = Co (5) and Zn (6), were synthesized and three of them structurally characterized. 1 forms 1-D chains connected by pyz ligands while isostructural 5 and 6 form 3-D frameworks via [AuBr2(CN)2]− and bipy linkers. Aqueous suspensions of 2, 5 and 6 or their precursors in situ (preferred) were heated hydrothermally to 125 °C, triggering the reductive elimination of bromine from the Au(III) centres, which yielded the [Au(CN)2]−-based coordination polymers M(pyz)[Au(CN)2]2, where M = Zn (3) or Co (4) and Zn(bipy)[Au(CN)2][AuBr0.68(CN)0.32}CN] (7), or a mixture of cyanoaurate(I)-containing products in the case of 5 and 6. The structural characterization of 3 revealed a [Au(CN)2]−/pyz-based framework similar to previously reported Cu(pyz)[Au(CN)2]2, whereas 7 formed an intricate network consisting of individual 2-D networks held together by Au⋯Au interactions and featuring the rare [AuBrCN]− unit. The kinetics of the thermally-induced reductive elimination of Br2 from K[AuBr2(CN)2] in 1-BuOH yielded a t½ of approx. 10 min to 4 h from 98 to 68 °C, and activation parameters of ΔH‡ = 131(15) kJ mol−1 and ΔS‡ = 14.97(4) kJ K−1mol−1, indicating that the elimination of the halogen provides the highest barrier to activation.
四种新的[AuBr2(CN)2]基配位聚合物,即 Zn(pyz)(NCMe)2[AuBr2(CN)2]2(1;合成了 Co(pyz)[AuBr2(CN)2]2-
H2O (2) 和 [M(bipy)2(AuBr2(CN)2)][nBu4N][AuBr2(CN)2]2(bipy = 4,4′-联
吡啶),其中 M = Co (5) 和 Zn (6)。1 通过 pyz
配体形成 1-D 链,而等结构的 5 和 6 则通过[AuBr2(CN)2]-和双
吡啶连接体形成 3-D 框架。将 2、5 和 6 或其原位前体(优选)的
水悬浮液
水热加热至 125 °C,引发 Au(III)中心
溴的还原消除,从而得到基于 [Au(CN)2]- 的配位聚合物 M(pyz)[Au(CN)2]2,其中 M = Zn (3) 或 Co (4) 和 Zn(bipy)[Au(CN)2][AuBr0.68(CN)0.32}CN](7),或 5 和 6 中含
氰基
金酸酯(I)产物的混合物。3 的结构特征显示出一种[Au(CN)2]-/pyz 基框架,类似于之前报道的 Cu(pyz)[Au(CN)2]2,而 7 则形成了一种复杂的网络,由 Au⋯Au 相互作用结合在一起的单个 2-D 网络组成,并具有罕见的[AuBrCN]-单元。在 1-BuOH 中,K[AuBr2(CN)2]中 Br2 的热诱导还原消除动力学显示,从 98 °C 到 68 °C 的 t½ 约为 10 分钟到 4 小时,活化参数为 ΔH‡ = 131(15) kJ mol-1 和 ΔS‡ = 14.97(4) kJ K-1mol-1,表明消除卤素提供了最高的活化障碍。