Bowmaker Graham A., Kennedy Brendan J., Reid Jason C.
Department of Chemistry, University of Auckland, Private Bag 92019, Auckland, New Zealand, and School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia.
Inorg Chem. 1998 Aug 10;37(16):3968-3974. doi: 10.1021/ic9714697.
The crystal structures of AuCN and AgCN have been determined by powder neutron diffraction measurements. The structure of AuCN consists of rows of linear AuCN chains parallel to [001] with alternating long Au-C = 2.06(2) and short Au-N = 1.82(2) Å. The Au atoms form sheets and are bonded to 6 other Au atoms at a distance of 3.396(2) Å, so that the local environment of each Au atom can be described as a compressed scalehedron. The Au- - -Au distance is within the range expected for an "aurophilic attraction" between these atoms. The AgCN structure is very similar to that for AuCN, in that it consists of rows of AgCN chains with alternating long Ag-C = 2.15(6) and short Ag-N = 1.86(8) Å. The major difference is that the Ag- - -Ag separation within the Ag sheets is noticeably longer, 3.881(5) Å, so that there are no significant Ag- - -Ag interactions. The IR spectra of MCN show nu(CN) at 2170, 2164, 2236; nu(MC,MN) at 591, 480, 598; delta(MCN) at 326, 272, 358; and delta(NMC) = 168, 112, 224 cm(-)(1) for M = Cu, Ag, and Au, respectively. This pattern of band positions strongly suggests that CuCN has the same infinite linear chain structure as AgCN and AuCN. Anomalies in the previously reported IR spectrum of CuCN are shown to be due to the formation of an unusual CuCN/KBr/H(2)O product in KBr disks, which is possibly an intercalation compound involving incorporation of KBr and H(2)O between the chains in the CuCN structure.
通过粉末中子衍射测量确定了AuCN和AgCN的晶体结构。AuCN的结构由平行于[001]的线性AuCN链排组成，长的Au-C键长为2.06(2) Å，短的Au-N键长为1.82(2) Å，二者交替排列。金原子形成片层结构，且与其他6个金原子以3.396(2) Å的距离相连，因此每个金原子的局部环境可描述为一个压缩的八面体。金原子之间的Au---Au距离在这些原子间“亲金作用”预期的范围内。AgCN的结构与AuCN非常相似，它由AgCN链排组成，长的Ag-C键长为2.15(6) Å，短的Ag-N键长为1.86(8) Å，二者交替排列。主要区别在于银片层内的Ag---Ag间距明显更长，为3.881(5) Å，因此不存在显著的Ag---Ag相互作用。MCN（M = Cu、Ag和Au）的红外光谱显示，ν(CN)分别在2170、2164、2236 cm⁻¹；ν(MC,MN)分别在591、480、598 cm⁻¹；δ(MCN)分别在326、272、358 cm⁻¹；δ(NMC)分别为168、112、224 cm⁻¹。这种谱带位置模式强烈表明CuCN与AgCN和AuCN具有相同的无限线性链结构。先前报道的CuCN红外光谱中的异常现象表明，这是由于在KBr片盘中形成了一种不寻常的CuCN/KBr/H₂O产物，它可能是一种插层化合物，涉及在CuCN结构的链间掺入KBr和H₂O。
