Brugos Javier, Cabeza Javier A, García-Álvarez Pablo, Pérez-Carreño Enrique, Polo Diego
Centro de Innovación en Química Avanzada (ORFEO-CINQA), Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, 33071 Oviedo, Spain.
Dalton Trans. 2018 Mar 26;47(13):4534-4544. doi: 10.1039/c7dt04561a.
The non-donor-stabilized PSnP pincer-type stannylene Sn(NCH2PtBu2)2C6H4 (1) has been prepared by treating SnCl2 with Li2(NCH2PtBu2)2C6H4. All attempts to synthesize the analogous PSiP silylene by reduction of the (previously unknown) silanes SiCl2(NCH2PtBu2)2C6H4 (2), SiHCl(NCH2PtBu2)2C6H4 (3) and SiH(HMDS)(NCH2PtBu2)2C6H4 (4; HMDS = N(SiMe3)2) have been unsuccessful. The almost planar (excluding the tert-butyl groups) molecular structure of stannylene 1 (determined by X-ray crystallography) has been rationalized with the help of DFT calculations, which have shown that, in the series of diphosphanetetrylenes E(NCH2PtBu2)2C6H4 (E = C, Si, Ge, Sn), the most stable conformation of the compounds with E = Ge and Sn has both P atoms very close to the EN2C6H4 plane, near (interacting with) the E atom, whereas for the compounds with E = C and Si, both phosphane groups are located at one side of the EN2C6H4 plane and far away from the E atom. The size of the E atom and the strength of stabilizing donor-acceptor PE interactions (both increase on going down in group 14) are key factors in determining the molecular structures of these diphosphanetetrylenes. The syntheses of the chloridostannyl complexes [Rh{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η4-cod)] (5), [RuCl{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η6-cym)] (6) and [IrCl{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η5-C5Me5)] (7) have demonstrated the tendency of stannylene 1 to insert its Sn atom into M-Cl bonds of transition metal complexes and the preference of the resulting PSnP chloridostannyl group to act as a κ2Sn,P-chelating ligand, maintaining an uncoordinated phosphane fragment. X-ray diffraction data (of 6), 31P{1H} NMR data (of 5-7) and DFT calculations (on 6) are consistent with the existence of a weak PSn interaction involving the non-coordinated P atom of complexes 5-7, similar to that found in stannylene 1.
通过用Li2(NCH2PtBu2)2C6H4处理SnCl2制备了非供体稳定的PSnP钳型亚锡烯Sn(NCH2PtBu2)2C6H4 (1)。通过还原(此前未知的)硅烷SiCl2(NCH2PtBu2)2C6H4 (2)、SiHCl(NCH2PtBu2)2C6H4 (3)和SiH(HMDS)(NCH2PtBu2)2C6H4 (4；HMDS = N(SiMe3)2)来合成类似的PSiP硅烯的所有尝试均未成功。借助DFT计算对亚锡烯1几乎呈平面状(不包括叔丁基)的分子结构(通过X射线晶体学确定)进行了合理化分析，结果表明，在二磷烷四价体E(NCH2PtBu2)2C6H4 (E = C、Si、Ge、Sn)系列中，E = Ge和Sn的化合物最稳定的构象是两个P原子都非常靠近EN2C6H4平面，靠近(与)E原子，而对于E = C和Si的化合物，两个膦基团都位于EN2C6H4平面的一侧且远离E原子。E原子的大小和稳定的给体-受体PE相互作用的强度(两者在第14族中向下都增加)是决定这些二磷烷四价体分子结构的关键因素。氯化亚锡配合物[Rh{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η4-cod)] (5)、[RuCl{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η6-cym)] (6)和[IrCl{κ2Sn,P-SnCl(NCH2PtBu2)2C6H4}(η5-C5Me5)] (7)的合成证明了亚锡烯1将其Sn原子插入过渡金属配合物的M-Cl键中的倾向，以及所得PSnP氯化亚锡基团作为κ2Sn,P-螯合配体的偏好，同时保留一个未配位的膦片段。(6的)X射线衍射数据、(5 - 7的)31P{1H} NMR数据以及(对6的)DFT计算与配合物5 - 7中涉及未配位P原子的弱PSn相互作用的存在一致，这与在亚锡烯1中发现的类似。
