Hexacoordinated Group‐14 Elements with Phosphorus Donor Ligands: Syntheses and Structures of Cl₂E[C(PMe₂)₂(SiMe₃)]₂ (E = Si, Ge, Sn)

Abstract

The group-14 tetrahalides ECll (E = Si, Ge, Sn) react with two equivalents of Li [C(PMe&(SiMe,)] to give the trans-hexacoordinated complexes ClzE[C(PMe2)z(SiMe3)]2, which were characterized spectroscopically and by structure determinations in the solid state. The complexes were found to crystallize with or without tetrahydrofuran (THF) molecules, depending on the presence or absence of this solvent. In the case of the silicon complex, the structures of both crystal forms were determined, showing slightly different molecular structures of the complexes in the solid state. Without cocrystahzed THF, C1zSi[C(PMe2)2(SiMe3)]z has no crystallogra-phically imposed molecular symmetry, while in the presence of THF its crystallographic symmetry is C,, (2/m). The tin and germanium complexes were crystallized either with and without THF molecules, respectively, their crystal structures being isotypic with the respective ones of the silicon camplex. In all cases, small amounts of the cis-hexacoordinated isomers were also observed in solution, but only in the case of the silicon complex, it was isolated in pure form. It rearranges to the trans isomer at ambient temperature. trans-Cl,Si[ C (PMe2) &, trans-Cl,Si[ C(PPh&(SiMe3) l2 and cis-Me2-Si[ C(PMe&(SiMe3)lZ were likewise obtained.

Syntheses and Structures of Potassium Complexes Containing Bis(diphenylphosphanyl)methanide Anions

“…[1] Due to the close proximity of the phosphorus and carbon donor atoms and their similar Pauling electronegativities of 2.19 and 2.55, [2] respectively, a variety of coordination modes of these ligands have been observed depending on the properties of the applied metal ion (radius, charge, electronegativity, polarizability), the substituents at phosphorus, and the neutral coligands present. [1] In mononuclear complexes, the κ 1 C, [3][4][5] κ 2 CP, [6,7] κ 2 PP [8][9][10] and κ 3 PCP [11][12][13] coordination modes shown in Scheme 1 are known.…”

Reactivity of Bis(diphenylphosphino)methanide Complexes of Manganese(I) toward Halogens and Pseudohalogens

“…A rich chemistry has been developed around the reactivity of alkali-metal diphosphinomethanides with halides of many metallic and nonmetallic elements (MX n ) . This has led to the preparation of a number of diphosphinomethanide derivatives displaying remarkable features, such as a variety of coordination modes (mono-, bi-, and tridentate through the carbon and phosphorus donor atoms), high coordination numbers, and the noteworthy stabilization of molecules with elements in low oxidation states, such as those of silicon(II) . However, as far as we know, the study of the reactivity of diphosphinomethanide anions with dihalogen molecules themselves (X 2 ) has been limited to the treatment of lithium bis(diphenylphosphino)methanide with iodine, leading to the formation of PPh 2 PCHPPh 2 PPh 2 CHPPh 2 , (Ph 2 P) 2 CPPh 2 CH 2 PPh 2 , and (Ph 2 P) 2 CHCH(PPh 2 ) 2 , which result from P−P, P−C, and C−C coupling, respectively. , Curiously, no halogenation product was isolated from the above reaction.…”

Germanium Coordination Compounds: Classification and Analysis of Crystallographic and Structural Data

“…The data for over thirty derivatives with coordination number six are given in [83,84,107,108], Also found are situations involving a bidentate plus four unidentate ligands [94], two bidentate and two unidentate ligands [85][86][87]99,109,110], three bidentate ligands [88,89,91], two terdentate ligands [100], one tetradentate and two unidentate ligands [92,[101][102][103][104][105][106], one penta-and one unidentate ligand [94][95][96][97][98] and by one hexadentate ligand [90], In six of the derivatives [85,103.106,108] six donor atoms create a near ideal Oh symmetry about Ge(IV). All the remaining examples exhibit a distorted geometry with a compressed tetragonal bipyramidal geometry.…”