Bis[2,3‐naphthalindiolato(2–)](pyrrolidiniomethyl)silicat‐Acetonitril‐Solvat: Synthese sowie Kristall‐ und Molekülstruktur eines zwitterionischen λ⁵‐Spirosilicats

Bis[2,3‐naphthalenediolato(2—)](pyrrolidiniomethyl)silicate Acetonitrile Solvate: Synthesis and Crystal and Molecular Structure of a Zwitterionic λ 5 ‐Spirosilicate The zwitterionic spirocyclic bis[2,3‐naphthalenediolato[2–)](pyrrolidiniomethyl)silicate ( 3 ) was synthesized and the crystal and molecular structure of its acetonitrile solvate 3 · CH 3 CN investigated. 3 was prepared by reaction of trimethoxy(pyrrolidinomethyl)silane ( 8 ) or dimethoxy(methyl)(pyrrolidinomethyl)silane ( 8 ) or dimethoxy(methyl)(pyrrolidinomethyl)silane ( 9 ) with 2,3‐dihydroxynaphthalene in acetonitrile. Reaction 9 → 3 involves a remarkable Si—C cleavage with formation of CH 4 . The pentacoordinate silicon atom of 3 · CH 3 CN is surrounded by 4 oxygen atoms and 1 carbon atom, the latter being in an equatorial position. The coordination polyhedron can be described as a distorted trigonal bipyramid (the structure is displaced by 20.5% from the trigonal bipyramid towards the square pyramid). The crystal lattice of 3 ·CH 3 CN contains centrosymmetric dimers of 3 , built up by intermolecular N—H … O hydrogen bonds.