Bis[2,3‐naphthalindiolato(2–)](pyrrolidiniomethyl)silicat‐Acetonitril‐Solvat: Synthese sowie Kristall‐ und Molekülstruktur eines zwitterionischen λ 5 ‐Spirosilicats

Abstract

Bis[2,3-naphthalenediolato(2—)](pyrrolidiniomethyl)silicate Acetonitrile Solvate: Synthesis and Crystal and Molecular Structure of a Zwitterionic λ5-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 · CH3CN 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 CH4. The pentacoordinate silicon atom of 3 · CH3CN 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·CH3CN contains centrosymmetric dimers of 3, built up by intermolecular N—H … O hydrogen bonds.