THE SYNTHESIS AND CHARACTERIZATION OF THE CYCLOTRIGERMOXANE: (Ph4C4GeO)3

The cyclotrigermoxane, (PLjC%GeO) 3 , first isolated adventitiously, was synthesized in good yield by the hydrolysis of 1,1-dichlorotetraphenylgermole.The cyclotrigermoxane crystallized as small yellow rectanglar blocks, which were analyzed by X-ray crystallography.The Ge-O ring is planar with a Ge-0 bond length of 1.7680(11) A and endocyclic bond angles of 132.45(17)° (Ge-O-Ge) and 107.55(17)° (O-Ge-O).The cyclotrigermoxane was fully characterized by 'H, ,3 C NMR, ir and mass spectrometry.Recent interest in the chemistry of germole derivatives [1] has focussed on the synthesis of and the extent of delocalization in anionic germole derivatives [2] as well as on the incorporation of the germole moiety into conjugated polymeric materials [3].The facile and high yield synthesis of the stable, bulky dilithiogermole, 1,1-dilithiotetraphenylgermole, was of particular interest to us since the dilithiogermole appeared to be well suited as a reagent for the synthesis of doublv-bonded germanium derivatives, such as digermenes and germasilenes [4], We envisioned a new synthetic mute to a stable germasilene by the reaction between the stable dilithiogermole and a dihalosilane such as dichloro-or difluorobis(2,4,6triisopropvlphenyl)silane in THF.However, all attempts to synthesize a stable germasilene failed [5], During the course of these studies, we did observe the formation of the cyclotrigermoxane 1, in low yield.Given the current interest in germole derivatives and the limited number of structurally characterized cyclotrigermoxanes [6], we synthesized the cyclotrigermoxane in good yield by a cyclocondensation reaction and fully characterized this compound, including the determination of its molecular structure.We report herein on the results of those studies. Results and DiscussionMany attempts were made to synthesize a germasilene by the reaction between 1,1dilithiotetraphenylgermole and a dihalosilane.In a typical experiment, a solution of the dilithiogermole in THF was added to an equivalent of either dichlom-or difiuorobis(2,4,6-triisopropylphenyl)silane dissolved in THF.No evidence for the formation of a germasilene was obtained.The use of toluene as a solvent, the addition of 12-crown-4, or the use of a less bulky silane (dichlorodimesitylsilane) all failed to provide any proof for the formation of a germasilene.During the course of these experiments, a small amount of a crystalline solid was often isolated.The solid was identified as the cyclotrigermoxane 1 (Figure 1) bv Xrav crystallography.To obtain enough material for complete characterization, the cyclotngermoxane was prepared, irr 76 % yreld, by the hydrolysis of 1,1-dichlorotetraphenylgermole with an excess of distilled water and triethvlamine.The product crystallized as small, rectangular, yellow blocks from a saturated hexancs solution or as small yellow plates from a CI LCN/hcxanes mixture.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.