Hypervalence in germanium compounds containing the tetracylic moiety {S(C 6H 3S) 2O}Ge via O···Ge transannular interactions: A structural study

• Published in: Polyhedron Vol. 28; no. 4; pp. 782 - 788
• Main Authors: Flores-Chávez, Benito, Alvarado-Rodríguez, José G., Andrade-López, Noemí, García-Montalvo, Verónica, Aquino-Torres, Eliazar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 12.03.2009
• Subjects: Dithioligands; Germanium compounds; Hypervalent compounds; Structure elucidation; Dithioligands; Germanium compounds; Structure elucidation; Hypervalent compounds
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2008.12.007

The synthesis of [{S(C 6H 3S) 2O}GeR n Hal 2− n ] compounds (R = Et, Ph; Hal = Cl, Br; n = 2–0) is described. The acidity of the GeRHal 2+ fragment enhances a transannular O···Ge interaction, prompting a trigonal bipyramidal germanium local geometry; the GeR 2 2+ less acid fragment present has an opposite effect. Treatment of R n GeCl 4− n with {S(C 6H 3SH) 2O} ( 1) afforded the stable phenoxathiin-4,6-dithiolate compounds [{S(C 6H 3S) 2O}GeR 2] [ n = 2; R = Et ( 2), Ph ( 3)] and [{S(C 6H 3S) 2O}GeRCl] [ n = 1; R = Et ( 4), Ph ( 5)]. Treatment of GeCl 4 with 1 in benzene afforded the dichloro compound [{S(C 6H 3S) 2O}GeCl 2] ( 8) at 7 °C. Bromo compounds [{S(C 6H 3S) 2O}GeRBr] [R = Et ( 6), Ph ( 7)] and [{S(C 6H 3S) 2O}GeBr 2] ( 9) were synthesized by halogen exchange from the appropriate chloro derivative using KBr/HBr. X-ray structure determinations of diorganyl dithiolate compounds 2 and 3 revealed that germanium atom is contained in a boat–chair-shaped eight-membered central ring and displays a tetrahedral geometry. In contrast, compounds 4– 6 display a boat–boat-shaped central ring with a significant intramolecular transannular O···Ge interaction. The geometry of the pentacoordinate Ge atom in these last complexes may be described as distorted trigonal bipyramidal with a 62–65% distortion displacement.