Multidentate, cyclic phosphorus ligands with a silicon-phosphorus backbone: Template synthesis of a 1,4,7-triphospha-2,3,5,6,8,9-hexasilacyclononane and a 1,3,5,7,9,11-hexaphospha-2,4,6,8,10,12-hexasilacyclododecane

Article abstract of DOI:10.1002/anie.199718921

The right template makes it possible: a one-pot cyclo-condensation starting from fac-[Mo(CO)₃(PH₂R)₃] (R=cyclohexyl), nBuLi, and 1,2-dichlorotetramethyldisilane gives complex 1 in 48% yield. This is the first complex with a nine-membered tridentate phosphorus ligand. The surprising 'fusion' of two 1,3,5-triphospha-2,4,6-trisilacyclohexanes in the presence of Cu(I) and Ag(I) triflates leads to binuclear complexes with an unprecedented hexadentate phosphorus ligand.