PENTACOORDINATE 10-ELECTRON PNICTOGEN MANGANESE ADDUCTS - VERIFICATION OF THE 10-PN-3 ARRANGEMENT IN ADPNO MOLECULES

The bis(cyclopentadienylmanganese dicarbonyl) complexes of 5-aza-2,8-dioxa-1-pnictabicyclo[3.3.0]octa-2,4,6-triene (ADPnO) molecules have been prepared and structurally characterized for arsenic and antimony. These complexes represent the first demonstration of chemical reactivity for both pnictogen lone pairs of electrons in ADPnO molecules. In the case of the phosphorus system (ADPO) only a monoadduct is obtained. The ADPO.Mn(Cp)(CO)2 adduct exhibits a tetracoordinate 8-electron arrangement at phosphorus. These results support the 10-Pn-3 designations previously assigned to the ADPnO molecules and are in accord with recent theoretical models. Comparisons are made with pnictinidene bis(metal) complexes as well as 5-coordinated antimony derivatives of ADSbO.