NEW ASPECTS IN HETEROATOM CHEMISTRY - AMBIDENT ANIONIC PHOSPHINOMETHANIDES AS BUILDING-BLOCKS IN NOVEL ORGANOMETALLIC COMPOUNDS

Phosphinomethanides bind to electrophiles via either phosphorus or car bon. The resulting compounds usually are unstable and/or can rearrange from carbon to phosphorus coordination or vice versa. Selective oxida tive coupling reactions of the phosphinomethanide ligands are found wi th metal centers in high oxidation states, but these ligands are stabl e to reduction. Thus, low-valency species can be stabilized. In additi on, diphosphinomethanides are useful ligands to promote high coordinat ion numbers with main-group elements (''hypervalent compounds''), tran sition or lanthanoid metals.