The metathesis reaction of LiP(SiR 3 )Ar* (R = iPr and Ph; Ar* = Mes and Tipp) with Ph 2 POCl yields Ar*(R 3 Si)P−P(O)Ph 2 . These diphosphane monoxides can be observed by NMR spectroscopy. However, they are intrinsically instable, and 1,3-trihydrylsilyl migration leads to the formation of 1λ 5 -diphosphenes of the type Ar*PP(OSiR 3 )Ph 2 with very large characteristic 1 J(P,P) coupling constants. A very short PP bond has been observed for the 1λ 5 -diphosphene TippPP(OSiPh 3 )Ph 2 . These 1λ 5 -diphosphenes are only stable in the crystalline state but degrade in solution to Ph 2 P−O−SiR 3 via elimination of the Ar*P: phosphinidenes which form secondary degradation products such as triaryl-cyclotriphosphanes. Formation of the 1λ 5 -diphosphene TippPP(OSiPh 3 )Ph 2 via 1,3-trihydrylsilyl migration from P to O and the fate due to PP bond cleavage has been verified by theoretical studies.

The reactions of [(thf) 2 TiCl 4 ] with sodiated 2,2'-bis[2-hydroxy-3,5-di(tert-butyl)benzylideneamino]-1,1'-biphenyl (1 a) and 2,2'bis[2-hydroxy-3,5-di(tert-butyl)benzylideneamino]-4,4'-dimethyl-1,1'-biphenyl (1 b) yield the corresponding Ti complexes 2 a and 2 b. Similarly, 1 a reacts with [(thf) 2 ZrCl 4 ] to the corresponding Zr derivative 3. For 2 a, a mixture of cis-β and trans isomers were observed in solution whereas the Zr congener exclusively forms the cis-α form. Quantum chemical calculations verify that these isomers are the preferred molecular structures. The crystal structures of cis-β isomeric 2 a and cis-α isomeric 3 have been determined. Metalation of 1 a with Ti(NMe 2 ) 4 yields 2,2'-bis[(2oxido-3,5-di(tert-butyl)phenyl)-dimethylaminomethylamino]-1,1'-biphenyl titanium(IV) (4) with a hexadentate ligand.

Metalation of N‐mesityl‐P,P‐diphenylphosphinic amide with nBuLi in toluene yields tetranuclear lithium N‐mesityl‐P,P‐diphenylphosphinimidate ([Ph2P(OLi)=N−Mes]4, 1). Metalation of Ph2P(O)−N(H)Mes with a mixture of dibutylmagnesium and butyllithium in DME leads to formation of dinuclear [Ph2P{OLi(dme)}=N−Mes]2 (2). Excess of Ph2P(O)−N(H)Mes gives dinuclear [Li(O−PPh2=N−Mes){Ph2P(=O)−N(H)−Mes}]2 (3) with three‐coordinate alkali ions. The metathetical approach via reaction of 1 with anhydrous magnesium bromide in ethereal solution yields [{(thf)LiBr}2{(thf)Li(O−PPh2=NMes)(Et2O)Li(O−PPh2=NMes)}] (4). Heterobimetallic Li/Mg compounds are not accessible by these protocols. Reactions of 1 with DME, with excess of Ph2P(O)−N(H)Mes or with LiBr allows the straightforward conversion to compounds 2, 3 and 4.