Lithiations of Bis-diphenyl-N-trimethylsilylphosphiniminomethane:  An X-ray Structure of a 1,1-Dilithiomethane Derivative

Synthesis and Characterization of a Sulfonyl- and Iminophosphoryl-Functionalized Methanide and Methandiide

“…Thereby, methandiides revealed to be highly efficient ligand systems stabilizing a variety of carbene complexes with main group metals [4][5][6][7], early and late transition metals [8][9][10][11][12] as well as lanthanides and actinides [13][14][15][16]. The first dilithium compound, which was employed in this chemistry, was the bis(iminophosphorano) system {Li 2 (bipm TMS )} 2 (A, bipm TMS =C(PPh 2 NSiMe 3 ) 2 ), which was simultaneously reported by the groups of Cavell and Stephan in 1999 ( Figure 1) [17,18]. Unlike all other methandiides reported before [19][20][21], A was found to be conveniently accessible by double deprotonation and isolable in high yields, thus allowing its application in carbene complex synthesis [22].…”

“…In contrast, donor side-arms lead to the formation of defined cluster structures [19]. For instance, the DPPM-based systems A and B and derivatives thereof typically form dimeric structures with a central structural motif consisting of a Li4 and Li2C2 fourmembered ring perpendicular to each other [17,18,[34][35][36][37][38]. This motif is also present in the structures of the heavier alkali metal derivatives [39,40].…”

Geminal dianions stabilized by phosphonium substituents

“…Treatment of a bis(iminophosphorane)methane precursor with one equivalent of an alkali metal base gave the expected methanide complexes for a variety of alkali metals (Li, Na, K) and iminosubstituents: R = Me 3 Si, mesityl, DIPP (2, 6-diisopropylphenyl) or P(O)(OPh) 2 [18][19][20][21][22][23][24][25]. Crystal structure determinations generally show zwitterionic behaviour, i.e.…”

“…The groups of Cavell [26] and Stephan [18] independently reported the first dilithio-methandiide complex (15) which was obtained by double deprotonation of H 2 C(Ph 2 P NSiMe 3 ) 2 with two equivalents of PhLi or with excess MeLi (Scheme 5). This compound crystallizes as a dimer with a unique C Li bonding mode (Fig.…”

“…Reaction of H 2 C(Ph 2 P NPh) 2 with two equivalents of benzylrubidium gave Rb 2 C(Ph 2 P NPh) 2 (18) in a yield of 67%. This compound is even more reactive than the analogous K-complex and decomposes immediately in THF.…”