Access to Metal Complexes of the Elusive Imidobis(phosphaalkene) Anion by N–Si Bond Cleavage of a N‐Silylimino‐Bridged Bis(phosphaalkene)

Abstract

Metalation of the aminophosphaalkene (iPrMe 2 Si) 2 C=PN(H)-SiMe 3 (2) with lithium diisopropylamide (LDA) in THF solution, followed by the reaction of the lithium salt 3 with the Pchlorophosphaalkenes (RMe 2 Si) 2 C=PCl (1a, R = Me; 1b, R = iPr; 1c, R = Ph), furnishes the first N-silylimino-bridged bis (phosphaalkenes)

Nitrogen- and oxygen-bridged bidentate phosphaalkene ligands

“…The NMR equivalence of the two 31 P nuclei of 5e in solution would be consistent with either a symmetric structure or with a less symmetric ground state conformation (Scheme 5), which still allows free rotation of the P-N bonds on the NMR time scale at room temperature in solution [19]. All the B3LYP/6-31 + G* optimized structures of the [(R 3 Si) 2 C = P] 2 N(SiR 3 ) molecules (R: H, Me) were non-planar.…”

“…[(Me 3 Si) 2 C P] 2 NSiMe 3 (5d), made from Li[(Me 3 Si) 2 C PNSiMe 3 ] (3d) with 4a, is a thermally unstable oil, [9b, 17,21] but bulkier (iPrMe 2 Si) 2 C P groups [19] stabilise type C compounds. The reactions of the bulkier aminophosphaalkene 2e with lithiumdiisopropylamide (LDA) in THF solution (Scheme 2), followed by reactions of the lithium salt 3e with P-chlorophosphaalkenes (RMe 2 Si) 2 C PCl (R = iPr: 4a; Me: 4b; Ph: 4c) at temperatures below À40 8C furnish solutions of N-trimethylsilylimino-bridged bisphosphaalkenes 5e and the unsymmetric compounds 8a, 8b (Scheme 6).…”

“…the insufficient stability of the products, precluded the isolation of single-crystalline solids, precursors with bulkier silyl groups at carbon were developed. These reactions are based on the new starting material (iPrMe 2 Si) 2 C PCl 4b [18,19]. To improve crystallisation properties of thermolabile N-alkyl products, N-1-adamantyl derivatives were also used [13].…”

Gold highlights at the 10th International Conference on Heteroatom Chemistry (ICHAC-10), in Uji, Kyoto, Japan, 20–25 May 2012

“…, Au I and Rh I leads to complexes of the 5c-6π-heteropentadiene imidobisphosphanaalkene anion [1]. Figure 1 shows an imidobisphosphaalkene gold complex.…”

“…This transformation features 1,3-phosphatyloxy group migration followed by 1,3-shifts of bromine and chlorine as well as the Fig. 1 Reaction with the Au I chloro complexes leading to gold complex of the imidobis(phosphaalkene) anion by N-Si cleavage-adapted from [1] and the Powerpoint slides unprecedented 1,3-migration of iodine. The reaction is stereodivergent: (Z)-1,3-dienes are formed in the presence of a Cu catalyst, whereas Au-catalysed reactions exhibit inverted stereoselectivity, producing the corresponding E products (Fig.…”