Diphosphastannylenes: Precursors for Phosphorus–Phosphorus Coupling?

Abstract

The preparation of the secondary phosphane (Ph){C6H3‐2,6‐(CH2NMe2)2}PH (1), a potentially base‐stabilized ligand, and the sterically protected carbaborane‐based phosphane (o‐CH3C2B10H10)2PH (2) is reported. Reaction of Sn{N(SiMe3)}2 with 1 gives the diphosphastannylene [(Ph){(C6H3‐2,6‐CH2NMe2)2}P]2Sn (3) in high yield. In contrast, the room‐temperature reaction of 2 with Sn{N(SiMe2)}2 does not proceed. By applying elevated temperatures, the heteroleptic amidophosphastannylene {(o‐CH3C2B10H10)2P}{(SiMe3)2N}Sn (4) was formed, instead of the expected diphosphastannylene {(o‐CH3C2B10H10)2P}2Sn. The thermal decomposition of compounds 3 and 4 was also studied. The thermal decomposition of 3 produced the new phosphorus–phosphorus‐bonded compound 5, an unprecedented 1,2‐diphosphol‐type molecule.

B-substituted group 1 phosphides: synthesis and reactivity

“…Both values are shifted downfield compared to starting compound 5 ( δ −33.5 ppm). The magnitudes of the 1 J M,P values correlate with those found for related phosphastannylenes (range of 875–1682 Hz) 26 h ,35 or phosphaplumbylenes (range of 1084–2852 Hz) 35 h , f ,36 having M–P single bonds. The 11 B{ 1 H} NMR spectra revealed signals at δ 2.1 ppm ( 12 ) and 2.7 ppm ( 13 ) in accordance with a tetrahedral boron atom.…”

“…The molecular structure proved the presence of a new Sn1–P1 bond (2.7214(7) Å) that was longer than the sum of the covalent radii of the parent atoms (Σ cov Sn,P = 2.51 Å). 19 The Sn1–P1 bond is also longer than those in phosphastannylenes (in the range of 2.4458(8)–2.6612(12) Å), 26 h ,35 where the p π –p π interaction of both atoms results in a shortening of the Sn–P bonds. 35 a – c , g In 12 , the existence of the B ← P interaction (the P1–B1 bond length is 2.083(2) Å) may prevent this p π –p π interaction of the Sn,P atoms, which results in their long bond length.…”

The role of the bis-trimethylsilylamido ligand, [N{SiMe3}2]−, in main group chemistry. Part 2: Structural chemistry of the metallic p-block elements

“…The rather exotic carbaborane-based phosphanide derivative, Sn(P{oMeC 2 B 10 H 10 } 2 )(N{SiMe 3 } 2 ) (114) was shown by crystallography to be monomeric with a 2-coordinate tin centre (Fig. 13) [99]. The monomeric 3-coordinate benzamidinate compound Sn(PhC{Nt-Bu} 2 )(N{SiMe 3 } 2 ) (115) was Examples of new stannylene compounds with chelating N,N'-ligands continue to be developed.…”