Bis(stannyl)phosphanyl‐Substituted Dichlorosilanes/Germanes — Potential Precursors for a Novel Strategy Toward P–Si/Ge Multiple Bonds?

Abstract

A general synthetic route to bis(stannyl)phosphanyl-substituted dichlorosilanes/germanes of the type R-SiCl 2 -P(SnMe 3 ) 2 and R-GeCl 2 -P(SnMe 3 ) 2 is reported. For R = Cp* (= 1,2,3,4,5-pentamethylcyclopentadienyl) crystal structures for the corresponding silane and germane could be obtained. These compounds are the first structurally characterized bis-

A Radical Approach to Hydroxylaminotrichlorosilanes: Synthesis, Reactivity, and Crystal Structure of TEMPO‐SiCl3 (TEMPO = 2,2,6,6‐Tetramethylpiperidine‐N‐oxyl)

“…A possible explanation is negative hyperconjugation through an n(O) Ǟ σ*(Si-Cl2) interaction as observed in related cases. [18][19][20] As mentioned initially, the formation of 1 proceeds from the reaction of TEMPO with SiCl 4 . In principle, the replacement of a chlorine radical from SiCl 4 may occur by TEMPO accompanied by the liberation of elemental chlorine.…”

The homologous series of 1,1′-ferrocenylenebisdihalophosphanes (C5H4PX2)2Fe (X = F, Cl, Br, I): precursors for the first metallocene bridged bisphosphaalkene

“…This is sterically not the least repulsive arrangement but ideal for negative hyperconjugation with the p-system of the cyclopentadienyl ring. [24][25][26] The phosphorus halogen distances in structures 3b and 3c show with 2.0588(5)-2.0808(6) A ˚(P-Cl) and 2.213(3)-2.261(3) A ˚(P-Br) typical values for this combination of elements. 27 Interestingly, the phosphorus contact to the halogen atom pointing towards the iron atom is slightly shorter than the distance to the halogen atom pointing away from the ferrocene system.…”

Effect of π-donating substituents on the dative or covalent character of adducts of some simple “enium” ions with PMe3 and NMe3

“…This difference is smallest for phosphorus (3 pm (2%)) increases for arsenic (5 pm (3%)) and amounts to 11 pm (6%) for selenium. This trend can be rationalized considering negative hyperconjugation as in related cases [34][35][36][37][38][39]. Such a hyperconjugative interaction competes with the r-donor-stabilization of the amine/phosphane and is more likely for polar donor acceptor bonds and is therefore weakest for the (formally) unpolar homonuclear bond in 1.…”