Acyl- und Alkylidenphosphane. XXXIV [1]. Methoxycarbonylphosphane - Verbindungen aus dem Umfeld des Phosphaalkins P?C?O?Li(dme)2

Reductive Elimination at Pb(II) Center of an (Amino)plumbylene-Substituted Phosphaketene: New Pathway for Phosphinidene Synthesis

A stable (amino)plumbylene‐substituted phosphaketene 3 was synthesized by the successive reactions of PbCl₂ with two anionic reagents (lithium amidophosphine and NaPCO). Of particular interest, the thermal evolution of 3, at 80 °C, leads to the transient formation of corresponding amino‐ and phosphanylidene‐phosphaketenes (6 and 7), via a reductive elimination at the Pb^II center forming new N−P and P−P bonds. Further evolution of 6 gives a new cyclic (amino)phosphanylidene phosphorane 4, which shows a unique reactivity as a phosphinidene. This result provides a new synthetic route to phosphinidenes, extending and facilitating further their access.

Unexpected Photodegradation of a Phosphaketenyl-Substituted Germyliumylidene Borate Complex

The first zwitterionic borata-bis(NHC)-stabilized phosphaketenyl germyliumylidene [(L₂ (O=C=P)Ge:] 2 (L₂ =(p-tolyl)₂ B[1-(1-adamantyl)-3-yl-2-ylidene]₂ ) has been synthesized by salt-metathesis reaction of [L₂ (Cl)Ge:] 1 with sodium phosphaethynolate [(dioxane)_n NaOCP]. Unexpectedly, its exposure to UV light affords, after reductive elimination of the entire PCO group, the unprecedented [L₂ Ge-GeL₂ ] complex 3 in 54 % yields bearing the Ge₂²⁺ ion with Ge in the oxidation state +1. In addition, the 1,3-digermylium-2,4-diphosphacyclobutadiene [L₂ Ge(μ-P)₂ GeL₂ ] 4 and bis(germyliumylidenyl)-substituted diphosphene [(L₂ Ge-P=P-GeL₂ )] 5 could also be obtained in moderate yields. The formation of 3-5 and their electronic structures have been elucidated with DFT calculations.

A Monoanionic Arsenide Source: Decarbonylation of the 2-Arsaethynolate Anion upon Reaction with Bulky Stannylenes

We report fundamental studies on the reactivity of the 2-arsaethynolate anion (AsCO- ), a species that has only recently become synthetically accessible. The reaction of AsCO- with the bulky stannylene Ter2 Sn (Ter=2,6-bis[2,4,6-trimethylphenyl]phenyl) is described, which leads to the unexpected formation of a [Ter3 Sn2 As2 ]- cluster compound. On the reaction pathway to this cluster, several intermediates were identified and characterized. After the initial association of AsCO- to Ter2 Sn, decarbonylation occurs to give an anion featuring monocoordinate arsenic, [Ter2 SnAs]- . Both species are not stable under ambient conditions, and [Ter2 SnAs]- rearranges to form [TerSnAsTer]- , an unprecedented anionic mixed Group 14/15 alkene analogue.

Exploiting the Brønsted acidity of phosphinecarboxamides for the synthesis of new phosphides and phosphines

We demonstrate that the synthesis of new N-functionalized phosphinecarboxamides is possible by reaction of primary and secondary amines with PCO(-) in the presence of a proton source. These reactions proceed with varying degrees of success, and although primary amines generally afford the corresponding phosphinecarboxamides in good yields, secondary amines react more sluggishly and often give rise to significant decomposition of the 2-phosphaethynolate precursor. Of the new N-derivatized phosphinecarboxamides available, PH2C(O)NHCy (Cy = cyclohexyl) can be obtained in sufficiently high yields to allow for the exploration of its Brønsted acidity. Thus, deprotonating PH2C(O)NHCy with one equivalent of potassium bis(trimethylsilyl)amide (KHMDS) gave the new phosphide [PHC(O)NHCy](-). In contrast, deprotonation with half of an equivalent gives rise to [P{C(O)NHCy}2](-) and PH3. These phosphides can be employed to give new phosphines by reactions with electrophiles, thus demonstrating their enormous potential as chemical building blocks.