Interpnictogen Compounds with Polarised Phosphorus–Element Bonds 

Abstract

Metathesis of chloro-substituted N-heterocyclic phosphanes, arsanes, and stibanes with lithium tetraethylphospholide or -arsolide gave interpnictogen compounds 2-4 with As-P or Sb-P bonds, respectively. The products were characterised by analytical and spectroscopic data and single-crystal X-ray diffraction studies. All compounds feature central E-E' bonds that are notably longer (5-12 %) than standard 1263 bond lengths, and the As-P bond in the isomers 2 and 3 which are merely distinguished by formal exchange of the pnictogen atoms between both rings differ by some 4 pm. The observed structural features suggest that compounds 2-4 may, like the corresponding diphosphanes, be perceived as adducts of Lewis-pairs which are held together by a dative interpnictogen bond.

An Unusual Isomerization to Tetraazastiboles

“…[18] Only little is known about compounds with dicoordinated Sb atoms containing a Sb À N double bond. [26,27] The first fully characterized compound with a partial SbÀN double bond (1.99(2) and 2.00 (2) [26a]…”

“…[18] Only little is known about compounds with dicoordinated Sb atoms containing a Sb À N double bond. [26,27] The first fully characterized compound with a partial SbÀN double bond (1.99(2) and 2.00(2) ) is the four-membered cationic heterocycle [Me 2 Si(NtBu) 2 Sb] + with [AlCl 4 ] À as counterion, prepared by Veith et al in 1988. [26a] The B À N bond length of 1.598(3) is in the typical range found for other B(C 6 F 5 ) 3 adducts, [28] cf.…”

Catalytic Hydrophosphination of Isocyanates by Molecular Antimony Phosphanides

“…The Sb−P bond lengths ( 1 a , 2.5762(4) Å; 1 b , 2.5776(6) Å) are slightly longer than the sum of the covalent radii (Σ cov (Sb,P)=2.46 Å), [29] with a more pronounced pyramidalization at the −PPh 2 phosphorus atom (Σ angles (P): 1 a , 316.55°; 1 b , 296.12°). Previous structurally characterized examples of the Sb−PR 2 bond (where R=alkyl, aryl) are restricted to a single compound consisting of an N ‐heterocyclic stibane phospholide with a Sb−P bond length of 2.667(2) Å [30] . A closely related secondary phosphanide (Ar*NH)ClSb−PHAr* (Ar*=2,6‐Mes 2 C 6 H 3 ) has also been reported with a Sb−P bond length of 2.5429(6) Å, [31] showing little variation in this parameter.…”

Eine ungewöhnliche Isomerisierung zu Tetraazastibolen

“…[18] Relativ wenig ist bekannt über Verbindungen mit zweifach koordinierten Sb-Atomen, die eine Sb-N-Doppelbindung enthalten. [26,27] Die erste vollständig charakterisierte Verbindung mit einer partiellen Sb-N-Doppelbindung (1.99(2) und 2.00(2) ) stellt der viergliedrige kationische Heterocyclus [Me 2 Si(NtBu) 2 Sb] + mit [AlCl 4 ] À als Gegenion dar, über den Veith et al 1988 berichteten. [26a] Die B-N-Bindungslänge mit 1.598(3) ist im typischen Bereich von B(C 6 F 5 ) 3 -Addukten [28] (z.…”