Selective Formation and Unusual Reactivity of Tetraarsabicyclo[1.1.0]butane Complexes

Abstract

The selective formation of the dinuclear butterfly complexes [{Cp'''Fe(CO)2}2(μ,η(1:1)-E4)] (E = P (1 a), As (1 b)) and [{Cp*Cr(CO)3}2(μ,η(1:1)-E4)] (E = P (2 a), As (2 b)) as new representatives of this rare class of compounds was found by reaction of E4 with the corresponding dimeric carbonyl complexes. Complexes 1 b and 2 b are the first As4 butterfly compounds with a bridging coordination mode. Moreover, first studies regarding the reactivity of 1 b and 2 b are presented, revealing the formation of the unprecedented As8 cuneane complexes [{Cp'''Fe(CO)2}2{Cp'''Fe(CO)}2(μ4,η(1:1:2:2)-As8)] (3 b) and [{Cp*Cr(CO)3}4(μ4,η(1:1:1:1)-As8)] (4). The compounds are fully characterized by NMR and IR spectroscopy as well as by X-ray structure analysis. In addition, DFT calculations give insight into the transformation pathway from the E4 butterfly to the corresponding cuneane structural motif.

Rearrangement of a P4 Butterfly Complex—The Formation of a Homoleptic Phosphorus–Iron Sandwich Complex

“…[2] Thea ctivation of P 4 can be mediated by main group elements [3] as well as by transition metals. [5] This so-called butterfly framework can either be stabilized by one [5,6] or two [7] covalently bound metal fragments or organic substituents. [5] This so-called butterfly framework can either be stabilized by one [5,6] or two [7] covalently bound metal fragments or organic substituents.…”

E4 Butterfly Complexes (E=P, As) as Chelating Ligands

“…[2] In our group,t he use of the complexes [Cp 2 Mo 2 (CO) 4 (m,h 2:2 -P 2 )] [3] (type A)a nd [Cp R Fe-(h 5 -P 5 )] (type B;C p R = C 5 Me 5 ,C 5 (CH 2 C 6 H 5 ) 5 ,C 5 (4-nBuC 6 H 4 ) 5 )a sb uilding blocks in supramolecular chemistry has been extensively investigated. [6] Since the isolation of the first transition-metal-stabilized bridging P 4 butterfly complex [{Cp''Fe(CO) 2 } 2 (m,h 1:1 -P 4 )] (type C), [7] the reactivity under thermolytic [8] and photolytic [7,9] conditions as well as its reactivity towards various alkynes [10] has been intensively investigated. [6] Since the isolation of the first transition-metal-stabilized bridging P 4 butterfly complex [{Cp''Fe(CO) 2 } 2 (m,h 1:1 -P 4 )] (type C), [7] the reactivity under thermolytic [8] and photolytic [7,9] conditions as well as its reactivity towards various alkynes [10] has been intensively investigated.…”

E4‐Butterfly‐Komplexe (E=P, As) als Chelatliganden

“…[6] Seit der Isolierung des ersten Übergangsmetall-stabilisierten verbrückten P 4 -Butterfly-Komplexes [{Cp''Fe-(CO) 2 } 2 (m,h 1:1 -P 4 )] [7] wurde dessen Reaktivität unter thermischen [8] und photolytischen [7,9] Bedingungen als auch gegenüber verschiedenen Alkinen [10] untersucht. Allerdings wurde dessen Koordinationsverhalten gegenüber Lewis-Säuren bisher nicht studiert.…”