Cp^PEt₂As₄—An Organic‐Substituted As₄ Butterfly Compound

Abstract

Cp As (Cp =C (4-EtC H ) ) (1) is synthesized by the reaction of Cp radicals with yellow arsenic (As ). In solution an equilibrium of the starting materials and the product is found. However, 1 can be isolated and stored in the solid state without decomposition. As can be easily released from 1 under thermal or photochemical conditions. From powder samples of Cp As , yellow arsenic can be sublimed under rather mild conditions (T=125 °C). A similar behavior for the P -releasing agent was determined for the related phosphorus compound Cp P (2; Cp =C (4-nBuC H ) ). DFT calculations show the importance of dispersion forces for the stability of the products.

Synthesis of a Gallaarsene {HC[C(Me)N-2,6-i-Pr2-C6H3]2}GaAsCp* Containing a Ga═As Double Bond

“…Alternatively, the structure of 3 can be described as a LGaAs 3 butterfly-shaped structure, which is η 1 -coordinated by an additional L­(Cp*)Ga fragment. Comparable structural motifs have been observed for dianionic As 4 complexes and in As 2 Si 2 rings. , The As2–As3 bond length (2.5175(3) Å) is elongated compared to the As1–As2/3 bond lengths (2.4382(3), 2.4588(3) Å), which are in the typical range observed for As–As single bonds, and agree well with values previously observed in As x polyanions including dianionic As 4 tetrahedra . In contrast, the As–As bonds in complexes containing intact As 4 tetrahedra are slightly shorter (2.37–2.43 Å), while those in butterfly-shaped As 2 Si 2 rings are significantly elongated (>2.60 Å). , The Ga1–As2/3 bonds to the η 2 -coordinated Ga atom in 3 are shorter (2.4183(3), 2.4224(3) Å) than the Ga2–As1 bond of the η 1 -coordinated Ga atom (2.5197(3) Å), most likely due to the increased steric pressure resulting from the presence of an additional Cp* ligand.…”

Coordination Behavior of [Cp″2Zr(µ1:1-As4)] towards Lewis Acids

“…In 5 , the As-As distance between the former bridgehead arsenic atoms is 3.032(3) Å, which clearly shows the cleavage of this bond. The other As-As bonds are still in the range of a single bond (2.4657(14) Å and 2.4721(13) Å) [ 13 , 16 , 19 ], and the As-Fe distances of 2.4151(16) Å to 2.4265(15) Å are in the same range as observed for 4 .…”

“…Due to the steric repulsion, the As 4 unit is slightly distorted. The As-As distances are still intact and in the range of a single bond ( 2 : 2.4363(6) Å to 2.4649(6)Å; 3 : 2.4394(4) Å to 2.4710(4) Å; 4 : 2.4321(6) Å to 2.4791(4) Å) [ 13 , 16 , 19 , 24 ]. Furthermore, the Zr-As distances are slightly elongated compared to 1 [ 24 ].…”

“…Selected representatives are depicted in Scheme 1 . A remarkable example is the reaction of yellow arsenic towards the Cp PEt radical (Cp PEt = C 5 (4-EtC 6 H 4 ) 5 ), which leads to the formation of the first organo-substituted As 4 butterfly compound [Cp Pet 2 As 4 ] ( I , Scheme 1 ) [ 13 ]. Furthermore, the reaction of the silylene [PhC(N t Bu) 2 SiN(SiMe 3 ) 2 ] with yellow arsenic results in the aggregation of the As 4 tetrahedron and compound II that contains a heptaarsa-nortricyclane unit can be isolated [ 14 ].…”

Facile storage and release of white phosphorus and yellow arsenic

“…Moreover, together with other coinage metal P 4 complexes, the air-sensitive silver(I) salts [Ag(η 2 -E 4 ) 2 ][pftb] (E = P, As; pftb = [Al{OC(CF 3 ) 3 } 4 ]) show to be suitable sources of intact E 4 (E = P, As) for particular chemical reactions, however with a limited scope due to the need of initial AgCl elimination 11–14 . Recently, we found two other systems, [(LCu) 2 (μ,η 2:2 -E 4 )] (E = P, As; L  = [{N(C 6 H 3 i Pr 2 -2,6)C(Me)} 2 CH − ]) and Cp R E 4 (E = P; Cp R  = Cp* (η 5 -C 5 Me 5 ), Cp″′ (η 5 -C 5 H 3 t Bu 2 ), Cp 4 i Pr (η 5 -C 5 H i Pr 4 ), Cp BIG (η 5 -C 5 (4- n BuC 6 H 4 ) 5 ); E = As, Cp R  = Cp PEt (η 5 -C 5 (4-EtC 6 H 4 ) 5 )), which coordinate either side-on the intact E 4 tetrahedra or radically opened an E–E bond to form a twofold organic-substituted compound with a tetraphospha/tetraarsabicyclo[1.1.0]butane as a central structural motif 15–17 . For both systems, we could show the release of intact E 4 tetrahedra, irreversible in solution, but reversible in the solid state for the latter case (except for E = As).…”