Cycloarsanes (AsCF3)n (n = 4, 5) – Precursors for the Highly Reactive Diarsene F3CAs=AsCF3

Synthesis of distibiranes and azadistibiranes by cycloaddition reactions of distibenes with diazomethanes and azides

Cycloaddition reactions of distibene [L(Me2N)GaSb]2 (L = HC[C(Me)NDipp]2; Dipp = 2,6-i-Pr2C6H3)[double bond, length as m-dash] with a series of organoazides RN3 (R = Ph, p-CF3Ph, 1-adamantyl (ada)) yielded azadistibiranes [L(Me2N)GaSb]2NR (R = Ph 1, p-CF3Ph 2, ada 3), whereas Me3SiN3 reacted with insertion into one Ga-Sb bond and formation of L(Me2N)GaSbSb(NSiMe3)Ga(NMe2)L (4). Analogous compounds 5 and 6 formed after heating of 1 and 2 above 60 °C. Prolonged heating of 5 resulted in a [2 + 2] cycloaddition accompanied by elimination of LGa(NMe2)2 and formation of tetrastibacyclobutane 7, while the reaction of 5 with a second equivalent of PhN3 gave heteroleptic azadistibirane 9, which isomerized at elevated temperature to distibene 10. Cycloaddition also occurred in reactions of [L(X)GaSb]2 (X = NMe2, OEt, Cl) with Me3Si(H)CN2, yielding distibiranes [L(X)GaSb]2C(H)SiMe3 (X = NMe211, OEt 12, Cl 13). Compounds 1-13 were characterized by IR, UV-Vis and NMR spectroscopy and sc-XRD. The mechanism of the reaction of [L(Me2N)GaSb]2 with PhN3 and Me3SiN3 and the electronic nature of the resulting compounds were studied by DFT calculations.

Aryl-substituted triarsiranes: synthesis and reactivity

Cyclotriarsanes are rare and described herein is a scalable synthetic protocol towards (AsAr)3, which allowed to study their reactivity towards [Cp2Ti(C2(SiMe3)2)], affording titanocene diarsene complexes, and towards N-heterocyclic carbenes (NHCs) to give straightforward access to a variety of NHC-arsinidene adducts.

The Parent Diarsene HAs=AsH as Side-on Bound Ligand in an Iron Carbonyl Complex

The terminal diarsene HAs=AsH ligand attracts special interest concerning its bonding relation in comparison to its isolable relative, ethene. Herein, by the methanolysis of [{Fe(CO)₄}As(SiMe₃)₃] (1) the synthesis of [{Fe(CO)₄}(η²‐As₂H₂)] (2) is reported, containing a parent diarsene as unprecedented side‐on coordinated ligand. Following this synthetic route, also the D‐labeled complex [{Fe(CO)₄}(η²‐As₂D₂)] (2D) could be isolated. The electronic structure and bonding situation of 2 was elucidated by DFT calculations revealing that 2 is best described as an olefin‐like complex. Moreover, the reactivity of 2 towards the Lewis acids [{M(CO)₅}(thf)] (M=Cr, W) was investigated, leading to the complexes [Fe(CO)₄AsHW(CO)₅]₂ (3) and [{Fe(CO)₄}₂AsH{Cr(CO)₅}] (4), respectively.