Transfer Reagent for Bonding Isomers of Iron Complexes

Abstract

The cothermolysis of As and [Cp″Zr(CO)] (Cp″ = η-CHtBu) results in the formation of [Cp″Zr(η-As)] (1) in high yields and the arsenic-rich complex [(Cp″Zr)(Cp″Zr)(μ,η-As)] (2) as a minor product. In contrast to yellow arsenic, 1 is a light-stable, weighable and storable arsenic source for subsequent reactions. The transfer reaction of 1 with [Cp‴Fe(μ-Br)] (Cp‴ = η-CHtBu) yields the unprecedented bond isomeric complexes [(Cp‴Fe)(μ,η-As)] (3a) and [(Cp‴Fe)(μ,η-cyclo-As)] (3b). In contrast, the analogous reaction with the Cp derivative [CpFe(μ-Br)] (Cp = η-C(CH(CH)) leads exclusively to the triple decker complex [(CpFe)(μ,η-As)] (4) possessing the tetraarsabutadiene-type ligand analogous to 3a. To elucidate the stability of the bonding isomers 3a and 3b, DFT calculations were performed. The oxidation of 4 with AgBF affords [(CpFe)(μ,η-As)][BF] (5), which is a product expanded by one arsenic atom, instead of the expected complex [(CpFe)(μ,η-cyclo-As)].

Modern applications of low-valent early transition metals in synthesis and catalysis

“…Outside of catalytic nitrene transfer, there are also many examples of stoichiometric atom-transfer reactions (As 4 (REF. 323 ), S 8 (REFS 324 , 325 ) and P 4 (REF. 326 )).…”

Synthesis and structural characterization of arsinoamides – early transition metal (Zr and Hf) and main group metal (Al, In, Sn, and Pb) complexes

“…[33][34][35][36] The N-E-N bond angles (N1-Sn-N2: 97.8(2)°and N1-Pb-N2: 97.4(2)°) are smaller than the comparable N-E-N bond angles (e.g. 106.13(8)°and 104.7(2)°( N-Sn-N) and 100.60(8)°and 105.75 (14)°(N-Pb-N)), [37][38][39] which may originate from the steric effect of the ligand. The sum of bond angles around the nitrogen atoms varies from 348.9°to 356.4°, indicating a slightly disordered pyramidal geometry of the nitrogen atoms.…”

“…Selected bond distances and angles are summarized in Table 1. According to the molecular structures of 1 and 2, the M-As interaction can be observed in both compounds (Zr-As: 3.2101 6 14,15 the weakness of the arsenic metal contact in 1 and 2 is evident from the longer M-As distances. We anticipate that packing effects play a significant role in these interactions.…”

Iodination of cyclo‐E5‐Complexes (E=P, As)

“…When compared to the monocationic triple decker complexes [CpFe(μ,η 5:5 ‐As 5 )FeCp*][PF 6 ] (av. 2.328 Å) and [Cp Bn Fe) 2 (μ,η 5:5 ‐As 5 )][BF 4 ] (av. 2.34 Å), the As−As bonds in 9 are slightly elongated.…”