Synthesis, reactivity and structures of cyclic arsenites with an N→As bond

Abstract

Synthesis and X-ray structures of the cyclic arsenites (NC9H6O)As(2.2′-OC6H4 -C6H4O) (1) and(NC9H6O)As [(O-2,4-(t-bu)2C6H2)2CH2 ] (2) are described. Compound 1 crystallizes in the monoclinic space group P21 with a = 10.469 (7)Å, b = 7.126 (4)Å, c = 11.837 (6)Å, β = 95.14 (5)°, V = 879.5 (9) Å3, Z = 2. Compound 2 crystallizes in the triclinic space group P1̄ with a = 11.320 (6)Å, b = 12.749 (7)Å, c = 14.257 (8)Å, α = 97.21 (4), β = 97.21 (4), γ = 102.62 (4)°, ν = 1732 (2) Å3, Ζ = 2. Both the compounds exhibit intramolecular N → As coordination with a distorted trigonal bipyramidal geometry around arsenic; the coordinated nitrogen is in the apical position and the stereochemically active lone pair on arsenic is located approximately in the equatorial plane. The hydrolytic behaviour of 1, 2 and(NC9 H6O)As(OCH2CMe2CH2O) (4) is compared with that of the corresponding phosphorus analogues.