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 α = 10.469 (7)Å, b = 7.126 (4)Å, c = 11.837 (6)Å β = 95.14 (5)°, V = 879.5 (9) ų, Z = 2. Compound 2 crystallizes in the triclinic space group P1 with α = 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)°, V = 1732 (2) ų, Z = 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 (NC₉H₆O)As(OCH₂CMe₂CH₂O) (4) is compared with that of the corresponding phosphorus analogues.

Key Words:

• Cyclic arsenites
• internal coordination
• X-ray structures