Palladium(II) complexes of N-sulfonylamino acids. Part 1. Solid-state behaviour of binary and ternary 2,2′-bipyridine-containing systems

Abstract

The crystal and molecular structure of the complexes K₂[Pd(bs-α-alaNO)₂]·3.5H₂O 1, [Pd(tsglyNO)(bipy)]2 and [Pd(bs-β-alaNO)(bipy)]·H₂O 3 were determined by X-ray diffraction (bs-α-alaNO = phenylsulfonyl-DL-α-alaninate dianion; tsglyNO =N-p-tolylsulfonylglycinate dianion; bipy = 2,2′-bipyridine; bs-β-alaNO =N-phenylsulfonyl-β-alaninate dianion). Compound 1 crystallizes in the triclinic space group P with a= 13.457(3), b= 9.855(2), c= 10.739(2)Å, α= 104.0(1), β= 100.8(1), γ= 78.0(1)°, Z= 2. The Pd atom has a square-planar-environment, being trans co-ordinated by two centrosymmetrically related ts-α-alaNO dianions acting in a bidentate manner through one carboxylic oxygen and the deprotonated sulfonamide nitrogen. Compound 2 crystallizes in the monoclinic space group P2₁/c with a= 1 2.210(1), b= 6.897(3), c= 21.449(2)Å, β= 95.55(1)°, Z= 4. Compound 3 crystallizes in the monoclinic space group Pc, with a= 8.320(5), b= 14.403(3), c= 8.477(4)Å, β= 101.81 (4), Z= 2. Both complexes contain a Pd²⁺ ion co-ordinated to the N atoms of the bipy molecule and to the deprotonated sulfonamide nitrogen and one carboxylic oxygen of the amino acid molecule in a square-planar geometry. The amino acid dianion forms a five-membered glycine-like chelate ring in 1 and 2, and a six-membered ring in 3. Infrared data are also discussed and compared with those of the free ligands and the corresponding binary complexes.