The crystal structure of silver(I) 2-hydroxybenzoate and silver(I) 2,6-dihydroxybenzoate

The crystal structures of silver(I) 2-hydroxybenzoate, (1), and silver(I) 2,6-dihydroxybenzoate, (2), have been determined by X-ray diffraction and refined to residuals of 0.027 and 0.043 for 1183 and 1573 observed reflections respectively. Both form crystals which are monoclinic with 2 centrosymmetric dimers in cells with dimensions a = 7.405(1), b = 8.826(2), c = 10.683(2) Â, β = 107.48(4)°, space group Pljc (1) and a = 7.322(1), b = 10.307(2), c = 9.701(2), 0=111.98(2)°, space group P2Jn (2). The complexes are dimeric with similar Ag—Ag, Ag—O distances and O— A g O angles [2.861(1), 2.181(4), 2.202(4) Â, 159.5(2)°, (1) and 2.910(1), 2.203(4), 2.240(4) A, 160.6(1)° (2)]. Introduction Dimeric silver(I) carboxylates have been categorised into four distinct types (Mak et al., 1986). The Type 1 complexes, which are essentially * Author to whom correspondence should be addressed. 2 7 6 Graham Smith, Colin H. L. Kennard and Thomas C. W. Mak unassociated in the solid state, have formula Ag2L2 and are typified by the examples silver(I) benzoate, silver(I) 4-hydroxybenzoate hemihydrate (Usubaliev et al., 1981) and silver(I) (2,3,4,5,6-pentafluorophenoxy)-acetate (Mak et al., 1988). These complexes are either centrosymmetric or pseudocentrosymmetric with relatively similar structural features (Ag—Ag range, 2.90-2.92 Â; A g O range 2.21 -2 .24 Â). In the case of silver(I) 4-hydroxybenzoate, introduction of the hydroxy group in the benzene ring results in the inclusion of a hydrogen bonded lattice water into the structure. In only one example [silver(I) (4-chloro-2-methyl-phenoxy)acetate] has a non-dimer structure been observed for a silver(I) carboxylate. Smith et al., 1987). It was therefore considered important to determine the structures of the silver® complexes with 2-hydroxybenzoic acid and 2,6-dihydroxybenzoic acid, to observe the influence of the more associative hydroxyl substituents on the type of dimer formed (Charbonnier et al., 1981).