Lewis-base adducts of group 1B metal(I) compounds. Part 12. Structural studies of some bis(methyl-substituted pyridine)-copper(I) and -silver(I) nitrates and perchlorates

Abstract

The crystal structure of a number of bis(monodentate pyridine base)-copper(I) and -silver(I) nitrate and perchlorate salts have been established at 295 K by single-crystal X-ray diffraction methods; the use of sterically hindered nitrogen bases enables the characterisation of these metal ions in a basically linear two-co-ordinate co-ordination environment. Crystals of bis(2,6-dimethylpyridine)copper(I) perchlorate, (1), are monoclinic, space group C2/c, with a= 15.175(6), b= 8.151(3), c= 13.227(10)Å, β= 99.26(4)°, Z= 4; R was 0.045 for N₀= 724 independent ‘observed’ reflections. The cation lies with the copper atom on a crystallographic inversion centre; Cu–N = 1.936(5)Å and N–Cu–N = 180 °. Crystals of bis (2,6-dimethylpyridine)copper(I) nitrate, (2), are monoclinic, space group P2₁/n, with a= 12.774(3), b= 14.252(4), c= 8.373(4)Å, β= 93.56(3)°, Z= 4; R= 0.051 for N₀= 1.203. Cu–N = 1.966(5), 1.956(5)Å and N–Cu–N = 165.9(2)°; there are close approaches to the copper atom from ‘bidentate’ nitrate oxygen atoms at 2.506(7), 2.518(7)Å. Crystals of bis(2,4-dimethylpyridine)copper(I) perchlorate, (3), are orthorhombic, space group Fdd2, with a= 29.69(1), b= 10.007(5), c= 11.285(4)Å, Z= 8; R= 0.060 for N₀= 291. The cation symmetry is 2 with Cu–N–N = 1.86(1)Å and N–Cu–N = 170(1)°. Crystals of bis(2,6-dimethylpyridine)silver(I) perchlorate, (4), are tetragonal, space group /4₁/acd, with a= 15.234(3)Å, c= 14.428(6)Å, Z= 8; R= 0.041 for N₀= 423. The cation symmetry is 2 with Ag–N = 2.166(4)Å and N–Ag–N = 180.0°. Bis(2,6-dimethylpyridine)silver(I) nitrate, (5), is isomorphous with the copper(I) analogue (2): a= 13.235(3), b= 14.280(3), c= 8.284(3)Å, β= 94.54(2)°; R= 0.037 for N₀= 1.288. Ag–N = 2.192(6), 2.182(6)Å, with N–Ag–N = 169.3(2)°; Ag–O(NO₃)= 2.715(8), 2.663(7)Å.