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

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) A, p = 99.26(4)", Z = 4; R was 0.045 for No = 724 independent 'observed' reflections. The cation lies with the copper atom on a crystallographic inversion centre; CU-N = 1.936(5) A and N-CU-N = 180". Crystals of bis(2,6-dimethylpyridine)copper(i) nitrate, (2), are monoclinic, space group P2,/n, with a = 12.774(3), b = 14.252(4), c = 8.373(4) A, p = 93.56(3)", 2 = 4; R = 0.051 for No = 1 203. Cu-N = 1.966(5), 1.956(5) A and N-CU-N = 165.9(2)"; there are close approaches to the copper atom from 'bidentate' nitrate oxygen atoms at 2.506(7), 2.51 8(7) A. 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) A, Z = 8; R = 0.060 for No = 291. The cation symmetry is 2 with CU-N = 1.86(1) A and N-CU-N = 170(1)". Crystals of bis(2,6-dimethylpyridine)silver(i) perchlorate, (4), are tetragonal, space group 14, /acd, with a = 15.234(3) A, c = 14.428(6) A, 2 = 8; R = 0.041 for No = 423. The cation symmetry is 2 with Ag-N = 2.1 66(4) A and N-Ag-N = 180.0". Bis(2,6-dimethylpyridine)silver(i) nitrate, (5), is isomorphous with the copper(t) analogue (2) : a = 13.235(3), b = 14.280(3), c = 8.284(3) A, p = 94.54(2)"; R = 0.037 for No = 1 288. Ag-N = 2.192(6), 2.182(6) A, with N-Ag-N = 169.3(2)"; AS-O(N03) = 2.715(8), 2.663(7) A.Full Tex