Coordination networks of C3ν and C2ν phenylacetylene nitriles and silver(I) salts: Interplay of ligand symmetry and molecular dipole moments in the solid state

Abstract

Five organic ligands of C-3v and C-2v symmetry, 3,5-bis(4-cyanophenylethynyl)cyanobenzene (1), 3,5-bis(4-cyanophenylethynyl)-4-methoxycyanobenzene (2), and 4,4'-dicyanobenzophenone (3), cyanotris(4-cyanophenyl)methane (4), and tris(4-cyanophenyl)methanol (5), have been prepared, crystallized with silver(I) salts, and characterized by single-crystal X-ray study. Crystallographic data are as follows: [Ag . 1 . CF3SO3]. 2C(6)H(6), triclinic, P (1) over bar (no. 2), a = 10.0864(6) Angstrom, b = 13.6029(10) Angstrom, c = 13.8822(12) Angstrom, alpha = 108.743(6)degrees, beta = 95.063(6)degrees, gamma = 95.484(5)degrees, Z = 2; [Agb . 2 . CF3SO3]. 1.75C(6)H(6), triclinic, P (1) over bar (no. 2), a = 14.6273(14) Angstrom, b = 15.161(2) Angstrom, c = 17.010(2) Angstrom, alpha = 85.481(7)degrees, beta = 65.745(5)degrees, gamma = 80.283(9)degrees, Z = 4; [Ag . 3 . CF3SO3], triclinic, P (1) over bar (no. 2), a = 8.8148(8) Angstrom, b = 10,5031(6) Angstrom, c = 10.8323(11) Angstrom, alpha = 81.782(6)degrees, beta = 67.448(8)degrees, gamma = 66.501(5)degrees, Z = 2; [Ag . 4]BF4. 1.5C(6)H(6), monoclinic, C2/c (no. 15), a = 18.0187(4) Angstrom, b =14.9717(3) Angstrom, c = 23.5469(5) Angstrom, beta = 105.5641(8)degrees, Z = 8; [Ag . 5 . CF3SO3]. 2C(6)H(6), monoclinic, P2(1)/n (no. 14), a = 10.230(2) Angstrom, b = 11.839(2) Angstrom, c = 26.071(4) Angstrom, beta = 90.589(8)degrees, Z = 4; [Ag . 2 . CF3SO3]. 2C(6)H(6), triclinic, P (1) over bar (no. 2), a = 14.4951(2) Angstrom, b = 16.5954(1) Angstrom, c = 17.0387(1) Angstrom, alpha = 84.360(1)degrees, beta = 79.728(1)degrees, gamma = 73.118(1)degrees, Z = 4. The crystal structures are similar to those previously found for the T-d and D-3h phenyl nitriles with Ag(I) salts and can be related to the diamond and graphite topologies. However, due to the intrinsic symmetry of C-3v and C-2v ligands, permanent molecular dipole moments are always present. The stacking sequences found in three graphite-like structures are in an antiparallel fashion so that the net dipole moments of the crystals are zero. Similarly, the diamond-like structure is composed of two interpenetrating diamondoid nets oriented in such a way that the net dipole moment of the two nets combined is zero.