Coordination Networks of<i>C</i>₃<i>_v</i>and<i>C</i>₂<i>_v</i>Phenylacetylene Nitriles and Silver(I) Salts: Interplay of Ligand Symmetry and Molecular Dipole Moments in the Solid State

Abstract

Five organic ligands of C3v and C2v 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]·2C6H6, triclinic, P1̄ (no. 2), a = 10.0864(6) Å, b = 13.6029(10) Å, c = 13.8822(12) Å, α = 108.743(6)°, β = 95.063(6)°, γ = 95.484(5)°, Z = 2; [Ag·2·CF3SO3]·1.75C6H6, triclinic, P1̄ (no. 2), a = 14.6273(14) Å, b = 15.161(2) Å, c = 17.010(2) Å, α = 85.481(7)°, β = 65.745(5)°, γ = 80.283(9)°, Z = 4; [Ag·3·CF3SO3], triclinic, P1̄ (no. 2), a = 8.8148(8) Å, b = 10.5031(6) Å, c = 10.8323(11) Å, α = 81.782(6)°, β = 67.448(8)°, γ = 66.501(5)°, Z = 2; [Ag·4]BF4·1.5C6H6, monoclinic, C2/c (no. 15), a = 18.0187(4) Å, b = 14.9717(3) Å, c = 23.5469(5) Å, β = 105.5641(8)°, Z = 8; [Ag·5·CF3SO3]·2C6H6, monoclinic, P21/n (no. 14), a = 10.230(2) Å, b = 11.839(2) Å, c = 26.071(4) Å, β = 90.589(8)°, Z = 4; [Ag·2·CF3SO3]·2C6H6, triclinic, P1̄ (no. 2), a = 14.4951(2) Å, b = 16.5954(1) Å, c = 17.0387(1) Å, α = 84.360(1)°, β = 79.728(1)°, γ = 73.118(1)°, Z = 4. Τhe crystal structures are similar to those previously found for the Td and D3h phenyl nitriles with Ag(I) salts and can be related to the diamond and graphite topologies. However, due to the intrinsic symmetry of C3v and C2v 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.