Coordination networks of C_3v and C_2v phenylacetylene nitriles and silver(I) salts: Interplay of ligand symmetry and molecular dipole moments in the solid state

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]·2C₆H ₆, 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]·1.75C₆H ₆, 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]·2C₆H ₆, 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]·2C₆H ₆, 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. 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. © 1999 American Chemical Society.