metal-organic compounds
Solvothermal reactions of Cu2(OH)2CO3 with 1,3-bis(pyridin-4-yl)propane (bpp) in the presence of aqueous ammonia in 4-iodotoluene/CH3CN or 1,4-diiodobenzene/CH3CN afforded two [Cu2I2]-based coordination polymers, namely catena-poly[[[di--iodido-dicopper(I)]-bis[-1,3-bis(pyridin-4-yl)propane-2N:N']] p-toluidine tetrasolvate], {[Cu2I2(C13H14N2)2]·4C7H9N}n, (I), and the analogous 1,4-diiodobenzene monosolvate, {[Cu2I2(C13H14N2)2]·C6H4I2}n, (II). The [Cu2I2] unit of (I) lies on a centre of symmetry at the mid-point of the two I atoms, while that of (II) has a twofold axis running through the II line. In (I) and (II), each Cu centre is tetrahedrally coordinated by two -I and two N atoms from two different bpp ligands. Each rhomboid [Cu2I2] unit can be considered as a four-connecting node linked to the symmetry-related [Cu2I2] units via two pairs of bpp ligands to form a one-dimensional double chain along the c axis. The dimensions of the [Cu2I2(bpp)2]2 rings in (I) and (II) are different, which may be due to the presence of different guest solvent molecules in the structures. In (I), one p-toluidine molecule, derived from an Ullmann coupling reaction of 4-iodotoluene with ammonia, interacts with the [Cu2I2] cluster fragment through N-HI hydrogen bonds, while the two p-toluidine molecules interact via N-HN hydrogen bonds. In (II), two I atoms of each 1,4-diiodobenzene molecule are linked to the I atoms of the [Cu2I2] fragments from a neighbouring chain via II secondary interactions.
organic compounds
At ambient temperature, the title compound, C16H14O3, is triclinic, with the n-butyl side chain disordered in an out-of-plane orientation. On cooling below 240 K, it converts into a different triclinic phase with an ordered planar conformation and denser packing, which is retained on warming to room temperature. The transition (occasionally) proceeds from single crystal to single crystal.