Preparation and physical properties of molecular materials based on metalloporphyrazines (M = cobalt, nickel, copper, zinc) and paddlewheel complexes (M = molybdenum, tungsten, ruthenium)

Two classes of molecular materials, the octa(n-alkylthio)metalloporphyrazines (M = Co, Ni, Cu, Zn) and a series of monomeric, dimeric, and oligomeric paddlewheel complexes have been prepared and their physical properties interrogated.; The metalloporphyrazine materials exhibit hexagonal columnar liquid crystalline phases. Their response to applied magnetic fields has been investigated by neutron scattering and NMR spectroscopy. The supramolecular columns of the derivatives with M = Co, Ni, Zn orient with their directors perpendicular to the applied magnetic field, and with the porphyrazine disks exhibiting tilt angles of 27° with respect to the columnar directors. The ease of alignment is metal-dependent, following the trend Co > Ni ∼ Zn > Cu. These observations are accounted for on the basis of the molecular paramagnetic and diamagnetic moments. Uniaxial alignment has been achieved by rotating the magnetic field vector. Aspects of the rheology and electrical resistivity of these materials are also described.; The electronic and vibrational spectroscopy and electrochemical properties of MM'(O2CBut)4 (M, M' = Mo, W) and their radical cations are discussed and compared with recent theoretical predictions. The single electron of MoW '(O2CBut)4+ resides in a polarized MM delta orbital having 70% Mo and 30% W character. Measurements of the third-order nonlinear optical responses of solutions of homodimetallic (M = Mo, W) complexes, using picosecond degenerate four-wave mixing at 1064 nm, are also described. These complexes exhibit only very small instantaneous electronic polarizations when excited with cross-polarized beams.; Dimers of these paddlewheel complexes may be formed with a variety of dicarboxylate bridging ligands. Electron paramagnetic resonance, electronic absorption, and resonance Raman spectroscopy reveal that in the oxalate-bridged compounds, [{lcub}(M2(O2CBut)3{rcub} 2(mu-O2CCO2)]+[PF6] - (M = MO, W), the unpaired electron is delocalized over four metals centers as a result of M2 delta to bridge pi conjugation, but in the related cationic perfluoroterephthalate-bridged species, the tungsten complex is delocalized and the molybdenum analogue valence trapped. The electronics of some related complexes and the formation of extended structures are also described.