Electronic and magnetic phenomena of inorganic and organic low-dimensional solids

This dissertation presents experimental results from the synthesis, structure determination, transport, and magnetic characterizations of two classes of low-dimensional solids. The first class of solids, one-dimensional manganese(III) quasi-linear-chain materials, and the second class of solids, conducting organic cation-radical salts are investigated. The magnetic properties of the S = 2 quasi-linear-chain Heisenberg antiferromagnetic system (2,2{dollar}spprime{dollar}-bipyridine)trichloromanganese(III), (MnCl{dollar}sb3{dollar}(bpy)) {dollar}sb{lcub}rm n{rcub}{dollar}, reveal the absence of long-range magnetic order down to 30 mK, with no magnetization observed until a critical magnetic field is achieved. These results are interpreted as the first evidence of Haldane gap in an S = 2 quasi-linear-chain antiferromagnet. The crystal structures of two Mn(III) complexes, (1,10-phenanthroline)trichloromanganese(III), (MnCl{dollar}sb3{dollar}(phen)) {dollar}sb{lcub}rm n{rcub}{dollar}, and (4,4{dollar}spprime{dollar}-dimethyl-2,2{dollar}spprime{dollar}-bipyridine)trichloromanganese(III) acetonitrile solvate, MnCl{dollar}sb3{dollar}(dmbpy){dollar}cdot{dollar}CH{dollar}sb3{dollar}CN, were determined by X-ray diffraction. The structure of (MnCl{dollar}sb3{dollar}(phen)) {dollar}sb{lcub}rm n{rcub}{dollar} contains quasi-linear-chains of Mn(III) ions bridged by chloride anions. From the magnetic susceptibility data, (MnCl{dollar}sb3{dollar}(phen)) {dollar}sb{lcub}rm n{rcub}{dollar} is identified as a one-dimensional Heisenberg "canted" antiferromagnet. The structure of MnCl{dollar}sb3{dollar}(dmbpy){dollar}cdot{dollar}CH{dollar}sb3{dollar}CN consists of five-coordinate Mn(III) monomers with the bidentate dmbpy ligand occupying both axial and equatorial positions.; Salts of the {dollar}pi{dollar}-donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) have been isolated with hydrogen dichloride (HCl{dollar}sb2sp-{dollar}) as the counterion. Two phases were obtained, {dollar}alphaspprime{dollar}-BEDT-TTF{dollar}sb2{dollar}(HCl{dollar}sb2{dollar}) and {dollar}varepsilon{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}) by electrocrystallization from solvent mixtures containing ClCH{dollar}sb2{dollar}COCl. {dollar}alphasp{lcub}prime{rcub}{dollar}-BEDT-TTF{dollar}sb2{dollar}(HCl{dollar}sb2{dollar}) contains sheets of twisted BEDT-TTF dimers, and conductivity and magnetic susceptibility are consistent with a description of nearly localized (BEDT-TTF){dollar}sb2sp+{dollar} radicals. {dollar}varepsilon{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}), space group C2/m, undergoes an anion ordering structural phase transition near 200 K, resulting in a new low temperature phase {dollar}varepsilonsp{lcub}prime{rcub}{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}) with space group {dollar}P2sb1/c.{dollar} Below 170 K, {dollar}varepsilonsp{lcub}prime{rcub}{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}) undergoes a paramagnetic to diamagnetic transition seen in EPR data. The HCl{dollar}sb2{dollar}- ion is linear in {dollar}alphasp{lcub}prime{rcub}{dollar}-BEDT-TTF{dollar}sb2{dollar}(HCl{dollar}sb2{dollar}) but bent in {dollar}varepsilon{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}) and {dollar}varepsilonsp{lcub}prime{rcub}{dollar}-BEDT-TTF(HCl{dollar}sb2{dollar}).; A new organic metal of the {dollar}pi{dollar}-donor bis(ethylenedioxy)tetrathiafulvalene, (BEDO-TTF){dollar}sb4{dollar} (C{dollar}sb4{dollar}N{dollar}sb6{dollar}) {dollar}cdot{dollar}H{dollar}sb2{dollar}O, has been isolated as the N,N{dollar}sp{lcub}prime{rcub}{dollar},N{dollar}sp{lcub}primeprime{rcub}{dollar}-tricyanoguanidinate monohydrate salt. The crystal structure indicates two-dimensional behavior in the BEDO-TTF donor layer demonstrated by the close intermolecular C-H{dollar}cdots{dollar}O, S{dollar}cdots{dollar}S, and S{dollar}cdots{dollar}O contacts. The N,N{dollar}sp{lcub}prime{rcub}{dollar},N{dollar}sp{lcub}primeprime{rcub}{dollar}-...