The relationship between charge and structure in restacked MS2 (M = Mo, W) has been probed by cation encapsulation and chemical oxidation and characterized by elemental analysis, electron diffraction, X-ray diffraction, and Differential Scanning Calorimetry. Alkali cations have been encapsulated in MoS2 and WS2 without the presence of a co-intercalated counterion, suggesting a negative charge in the 0.15−0.25 electrons per M atom range. Electron diffraction studies show ordering of these cations between the layers. Chemical oxidation with I2 or Br2 results in a change in the structure of restacked MoS2, giving rise to a a × a superlattice, whereas no change is observed in the structure of restacked WS2. Differential Scanning Calorimetry studies show that the irreversible exothermic transition to 2H-MS2 shifts to lower temperature with oxidation. The observed structural distortion and residual negative charge uniquely explain the thermopower measurements, which indicate that restacked MoS2 and WS2 are p-type metallic conductors.

There has been a lot of confusion about the nature of restacked MoS2 and WS2. The structure has been proposed to be trigonal TiS2 type with octahedral M4+ and called 1T-MoS2. The presence of a distortion in the metal plane that gives rise to a superstructure has been suggested. We have performed electron crystallographic studies on small (submicron) single crystal domains of restacked WS2 and MoS2 to solve their superstructure. We find that what initially seems to be a trigonal crystal is actually a “triplet” of three individual orthorhombic crystals. Using two-dimensional hk0 data from films for both “triple” and “single” crystals we calculated corresponding Patterson projections, which reveal a severe distortion in the Mo/W plane, forming infinite zigzag chains. The projection of the structure suggests M−M distances of 2.92 and 2.74 Å for MoS2 and WS2, respectively. Least-squares refinement from the single-crystal data gives R 1 = 13.3% for WS2 and R 1 = 15.3% for MoS2. Therefore, we submit that restacked MoS2 and WS2 are not 1T form but rather WTe2 type.

A modified method for obtaining large quantities of exfoliated single layers of WS2 is reported. The restacked WS2 obtained from the precipitation of the single layers is metastable with respect to 2H-WS2 with an apparent activation energy of 82.4 kJ/mol, and a conversion temperature of 207 °C at 5 °C/min. Pressed pellets of restacked WS2 have electrical conductivity of ∼7 S/cm. The material exhibits Pauli paramagnetism.

It has been discovered that the use of excess zirconium in reactions with 4,4'-biphenyl and 4,4'-terphenylbis(phosphonic acid) in DMSO or DMSO-ethanol mixtures produces microporous inorganic-organic hybrids. Surface areas of 400 m(2)/g and pore sizes in the range of 10-20 A in diameter are routinely obtained. These materials are readily sulfonated with SO(3) under pressure to yield strong Bronsted acids. The acid strength, measured by (13)C NMR shifts of acetone and cyclopentanone in contact with the sulfonates, indicates an acidity close to that of 100% H(2)SO(4). Condensation and cracking reactions were obtained for both ketones under mild conditions. A working hypothesis is presented to account for the high surface area and microporosity. The combination of high surface areas and pore dimensions that are between those of zeolites and mesoporous silicas commends these materials for applications in separations, ion exchange, and catalysis.