Coordination compounds of molybdenum

Molybdenum-Sulfur Bond: Electronic Structure of Low-Lying States of MoS

The molybdenum-sulfur bond plays an important role in many processes such as nitrogen-fixation, and it is found as a building block in layered materials such as MoS₂, known for its various shapes and morphologies. Here, we present an accurate theoretical and experimental investigation of the chemical bonding and the electronic structure of 20 low-lying states of the MoS molecule. Multireference and coupled cluster methodologies, namely, MRCISD, MRCISD + Q, RCCSD(T), and RCCSD[T], were employed in conjunction with basis sets up to aug-cc-pwCV5Z-PP/aug-cc-pwCV5Z for the study of these states. We note the significance of including the inner 4s²4p⁶ electrons of Mo and 2s²2p⁶ of S in the correlated space to obtain accurate results. Experimentally, the predissociation threshold of MoS was measured using resonant two-photon ionization spectroscopy, allowing for a precise measurement of the bond dissociation energy. Our extrapolated computational D₀ value for the ground state is 3.936 eV, in excellent agreement with our experimental measurement of 3.932 ± 0.004 eV. The largest calculated adiabatic D₀ (5.74 eV) and the largest dipole moment (6.50 D) were found for the ⁵Σ⁺ state, where a triple bond is formed. Finally, the connection of the chemical bonding of the isolated MoS species to the relevant solid, MoS₂, is emphasized. The low-lying septet states of the diatomic molecule are involved in the material as a building block, explaining the stability and the variety of the shapes and morphologies of the material.

Molybdate and the molecular properties of the vervet monkey estrogen receptor

The Vervet monkey (Cercopithecus aethiops pygerythrus) uterine estrogen receptor was partially characterised. The effect of the molybdate oxyanion on various molecular properties of the receptor was investigated. Molybdate appeared to affect the subunit structure and apparent heterogeneity of the receptor. Anion exchange chromatography of uterine cytosols yielded two ligand binding subunits in a 1:1 ratio in the absence of sodium molybdate, while only a single labelled complex could be demonstrated in cytosols prepared in molybdate containing buffers. Chromatofocussing of the nonstabilized cytosols revealed substantial receptor heterogeneity (7 peaks) while a much simpler pattern (2 peaks) could be observed in the presence of the molybdate. Likewise, iso-electric focussing of labelled cytosols on agarose gels yielded at least 3 high affinity binding components (pI:6.8, 6.2, 5.9) in the absence and only one major band in the presence of sodium molybdate (pI 5.9).