A quadrupole–quadrupole stacking synthon in (2,3,5,6‐tetra­fluorobenzene­thiol­ato‐κS)(tri­phenylphosphine‐κP)­gold(I)

The title compound, [Au(C₆HF₄S)(C₁₈H₁₅P)], with both aromatic and fluorinated aromatic rings in its molecular system, shows dimerization through a quadrupole–quadrupole stacking synthon. The dimer further aggregates through intermolecular π–π stacking and C—H⋯π interactions, giving a supramolecular three‐dimensional network.     

A binuclear Fe(III)Dy(III) single molecule magnet. Quantum effects and models

The binuclear [FeIII(bpca)(mu-bpca)Dy(NO3)4], having Single Molecule Magnet (SMM) properties, belonging to a series of isostructural FeIIILnIII complexes (Ln = Eu, Gd, Tb, Dy, Ho) and closely related FeIILnIII chain structures, was characterized in concise experimental and theoretical respects. The low temperature magnetization data showed hysteresis and tunneling. The anomalous temperature dependence of M?ssbauer spectra is related to the onset of magnetic order, consistent with the magnetization relaxation time scale resulting from AC susceptibility measurements. The advanced ab initio calculations (CASSCF and spin-orbit) revealed the interplay of ligand field, spin-orbit, and exchange effects and probed the effective Ising nature of the lowest states, involved in the SMM and tunneling effects.     

Generating even triangulations on the torus

A triangulation on a surface $\mathbf{F}$ is a fixed embedding of a loopless graph on $\mathbf{F}$ with each face bounded by a cycle of length three. A triangulation is even if each vertex has even degree. We define two reductions for even triangulations on surfaces, called the 4-contraction and the twin-contraction. In this paper, we first determine the complete list of minimal 3-connected even triangulations on the torus with respect to these two reductions. Secondly, allowing a vertex of degree 2 and replacing the twin-contraction with another reduction, called the 2-contraction, we establish the list for all minimal even triangulations on the torus. We also describe several applications of the lists for solving problems on even triangulations.     

Highly selective one-pot synthesis of spirophosphoranes exhibiting reversed apicophilicity by oxidation of dianions generated from P-H spirophosphorane

[see reaction]. Mild and highly selective one-pot procedures for obtaining phosphoranes that exhibit reversed (O-cis) apicophilicity are described. On the basis of the procedures, O-cis phosphorane bearing an aryl group (R = 2,4,6-tri-i-propylphenyl) could be isolated for the first time; the procedure is also applicable for alkyl derivatives. Particularly effective was the use of I2 as an oxidizing reagent.     

Cycle reversals in oriented plane quadrangulations and orthogonal plane partitions

Aplane quadrangulation G is a simple plane graph such that each face ofG is quadrilateral. A (^*) -orientation D ^*(G) ofG is an orientation ofG such that the outdegree of each vertex on G is 1 and the outdegrees of other vertices are all 2, where G denotes the outer 4-cycle ofG. In this paper, we shall show that every plane quadrangulationG has at least one (^*)-orientation. We also show that any two (*)-orientations ofG can be transformed into one another by a sequence of 4-cycle reversals. Moreover, we apply this fact toorthogonal plane partitions, which are partitions of a square into rectangles by straight segments.A research fellow of the Japan Society for the Promotion of Science.     

Metal Isotope Effect on Metal-Ligand Vibrations

Exploitation of the isotope effect using heavy metal isotopes now makes it possible to give clear-cut assignments of the metal-ligand vibrations in the IR and Raman spectra of complex compounds. The results previously obtained with this new method and their current limitations form the subject of this progress report.     

Note on irreducible triangulations of surfaces

In this paper, we shall show that an irreducible triangulation of a closed surface F² has at most cg vertices, where g stands for a genus of F² and c a constant. © 1995, John Wiley & Sons, Inc.