Crystal structure and mixed-valence state in 1′,1‴-dibutylbiferrocenium triiodide

In 1′, 1‴-dibutylbiferrocenium triiodide crystals A show temperature-independent trapped-valence state, while crystals B show a valence-delocalization of the mixed-valence state. The mixed-valence states of both crystals are discussed in relation to their crystal structures. Address after October 1991: Department of Chemistry, Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 724, Japan     

Synthesis of polyester dendrimers and dendrons starting from Michael reaction of acrylates with 3-hydroxyacetophenone

A new AB₂ type building block for synthesis of dendritic compounds is made starting from Michael addition of 2 equiv of 3-hydroxyacetophenone to acrylate, followed by decarboxylation and deprotection of either carboxyl or hydroxyl protecting groups. [G1]-[G4] dendrons and [G2] dendrimer were synthesized by the reiterative [hydrogenolysis then DCC/DPTS coupling] sequence using a combination of convergent and divergent growth methods.     

Real-time spectroscopy of Frenkel exciton system

We performed selective excitations of the first- and second-excited Frenkel exciton states (Q- and B-excitons) with use of sub-40-fs and sub-5-fs visible laser pulses. The transient absorption signals exhibit oscillatory features associated with molecular vibrations. From an analysis of the spectral profiles of the phase and amplitude of the oscillation, the experimental result is well explained by the modulated transition dipole moment, which is caused by the dynamic intensity borrowing from the intense B-transition to the weak Q-transition.     

Some results on odd factors of graphs

A {1, 3, …,2n ? 1}-factor of a graph G is defined to be a spanning subgraph of G, each degree of whose vertices is one of {1, 3, …, 2n ? 1}, where n is a positive integer. In this paper, we give a sufficient condition for a graph to have a {1, 3, …, 2n ? 1}-factor.     

Highly sensitive laser fluorimetry of europium(III) with1,1,1-trifluoro-4-(2-thienyl)-2,4-butanedione

The detection limit for tris(1,1,1-trifluoro-4-(2-thienyl)-2,4-butanediono)-europium(III) is established as 2 pg l^-1. A highly sensitive fluorimetric system consisting of a nitrogen laser and a pulse-gated photon counter is used.     

Construction of additional variables conforming to a common factor model

It is shown that if a random p-vector x conforms to an r-common factor model and an external variable Z is given, then there exists a family of linear combinations X of x and Z such that [x′: X]′ conforms to an r-common factor model