catena-Poly[[[tetra-aqua-manganese(II)]-μ-4,4'-bipyridine] bis-(3-hydroxy-cinnamate) dihydrate].

The title compound, {[Mn(C(10)H(8)N(2))(H(2)O)(4)](C(9)H(7)O(3))(2)·2H(2)O}(n), was obtained by the hydro-thermal reaction of manganese chloride with mixed 3-hydroxy-lcinnamic acid (H(2)L) and 4,4'-bipyridine (4,4'-bipy) ligands. The structure contains [Mn(C(10)H(8)N(2))(H(2)O)(4)](2+) cations with the Mn(II) atoms lying on a centres of inversion and bridged into a linear chain along the a axis by 4,4'-bipy ligands, surrounded by HL(-) anions and uncoordinated water mol-ecules. Extensive O-H⋯O hydrogen-bonding and weak π-π inter-actions [centroid-centroid distance = 3.

[Study on the auxochrome of the electronic spectrum of organic compounds and its effect mechanism (II)].

The interaction between the p orbit of the auxochrome, the maximum bonding orbit (pi) and the minimum antibonding orbit (pi*) of the chromophore forms three new molecular orbit, among which the antibonding orbit (pi*') has the highest energy that is higher than those of the original pi*. The maximum occupied orbit (pi') will have energy lower or higher than those of pi according to different auxochrome and chromophore, and the energy of n orbit will remain steady, because the n orbit of the original chromophore is perpendicular to the p orbit of the auxochrome and the interaction is negligeable. As a result, the absorption wavelength of transition n-->pi* will shift towards higher photon energy, but for transition pi-->pi*, the absorption wavelength will shift towards either lower or higher photon energy, depending on the species of auxochrome and chromophore.

[Study on the auxochrome of the electronic spectrum of organic compounds and its effect mechanism (I)].

This paper discusses the effect mechanism of auxochrome of electronic spectrum. The study proves that the auxochrome does not invariably make the maximum absorption wavelength of chromophore shift towards lower photon energy. For the transition of n-->pi*, the p orbit of the auxochrome interacts with the minimum antibonding empty orbit(pi*), which will make the energy of pi* increase, while the p orbit of the auxochrome is perpendicular to the n orbit of chromophore, and the energy of the n orbit will remain steady ultimately, so the transition energy of n-->pi* will increase.