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Ladder‐type pentaphenyl chromophores have a rigid, planar π‐system and show bright fluorescence featuring pronounced vibrational structure. Such moieties are ideal for studying interchromophoric interactions and delocalization of electronic excitations. We report the synthesis of helical polymers with a rigid square structure based on spiro‐linked ladder‐type pentaphenyl units. The variation of circular dichroism with increasing chain length provides direct evidence for delocalization of electronic excitations over at least 10 monomeric units. The change in the degree of circular polarization of the fluorescence across the vibronic side bands shows that vibrational motion can localize the excitation dynamically to almost one single unit through breakdown of the Born‐Oppenheimer approximation. The dynamic conversion between delocalized and localized excited states provides a new paradigm for interpreting circular dichroism in helical polymers such as proteins and polynucleic acids. [ABSTRACT FROM AUTHOR]

Reactions of the borane carbonyl (CF3)3BCO with selected amines and phosphines are studied. The exclusive attack at the carbonyl C atom is remarkable, although ligand exchange under release of CO is thermodynamically favored, as predicted by density functional theory calculations.

Ring closing alkyne metathesis and alkyne cross metathesis were used to produce novel prostaglandins and analogues.

The synthesis of the cyclic prodigiosin derivative is presented. Results indicate that it constitutes a lead compound for the immunosuppressive agents development.

The single crystal structure determination of the low-temperature phase of unsubstituted cyclobutane is investigated. The statistically disordered model is deemed more reliable than the I2/m model. The disordered model is tested for the space groups I2 and Im, with the refinement concurring if the hydrogen atoms are maintained at sites obtained in I2/m and destabilizing if the hydrogen atoms are allowed to refine. Both models in the tested space groups exhibit the same molecular arrangement.

Square‐planar dinuclear nickel(II) complexes containing [S,N,O]2– ligands formed by condensation of acetyl acetone or benzoyl acetone with cysteamine were prepared. These dimeric nickel(II) compounds undergo bridge‐cleavage reactions with the cage phosphine PTA (PTA = 1,3,5‐triaza‐7‐phosphaadamantane) or in situ generated N‐heterocyclic carbenes. The resulting diamagnetic, square planar NiII complexes were characterized by spectroscopic methods and X‐ray diffraction. [ABSTRACT FROM AUTHOR]

Uniform and highly dispersed [gamma]-[Fe.sub.2][O.sub.3] nanoparticles supported on CMK-5 carbons and C/SBA-15 composites are prepared by simple impregnation and thermal treatment. [gamma]-[Fe.sub.2][O.sub.3] nanparticles are fully immobilized within the channels of the supports because of the confinement effect and they have showed the highest ammonia decomposition activity of Fe-based catalysts in the reaction.

The synthesis and characterization of the strong acid bis[bis(pentafluoroethyl)phosphinyl]imide and some of its salts [M.sup.+]N[[[([C.sub.2][F.sub.5]).sub.2]P(O)].sub.2.sup.-], M = H, Na, K, Cs, Ag, [Me.sub.5]N are presented. The results provide insights into the thermal and spectroscopic properties and single crystal structure.

The surface topology of well-known ordered mesoporous silica (SBA-15, MCM-41, and KIT-6) and a series of nanocast [Co.sub.3][O.sub.4], [Co.sub.3][O.sub.4]/Co[Fe.sub.2][O.sub.4] composites is studied by using high resolution scanning electron microscopy (HR-SEM). The low voltage HR-SEM technique with extremely high resolution has shown the influence of the template properties on the structure of the nanocast metal oxides.

A series of unprecedented organoiron complexes of the formal oxidation states -2, 0, +1, +2 and +3 is described, which are largely devoid of stabilizing ligands and in part, also electronically unsaturated (14-, 16-, 17- and 18-electron counts). These different manifolds are likely interconnected, an unambiguous decision as to which redox cycle dominates in solution remains difficult, even though iron complexes of the lowest accessible formal oxidation states promote the reactions most effectively.

The study about ferrocene which serves as a convenient and very cheap starting material for the preparation of a family of low valent ion olefin complexes of formal oxidation states -2, 0 and +1 is described. The catalysts ability to induce oxidative cyclization reaction is demonstrated by variety of cycloaddition and cycloisomerization reaction of the Alder-ene, [4+2], [5+2], and [2+2+2] type.

An alternative concept is described for uncoupling the electronic and structural parameters, which is obtained by embedding the N-heterocyclic carbenes (NHC) into a planar chiral cyclophane scaffold that has an effective electronic cross-talk between its layers. Preparative HPLC is used for obtaining the imidazolium salt in optically pure form.

Study presents a convenient one-step synthesis for [[Mn(CO6]sup.+]. This approach involves the one electron oxidation of Mn2(CO)10 by protons in solutions of Lewis acids (BF3, (CF3)3BC) and anhydrous HF.