Spectroscopic properties of morin in various CH3OH-H2O and CH3CN-H2O mixed solvents.

The specific fluorescence properties of morin (3,2',4',5,7-pentahydroxyflavone) were studied in various CH3OH-H2O and CH3CN-H2O mixed solvents. Although the dihedral angle is large in the S0 state, morin has an almost planar molecular structure in the S1 state owing to the very low rotational energy barrier around the interring bond between B and the A, C ring. The excited state intramolecular proton transfer (ESIPT) at the S1 state cannot occur immediately after excitation, S1 → S0 fluorescence can be observed.

Synthesis and characterization of carbazolide-based iridium PNP pincer complexes. Mechanistic and computational investigation of alkene hydrogenation: evidence for an Ir(III)/Ir(V)/Ir(III) catalytic cycle.

New carbazolide-based iridium pincer complexes ((carb)PNP)Ir(C2H4), 3a, and ((carb)PNP)Ir(H)2, 3b, have been prepared and characterized. The dihydride, 3b, reacts with ethylene to yield the cis-dihydride ethylene complex cis-((carb)PNP)Ir(C2H4)(H)2. Under ethylene this complex reacts slowly at 70 °C to yield ethane and the ethylene complex, 3a.

Monomeric, trimeric, and tetrameric transition metal complexes (Mn, Fe, Co) containing N,N-bis(2-pyridylmethyl)-2-aminoethanol/-ate: preparation, crystal structure, molecular magnetism and oxidation catalysis.

The reaction of N,N-bis(2-pyridylmethyl)-2-aminoethanol (bpaeOH), NaSCN/NaN(3), and metal (M) ions [M = Mn(II), Fe(II/III), Co(II)] in MeOH, leads to the isolation of a series of monomeric, trimeric, and tetrameric metal complexes, namely [Mn(bpaeOH)(NCS)(2)] (1), [Mn(bpaeO)(N(3))(2)] (2), [Fe(bpaeOH)(NCS)(2)] (3), [Fe(4)(bpaeO)(2)(CH(3)O)(2)(N(3))(8)] (4), [Co(bpaeOH)(NCS)(2)] (5), and [Co(3)(bpaeO)(2)(NO(3))(N(3))(4)](NO(3)) (6). These compounds have been investigated by single crystal X-ray diffractometry and magnetochemistry. In complex 1 the Mn(II) is bonded to one bpaeOH and two thiocyanate ions, while in complex 2 it is coordinated to a deprotonated bpaeO(-) and two azide ions.

A zigzag tetranuclear iron(III) complex, [Fe4(bpaeO)2(CH3O)2(N3)8] coexisting both ferromagnetic and antiferromagnetic couplings (bpaeOH = N,N-bis(2-pyridylmethyl)-2-aminoethanol).

A zigzag tetranuclear [Fe(4)(bpaeO)(2)(CH(3)O)(2)(N(3))(8)] possesses two different high-spin ferric sites and both ferromagnetic and antiferromagnetic interactions exist within the iron(III) ions.

trans-(1,8-Dibenzyl-1,3,6,8,10,13-hexa-azacyclo-tetra-deca-ne)diisonicotinatonickel(II).

In the centrosymmetric title compound, [Ni(C(6)H(4)NO(2))(2)(C(22)H(34)N(6))], the Ni(II) ion is bonded to the four secondary N atoms of the macrocyclic ligand in a square-planar fashion and two carboxyl-ate O atoms of the isonicotinate ions in axial positions, resulting in a tetra-gonally distorted octa-hedron. An offset face-to-face π-π stacking inter-action [centroid-centroid distance = 3.674(4) Å] and N-H⋯N and N-H⋯O hydrogen-bonding inter-actions give rise to a one-dimensional supra-molecular structure in the solid state.

Crystal structure of 6-oxa-3,9-dithiabicyclo[9.2.2]pentadeca-1(15),11,13-triene.

The structure of an S2O mixed-donor macrocycle incorporating para-substituted xylyl subunit was characterized by a single crystal X-ray analysis. The crystal structure shows an exo-dentate orientation of sulfur and oxygen donor atoms due to the fully stretched aliphatic ring conformation. Thus all of torsional angles between donor atoms are arranged anti and S.