Stacking-induced diamagnetic/paramagnetic conversion of imidazo[1,2-a]pyridin-2(3 H)-one derivatives: near-infrared absorption and magnetic properties in the solid state.

Herein, we present three imidazo[1,2-a]pyridin-2(3 H)-one derivatives that are diamagnetic in solution, but paramagnetic in the solid state, possibly owing to a stacking-induced formation of phenoxide-type radicals. Notably, a larger bathochromic shift of the absorption (even up to the near- infrared region) of these three compounds was observed in the solid state than in solution, which was attributable to the ordered columnar stacking arrangements or their single-electron character as radicals in the solid state. Interestingly, compared to that in solution, (E)-3-(pyridin-4'-ylmethylene)imidazo[1,2-a]pyridine 2(3 H)-one displayed a largely red-shifted emission (centered at 660 nm, with tailing above 800 nm) in the solid state.

Isostructural metal-anion radical coordination polymers with tunable phosphorescent colors (deep blue, blue, yellow, and white) induced by terminal anions and metal cations.

Five phosphorescent metal-anion radical coordination polymers based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described. The N,O,N-tripodal anion radical ligand links metal cations, which leads to five isostructural coordination polymers, [M(3)(bipo(-.))(4)(L)(2)](n) (M=Cd or Mn, Hbipo(-.

Direct arylation of unactivated aromatic C-H bonds catalyzed by a stable organic radical.

A stable zwitterionic radical can catalyze direct arylation of unactivated aromatic C-H bonds via a chain homolytic aromatic substitution mechanism in the presence of potassium tert-butoxide.

New metal-anion radical framework materials: Co(II) compounds showing ferromagnetic to antiferromagnetic phase transition at about 344 K, and Zn(II) compounds exhibiting terminal anion ligand induced direct white-light-emission.

The preparation, X-ray crystallography, EPR, magnetic and luminescent investigation of new metal-anion radical framework materials based on a new anion radical ligand generated by in situ deprotonation of a stable zwitterionic radical are described herein. N,O,N-tripodal anion radical ligand (bipo(-)˙) links metal cations, giving rise to four isostructural one-dimensional metal-organic frameworks, [M(bipo(-)˙)(L)](n) [M = Zn, L = HCOO(-) (1), SCN(-) (1a), N(3)(-) (1b); M = Co, L = Br(-) (3)]. The tripodal bipo(-)˙ ligand and one co-ligand, 1,4-benzenedicarboxylate, coordinate to metals leading to two isostructural two-dimensional metal-organic frameworks, [M(bipo(-)˙)(BDC)(0.

New zwitterionic radical salts: dimers in solution and unusual magnetic and luminescent properties in the solid state.

A new and stable zwitterionic (neutral) radical and its perchlorate salts exist as diamagnetic pi-dimers in solution, and pi-stacking 1D chains with interesting magnetic and luminescent properties in solid state.

Free and conjugated phytosterols in cured tobacco leaves: influence of genotype, growing region, and stalk position.

Although phytosterols in tobacco leaves have specific effects on tobacco quality, there is little research on the distribution of free and conjugated phytosterols in various tobacco leaves. In this paper, we explored the content and composition of phytosterols in representative cured tobacco leaves by gas chromatography of TMS-ether derivatives. We found that phytosterol contents in tobacco leaves ranged from 1.

[Spectroscopic characterization of structure of cerium incorporated MCM-48 mesoporous molecular sieve].

Cerium incorporated MCM-48 molecular sieves have been hydrothermally synthesized using a mixed template and pH adjusting route. The samples were characterized by various physicochemical methods, including X-ray diffraction, diffuse reflectance UV-Vis spectroscopy, FTIR spectroscopy, XRF spectroscopy, and nitrogen adsorption. These results reveal that cerium is incorporated in MCM-48 and it is in the form of well-dispersed tetra-coodinated cerium ion.