Interception and Synthetic Application of Diradical and Diene Forms of Dual-Nature Azabicyclic o-Quinodimethanes Generated by 6π-Azaelectrocyclization.

We demonstrate that 2-alkenylarylaldimines and ketimines undergo thermal 6π-azaelectrocyclization to generate a wide range of azabicyclic o-quinodimethanes (o-QDMs). These o-QDMs exist as a hybrid of a diene and a benzylic diradical. The diradical nature was confirmed by their ability to undergo dimerization and react with H-atom donor, 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) and O.

Synthesis and crystal structures of two racemic 2-heteroaryl-3-phenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-ones.

3-Phenyl-2-(thio-phen-3-yl)-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-one (CHNOS, ) and 2-(1-indol-3-yl)-3-phenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-one 0.438-hydrate (CHNOS·0.438HO, ) crystallize in space groups 2/ and 2/, respectively.

Bis(tetra-butyl-ammonium) tetra-chlorido-manganate(II) di-chloro-methane disolvate.

The title compound, (CHN)[MnCl]·2CHCl, is an ionic organic-inorganic hybride compound consisting of a tetra-butyl-ammonium cation and a tetra-chlorido-manganate(II) anion in a 2:1 stoichiometric ratio. The cation contains a central nitro-gen atom bonded to four -butyl groups in a tetra-hedral arrangement, while the anion contains a central Mn atom tetra-hedrally coordinated by four chlorido ligands. It co-crystallized with two equivalents of di-chloro-methane solvent, CHCl, to give the following empirical formula: [(CH)N][MnCl]·(CHCl).

6,7-Diphenyl-5-thia-7-aza-spiro-[2.6]nonan-8-one 5,5-dioxide.

The racemic mixture of the title compound, CHNOS, crystallizes in space group with two homochiral mol-ecules in each asymmetric unit. The seven-membered ring in both mol-ecules is in a pucker-chair conformation. The extended structure exhibits C-H⋯O hydrogen bonds, of which two connect crystallographically independent mol-ecules to generate a chain propagating along the axis direction.

Crystal structures of the sulfones of 2,3-diphenyl-2,3-di-hydro-4-1,3-benzo-thia-zin-4-one and 2,3-diphenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-one.

The title sulfones, 2,3-diphenyl-2,3-di-hydro-4-1,3-benzo-thia-zine-1,1,4-trione, CHNOS, and 2,3-diphenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zine-1,1,4-trione, CHNOS, crystallize in space group 2/ with two mol-ecules in each of the asymmetric units and have almost identical unit cells and extended structures. In both structures, the thia-zine rings exhibit a screw-boat pucker. The inter-molecular inter-actions observed are C-H⋯O-type hydrogen bonds and parallel partial π-π stacking between the fused aromatic rings (benzo- or pyrido-) of the core of the mol-ecules within each asymmetric unit, and also connecting to mol-ecules with translational periodicity in the -axis direction in what can be described as columns (two per asymmetric unit) of stacked mol-ecules with alternating chirality.

Crystal structures of three newly synthesized flavanone hydrazones.

The crystal structures of racemic mixtures of three new flavanone-hydrazones in the centrosymmetric space group ( ), are reported. The structures of (±,)-'-[5,7-dihy-droxy-2-(4-hy-droxy-phen-yl)chroman-4-yl-idene]-2-(naphthalen-1-yl)acetohydrazide ethyl acetate monosolvate, CHNO·CHO, and of (±,)-'-[5,7-dihy-droxy-2-(4-hy-droxy-phen-yl)chroman-4-yl-idene]-4-hy-droxy-benzo-hydra-zide ethanol monosolvate, CHNO·CHOH, both exhibit an intra-molecular O-H⋯N and multiple inter-molecular O-H⋯O and C-H⋯O-type hydro-gen bonds. The third structure, that of (±,)-'-(6-methoxy-2-phenyl-chroman-4-yl-idene)-2-(naphthalen-1-yl-oxy)acetohydrazide, CHNO, has only one inter-molecular N-H⋯O-type hydrogen bond.

Crystal structures of -2,3-diphenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zine-1,1,4-trione and -[(2,5)-1,1,4-trioxo-2,3-diphenyl-1,3-thia-zinan-5-yl]acet-amide.

The syntheses and crystal structures of two thia-zinone compounds, namely, -2,3-diphenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zine-1,1,4-trione, CHNOS, in its racemic form, and -[(2,5)-1,1,4-trioxo-2,3-diphenyl-1,3-thia-zinan-5-yl]acet-amide, CHNOS, in an enanti-opure form, are reported. The thia-zine rings in the two structures differ in their puckering, as a half-chair in the first and a boat pucker in the second. The extended structures for both compounds have only C-H⋯O-type inter-actions between symmetry-related mol-ecules, and exhibit no π-π stacking inter-actions in spite of each having two phenyl rings.

Stabilization of Dinuclear Rhodium and Iridium Clusters on Layered Titanate and Niobate Supports.

Atomically dispersed organometallic clusters can provide well-defined nuclearity of active sites for both fundamental studies as well as new regimes of activity and selectivity in chemical transformations. More recently, dinuclear clusters adsorbed onto solid surfaces have shown novel catalytic properties resulting from the synergistic effect of two metal centers to anchor different reactant species. Difficulty in synthesizing, stabilizing, and characterizing isolated atoms and clusters without agglomeration challenges allocating catalytic performance to atomic structure.

Crystal structure of racemic (/,)-2-(4-hy-droxy-phen-yl)-4-(2-phenyl-hydrazin-1-yl-idene)chromane-5,7-diol ethanol monosolvate.

The crystal structure of racemic (/,)-2-(4-hy-droxy-phen-yl)-4-(2-phenyl-hydrazin-1-yl-idene)chromane-5,7-diol ethanol monosolvate, CHNO·CHO, in a centrosymmetric lattice is reported. The two racemates occupy the same position in the asymmetric unit - . Hydrogen bonds of the type O-H⋯C(π) in addition to typical C-H⋯O, O-H⋯O and O-H⋯N are identified.

Synthesis and crystal structure of racemic (*,*)-2,2'-(1,4-phenyl-ene)bis-(3-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one).

In the racemic title compound, CHNOS, one of the thia-zine rings shows a twisted boat conformation ( = 0.743 Å, θ = 92.1°) and the other a half-chair puckering ( = 0.

T3P-Promoted Synthesis of a Series of 2-Aryl-3-phenyl-2,3-dihydro-4-pyrido[3,2-][1,3]thiazin-4-ones and Their Activity against the Kinetoplastid Parasite .

A series of fourteen 2-aryl-3-phenyl-2,3-dihydro-4-pyrido[3,2-][1,3]thiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of -phenyl--aryl imines with thionicotinic acid, two difficult substrates. The reactions were operationally simple, did not require specialized equipment or anhydrous solvents, could be performed as either two or three component reactions, and gave moderate-good yields as high as 63%. This provides ready access to -phenyl compounds in this family, which have been generally difficult to prepare.

Maize unstable factor for orange1 is essential for endosperm development and carbohydrate accumulation.

Maize (Zea mays L.) Ufo1-1 is a spontaneous dominant mutation of the unstable factor for orange1 (ufo1). We recently cloned ufo1, which is a Poaceae-specific gene highly expressed during seed development in maize.

Hydrothermal Synthesis and Structure of a Dinuclear Molybdenum(III) Hydroxy Squarate with a Mo-Mo Bond.

The reaction of molybdenum(II) and chromium(II) acetates with squaric acid in degassed and deionized water under hydrothermal conditions at 150 °C is described. The products have been formulated as M(μ-OH)(μ-CO)(HO)·2HO, where M = Cr () and Mo (), based on combustion elemental analysis, infrared spectroscopy, magic angle spinning (MAS) solid-state carbon-13 nuclear magnetic resonance (NMR), and single-crystal X-ray diffraction. The edge-shared bioctahedral structures involve doubly bridging hydroxide ligands and μ-squarate ligands.

A General Strategy to Enhance Donor-Acceptor Molecules Using Solvent-Excluding Substituents.

While organic donor-acceptor (D-A) molecules are widely employed in multiple areas, the application of more D-A molecules could be limited because of an inherent polarity sensitivity that inhibits photochemical processes. Presented here is a facile chemical modification to attenuate solvent-dependent mechanisms of excited-state quenching through addition of a β-carbonyl-based polar substituent. The results reveal a mechanism wherein the β-carbonyl substituent creates a structural buffer between the donor and the surrounding solvent.

Crystal structures of two solvated 2-aryl-3-phenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-ones.

The synthesis and crystal structures of 2-(4-fluoro-phen-yl)-3-phenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-one toluene hemisolvate (), CHFNOS·0.5CH, and 2-(4-nitro-phen-yl)-3-phenyl-2,3-di-hydro-4-pyrido[3,2-][1,3]thia-zin-4-one iso-propanol 0.25-solvate 0.

Crystal structures of three hexakis-(fluoroar-yloxy)cyclo-triphosphazenes.

The syntheses and crystal structures of three cyclo-triphosphazenes, all with fluorinated ar-yloxy side groups that generate different steric characteristics, . hexa-kis-(penta-fluoro-phen-oxy)cyclo-triphosphazene, NP(OCF), , hexa-kis-[4-(tri-fluoro-methyl)-phen-oxy]cyclo-triphosphazene, NP[OCH(CF)], and hexa-kis-[3,5-bis(-tri-fluoro-methyl)-phen-oxy]cyclo-triphosphazene, NP[OCH(CF)] , are reported. Specifically, each phospho-rus atom bears either two penta-fluoro-phen-oxy, 4-tri-fluoro-methyl-phen-oxy, or 3,5-tri-fluoro-methyl-phen-oxy groups.

Crystal structures of two isomeric 2-aryl-3-phenyl-1,3-thia-zepan-4-ones.

The crystal of 6-(3-nitro-phen-yl)-7-phenyl-5-thia-7-aza-spiro-[2.6]nonan-8-one (), CHNOS, has monoclinic (2/) symmetry while that of its isomer 6-(4-nitro-phen-yl)-7-phenyl-5-thia-7-aza-spiro-[2.6]nonan-8-one (), has ortho-rhom-bic (2) symmetry: compound has two mol-ecules, and , in the asymmetric unit while has one.

Crystal structure of a 1:1 adduct of tri-phenyl-tin chloride with 3-cyclo-hexhyl-2-phenyl-1,3-thia-zolidin-4-one.

In the centrosymmetric (racemic) title compound, chlorido-(3-cyclo-hexhyl-2-phenyl-1,3-thia-zolidin-4-one-κ)tri-phenyl-tin(IV), [Sn(CH)Cl(CHNOS)], the tin(IV) atom exhibits a trigonal-bipyramidal coordination geometry with the three phenyl groups in equatorial positions and the chloride anion and ligand oxygen atom present at axial sites [O-Sn-Cl = 175.07 (14)°]. The thia-zolidinone ring of the ligand adopts an envelope conformation with the S atom as the flap.

Crystal structures of two 1,3-thia-zolidin-4-one derivatives featuring sulfide and sulfone functional groups.

The crystal structures of two closely related compounds, 1-cyclo-hexyl-2-(2-nitro-phen-yl)-1,3-thia-zolidin-4-one, CHNOS, and 1-cyclo-hexyl-2-(2-nitro-phen-yl)-1,3-thia-zolidin-4-one 1,1-dioxide, CHNOS, , are presented. These compounds are comprised of three types of rings: thia-zolidinone, nitrophenyl and cyclo-hexyl. In both structures, the rings are close to mutually perpendicular, with inter-planar dihedral angles greater than 80° in each case.

Crystal structure of -3,3'-(1,4-phenyl-ene)bis-(2-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one).

The crystal structure of the title compound - -CHNOS with two stereocenters - has half the mol-ecule in the asymmetric unit with the other half generated by a crystallographic center of inversion. The thia-zine ring is in a conformation that is between half-chair and envelope [θ = 52.51 (17)°].

Modulation of Fluorescent Protein Chromophores To Detect Protein Aggregation with Turn-On Fluorescence.

We present a fluorogenic method to visualize misfolding and aggregation of a specific protein-of-interest in live cells using structurally modulated fluorescent protein chromophores. Combining photophysical analysis, X-ray crystallography, and theoretical calculation, we show that fluorescence is triggered by inhibition of twisted-intramolecular charge transfer of these fluorophores in the rigid microenvironment of viscous solvent or protein aggregates. Bioorthogonal conjugation of the fluorophore to Halo-tag fused protein-of-interests allows for fluorogenic detection of both misfolded and aggregated species in live cells.

Spontaneous resolution and crystal structure of (2)-2-(3-nitro-phen-yl)-3-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one; crystal structure of -2-(4-nitro-phen-yl)-3-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one.

The crystal structures of isomeric -2-(4-nitro-phen-yl)-3-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one (CHNOS) () and (2)-2-(3-nitro-phen-yl)-3-phenyl-2,3,5,6-tetra-hydro-4-1,3-thia-zin-4-one (CHNOS) () are reported here. While crystallizes in a centrosymmetric space group, the crystal of chosen for data collection has mol-ecules only with (2) chirality. This is the result of spontaneous resolution during crystallization, as the synthesis produces a racemic mixture.

Crystal structures of two 2,3-diaryl-2,3-di-hydro-4-1,3-benzo-thia-zin-4-ones.

The syntheses and crystal structures of 2,3-bis-[3-(tri-fluoro-meth-yl)phen-yl]-2,3-di-hydro-4-1,3-benzo-thia-zin-4-one (di--CF; CHFNOS) () and 2,3-bis-(4-methyl-phen-yl)-2,3-di-hydro-4-1,3-benzo-thia-zin-4-one (di--CH; CHNOS) () are reported. Each structure is racemic: the asymmetric unit of consists of two mol-ecules. In both and , the six-membered 1,3-thia-zine ring is close to an envelope conformation with the chiral C atom forming the flap.

Crystal structure of (1,2,5)-5-acetyl-amino-4-oxo-2,3-diphenyl-1,3-thia-zinan-1-ium-1-olate.

The asymmetric unit of the enanti-omerically pure title compound, CHNOS, comprises two independent mol-ecules ( and ) having almost identical conformations. When overlayed, the alignment-r.m.

Crystal structure of 2,3-diphenyl-2,3-di-hydro-4-1,3-benzo-thia-zin-4-one 1-oxide.

In the racemic title compound, CHNOS, the planes of the two phenyl substituents form dihedral angles of 48.97 (15) and 69.26 (15)° with that of the fused benzene ring of the parent benzo-thia-zine ring, while the heterocyclic thia-zine ring exhibits a screw-boat pucker.