New synthesis,x‐ray structural determination,conformational analysis and anomeric effect study of 3,7‐di (3‐nitrophenyl)‐1,5‐dioxa‐3,7‐diazacyclooctane

3,7‐Di(3‐nitrophenyl)‐1,5‐dioxa‐3,7‐diazacyclooctane was prepared from 3‐nitroaniline and formaldehyde in acetonitrile. Conformational behavior of ring inversion of the molecule was studied so it prefers a crown conformation. The evaluated ΔG^* was approximately 58.0 ± 1.0 kJ/mole. The X‐ray structure determination of the compound shows a crown conformation, in line with two‐anomeric effect in N‐C‐O moiety.     

(−)‐3,7‐Dioxo‐5β‐cholanic acid: dual hydrogen‐bonding modes in a diketonic bile‐acid derivative

The asymmetric unit of the title compound, C₂₄H₃₆O₄, contains three mol­ecules, all differing in their side‐chain conformations and all linked by hydrogen bonding confined entirely within a three‐mol­ecule block. One connection is of the acid‐to‐ketone type [O⋯O = 2.7055 (19) Å and O—H⋯O = 180°] and the other involves carboxyl pairing [O⋯O = 2.6485 (18) and 2.6598 (18) Å, and O—H⋯O = 168 and 174°]. Numerous inter­molecular C—H⋯O close contacts connect neighbouring mol­ecules.     

Syntheses and Optoelectronic Properties of Planar Compounds 3,7‐diaryl‐1,5,2,4,6,8‐dithiotetrazocine

Planar molecules 3,7‐diaryl‐1,5,2,4,6,8‐dithiotetrazocines would be potential acceptor materials of organic solar cell because of their containing SN units. One‐pot synthetic procedures of 3,7‐diaryl‐1,5,2,4,6,8‐dithiotetrazocine compounds are developed to improve their yields up to 2.1–5.9 times as much as those in literatures. The geometries of title compounds were optimized by the density functional theory calculations. Their optoelectronic properties were studied by ultraviolet and cyclic voltammetry spectra and fluorescence quenching experiments. The highest occupied and lowest unoccupied molecular orbital energy level values show that these compounds are suitable to be employed as acceptor materials for developing bulk heterojunction organic solar cells with high open circuit voltages. Emission fluorescence of poly(3‐hexylthiophene) at excited state in dichloromethane was quenched by addition of title compound. Therefore, these compounds used as acceptor materials could exhibit good mobility.     

Two new heterocyclic [3.3.3.01,5]‐propellanoid compounds: 2,8‐dioxatricyclo[3.3.3.01,5]undecane‐3,7‐dione and a related dimer

2,8‐Dioxatri­cyclo­[3.3.3.0^1,5]­un­decane‐3,7‐dione, C₉H₁₀O₄, (I), is the dilactone acylal of cyclo­pentanone‐2,2‐di­acetic acid. Both mol­ecules in the asymmetric unit have conformational chirality and differ principally in the flexing of the carbon ring, which produces a resolvable conformational disorder in one of the mol­ecules. Three intermolecular C—H⋯O close contacts exist. 7,7′‐Oxybis(2,8‐dioxatri­cyclo­[3.3.3.0^1,5]­undecan‐3‐one), C₁₈H₂₂O₇, (II), a racemate, lies on a C₂ axis and is a non‐meso furan­osyl furan­oside dimer derived from the monoacid mono­aldehyde corresponding to (I). One intermolecular C—H⋯O close contact exists. Diminished intramolecular void space in these small propellanoids generates unusually high crystal density in both species, particularly (I).     

The solid‐state 2:1 molecular complex of 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine with hydroquinone

The title compound, 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine–hydroquinone (2/1), 2C₁₁H₁₄N₄·C₆H₆O₂, crystallizes with the hydroquinone molecule located on a center of inversion. In contrast to other hydroquinone–adamanzane adducts, which form extended hydrogen‐bonded networks, in the present case, one hydroquinone molecule is linked to two 1,5:3,7‐dimethano‐1,3,5,7‐benzotetrazonine molecules, forming a 2:1 cluster through O—H...N hydrogen bonds.     

4‐Carboxyanilinium (2R,3R)‐tartrate and a redetermination of the α‐polymorph of 4‐aminobenzoic acid

In the title compounds, 4‐carboxyanilinium (2R,3R)‐tartrate, C₇H₈NO₂⁺·C₄H₅O₆⁻, (I), and 4‐aminobenzoic acid, C₇H₇NO₂, (II), the carboxyl planes of the 4‐carboxyanilinium cations/4‐aminobenzoic acid are twisted from the aromatic plane. In (I), the characteristic head‐to‐tail interactions are observed through the tartrate anions, forming two C₂²(7) chain motifs propagating parallel to the a and c axes of the unit cell. Also, the tartrate anions are connected through two primary C₁¹(6) and C₁¹(7) chain motifs, leading to a secondary R₄⁴(22) ring motif. In (II), head‐to‐tail interaction is seen through a discrete D₁¹(2) motif and carboxyl group dimerization is observed through centrosymmetrically related R₂²(8) motifs around the inversion centres of the unit cell. The crystal structures of both compounds are stabilized by intricate three‐dimensional hydrogen‐bonding networks. Alternate hydrophobic and hydrophilic layers are observed in (I) as a result of a column‐like arrangement of the anions and the aromatic rings of the cations.     

4‐Phenyl‐1H‐imidazole (a low‐temperature redetermination), 1‐benzyl‐1H‐imidazole and 1‐mesityl‐1H‐imidazole

Low‐temperature studies of the simple variously substituted imidazole types 4‐phenyl‐1H‐imidazole, C₉H₈N₂, 1‐benzyl‐1H‐imidazole, C₁₀H₁₀N₂, and 1‐mesityl‐1H‐imidazole, C₁₂H₁₄N₂, extend comparisons between parent imidazole species and their derivatives, the pronounced double‐bond localization opposite the substituted N atom common to simple neutral species being redistributed aromatically on protonation.     

Synthesis of 7‐acetyloxy‐3,7‐dimethy1‐7,8‐dihydro‐6H‐isochromene‐6,8‐dione and its analogues

7‐Alkanoyloxy‐3,7‐dimefhyl‐7,8‐dihydro‐6H‐isochromene‐6,8‐diones 12‐15 were synthesized in 69‐16% yields from the reaction of 2,4‐dihydroxy‐3‐methyl‐6‐(2‐oxopropyl)benzaldehyde 11 with p‐toluenesulfonic acid in various carboxylic acids such as acetic acid, propionic acid, butyric acid and heptanoic acid followed by oxidation with lead tetraacetate. On the other hand, (±)‐daldinin A 5 (oleate) was not obtained using oleic acid as a medium. In the cases of heptanoic acid and oleic acid, esters 16 and 17 were produced in 23 and 9% yields, respectively. 6,8‐Dihydroxy‐3,7‐dimethyl‐2‐benzopyrylium p‐toluenesulfonate 31 is considered as the intermediate for the production of 12‐15. Overall yields of isochromenes 12‐15 were 26‐6% starting from 2‐methylresorcinol for seven steps.     

The synthesis and crystal structure of 2,6,9‐trimethyl‐4,8‐dinitro‐2,6,9‐triazabicyclo[3.3.1]nona‐3,7‐diene

The first preparation of title compound 1 is accomplished. Its heterocyclic structure was characterized spectroscopically and by X‐ray structure analysis.     

Synthesis,Molecular Structure and Coordination Chemistry of the First 1‐Aza‐3,7‐diphosphacyclooctanes

The first representatives of a novel type of cyclic bis‐phosphines, namely, 1‐aza‐3,7‐diphosphacyclooctanes ( 4 , 5 ), were synthesized by condensation of 1,3‐bis(arylphosphino)propanes ( 2 , 3 ; aryl = phenyl or mesityl), formaldehyde and 5‐aminoisophthalic acid. Only the meso isomers were obtained, in good to satisfactory yield. The cyclic bis‐phosphines readily form P,P chelate complexes ( 6 , 7 ) with [PtCl₂(cod)] (cod = 1,5‐cyclooctadiene). The bisphosphine 4 and the corresponding complex 6 are soluble in water in the presence of two equivalents of alkali metal hydroxide. The molecular structures of 1‐(meta‐dicarboxyphenyl)‐3,7‐dimesityl‐1‐aza‐3,7‐diphosphacyclooctanes ( 5 ) and cis‐{P,P‐1‐(meta‐dicarboxyphenyl)‐3,7‐diphenyl‐1‐aza‐3,7‐diphosphacyclooctane}dichloroplatinum(II) ( 6 ) are reported.     

Spectroscopic Studies on the Binding of Kaempferol‐3,7‐α‐L‐rhamnopyranoside to Bovine Serum Albumin

The binding of kaempferol‐3,7‐α‐L‐rhamnopyranoside (KRR) with bovine serum albumin (BSA) was investigated by different spectroscopic methods under simulative physiological conditions. Analysis of ?uorescence quenching data of BSA by KRR at different temperatures using Stern‐Volmer methods revealed the formation of a ground state KRR‐BSA complex with moderate binding constant of the order 10⁴ L·mol^?1. The existence of some metal ions could weaken the binding of KRR on BSA. The changes in the van't Hoff enthalpy (ΔH⁰) and entropy (ΔS⁰) of the interaction were estimated to be ?26.53 kJ·mol^?1 and 3.33 J·mol^?1·K^?1 and both hydrophobic and electrostatic forces contributed to stabilizing the BSA‐KRR complex. According to the F?ster theory of non‐radiation energy transfer, the distance r between the donor (BSA) and the acceptor (KRR) was obtained (r=2.83 nm). Site marker competitive experiments showed that KRR could bind to Site I of BSA. In addition, synchronous fluorescence, UV‐Vis absorption and circular dichroism (CD) results indicated that the KRR binding could cause conformational changes of BSA.     

Synthesis of some novel 3,7‐dimethyl‐4H‐pyrazolo[5,1‐c][1,2,4]triazin‐4‐ones

Some novel 3,7‐dimethyl‐6H‐pyrazolo[5,1‐c][1,2,4]triazin‐4‐ones were prepared (3a‐g) . Compounds 3a,b were treated with hydrazines to afford various products 7a,b, 8a,b, 9 and lla,b depending on the type of hydrazine derivative and reaction conditions. The benzoyloxyimino‐pyrazolo[5,1‐c][1,2,4]triazines (13a,b) were synthesized by refluxing of compounds 3a,b with hydroxylamine hydrochloride to afford the corresponding oxime derivatives followed by treatment with benzoyl chloride.     

Three‐Component Reaction for Construction of Spiro[indoline‐3,7′‐thiazolo[3,2‐a]pyridines] and Spiro[benzo[4,5]thiazolo[3,2‐a]pyridine‐3,3′‐indolines]

The three‐component reaction of thiazole (benzothiazole), dialkyl but‐2‐ynedioate, and isatinylidene malononitriles in toluene at 110–120°C in a sealed tube afforded a mixture of cis/trans‐isomers of functionalized diastereoisomeric spiro[indoline‐3,7′‐thiazolo[3,2‐a]pyridines] and spiro[benzo[4,5]thiazolo[3,2‐a]pyridine‐3,3′‐indolines] in good yields. Both cis‐isomers and trans‐isomers were successfully separated out and fully characterized with spectroscopy and single crystal determination. Under similar conditions, the three‐component reaction containing 2‐(1,3‐dioxo‐1H‐inden‐2(3H)‐ylidene)malononitrile resulted in spiro[indene‐2,7′‐thiazolo[3,2‐a]pyridine] derivatives.     

Pyridyl Containing 1,5‐Diaza‐3,7‐diphosphacyclooctanes as Bridging Ligands for Dinuclear Copper(I) Complexes

1,5‐bis(R)‐3,7‐bis[2‐(pyridine‐2′‐yl)ethyl)‐1,5‐diaza‐3,7‐diphosphacyclooctanes 1 and 2 and their copper(I) complexes 3 and 4 were developed. The butterfly‐shaped copper‐iodide core and unusual P,N‐chelate and P,P‐bridged coordination mode of the heterocyclic ligand in the dinuclear complexes 3 and 4 were revealed. Complexes 3 and 4 display emission in green range of spectra, with lifetimes in a microsecond domain and quantum yields of luminescence in solid‐state up to 38 %. Thermochromic effects found for the phosphorescence of 4 in solutions are ascribed to rigidochromism.     

μ‐Cyano‐1:2κ2C:N‐tetracyano‐1κ4C‐(5‐methyl‐5‐nitro‐3,7‐diazanonane‐1,9‐diamine‐2κ4N1,3,7,9)‐nitrosyl‐1κN‐copper(II)iron(II) dihydrate

The title binuclear complex, [CuFe(CN)₅(C₈H₂₁N₅O₂)(NO)]·2H₂O or [CuFe(nelin)(CN)₅(NO)]·2H₂O (nelin is 5‐methyl‐5‐nitro‐3,7‐di­aza­nonane‐1,9‐di­amine) consists of discrete binuclear mixed‐metal species, with a Cu centre linked to an Fe centre through a cyano bridge, and two water mol­ecules of crystallization. In the complex, the Cu^II ion is coordinated by five N atoms and has a distorted square‐pyramidal geometry. The Fe^II centre is in a distorted octahedral environment.