极谱催化波法测定苯甲醛

在磷酸盐缓冲溶液中 ,苯甲醛与联氨反应生成的产物苯甲醛腙在K2 S2 O8存在时于 - 1.2 2V(vs.SCE)产生一灵敏的极谱催化波。基于此 ,拟定了测定痕量苯甲醛的新方法。在 8.0× 10 -2 mol/LKH2 PO4 NaOH(pH 8.0± 0 .2 ) 2 .5× 10 -2 mol/L联氨 - 3.5× 10 -2 mol/LK2 S2 O8底液中 ,极谱催化波峰电流与苯甲醛浓度在 1.0× 10 -9～ 6 .2× 10 -8mol/L范围内呈线性关系 ,比无K2 S2 O8存在时灵敏度提高约 6 0倍。本方法适用于生活污水中苯甲醛含量的测定     

中孔分子筛MSU及其杂原子衍生物的合成、表征和催化性能研究

以十八烷基聚氧乙烯基醚为模板剂,在ＳiＯ２的等电点（ＰＨ值为２）下,成功地合成了 具有ＭＳＵ结构的中孔ＳiＯ２分子筛及其Ｔｉ、Ｚｒ和Ｖ取代衍生物。用ＸＲＤ、Ｘ２吸 附／脱附、ＤＲＵＶ－Ｖｉｓ和元素分析等手段,对它们的孔道及骨架结构进行了全面表征。催化性能评价结果表明,在乙酸介质中,Ｔｉ、Ｚｒ和Ｖ等过渡金属原子取代的分子筛样品可以催化苯乙烯氧化为苯甲醛的反应,且活笥和选择性较高。     

Hydrothermal Preparation of a Series of Luminescent Cadmium(II) and Zinc(II) Coordination Complexes and Enhanced Real‐time Photo‐luminescent Sensing for Benzaldehyde

Two cadmium(II) and two zinc(II) coordination complexes with diverse structural motifs, [Cd₂(HL)I₃H₂O] · H₂O ( 1 ), [Cd₂(H₂L)₂(H₂O)₄] · 2SO₄ · 14H₂O ( 2 ), [Zn₃(L′)₂(H₂O)₆] · 4H₂O · 2(NO₃) ( 3 ), and [Zn₃L'₂(H₂O)₂Cl₂] · H₂O ( 4 ) [H₂L = 1,1‐bis(5‐(pyrid‐2‐yl)‐1,2,4‐triazol‐3‐yl)methane; H₂L′ = 1,1‐bis(5‐(pyrid‐2‐yl)‐1,2,4‐triazol‐3‐yl)methanone] were synthesized through a hydrothermal method. These coordination complexes were characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction (PXRD), FT‐IR spectroscopy, and photo‐luminescent experiments. Single crystal structural analysis revealed that 1 – 4 belong to polynuclear coordination compounds. PXRD analysis of 1 – 4 unambiguously confirmed the purity of the as‐synthesized coordination compounds. It is the first time to synthesize coordination compounds based on H₂L′, which reacted from the original material H₂L through in‐situ hydrothermal conditions. In addition, photo‐luminescent experiments revealed that 1 – 4 have real‐time sensing effects for benzaldehyde through fluorescence quenching. For 1 – 4 , the photo‐luminescent quenching effect for benzaldehyde was also compared and the coordination complexes 3 and 4 based on H₂L′ have higher photo‐luminescent quenching effect than compounds 1 and 2 .     

On the structure of guanylhydrazones derived from aromatic aldehydes

Summary The synthesis of some novel guanylhydrazones derived from aromatic aldehydes (benzylideneaminoguanidines) is described. Structural assignments of these compounds as well as of some already known congeners, particularly with respect to the configuration of the HC=N double bond, were achieved using¹H- and¹³C-NMR data as well as homonuclear NOE difference spectroscopy.

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Zur Struktur von Guanylhydrazonen aromatischer Aldehyde

Zusammenfassung Die Synthese einiger neuer Guanylhydrazone abgeleitet von aromatischen Aldehyden (Benzylidenaminoguanidine) wird beschrieben. Die Strukturzuordnung bei diesen Verbindungen sowie bei einigen literaturbeschriebenen Analoga — besonders im Hinblick auf die Konfiguration an der HC=N Doppelbindung — erfolgte mittels¹H- und¹³C-NMR Spektroskopie sowie mit Hilfe homonuklearer NOE-Differenzspektroskopie.

     

Stereoselective synthesis of novel benzoins catalysed by benzaldehyde lyase in a gel-stabilised two-phase system

Asymmetric benzoin condensation was performed using recombinant benzaldehyde lyase (BAL) from Pseudomonas fluorescens Biovar I. To enable the conversion of hydrophobic substrates, the enzyme was entrapped in polyvinyl alcohol and suspended in hexane. Compared to the reported application of the biocatalyst in an aqueous phase containing 20% DMSO, the productivity of the resulting gel-stabilised two-phase system was 3-fold better. The entrapment process had an efficiency of >90%, no enzyme or cofactor was lost during reaction or storage. The entrapped enzyme was stable in hexane for 1 week at 4 °C and more than 1 month at −20 °C. Without preceding optimisation the novel benzoins (R)-1,2-di(3-furanyl)-2-hydroxyethanone, (R)-2-hydroxy-1,2-di(3-thienyl) ethanone, (R)-1,2-di(4-ethoxyphenyl)-2-hydroxyethanone, (R)-1,2-di(3-ethoxyphenyl)-2-hydroxyethanone, (R)-2-hydroxy-1,2-di(3-tolyl)ethanone, and (R)-1,2-di(benzofuran-2-yl)-2-hydroxyethanone were prepared with yields up to 31.8% and enantiomeric excess >99%.     

Chiral Aryl Pyridyl Alcohols as Enantioselective Catalysts in the Addition of Diethylzinc to Substituted Benzaldehydes

Chiral (5‐aryl‐10, 10‐dimethyl‐6‐aza‐tricyclo[7.1.1.0^2,7]undeca‐2(7),3,5‐trien‐8‐yl)‐diphenyl‐methanols were prepared from highly enantiopure (1R)‐(+)‐α‐pinene (> 97% ee), and applied in the enantioselective addition of diethylzinc to substituted benzaldehydes, to yield alcohols with the (S)‐configuration with an enantiomeric excess that typically ranges from 19 to 86%. Importantly, the electron‐withdrawing substituents at the meta‐position of the substituted benzaldehydes exhibited high enantioselectivity during alkylation using diethylzinc.     

Synthesis of Isodrin Homologues with Parallel-Aligned Double Bonds

A formal synthesis of an alcohol 6 (X = OH) possessing three parallel-aligned double bonds was accomplished starting from 7 through thirteen steps in an optimal yield of 10%.     

First Total Synthesis of Mappain with a Prenylated and Geranylated Stilbene

The first total synthesis of naturally occurring mappain has been achieved by a convergent sequence. The key strategy involved in the synthesis of mappain was a (E)‐stilbene formation by Horner–Wadsworth–Emmons reaction of the corresponding prenylated benzaldehyde with a geranylated benzyl phosphonate.     

Synthesis and Characterizations of Ti(O‐i‐Pr)Cl3(THF)(PhCOR) (R = H,Me, Ph) and Ti(O‐i‐Pr)Cl3(PhCOR)2 (R = Me,Ph). The Molecular Structure of Ti(O‐i‐Pr)Cl3(PhCOPh)2

A series of titanium(IV) complexes Ti(O‐i‐Pr)Cl₃(THF)(PhCOR) (R = H ( 1 ), CH₃ ( 2 ), or Ph ( 3 )) is prepared quantitatively from reactions of [Ti(O‐i‐Pr)Cl₂(THF)(μ‐Cl)]₂ with 2 molar equiv. PhCOR. Treatment of Ti(O‐i‐Pr)Cl₃ with 2 molar equiv. of PhCOR affords the disubstituted complexes Ti(O‐i‐Pr)Cl₃(PhCOR)₂ (R = CH₃ ( 4 ) or Ph ( 5 )). The ¹³C NMR study of these complexes shows that the relative bonding abilities are in the order of PhCOCH₃ > PhCHO > PhCOPh. The molecular structure of 5 reveals that one of the benzophenone ligands is trans to the strongest 2‐propoxide ligand with a long Ti‐O(carbonyl) distance of 2.193(5) Å which is much longer than the other Ti‐O(carbonyl) distance of 2.097(4) Å by ?0.1 Å. All ligands cis to the alkoxide ligand are bending away from the alkoxide ligand with the RO‐Ti‐L angles ranging from 93.6(2) to 99.0(2)°.