甲基丙烯酸三苯墓甲酯和甲基丙烯酸酯类的共聚物在溶液中的螺旋诱导和解旋作用

甲基丙烯酸三苯墓甲酯和甲基丙烯酸酯类的共聚物在溶液中的螺旋诱导和解旋作用陈传福，刘卫宏，陈永明，任长玉，习复（中国科学院化学研究所北京１０００８０）关键词甲基丙烯酸三苯基甲酯，甲基丙烯酸甲酯，光学活性，螺旋诱导，解旋在手性阴离子复合引发剂存在下，甲基...     

甲基丙烯酸三苯基甲酯与甲基丙烯酸甲酯光学活性共聚物的结构特征

采用１３Ｃ－ＮＭＲ，ＩＲ及ＷＡＸＳ表征了甲基丙烯酸三苯基甲酯（ＴｒＭＡ）与甲基丙烯酸甲酯（ＭＭＡ）光学活性共聚物结构．阐明了具有单向螺旋链的光学活性共聚物组成的非均一性及其光学活性随组成变化呈ｓ型曲线的特征．     

Structural,spectroscopic, molecular docking,thermal and DFT studies on metal complexes of bidentate orthoquinone ligand

4‐Triphenylmethyl‐1,2‐benzoquinone (TPMBQ) reacted with some metal ions and the structure of the new compounds had been identified. The metal to ligand ratio was 1:2 which was revealed by elemental analysis. The complexes were found to have octahedral geometry and their thermal stability was studied using thermogravimetric analysis technique. The molar conductance measurements revealed the electrolytic nature of the synthesized chelates. The IR spectra concluded the bidentate nature of the TPMBQ ligand while the ¹H NMR revealed the presence of water molecules. The XRD spectra of Mn (II) and Fe (III) complexes concluded their crystalline structure while Co (II) and Cu (II) chelates refer to amorphous structures. The geometries of the TPMBQ ligand were optimized using Gaussian 09 W; density functional theory B3LYP method. (DFT)/basis set 6–311++G (d, p). HOMO and LUMO energy values for chelates, chemical hardness and electro‐negativity had been calculated. The ligand and its metal complexes had been examined against different kinds of bacteria such as Proteus vulgaris, Escherichia coli, Staphylococcus aurous and Bacillus subtitles to examine their antimicrobial activity. Molecular docking using Auto Dock tools were utilized.     

Untersuchungen zur Bildung multifunktioneller 1,2‐Bis(tritylierter) Diphosphin‐Monoxide

Studies on the Formation of Multifunctional 1,2‐Bis(tritylated) Diphosphine Monoxides The products formed in the systems Ph₃CPH(:O) X /Ph₃CP( Y )Cl/NEt₃ with X = F, H, OH and Y = Cl, H, TMG (= N,N,N′,N′‐tetramethylguanidinyl) are discussed. In the case of the systems X =F/ Y =Cl, X =F/ Y =H, and X = Y =H the diphosphine monoxides 4 a , 5 a and 13 a were formed, while in the case of X =H/ Y =Cl, instead of the expected diphosphine monoxide 14 , a mixture of 13 a and of the POP compound 16 (molar ratio ca. 2 : 1) was observed. Treatment of 4 a with N,N,N′,N′‐tetramethylguanidine (= HTMG) led to the diphosphine monoxide, 7 a whereas its tautomer 7 b was formed, when Ph₃CP(TMG)Cl 6 reacted with Ph₃CPH(:O)F 1 . The conversion of one tautomer, 7 a or 7 b , into the other was not observed. On the other hand Cl₂P–PCPh₃(:O)F 8 a , formed as an intermediate in the reaction of 4 a with PCl₅, spontaneously rearranged to give Ph₃CPClF 9 and P(:O)Cl₃ as the final products. Surprisingly, oxidation of the σ³(P)‐atom in 4 a , 5 a and 13 a was impossible with H₂O₂ · (O:)C(NH₂)₂ as the oxidizing agent. The diphosphite 19 showed no rearrangement to the tautomeric diphosphine dioxide 18 , but oxidation to 20 was possible. All the products containing two asymmetrically substituted phosphorus atoms were obtained as diastereomeric mixtures of the meso and racemic form, as proved by ³¹P NMR spectroscopy.     

The Reaction of Triphenylmethyl-substituted Primary and Secondary Phosphines with Phosgene

The nature of the products from the reaction of TrtPH₂ ( 1 ) with an equimolar amount of phosgene strongly depends on the solvent. The initial intermediate 2 was isolated from toluene, but lost CO in dichloromethane, and HCl in diethyl ether, yielding TrtP(H)Cl ( 3 ), and (TrtPCO)₂ ( 4 b ), respectively. TrtP(H)Cl ( 3 ) was found to be a halophosphine of amazing stability. Treatment of 3 with excess phosgene led to partial substitution of the P-bonded proton for C(:O)Cl with formation of 5 , which did not eliminate CO to give TrtPCl₂. Substitution of chlorine in TrtP(H)Cl ( 3 ) for fluorine or bromine furnished the halophosphines, 6 and 7 . Minute quantities of the diphosphene 8 were formed upon treatment of 3 with NEt₃ or DBU. The course of the reaction between the secondary phosphines Trt(R)PH and phosgene depends on the group R. If R was t-Bu, formation of a mixture of Trt(t-Bu)PCl ( 10 ), and t-BuPCl₂ (resulting from partial cleavage of the P–C-bond) was observed. Although in the case of R = Ph, the intermediate 12 could be isolated, at elevated temperature HCl was eliminated from 12 , giving Trt(Ph)PCl ( 13 ). The diphosphine (TrtPH)₂ ( 14 ) is inert towards HCl-free phosgene. In the presence of HCl the P–P-bond in 14 was cleaved, and upon chlorination of the resulting TrtPH₂ ( 1 ) by phosgene, TrtP(H)Cl ( 3 ) was obtained as the only phosphorus-containing product.     

Atom transfer radical polymerization of styrene initiated by triphenylmethyl chloride

Triphenylmethyl chloride (TPMCl) was employed for the first time as the initiator of atom transfer radical polymerization (ATRP) of styrene in the presence of CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA) as catalyst and cyclohexanone as solvent. The kinetic plot was first-order with respect to monomer. A linear increase of number average molecular weight (M_n) vs. monomer conversion was observed, and the molecular weight distribution (MWD) was relatively narrow (M_w/M_n = 1.2-1.5). ¹H NMR spectra revealed the ω-Cl group at the chain end. Another two initiators, benzyl chloride (BzCl) and diphenylmethyl chloride (DPMCl), were also employed in contrast with triphenylmethyl chloride to investigate the influence of phenyl numbers on the polymerization.     

Aminolysis of allyl esters with bislithium aryl amides

The aminolysis of allyl esters with bislithium amides is reported. Tertiary aryl amides were synthesized in a one-pot reaction with bislithium amides and a suitable electrophile in good yields. The scope of this reaction was demonstrated with a variety of anilines and aminopyridines and applied to the synthesis of triphenylmethylacetamides.     

Air-Stable Trifluorophosphoranes: Preparation,X-Ray Crystal Structure Determinations,and Reactions

The trifluorophosphoranes TrtRPF₃ (R = tert.-Bu ( 1 ), Ph ( 2 ), NEt₂ ( 3 )) were obtained by the oxidative addition of TrtF (Trt = triphenylmethyl) to the difluorophosphines RPF₂. At room temperature only 1 exhibited dynamic behaviour in solution, but at –5 °C the pseudorotation was slow enough to permit the differentiation of ¹J(PF_ax) and ¹J(PF_eq) by ³¹P NMR spectroscopy. X-ray structure analyses of 1 , 2 , and 3 confirm the expected trigonal bipyramidal geometry at phosphorus, with axial fluorine substituents. The trifluorophosphoranes 1 – 3 are of such stability towards water that hydrolysis was effected only under vigorous, basic conditions. The action of HCl or HBr on Trt(NEt₂)PF₃ ( 3 ) led, in a complex reaction, to the formation of TrtPF₄ ( 5 ), besides 3 and PF₃. As first observed for 1 by NMR spectroscopy at elevated temperature, in the case of 1 and 2 an equilibrium exists between TrtRPF₃ and TrtF/RPF₂. Accordingly, it was possible to trap TrtF or RPF₂ by addition of I₂, PCl₃, AlCl₃, and tetrachloro-o-benzoquinone (TOB) to solutions of 1 or 2 . 3 was unreactive towards I₂ and PCl₃, whereas treatment with AlCl₃ caused formation of (Et₂N)PCl₂ by cleavage of the P–C bond, and halogen exchange. If a mixture of toluene and ether was used, LiAlH₄ reduced 1 and 2 to the corresponding secondary phosphines 8 and 9 , while if only diethyl ether was employed under the same conditions, P–C bond rupture occurred in 2 , and a mixture of PhPH₂ and TrtH was obtained.     

Unusual Stability despite a P‐bonded Proton: Phospha and Diphospha Ureas with the TrtP(H)‐Moiety

As the first diphospha‐urea with P‐bonded protons, [TrtP(H)]₂C=O ( 3 ) was found to be of amazing stability, which is thought to be due to the presence of the triphenylmethyl groups. Unlike known cyclic or non‐cyclic analogues, 3 showed next to no tendency to eliminate carbon monoxide. 3 was obtained by reaction of the dimeric phospha‐isocyanate (TrtPCO)₂ ( 1 ) with LiAlH₄, in which the intermediary phosphaalkene 2 was observed. Caused by its two asymmetric phosphorus atoms, 3 appeared as a mixture of two isomers, meso‐3 and rac‐3 (ratio: 20 : 1). Theoretical considerations, and the analysis of the proton‐coupled ³¹P NMR spectrum (spin system: AA′XX′), allowed the assignment of the signals to the two isomers. The action of anhydrous hydrogen chloride on 3 led to the cleavage of one P–C(:O)‐bond, and formation of an equimolar mixture of TrtPH₂ ( 5 ) and TrtP(H)C(:O)Cl ( 6 ). Cleavage of a P–C(:O)‐bond in 3 was also observed in its reaction with tetramethylguanidine (TMG) or ammonia. As proved by ³¹P NMR spectroscopy in the case of TMG, the reaction proceeded via the phosphaalkene intermediate 8 . Acting as nucleophiles, TMG and ammonia substituted TrtP(H) in 3 , and the P,N‐ureas 9 and 10 , with TrtPH₂ ( 5 ) as a side product, were obtained.     

Selective P–C-Bond Cleavage in P(III)-Triphenylmethyl Compounds

The phosphorus-carbon bond in various P-triphenylmethyl-substituted phosphorus compounds of simple as well as more complex structure can be cleaved selectively by treatment with Lewis acids, halogens (or halogen transfer agents), and hydrogen halides. The course of the reaction can be followed easily by NMR spectroscopy, in certain cases this P–C-bond cleavage can be used as a synthetic principle for phosphorus difluorohalides, F₂PHal (Hal = Cl, Br, F). In the presence of the appropiate structural elements, cleavage of P–P-bonds or rearrangements are observed.