Pt-Sn脱氢催化剂浸渍状态的Sn-119和Pt-195的多核NMR研究

测定了Ｐｔ－Ｓｎ型催化剂浸渍状态下的Ｓｎ－１１９、Ｐｔ－１９５的多核核磁共振。当ＳｎＣｌ２／ＤＣｌ溶液体系中加入Ｈ２ＰｔＣｌ６以后，出现了Ｓｎ（Ⅳ）和另外一种Ｓｎ（Ⅱ）的构型，Ｓｎ－１１９峰向高场位移，说明部分Ｓｎ（Ⅱ）被氧化成Ｓｎ（Ⅳ），Ｈ２ＰｔＣｌ６的量对这种氧化性影响较小。而Ｈ２ＰｔＣｌ６／Ｄ２Ｏ溶液体系中加入ＳｎＣｌ２以后部分Ｐｔ（Ⅳ）被还原成Ｐｔ（Ⅱ），随着ＳｎＣｌ２量的增加，Ｐｔ（Ⅱ）     

Pt－Sn脱氢催化剂浸渍状态的Sn－119和Pt－195的多核NMR研究

测定了Ｐｔ－Ｓｎ型催化剂浸渍状态下的Ｓｎ－１１９、Ｐｔ－１９５的多核核磁共振。当ＳｎＣｌ２／ＤＣｌ溶液体系中加入Ｈ２ＰｔＣｌ６以后，出现了Ｓｎ（Ⅳ）和另外一种Ｓｎ（Ⅱ）的构型，Ｓｎ－１１９峰向高场位移，说明部分Ｓｎ（Ⅱ）被氧化成Ｓｎ（Ⅳ），Ｈ２ＰｔＣｌ６的量对这种氧化性影响较小。而Ｈ２ＰｔＣｌ６／Ｄ２Ｏ溶液体系中加入ＳｎＣｌ２以后部分Ｐｔ（Ⅳ）被还原成Ｐｔ（Ⅱ），随着ＳｎＣｌ２量的增加，Ｐｔ（Ⅱ）－１９５峰的强度逐渐增加而Ｐｔ（Ⅳ）－１９５峰逐渐减小。Ｐｔ（Ⅳ）－１９５较Ｐｔ（Ⅱ）－１９５峰向高场位移。在溶液状态下未发现Ｐｔ－Ｓｎ间的偶合分裂     

Enantioselective access to (−)-indolizidines 167B, 209D, 239AB, 195B and (−)-monomorine from a common chiral synthon

An enantioselective access to (?)-indolizidine alkaloids 167B, 209D, 239AB, 195B and (?)-monomorine from a new chiral synthon is described. The use of (S)-3-(Cbz-amino)-4-(tert-butyldimethylsilyloxy)butanal, obtained from l-aspartic acid, has provided efficient access of the indolizidine frame work through a Horner–Wadsworth–Emmons reaction and reductive cyclization as the key steps.     

大型仪器科学管理(192~195)超分辨荧光共聚焦显微技术进展、自主创新研发和开放共享使用现状

简要梳理了超分辨荧光共聚焦显微成像技术的发展历史.在此基础上, 重点总结了中国自主创新高分辨荧光共聚焦显微成像技术取得的突破, 特别是2006年以来, 中国科学院和北京大学成功研发了几款较为成熟的超分辨荧光共聚焦显微系统, 有力地推动了中国自主创新仪器研制的进展.最后, 在大型仪器设备开放共享评价考核数据分析的基础上, 着重分析了高校和科研院所激光共聚焦显微镜的开放共享使用情况.     

含氮配体铂配合物—宁辛铂的~1H~,~(13)C和~(195)PtNMR研究

本文测定了具有抗癌活性的含氮配体铂配合物——宁辛铂Pt(C_8H_(18)N_2)(CICH_2COO)_2的~1H,~(13)C及~(195)Pt NMR谱,用DEPT及选择去偶等技术对~1H,~(13)C谱线进行了归属,并用位移理论和经验规律对~(195)Pt NMR化学位移进行了初步探讨,从而进一步确证了该化合物双齿配位的平面正方形结构。     

Accurate prediction of 195Pt-NMR chemical shifts for hydrolysis products of [PtCl6]2− in acidic and alkaline aqueous solutions by non-relativistic DFT computational protocols

The ¹⁹⁵Pt-NMR chemical shifts of all possible hydrolysis products of [PtCl₆]^2? in acidic and alkaline aqueous solutions are calculated employing simple non-relativistic density functional theory computational protocols. Particularly, the GIAO-PBE0/SARC-ZORA(Pt) ∪ 6-31 + G(d)(E) computational protocol augmented with the universal continuum solvation model (SMD) performs the best for calculation of the ¹⁹⁵Pt-NMR chemical shifts of the Pt(IV) complexes existing in acidic and alkaline aqueous solutions of [PtCl₆]^2?. Excellent linear plots of δ_calcd(¹⁹⁵Pt) chemical shifts versus δ_exptl(¹⁹⁵Pt) chemical shifts and δ_calcd(¹⁹⁵Pt) versus the natural atomic charge Q_Pt are obtained. Very small changes in the Pt–Cl and Pt–O bond distances of the octahedral [PtCl₆]^2?, [Pt(OH)₆]^2?, and [Pt(OH₂)₆]⁴⁺ complexes have significant influence on the computed σ^{iso 195}Pt magnetic shielding tensor elements of the anionic [PtCl₆]^2? and the computed δ ¹⁹⁵Pt chemical shifts of [Pt(OH)₆]^2? and [Pt(OH₂)₆]⁴⁺. An increase of the Pt–Cl and Pt–O bond distances by 0.001 Å (1 mÅ) is accompanied by a downfield shift increment of 17.0, 19.4, and 37.6 ppm mÅ^?1, respectively. Counter-anion effects in the case of the highly positive charged complexes drastically improve the accuracy of the calculated ¹⁹⁵Pt chemical shifts providing values very close to the experimental ones.     

Unusual coupling constants n J(195Pt—1H) and Pt↼H—C interactions in new Schiff base complexes of N-alkyl-1-(ferrocen-1-yl)methanimine

A series of novel ferrocenylimine complexes of platinum(II) ethene of general formula trans-[PtCl₂( ²-C₂H₄) (imine)], imine = N-alkyl-1-(ferrocen-1-yl)methanimine, (alkyl = Me; i-Pr, i-Bu, s-Bu, t-Bu, ±CH(Me)Ph, CH₂Ph and Ph) have been prepared and characterized by elemental analysis, i.r, ¹H-, ¹³C-n.m.r. spectra (¹⁵N- and ¹⁹⁵Pt-n.m.r. in part). Unusual coupling constants ³ J(¹⁹⁵Pt—¹H), 92–98 Hz were observed between the imino proton H₆ and platinum(II) which are too large for three bond coupling constants, thereby suggesting a PtH—C interaction.     

Photodissociation Dynamics of Carbon Dioxide Cation via the Vibrationally Mediated Ã2Πu,1/2 State: A Time-Sliced Velocity-Mapped Ion Imaging Study

We report on the photodissociation dynamics of CO₂⁺ via its òΠ_u,1/2 state using the scheme of [1+1] photon excitation that is intermediated by the mode-selected òΠ_u,1/2( u1,u2,0) vibronic states. Photodissociation fragment exciation spectrum and images of photofragment CO⁺ have been measured to obtain reaction dynamics parameters such as the available energy and the average translational energy. Combining with the potential energy functions of CO₂⁺, the dissociation mechanism of CO₂⁺ is discussed. The conformational variation of CO₂⁺ from linear to bent on the photodissociation dynamics of CO₂⁺ is verified.     

Synthesis,structural and multinuclear natural abundance (<Superscript>13</Superscript>C, <Superscript>31</Superscript>P, <Superscript>195</Superscript>Pt) CP/MAS NMR studies of crystalline O,O′-dialkyldithiophosphate platinum(II) complexes

Platinum(II) O,O′-dicyclohexyl dithiophosphate [Pt{S₂P(O-cyclo-C₆H₁₁)₂}₂] (I) and platinum(II) O,O′-diisopropyl dithiophosphate [Pt{S₂P(O-iso-C₃H₇)₂}₂] (II) complexes were obtained and studied by solidstate ¹³C, ³¹P, and ¹⁹⁵Pt CP/MAS NMR spectroscopy. The dithiophosphate (Dtph) ligands in molecular structure I were found to be coordinated by platinum in S,S′-bidentate fashion to form the planar chromophore [PtS₄] (single-crystal X-ray diffraction data). For complex II, a new α-form (α-II) was obtained and identified by ³¹P MAS NMR spectroscopy. The ³¹P chemical shift anisotropy δ_aniso and the asymmetry parameter η of the ³¹P chemical shift tensor were calculated from the whole MAS spectra.     

Platinum(II) O,O′-diisobutyl dithiophosphate: Synthesis,structure, thermal properties,and solid-state <Superscript>13</Superscript>C, <Superscript>31</Superscript>P,and <Superscript>195</Superscript>Pt CP/MAS NMR spectra. Model of the structural state of platinum in cooperite

The complex bis(O,O′-diisobutyl dithiophosphato)platinum(II) (I) was obtained and characterized by solid-state ¹³C, ³¹P, and ¹⁹⁵Pt CP/MAS NMR spectroscopy. In complex I, the dithiophosphate fragments are structurally equivalent with a predominantly orthorhombic tensor of the ³¹P chemical shift (η = 0.73). The tensor of the ¹⁹⁵Pt chemical shift approximates to an axially symmetric one (for δ_zz> δ_xx and δ_yy), which suggests the existence of square chromophores [PtS₄], as in cooperite (natural PtS). The crystal and molecular structures of complex I were determined from X-ray diffraction data. The Pt atom coordinates two Dtph ligands in a S,S′-anisobidentate fashion (the Pt-S bonds are nonequivalent: 2.315 and 2.329 Å) to form two four-membered chelate rings [PtS₂P] with platinum as a spiro atom. The P-S bond length (1.997 and 1.986 Å), which is intermediate between the idealized lengths of the single and double phosphorus-sulfur bonds, suggests the delocalization of the π-electron density in the structural fragments PS₂. In complex I, the electron shielding of the platinum nucleus in the direction perpendicular to the plane of the chromophore [PtS₄] was found to be noticeably higher than that in cooperite. The thermal properties of complex I were examined by combined DSC-TG thermal analysis. The intermediate product of the thermolysis of complex I was platinum(II) dithiometaphosphate [Pt(S₂PO)₂] and the final thermolysis product was PtS.