Synthesis,Structure, and Radical Anion of the First Stable p‐Phosphaquinone

Significant localization of the unpaired electron on the phosphorus atom of phosphasemiquinone radical anion 1 was revealed by EPR spectroscopy. This species was generated by reduction of 1 , the first stable p‐phosphaquinone. Employment of the 3,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐ylidene moiety was essential for the synthesis as well as the effective kinetic protection of 1 .     

一种苯并噻唑类稳定烯醇的合成及晶体结构

以2-甲基苯并噻唑和1,3-丙磺酸内酯为起始原料,合成了一种菁染料中间体2-(2-乙氧基-1-丁烯基)-1-(3-磺酸丙基)苯并噻唑(3).该染料中间体极易水解,对其水解产物(4e)采用红外光谱、核磁共振、质谱、元素分析和X射线单晶衍射分析等方法进行了表征.MS结果显示水解产物4e的分子量为327;在13C NMR谱图中,烯醇结构中与羟基相连的碳的化学位移为194.05,与之相连的另一个双键碳的化学位移为δ92.52;在IR谱图中,1618 cm-1处存在烯醇的特征吸收峰;通过X射线单晶衍射分析测定了水解产物的结构,进一步证实该水解产物是一种存在共轭芳基结构的稳定烯醇.     

First Synthesis and Structure of a Tetraazasilafenestrane

A shift from the computational to the synthetic side has taken place in the quest for compounds containing planar‐tetracoordinate silicon: The first tetraazasilaspiro[4.4]nonane with two alkylene bridges has been prepared [Eq. (1)]. According to the X‐ray structure analysis, the angle between the two diazasilacyclopentene rings is 84.7°. AIBN=azobisisobutyronitrile, X=Br.     

Synthesis and Structure of the First Terminal Borylene Complexes

A nearly linear arrangement is observed for the three atoms in the central W-B-N unit of the tungsten complex [(CO)₅WBN(SiMe₃)₂] ( 1 ) in the crystal (W-B-N 177.9°; see picture). This compound along with its Cr analogue represent the first examples of terminal borylene complexes with a two-coordinate metal-bound boron atom. The geometries of the axial and equatorial CO groups in 1 are similar, and thus indicate that there is no trans effect of the borylene ligand.     

Thermodynamically Stable o-Quinodimethane: Synthesis,Structure, and Reactivity

Thermal isomerization of cyclobutaphenanthrene to o-quinodimethane was investigated. Sterically congested substituents or electron-donating substituents on the four-membered ring promoted the ring-opening, affording o-quinodimethane in a relatively stable form. Isolation of the newly prepared o-quinodimethane allowed its structural elucidation and investigation of its potential reactivities. Dual [4+2] cycloaddition of an aryne and o-quinodimethane afforded tetrabenzopentacene, demonstrating the synthetic application of the isolated compound.     

Synthesis and Crystal Structure of the First Guanidinate Complex of Tetravalent Cerium

Reaction of Ce(O-t-Bu)2(NO3)2 and sodium guanidinate GuaNa (Gua-=TMS2NC(NC6H11)2-) in THF affords the first guanidinate Ce(IV) complex of Ce2(O-t-Bu)7(Guaˊ) (1, Gua-=(C6H11NH)C(NC6H 11)(NH)-). It crystallizes in monoclinic, space group P21/n with a=15.2937(14), b=17.8409(16), c=19.0454(16), β=97.713(2)°, V=5149.6(8)3 , Z=4, Mr=1014.38, Dc=1.308 g/cm3 , μ=1.787 mm-1 , F(000)=2104, S=1.015, R=0.0451 and wR=0.0901 (I > 2σ(I)). In the reaction the cleavage of TMS-N bonds happened unexpectedly.