From Disilene (SiSi) to Phosphasilene (SiP) and Phosphacumulene (PCN)

The generation of heavier double‐bond systems without by‐ or side‐product formation is of considerable importance for their application in synthesis. Peripheral functional groups in such alkene homologues are promising in this regard owing to their inherent mobility. Depending on the steric demand of the N‐alkyl substituent R, the reaction of disilenide Ar₂Si?Si(Ar)Li (Ar=2,4,6‐iPr₃C₆H₂) with ClP(NR₂)₂ either affords the phosphinodisilene Ar₂Si?Si(Ar)P(NR₂)₂ (for R=iPr) or P‐amino functionalized phosphasilenes Ar₂(R₂N)Si? Si(Ar)?P(NR₂) (for R=Et, Me) by 1,3‐migration of one of the amino groups. In case of R=Me, upon addition of one equivalent of tert‐butylisonitrile a second amino group shift occurs to yield the 1‐aza‐3‐phosphaallene Ar₂(R₂N)Si? Si(NR₂)(Ar)? P?C?NtBu with pronounced ylidic character. All new compounds were fully characterized by multinuclear NMR spectroscopy as well as single‐crystal X‐ray diffraction and DFT calculations in selected cases.     

Ce(C_8H_8)_2和Ce(C_8H_8)_2~-的化学键性质

结合改进的重叠模型Xa-SW法和Ziegler过渡态法,通过将中心原子与配体的作用选成离子聚集、中心原子只有s和p轨道参与成键、中心原子只有d轨道参与成键、中心原子只有f轨道参与成键、中心原子的s、p、d和f轨道同时参与成键5种类型,从能量角度分析了Ce(C_8H_8)_2和Ce(C_8H_8)~-_2的化学键性质。     

The gas-phase equilibrium structures of Si8O12(OSiMe3)8 and Si8O12(CHCH2)8

The equilibrium molecular structure of Si(8)O(12)(OSiMe(3))(8) has been determined in the gas phase by electron diffraction (GED). With OSi-containing substituents on the cage silicon atoms, this molecule contains a moiety, which would, if reproduced in a periodic manner, yield a zeolite-type structure. Extensive ab initio calculations were used to identify two conformers of this molecule, with D(4) and D(2) point-group symmetries; the D(4)-symmetric conformer was approximately 1.2 kJ mol(-1) lower in energy. With 132 atoms in each conformer, this is one of the largest studies to be undertaken using gas electron diffraction. Semiempirical molecular-dynamics (SE-MD) calculations were used to give amplitudes of vibration, vibrational distance corrections (differences between interatomic distances in the equilibrium structure and the vibrationally averaged distances that are given directly by the diffraction data), and anharmonic constants. The structure of Si(8)O(12)(CHCH(2))(8) has also been determined by GED. Calculations showed that the vinyl groups are fairly unhindered and rotate between three minimum-energy positions. Ultimately, all possible combinations of the vinyl groups in these low-energy positions were accounted for in the GED model.     

Syntheses of(C_8H_8)Ln(C_9H_7)·(THF)_2(Ln=Pr,Nd)and crystal structure of(C_8H_8)Pr(C_9H_7)·(THF)_2

This paper reports two lanthanide complexes of formula (C_9H_7)Ln(C_8H_8)·(THF)_2 whereLn is Pr or Nd,C_9H_7 is indenyl,and C_8H_8 is cyclooctatetraene (COT).The complexes were preparedby the reaction of LnCl_3 with K(C_9H_7) and K_2(C_8H_8) in THF.(C_9H_7)Pr(C_8H_8)·(THF)_2 crystallizes inTHF at - 15℃ in the monoclinic space group P2_1:with unit cell dimensions a=8.446(0),b=10.083(2),c=13.407(3),β=105.48(1)°,V=1100.43(35)~3,Dc=1.52g/cm~3 and Z=2.The final R valueis 0.033,R_w value is 0.030,respectively.In (C_9H_7)Pr(C_8H_8)·(THF)_2 a five-membered ring centroid ofC_9H_7,the C_8H_8 ring centroid and the two oxygen atoms from the two THF molecules form a distortedtetrahedral geometry around the metal.     

Syntheses of substituted 8-(aminobenzyl)dinaphthodioxaphosphocine 8-oxides

Substituted (8-aminobenzyl)dinaphthodioxaphosphocine 8-oxides were prepared in a two-step process. The first step of the reaction is one-pot synthesis of α-aminophosphonates by the reaction of aldehydes, amines, and trialkyl phosphite in the presence of ceric ammonium nitrate. The second step is cyclization of α-aminophosphonates with bis(2-hydroxy-1-naphthyl)methane in the presence of a catalytic amount of p toluenesulphonic acid under reflux conditions. Their structures were established by elemental analyses, IR, ¹H, ¹³C, ³¹P NMR, and mass spectral data. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1574–1580, September, 2007.     

A new cyclic borazine species B(8)(NH)(4)(NMe(2))(8) containing a twelve-membered B(8)N(4) ring

The reaction between B(2)(NMe(2))(4) and two equivalents of [NH(4)][PF(6)] in thf at room temperature affords the new cyclic borazine B(8)(NH)(4)(NMe(2))(8) containing a non-planar twelve-membered ring with alternating B(2)(NMe(2))(2) and NH units.     

Synthesis and Structure of Tris(8-mercaptoquinolinato)thallium and Tris(8-hydroxyquinolinato)thallium Monohydrate

Tris(8-mercaptoquinolinato)thallium Tl(C₉H₆NS)₃ and tris(8-hydroxyquinolinato)thallium monohydrate Tl(C₉H₆NO)₃·H₂O have been synthesized. Their structures have been confirmed by X-ray crystallographic analysis.     

CRYSTAL STRUCTURE OF （C8H8）Sm（2,4—C7H11）（THF）

<正> The crystal structure of (C8H8)Sm(2,4-C7H11)(THF)(2,4-C7H11 = 2, 4-dimethylpentadienyl) , Mr=421. 8, has been determined which, belongs to monoclinic space group P21 with a = 8. 682(3), 6 = 10. 968(3), c=9. 744(3) (?) ,β= 104.24(2)°, V = 899. 3(4)(?)3, Z = 2, Dc=1. 66g/cm3, μc=33. 2cm-1, F(000) = 422 and final R = 0. 041 for 2021 observed reflections with I≥ 2σ(I). The 2,4-dimethylpentadienyl group is in "U " conformation. The carbon-carbon bond distances within the pentadienyl ligand fall essentially in two sets. The average distance of external C - C bonds is shorter than that of the internal bonds.