Mono- and diaminocarbenes from chloroiminium and -amidinium salts: synthesis of metal-free bis(dimethylamino)carbene

Bis(trimethylsilyl)mercury cleanly reacts at low temperature with chloroamidinium and -iminium chlorides, generating persistent metal-free cyclic and acyclic diaminocarbenes, as well as transient aryl-, chloro-, and hydrogenoaminocarbenes; with the latter, the corresponding olefin dimers were isolated, whereas with the former, no dimerization processes were observed.     

Acyclic diaminocarbenes: simple, versatile ligands for cross-coupling reactions

Acyclic diaminocarbenes are found to be useful ligands for palladium catalyzed Suzuki-Miyaura, Sonogashira and Heck cross-coupling reactions of aryl/alkenyl bromides and chlorides.     

二（2,6-二甲基-4-甲氧基）苯基卡宾的产生和反应

为了考察卡宾稳定性的电子效应,合成了对位具有强推电性甲氧基的二（2, 6-二甲基-4-甲氧基）苯基重氮甲烷(1c),通过光分解而产生了二（2,6-二甲基- 4-甲氧基）苯基卡宾(2c)。分别用电子顺磁共振（EPR）光谱,紫外可见(UV/vis) 光谱及激光闪光光分解法对二（2,6-二甲基-4-甲氧基）苯基卡宾(2c)的产生和衰 减过程进行了详细的观察。由于甲氧基的强推电子作用使二苯基卡宾的稳定性大大 降低,其二次动力学衰减速度常数为130s~(-1),是对位非取代二苯基卡宾(2b) (14s~(-1))的约9倍,且室温苯溶液中的寿命为20ms,仅为2b(180ms)的1/9。且通过 产物分析对二（2,6-二甲基-4-甲氧基）苯基卡宾(2c)的反应及甲氧基的取代基效 应进行了详细探讨。     

Bis(diisopropylamino)phosphanyldiazomethane: A building block for the synthesis of stable carbene and nitrilimines

Thermolysis of [bis(diisopropylamino)phosphanyl](trimethylsilyl)diazomethane 1 affords the corresponding carbene 2 , which is stable enough to be spectroscopically characterized. This species possesses a phosphorus–carbon multiple-bond character as shown by the 2 + 3 and 2 + 2 cycloaddition reactions observed with trimethylsilyl azide or N₂O and ethyl cyanoformate, respectively. On the other hand, 2 undergoes all the classical reactions of a carbene: cyclopropanation reaction with electron-poor alkenes, carbon–hydrogen bond insertion, and carbene–carbene coupling with isonitriles. Compound 2 reacts with trimethylsilyl triflate affording a stable methylenephosphonium salt 15 . Treatment of the lithium salt of the [bis(diisopropylamino)thiophosphoranyl]diazomethane 18 with the bis(diisopropylamino)phosphanyl chloride leads to a stable nitrilimine 3 . Thermolysis of 3 affords the isomeric diazo derivative 20 , while photolysis gives rise to thiophophoranylnitrile 21 and cyclodiphosphazene 23 . Regioselective 2 + 3 cycloadditions are observed with electron-poor dipolarophiles. Addition of trimethylsilyl triflate to 3 leads to a stable electrophilic nitrilimine 29 .     

Bis(carbene)pyridine complexes of Cr(III): exceptionally active catalysts for the oligomerization of ethylene

Pincer-heterocyclic carbene complexes of Cr(III), of the form [2,6-(1-alkylimidazol-2-ylidene)pyridine]CrCl3, have been prepared and evaluated as catalysts for the oligomerization of ethylene to alpha-olefins. In combination with methylaluminoxane cocatalyst, exceptionally high activities are obtained, ranging up to ca. 40 000 g mmol-1 bar-1 h-1.     

具有聚集荧光增强性质的双(4-二乙氨基水杨醛)缩偶氮二甲酰肼二丁基锡的合成和晶体结构

在甲醇溶液中,卡巴肼、(4-二乙氨基)水杨醛和二乙酸二丁基锡"一锅法"反应,合成了一个新颖的基于双(4-二乙氨基水杨醛)缩偶氮二甲酰肼(L)的七配位有机锡配合物[Sn(L)(n-butyl)_2]n(T)。经元素分析、IR、(1H,119Sn,13C)NMR和X射线衍射晶体结构表征,T的晶体属单斜晶系C2/c空间群,中心锡周围由双(4-二乙氨基水杨醛)缩偶氮二甲酰肼的O,N配位原子占据赤道位置和2个丁基占据顶端位置形成畸变五角双锥构型。通过烯醇式氧原子的桥联配位作用,T向一维带状无限扩展产生"竹筏状"超分子结构。配合物T在二甲基甲酰胺、四氢呋喃、乙醇、甲醇和甲苯有机溶剂及其有机溶剂-水混合物中具有强荧光发射峰,当含水量的体积分数在0～10%(V/V)时具有良好的聚集荧光增强效应,含水量大于10%(V/V)时发生荧光淬灭。     

Highly efficient P-N nickel(II) complexes for the dimerisation of ethylene

New P-N ligands featuring a phosphino group and an iminophosphorane moiety were successfully employed in the nickel-catalysed dimerisation of ethylene.     

Synthesis and Crystal Structure of Bis[2-[2-(diethylamino)ethyliminomethyl]-4-nitrophenolato]dimethanolcobalt(II) Dinitrate

1 INTRODUCTION The significance of cobalt coordination com- pounds in biological systems is recognized[1～3]. In many instances the cobalt coordination compounds of Schiff bases have been suggested as models to describe energy transfer in naturally occurring systems. In such cases the coordination sphere about the metal ion is believed to play an important role in determining the nature of the model system[4, 5]. In order to investigate the structures of such complexes, we report herein t…     

Synthesis and Crystal Structure of Bis[2-[2-(diethylamino)ethyliminomethyl]-4-nitrophenolato]dimethanolcobalt(Ⅱ) Dinitrate

The title mononuclear cobalt(Ⅱ) complex [Co(DENP)2(MeOH)2]·2NO3 (DENP =2-[2-(diethylamino)ethyliminomethyl]-4-nitrophenolate) was prepared and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group Pī with a = 8.297(1), b = 11.075(2), c = 11.134(2) (A), α = 69.69(1),β = 70.97(2), γ =84.02(2)°, Z = 1, V = 907.0(4) (A)3, Dc = 1.424 g/cm3, Mr = 777.66, λ(MoKα) = 0.71073 (A), μ = 0.548mm-1, F(000) = 409, R = 0.0628 and wR = 0.1734. The complex consists of a [Co(DENP)2-(MeOH)2]2+ cation and two disordered nitrate anions. The Co atom, lying at the inversion centre, is six-coordinated by two DENP ligands and two MeOH molecules in an octahedral geometry. The molecules in the crystal are linked through intermolecular O-H…O, O-H…N and N-H…O hydrogen bonds, forming chains parallel to the b axis.     

Reaction of dialkyl-(diethylamino)-silanes with glycols

Summary The reaction of dimethyl-(diethylamino)-silane with ethylene glycol, propane-1,2-diol, butane-1,4-diol, and diethyleneglycol has been studied. The reaction takes place with the evolution of hydrogen and diethylamine and the formation of cyclic ethers of dialkylsilanediols.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2229–2231, December, 1966.