Bildung Siliciumorganischer Verbindungen. LV. Die Konformeren des 1,3,5,7-Tetrasila-bicyclo[3,3,1]nonans und 2,4,6,8,9-Pentasila-bicyclo[3,3,1]nonans

Formation of Organosilicon Compounds. LV. Conformeres of the 1,3,5,7-Tetrasilabicyclo [3,3,1] nonane and 2,4,6,8,9-Pentasila-bicyclo [3,3,1] nonane Two types of carbosilanes with a bicyclo [3,3,1] nonane structure are reported, derivatives of 1,3,5,7-Tetrasila-bicyclo-[3,3,1] nonane (a) and of 2,4,6,8,9-Pentasila-bicyclo [3,3,1] nonane (b) with an inverse structure in respect to the Si- and C-atoms. By means of NMR-investigations the structure can be determined. Derivatives of (a) are present in the Si₄C₁₁H₂₈ with fully methylated Si-atoms, the 1,5 dichloro-1,3,5,7-tetrasila-bicyclo [3,3,1] nonane and Si₄Cl₆C₅H₁₀ with fully chlorinated Si-atoms with twofold boat conformation. In the derivatives of type (b) as Si₅H₁₀C₄H₆ with hydrogenated Si-atoms as well as in 9,9-dichloro-2,4,6,8,9-pentasila-bicyclo [3,3,1] nonane a change in conformation is observed, whereas a rigid chair conformation is found for both rings in the Si-chlorimated derivative Si₅Cl₁₀C₄H₁₀. A comparison of atom-resp. H? H distances in cyclohexane and 1,3,5-Trisilacyclohexane gives evidence that the boat conformation is more preferable for the 1,3,5-Trisilacyclohexane than for cyclohexane due to larger H? H-distances (caused by Si? C-distances).     

1,5-Diphosphabicyclo[3.3.1]nonan

1,5-Diphosphabicyclo [3.3.1]nonane 1,5-Diphosphabicyclo[3.3.1]nonane 8 has been obtained by free-radical cyclization of CH₂?CHCH₂(H)PCH₂P(H)CH₂CH?CH₂ 6 and 1-allyl-1,3-diphosphorinane 7 . For the synthesis of 6 and 7 the chlorophosphine Cl₂PCH₂PCl₂ 1 is used as a starting material, which can be converted into Me₂N(Cl)PCH₂P(Cl)NMe₂ 3 by reaction with (Me₂N)₂PCH₂P(NMe₂)₂ 2 . Treatment of 3 with two equivalents of allyl lithium and cleavage of the PN bonds in CH₂?CHCH₂(Me₂N)PCH₂P(NMe₂)CH₂CH?CH₂ 4 with diluted HCl affords CH₂?CHCH₂(H)(O)PCH₂P(O)(H)CH₂CH?CH₂ 5 . Phenylsilane is used for the first time as a reducing agent to obtain a secundary phosphine like 6 from the secundary phosphine oxide ( 5 ). Prolonged heating increases the yield of the byproduct 7 in the mixture of 6 and 7 . Reactions of the trivalent phosphorus in 8 with CS₂, CH₃I, POCl₃, NO, sulfur, and KSeCN, respectively, delivers the corresponding derivatives 9–17 . The compounds decribed are characterized by ¹H, ¹³C, ³¹P, ⁷⁷Se n.m.r., i.r., and m.s. data.     

Cis- und trans-1-Phosphabicyclo[4.4.0]decan

Cis- and trans-1-Phosphabicyclo[4.4.0]decane A mixture of cis-( 5a ) and trans-1-phosphabicyclo [4.4.0] decane 5b has been prepared by free-radical cyclization of (CH₂ = CH? CH₂? CH₂)₂CH? PH₂ 10 . The isomers could be separated in a pure state. Stereostructures have been assigned by ¹³C n.m.r. at 153—302 K. Equilibration of 5a and 5b by u.v. irradiation gave ?G°₃₅ ≈? 0 kJ ° mol^?1 · Activation parameters for ring inversion of “cis” stereoisomer 5a and its “cis” P-sulfid 17a are found to be ΔG° = 41.9 kJ · mol^?1 and 39.7 kJ · mol^?1, respectively. Treatment of 5a and 5b with H₂O₂, sulfur, selenium, HSO₃F, CH₃I, CS₂, and Ni(CO)₄, respectively, yield the corresponding derivatives. ¹H, ¹³C, ³¹P, ⁷⁷Se n.m.r. and i.r. data are reported.     

Characterization of isomeric [CH5P]+˙ and [C2H7P]+˙ radical cations and some [C2H6P]+ phosphonium ions in the gas phase by their collisional activation spectra

Collisional activation spectra were used to characterize isomeric ion structures for [CH₅P]^+˙ and [C₂H₇P]^+˙ radical cations and [C₂H₆P]⁺ even-electron ions. Apart from ionized methylphosphane, [CH₃PH₂]^+˙, ions of structure [CH₂PH₃]^+˙ appear to be stable in the gas phase. Among the isomeric [C₂H₇P]^+˙ ions stable ion structures [CH₂PH₂CH₃]^+˙ and [CH₂CH₂PH₃]^+˙/[CH₃CHPH₃]^+˙ are proposed as being generated by appropriate dissociative ionization reactions of alkyl phosphanes. At least three isomeric [C₂H₆]⁺ ions appear to exist, of which \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm CH}_{\rm 3} - \mathop {\rm P}\limits^{\rm + } {\rm H = CH}_{\rm 2} $\end{document} could be identified positively.     

Structure and formation of gaseous [C4H6O]+˙ ions: 1—The enolic ions [CH2C(OH)?CHCH2]+˙ and [CH2CH?CHCH(OH)]+˙ and their relationship with their keto counterparts

The [C₄H₆O]^+˙ ion of structure [CH₂?CHCH?CHOH]^+˙ (a) is generated by loss of C₄H₈ from ionized 6,6-dimethyl-2-cyclohexen-1-ol. The heat of formation ΔH_f of [CH₂?CHCH?CHOH]^+˙ was estimated to be 736 kJ mol^?1. The isomeric ion [CH₂?C(OH)CH?CH₂]^+˙ (b) was shown to have ΔH_f, ? 761 kJ mol^?1, 54 kJ mol^?1 less than that of its keto analogue [CH₃COCH?CH₂]^+˙. Ion [CH₂?C(OH)CH?CH₂]^+˙ may be generated by loss of C₂H₄ from ionized hex-1-en-3-one or by loss of C₄H₈ from ionized 4,4-dimethyl-2-cyclohexen-1-ol. The [C₄H₆O]^+˙ ion generated by loss of C₂H₄ from ionized 2-cyclohexen-1-ol was shown to consist of a mixture of the above enol ions by comparing the metastable ion and collisional activation mass spectra of [CH₂?CHCH?CHOH]^+˙ and [CH₂?C(OH)CH?CH₂]^+˙ ions with that of the above daughter ion. It is further concluded that prior to their major fragmentations by loss of CH₃˙ and CO, [CH₂?CHCH?CHOH]⁺˙ and [CH₂?C(OH)CH?CH₂]^+˙ do not rearrange to their keto counterparts. The metastable ion and collisional activation characteristics of the isomeric allenic [C₄H₆O]^+˙ ion [CH₂?C?CHCH₂OH]^+˙ are also reported.     

High-Field 1H-NMR Study of Poly(Vinyl Chloride) Defects

Radical poly(vinyl chlorides), (PVC), obtained in bulk and in suspension polymerizations, and their low molecular weight extracts have been thoroughly studied by high-field NMR to obtain better qualitative and quantitative analyses of their structural defects. Assignments have been achieved by ¹H-¹H decoupling experiments and hyperfine spectral structure analysis of model compounds and low molecular weight extracts. Strong effects of the nature of the solvents used in ¹H-NMR analysis were observed. Most of the defects of these radical PVC's have been quantitatively estimated in terms of average number values in correlation with their [Mbar]_n. End-groups of type [I'] (= ?CH₂?CH[dbnd]CH[sbnd]CH₂C1) are about 0.5 per chain; internal double bonds can only be estimated by difference, and their amount increases with increasing conversion. A very low quantity of vinyl chain end [I'] ([dbnd] [sbnd]CHC1[sbnd]CH[dbnd]CH₂) has been found only in low molecular weight extracts. For the three probable saturated chloromethyl ends [II] ([dbnd][sbnd]CHCl[sbnd]CH₂Cl), [III] ([dbnd] [sbnd]CH₂[sbnd]CH₂Cl), and [IV] ([dbnd] >CH[sbnd]CH₂C1), only [II] and [III] were definitely identified. Finally, in taking into account all the endgroups, it has been concluded that branches would be grafted throughout the process. On the average, 4 to 5 branches have been found per chain of high molecular weight PVC.     

NMR-Untersuchungen an Methylphosphoniumchlorid

N.M.R. Investigation of Methylphosphonium Chloride The n.m.r. spectra of [CH₃PH₃]Cl in aqueous hydrochloric acid as solvent and of [OP(CH₃) (OCH₂CH₂Cl)OCH₂? ]₂ in C₆D₆ und CD₂Cl₂ are described. ³¹P n.m.r. resonances with a line width at half height of 55 Hz are found for the H₂O? HCl solutions of [CH₃PH₃]Cl in the solid state at 183 K.     

Carbon-13-nuclear magnetic resonance spectra of 5-coordinate tris-olefin complexes of rhodium(I)

Studies of the ¹³C N.M.R. spectra of the series RhX[P(Ch₂CH₂CHCH₂)₃] and RhX[P(CH₂CH₂CH₂CHCH₂)₃] where x  Cl or Br have revealed that (a) the J(¹⁰³Rh-¹³C) (olefin) for the complexes studied is only $\text{1}\text{2}$ ? $\text{1}\text{3}$ that found for square-planar complexes, and (b) the fluxional character in the olefinic carbons observed for the compounds RhX[P(CH₂CH₂CHCH₂)₃] is related to the partial rotation of the olefin about the rhodium-olefin bond.     

Di- and trinuclear olato-bridged copper(II) compounds of 3,7-bis(3-olatopropyl)-1,3,5,7-tetraazabicyclo[3,3,1]nonane (protan); the structures of [{Cu(μ-protan)}2Cu](ClO4)2·H2O and [{Cu(μ-protan)}Cu(OH)2](ClO4)2·0.5(EtOH)

A compound with a linear trinuclear copper(II) cation, [Cu₃(μ-protan)₂](ClO₄)₂·H₂O (protanH₂ = 3,7-bis(3-hydroxypropyl)-1,3,5,7-tetraazabicyclo[3,3,1]-nonane) is formed by reaction of copper(II) perchlorate, 3-aminopropanol, ammonia and methanal. The cation is approximately centrosymmetrical with Cu?Cu = 2.9870(5) and 2.9485(5) Å. The terminal copper(II) ions are coordinated by nitrogen atoms 3 and 7 of the tetraazabicycle (Cu–N_mean = 2.021(5) Å) and the two oxygen atoms of the 3,7-bis(3-olatopropyl) substituents (Cu–O_mean = 1.911(3) Å), which also act as bridging groups to the central copper(II) ion (Cu–O_mean = 1.926(4) Å). The cation is both helically twisted (dihedral angle N3?N7?N3′?N7′ = 20(1)°) and bent (angle Cu?Cu?Cu = 171(1)°). The copper(II) ions have tetrahedrally twisted square planar primary coordination, with perchlorate ion oxygen atoms weakly coordinated axially to the two terminal copper(II) ions, on opposite sides of the “plane” of the molecule, while the central copper(II) ion is weakly coordinated axially by a water molecule, with all axial Cu–O distances ca. 2.9 Å. One N·CH₂·CH₂·CH₂·O chelate ring for each protan²⁻ ligand shows conformational disorder and the perchlorate ions show rotational disorder. Partial hydrolysis of the protan²⁻ compound gave a compound [{Cu(μ-protan)}Cu(OH)₂](ClO₄)₂·0.5(EtOH) which has a dinuclear cation, with one copper(II) ion in square-planar coordination by tetradentate protan²⁻ and the other in square-planar coordination by the two bridging oxygen atoms of the protan²⁻ ligand and by two hydroxide ions, with Cu?Cu = 3.045(1) Å. With differing mole ratios of the same reactants compounds of the dinuclear cation [{Cu(μ-pta)}₂]²⁺ (ptaH = 3(3-hydroxypropyl)-1,3,5,7-tetraazabicyclo[3,3,1]nonane) are formed.     

Structures and stabilities of [C3H3O]+ ions in the gas phase: A molecular orbital study

The relative energies of 11 [C₃H₃O]⁺ ions are calculated by different molecular orbital methods (MINDO/3, MNDO, ab initio with 3-21G and 4-31G* basis set and configuration interaction). The four most stable structures are: a ([CH₂?CH? CO]⁺), b c ([CH?C? CHOH]⁺) and d ([CH₂?C?COH]⁺); their relative energies at the CI/4-31G*//3-21G level are 0, 117, 171 and 218 kJ mol^?1, respectively. The isomerizations c→[CH?CH? CHO]⁺→[CH₂?C? CHO]⁺→ a and dissociations into [C₂H₃]⁺+CO and [HCO]⁺+C₂H₂ are explored. The calculated potential energy profile reveals that the energy-determining step is the 1,3-H migration c→[CH?CH? CHO]⁺. This explains the value of unity of the branching ratio and the spread of kinetic energy released for the two dissociation channels.     

Synthesis of Mixed Silylene–Carbene Chelate Ligands from N‐Heterocyclic Silylcarbenes Mediated by Nickel

The Ni^II‐mediated tautomerization of the N‐heterocyclic hydrosilylcarbene L²Si(H)(CH₂)NHC 1 , where L²=CH(C?CH₂)(CMe)(NAr)₂, Ar=2,6‐iPr₂C₆H₃; NHC=3,4,5‐trimethylimidazol‐2‐yliden‐6‐yl, leads to the first N‐heterocyclic silylene (NHSi)–carbene (NHC) chelate ligand in the dibromo nickel(II) complex [L¹Si:(CH₂)(NHC)NiBr₂] 2 (L¹=CH(MeC?NAr)₂). Reduction of 2 with KC₈ in the presence of PMe₃ as an auxiliary ligand afforded, depending on the reaction time, the N‐heterocyclic silyl–NHC bromo Ni^II complex [L²Si(CH₂)NHCNiBr(PMe₃)] 3 and the unique Ni⁰ complex [η²(Si‐H){L²Si(H)(CH₂)NHC}Ni(PMe₃)₂] 4 featuring an agostic Si? H→Ni bonding interaction. When 1,2‐bis(dimethylphosphino)ethane (DMPE) was employed as an exogenous ligand, the first NHSi–NHC chelate‐ligand‐stabilized Ni⁰ complex [L¹Si:(CH₂)NHCNi(dmpe)] 5 could be isolated. Moreover, the dicarbonyl Ni⁰ complex 6 , [L¹Si:(CH₂)NHCNi(CO)₂], is easily accessible by the reduction of 2 with K(BHEt₃) under a CO atmosphere. The complexes were spectroscopically and structurally characterized. Furthermore, complex 2 can serve as an efficient precatalyst for Kumada–Corriu‐type cross‐coupling reactions.     

1‐Silacyclopent‐2‐enes and 1‐silacyclohex‐2‐enes bearing functionally substituted silyl groups in 2‐positions. Novel electron‐deficient Si?H?B bridges

The reactions of alkyn‐1‐yl(vinyl)silanes R₂Si[C?C‐Si(H)Me₂]CH?CH₂ [R = Me (1a), Ph (1b)], Me₂Si[C?C‐Si(Br)Me₂]CH?CH₂ (2a), and of alkyn‐1‐yl(allyl)silanes R₂Si[C?C‐Si(H)Me₂]CH₂CH?CH₂ (R = Me (3a), R = Ph (3b)] with 9‐borabicyclo[3.3.1]nonane in a 1:1 ratio afford in high yield the 1‐silacyclopent‐2‐ene derivatives 4a, b and 5a, and the 1‐silacyclohex‐2‐ene derivatives 6a, b, respectively, all of which bear a functionally substituted silyl group in 2‐position and the boryl group in 3‐position. This is the result of selective intermolecular 1,2‐hydroboration of the vinyl or allyl group, followed by intramolecular 1,1‐organoboration of the alkynyl group. In the cases of 4a, b, potential electron‐deficient Si? H? B bridges are absent or extremely weak, whereas in 6a,b the existence of Si? H? B bridges is evident from the NMR spectroscopic data (¹H, ¹¹B, ¹³C and ²⁹Si NMR). The molecular structure of 4b was determined by X‐ray analysis. Copyright © 2005 John Wiley & Sons, Ltd.     

Kupfer(I)-Komplexe mit 1-Azadien-Chelatliganden und ihre Reaktion mit Sauerstoff

Copper(I) Complexes with 1-Azadiene Chelate Ligands and Their Reaction with Oxygen The reaction of the bidendate 1-azadiene ligands Me₂N? (CH₂)_n? N?CH? CH?CH? Ph with CuX results in the formation of the dimeric compounds [ A CuX]₂ and [ B CuX]₂ ( A : n = 2, B : n = 3, X: I, Cl). The structure of complex 1 [ A CuI]₂ was determined by X-ray crystal structure analysis. 1 consists of two tetrahedrally coordinated Cu atoms connected by two iodo bridges. (Cu? Cu bond length: 261 pm). The ligand Me? N(CH₂CH₂N?CH? CH?CH? Ph)₂ ( C ) reacts with CuX to form the monomeric complexes [ C CuX] ( 5 : X?I, 6 : X?Cl). The crystal structure of 5 shows that the ligand acts as a tridendate ligand. The bond lengths of the CuN(sp²) bonds are significantly shorter than the Cu? N(sp³) distance. Reacting the podand-type ligands N(CH₂CH₂? N?CH? R)₃ ( D : R?Ph, E : R?-CH?CH? Ph) with CuX yields the ionic complexes 7 [ D Cu][CuCl₂] and 8 [ E Cu][CuCl₂]. 7 was characterized by X-ray analysis which confirmed that D acts as a four-dendate podand ligand. The compounds 1 ? 8 are unreactive towards CO₂ but take up O₂ even at deep temperatures. At ?78°C the orange-red complex 4 [ B CuCl]₂ reacts with O₂ in CH₂Cl₂ to form a deep violet solution, but the primary product of the oxidation could not be isolated. It reacts at room temperature to form the green complex 9 [μ-Cl, μ-OH][ B CuCl]₂. The X-ray structure analysis of 9 confirms that a dimeric Cu^II complex is formed in which both a chloro- and a hydroxo group are bridging the monomeric units. The Cu^II centers exhibit a distorted tetragonal-pyramidal coordination. The pathway of the reaction with O₂ will be discussed.     

Characterization of five [C4H7O]+ Ion structures. Fragmentation of the 2-pentanone molecular ion

The [C₄H₇0]⁺ ions [CH₂?CH? C(?OH)CH₃]⁺ (1), [CH₃CH?CH? C(?OH)H]⁺ (2), [CH₂?C(CH₃)C(?OH)H]⁺ (3), [Ch₃CH₂CH₂C?O]⁺ (4) and [(CH₃)₂CHC?O]⁺ (5) have been characterized by their collision-induced dissociation (CID) mass spectra and charge stripping mass spectra. The ions 1–3 were prepared by gas phase protonation of the relevant carbonyl compounds while 4 and 5 were prepared by dissociative electron impact ionization of the appropriate carbonyl compounds. Only 2 and 3 give similar spectra and are difficult to distinguish from each other; the remaining ions can be readily characterized by either their CID mass spectra or their charge stripping mass spectra. The 2-pentanone molecular ion fragments by loss of the C(1) methyl and the C(5) methyl in the ratio 60:40 for metastable ions; at higher internal energies loss of the C(1) methyl becomes more favoured. Metastable ion characteristics, CID mass spectra and charge stripping mass spectra all show that loss of the C(1) methyl leads to formation of the acyl ion 4, while loss of the C(5) methyl leads to formation of protonated vinyl methyl ketone (1). These results are in agreement with the previously proposed potential energy diagram for the [C₅H₁₀O]⁺˙ system.     

螺桨烷型分子BX[(CH_2)_n]_3和BX(CH_2)[CH(CH_2)_nCH](X=N,P)的结构和性质

采用密度泛函理论(DFT)研究了螺桨烷型分子BX[(CH2)n]3和BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的结构、稳定性、化学键和电子光谱性质.计算结果表明这些分子都是稳定的.BX[(CH2)n]3(X=N,P;n=1-6)的最高占据分子轨道(HOMO)和最低空分子轨道(LUMO)之间的能隙均大于5.20 eV,其中BN[CH2]3和BP[CH2]3的能隙超过7.0 eV,与C5H6的能隙(7.27 eV)很接近,BX(CH2)[CH(CH2)n CH](X=N,P;n=1-6)的能隙在6.80 eV左右.所研究分子能量的二阶差分表明BN[(CH2)3]3、BP[(CH2)4]3及BX(CH2)[CH(CH2)2CH](X=N,P)是最稳定的.BX[(CH2)n]3的Wiberg键级表明除了BN[(CH2)n]3(n=2和6)中不存在B―N键,其它化合物中B和N均形成了化学键,BP[(CH2)n]3中除了BP[(CH2)2]3不存在B―P键,其它的均存在.电子密度的拓扑分析表明N―B键属于离子键,而P―B键具有共价键特征.BX[(CH2)n]3(X=N,P)的第一垂直激发能分别在191.1-284.8 nm和191.8-270.1 nm之间,BX(CH2)[CH(CH2)n CH](X=N,P)的第一垂直激发能分别在190.5-199.7 nm和209.0-221.3 nm之间.     

31P-NMR-Daten heterocyclischer phosphine. Diastereomerenzuordnung an 1,3-Oxa-, 1,3-Aza- und 1,3-thiaphospholanen

The diastereomers of 16 1,3-oxa-, 1,3-aza- and 1,3- thiaphospholanes were assigned by means of the coupling constants ²J(P? C? H) and ³J(P? C? CH₃) and the linewidths of the ³¹P signals and ¹H chemical shifts of CH₃ groups. It is shown that the change in the ³¹P chemical shifts allows the estimation of the relative configuration in these compounds.     

Bildung von NaAl(PH2)4, NaAl(HPCH3)4 und die präparative Darstellung von H3Si?PH2 und seiner PH-haltigen Derivate

NaAl(PH₂)₄ is prepared by the reaction of NaPH₂ with AlCl₃ in diglyme according to equation (a) in ?Inhaltsübersicht”?. In the same way NaAl(HPCH₃)₄ is obtained from CH₃PH₂. Für obtainung the analogous compound LiAl(HPCH₃)₄, LiPHCH₃ was prepared acc. to equ. (b). NaAl(PH₂)₄ (soluble in diglyme) allows the formation of SiH- and PH₂-containing silylphosphines in preparative yields acc. to equ. (c). H₃SiBr, CH₃SiH₂Br, (CH₃)₂SiHBr and CH₃SiHCl₂ react with NaAl(PH₂)₄ to form H₃Si? PH₂, CH₃SiH₂? PH₂, (CH₃)₂SiH? PH₂ and CH₃SiH(PH₂)₂, respectively, in about 70% yield. By analogous reaction of NaAl(HPCH₃)₄ and LiAl(HPCH₃)₄ the compounds H₃Si? PHCH₃, CH₃SiH₂? PHCH₃, (CH₃)₂SiH? PHCH₃ and (CH₃)₃Si? PHCH₃ have been obtained. These reaarange acc. to equ. (d), silylphosphones richer in SiH reaaranging faster. ¹H and ³¹P n.m.r. spectra are reported.     

Nucleophilic Aromatic Addition Reactions of the Metallabenzenes and Metallapyridinium: Attacking Aromatic Metallacycles with Bis(diphenylphosphino)methane to Form Metallacyclohexadienes and Cyclic η2‐Allene‐Coordinated Complexes

The reactions of phosphonium‐substituted metallabenzenes and metallapyridinium with bis(diphenylphosphino)methane (DPPM) were investigated. Treatment of [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl₂(PPh₃)₂]Cl with DPPM produced osmabenzenes [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl₂{(PPh₂)CH₂(PPh₂)}]Cl ( 2 ), [Os{CHC(PPh₃)CHC(PPh₃)CH}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 3 ), and cyclic osmium η²‐allene complex [Os{CH?C(PPh₃)CH?(η²‐C?CH)}Cl₂{(PPh₂)CH₂(PPh₂)}₂]Cl ( 4 ). When the analogue complex of osmabenzene 1 , ruthenabenzene [Ru{CHC(PPh₃)CHC(PPh₃)CH}Cl₂(PPh₃)₂]Cl, was used, the reaction produced ruthenacyclohexadiene [Ru{CH?C(PPh₃)CH?C(PPh₃)CH}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 6 ), which could be viewed as a Jackson–Meisenheimer complex. Complex 6 is unstable in solution and can easily be convert to the cyclic ruthenium η²‐allene complexes [Ru{CH?C(PPh₃)CH?(η²‐C?CH)}Cl{(PPh₂)CH₂(PPh₂)}₂]Cl₂ ( 7 ) and [Ru{CH?C(PPh₃)CH?(η²‐C?CH)}Cl₂{(PPh₂)CH₂(PPh₂)}₂]Cl ( 8 ). The key intermediates of the reactions have been isolated and fully characterized, further supporting the proposed mechanism for the reactions. Similar reactions also occurred in phosphonium‐substituted metallapyridinium [OsCl₂{NHC(CH₃)C(Ph)C(PPh₃)CH}(PPh₃)₂]BF₄ to give the cyclic osmium η²‐allene‐imine complex [OsCl₂{NH?C(CH₃)C(Ph)?(η²‐C?CH)}{(PPh₂)CH₂(PPh₂)}(PPh₃)]BF₄ ( 11 ).     

Synthese und Eigenschaften Pentamethylcyclopentadienyl-substituierter PPC- bzw. AsPC-Dreiring-Systeme

Synthesis and Properties of Pentamethylcyclopentadienylsubstituted PPC and AsPC three-membered Rings Via the reaction of bis-(pentamethylcyclopentadienyl)diphosphene [Cp*P?PCp*, 1 ] and 1-(pentamethylcyclopentadienyl)-2-(2,4,6-tri^tbutylphenyl)- diphosphene [Cp*P?PMes*, 2 ] with the diazomethanes N₂CHR [R = H, Si(CH₃)₃] the four new diphosphiranes Cp*PPCp*CHSi(CH₃)₃, 4a , Cp*PPMes*CHSi(CH₃)₃, 4b , Cp*PPCp*CH₂, 5a , Cp*PPMes*CH₂, 5b , are obtained. The formation of 4a results via a 2 + 3-cyclo-addition product, which could be proved by nmr spectroscopy. The reaction of As-(pentamenthylcyclopentadienyl)-P-(2,4,6-tri^tbutylphenyl) arsaphosphene [Cp*As?PMes*, 3 ] with diazomethane leads to 1-(pentamethylcyclopentadienyl)-2-(2,4,6-tri^tbutylphenyl)-1-arsa-2 -phosphacyclopropane [phospharsiran, Cp*AsPMes*CH₂, 6 ]. Analysis of the structures by nmr spectroscopy gives clear evidence for a trans-orientation of the substituents at the El? P bond (El = As, P) in all of the three membered ring systems. For the diphosphirane Cp*PPCp*CH₂ ( 5a ) a Cp*-phosphorus bond cleavage by thermolysis cannot be observed. From the reaction of compound 5a with Cr(CO)₅thf one obtains 1-(pentacarbonylchrom)-1,2-bis(pentamethylcyclopentadienyl)-1,2- diphosphacyclo-propane, 7 .     

Coordination Chemistry of Acrylamide: 1. Cobalt(II) Chloride Complexes with Acrylamide – Synthesis and Crystal Structures

The molecular structures of blue dichloro‐tetrakis(acrylamide) cobalt(II), [Co{O‐OC(NH₂)CH=CH₂}₄Cl₂] ( 1 ) and pink hexakis(acrylamide)cobalt(II) tetrachlorocobaltate(II), [Co{O‐OC‐(NH₂)CH=CH₂}₆][CoCl₄] ( 2 ), characterized by single X‐ray diffraction, IR spectroscopy and elemental analyses, are described. The coordination of Co^II in 1 involves a tetragonally distorted octahedral structure with four O‐donor atoms of acrylamide in the equatorial positions and two chloride ions in the apical positions. The second complex 2 in ionic form contains Co^II cations surrounded by an octahedral array of O‐coordinated acrylamide ligands, accompanied by a [CoCl₄]^2? anion.