1-Alkoxy-2-azaallenyl-komplexe von chrom und wolfram

The successive reaction of (CO)₆M with Na[NCR₂¹] and [Et₃O]BF₄ yields (CO)₅M[C(NCR₂¹)OEt] (II: M = Cr; III: M = W; CR₂¹ = C(C₆H₄Br-p)₂ (a), CPh₂ (b), C(C₆H₄OMe-p)₂ (c), C(C₆H₄)₂O (d), CBu₂^tt (e)). Hexacarbonyltungsten, (CO)₆W, reacts with Na[NCPh₂] and MeOSO₂F to give (CO)₅W[C(NCPh₂) OMe] (IV). X-Ray analysis of IIe shows that: (1) the CNC fragment is almost linear (171.7°); (2) the two NC bond lengths are equal within experimental error; and (3) the O,C,Cr,N plane is perpendicular to the C(Me₃),C,N,C(Me₃) plane (90.0°). Therefore compounds II–IV are best described as 1-alkoxy-2-azaallenyl complexes.     

Synthese von sulfinsäureimidamidostannanen

N-Lithiomethanesulfinicacidimide amides of the general composition MeS(NR)NRLi (II) are prepared by addition of methyllithium to sulfur diimides RNSNR (I) (R  t-Bu or SiMe₃. The corresponding reaction with Me₃SnNSNSnMe₃ yields the N-lithio salt (Me₃SnNSN)Li (III) and tetramethylstannane; addition compounds are not formed. Methatetical reactions of II with chlorostannanes, Me₃SnCl or Me₂SnCl₂, leads to the formation of the sulfinicacidimideamidostannanes MeS(NR)NRSnMe₃ (IV) and MeS(NR)NRSnClMe₂ (Va), respectively.     

The preparation of functional alkylidynetricobalt nonacarbonyl complexes from dicobalt octacarbonyl

Various functionally-substituted methylidynetricobalt nonacarbonyl derivatives, RCCo₃(CO)₉, where R is D, Me₃Si, PhMe₂Si, (MeO)₂P(O), (EtO)₂P(O), Me₃COC(O), Me₃SiOC(O), Et₂NC(O), CH₃C(O), C₂H₅C(O), n-C₃H₇C(O), Me₂-CHC(O), n-C₄H₉C(O), Me₃C(O), PhC(O), p-CH₃C₆H₄C(O), p-BrC₆H₄C(O), HOCH₂, HC(O), CH₃O and Me₂N, have been prepared by reaction of dicobalt octacarbonyl with the appropriate RCX₃ or RCHX₂ (XCl or Br) compound.     

Insertion of N-sulfinylsulfonamides and bis(methylsulfonyl)sulfur diimide into ironcarbon σ bonds

The N-sulfinylsulfonamides R′S(O)₂NSO (R′ = CH₃, p-CH₃C₆H₄) insert into the FeR bonds of η⁵-C₅H₅Fe(CO)₂R (R = CH₃, CH₂C₆H₅) to afford η⁵-C₅H₅Fe(CO)₂N[S(O)₂R′][S(O)R]. These products undergo oxidation by m-ClC₆H₄C(O)-OOH to η⁵-C₅H₅Fe(CO)₂N[S(O)₂R′][S(O)₂R] and rearrange on storage to η⁵-C₅H₅Fe(CO)₂S(O)[NS(O)₂R′]R. Reaction between the η⁵-C₅H₅Fe(CO)₂R and CH₃S(O)₂NSNS(O)₂CH₃ leads to the insertion products η⁵-C₅H₅Fe(CO)₂N-[S(O)₂CH₃][S(R)NS(O)₂CH₃].     

Reactions of palladium(II) cyclometallated benzylideneaniline Schiff's bases. Some relative rates for the synthesis of ortho-substituted carbomethoxy derivatives via CO insertion

The synthesis and characterisation of the complexes [(p-CH₃C₆H₄NCH($\text{C}{}_6\text{H}{}_3\text{Y))P}$d(OAc)]₂ (II) are reported. These complexes react at very different rates with carbon monoxide in methanol to give the ortho-substituted esters, p-CH₃C₆H₄NCHC₆H₃Y - 2R, R = CO₂CH₃, with electron withdrawing Y substituents slowing the reaction. The ¹³C{¹H} data for II show a linear correlation of δ(C(2)) in the 5′-complexes (Y trans to PdC) with δ(C(4)) of monosubstituted benzene compounds. For Y = 5′-NO₂, 4′-NO₂ and 4′-Cl, the bis complex [{p-CH₃C₆H₄NCH(

is formed in a secondary reaction.     

Reactions of pentafluorosulfanyliminodihalosulfanes,SF5NSX2, with nucleophiles. Preparation and characterization of pentafluorosulfanylsulfinylamine,SF5NSO.

Reactions of SF₅NSF₂ with sodium alkoxides and aryloxides have produced both the mono- and disubstituted derivatives SF₅NS(F)OR and SF₅NS(OR)₂, where RCH₃, CH₂CHCH₂, C₆H₅, p-C₆H₄NO₂, p-C₆H₄Br, p-C₆H₄CN. The reaction of SF₅NSCl₂ with AgNCO produced SF₅NS(NCO)₂. This diisocyanate can also be prepared from the reaction of SF₅NSCl₂ with KOCN in liquid SO₂. The proposed intermediate, SF₅NSO, in the hydrolysis of SF₅NSF₂ was prepared from the low temperature reaction of SF₅NSCl₂ and Ag₂O in C₆H₅NO₂. The new pentafluorosulfanyl derivatives were characterized by IR, ¹H and ¹⁹F NMR, mass spectrometry and where possible ¹³C NMR and elemental analysis.     

Amino-sulphur-fluorine derivatives as fluoride ion donors: preparation of three- and four-coordinated cations of sulphur (IV) and (VI) [1,2]

Pentacoordinated aminosulphur (IV) trifluorides, R₂N$\text{S}$F₃, (in this paper the lone pair in S(IV)-derivatives is always considered as a ligand) and aminosulphur(VI)-oxidetrifluorides, R₂NS(O)F₃, readily lose a fluoride ion to Lewis acids (AsF₅, SbF₅, BF₃) to give sulphur-containing cationic species [R₂N$\text{S}$F₂]⁺ and [R₂NS(O)F₂]⁺ with tetracoordinated sulphur. Tetracoordinated neutral dialkylaminosulphur(IV)-oxidefluorides, R₂N$\text{S}$(O)F, and amino-imino sulphur(IV)fluorides, R₂N$\text{S}$(=NR_f)F, give three-coordinated sulphur cations [R₂N$\text{S}$O]⁺] or [R₂N$\text{S}$NR_f]⁺.The three-coordinated sulphur(VI)cation [R₂NS(O)NR]₊ has also been formed.     

Dipole moment,isomerization, and intramolecular hydrogen bond in some benzene derivatives (computations)

The dipole moment vectors of some benzene monoderivatives are calculated to test the method used in an attempt to explain the dipole moments of o-, m- and p-substituted phenols (X-C₆H₄-OH; X = -OH, -F, -NO₂, -CHO, -COOH, -CH₃). The vectors seem to include contributions from a mixture of planar conformers whose populations obey a Boltzmann-type distribution. The calculated intramolecular interaction moment is proposed as a simple criterion indicating the strength of the intramolecular hydrogen bond in o-phenols.     

The electronic effect of positively charged substituents on an aromatic ring: a 13cmr and theoretical study

The effects of the substituents -N⁺Me₃, -CH₂N⁺Me₃ and -P⁺Me₃ on the relative ¹³C chemical shifts at meta and para positions accord with the σ_r° values obtained from IR intensities provided the correlation equation of Syrova et al. is used. SCF-MO calculations using a minimal STO-3G basis set suggest that the -N⁺H₃ substituent acts as a weak π-electron donor and the -P⁺H₃ substituent as a π-electron acceptor in accord with the σ_r° constants for the methylated poles. In these calculations, the action of -PH₃⁺ as a π-electron acceptor can be rationalised in terms of an hyperconjugative effect involving the empty π-type group MO, that in -PH₃⁺ is located at a significantly lower energy than in -NH₃⁺. This π-type group MO is formed by suitable combinations of the 3p AO's of P with the 1s AO's of the hydrogens and therefore there is no need to invoke 3d-orbitals participation in -PH₃⁺ to explain this differential behaviour.     

On the conformational problem in trisulphides: Preparation,properties and conformational analyses of bis(fluorocarbonyl)trisulphide,FC(O)SSSC(O)F

Bis(fluorocarbonyl)trisulphide, FC(O)SSSC(O)F, was prepared both by reaction of FC(O)SCl with H₂S and by ultraviolet irradiation of FC(O)SSC(O)F. Infrared data for the vapour, liquid and matrices (in Ar, Ne and N₂), as well as Raman, u.v. mass and ¹⁹F and ¹³C NMR spectra have been obtained and interpreted. Complementary measurements were also carried out to determine the dipole moment of the liquid substance.From these data, the most stable conformer was deduced to have a trans conformation of the FC(O) groups with respect to the SSS plane, with both CO bonds syn to the SS bonds.     

Organosilicon compounds : LI. Further studies of the base-catalysed solvolysis of N-(triorganosilyl)anilines

Relative rates of solvolysis of some N-triorganosilylanilines in mixtures of ethanol and aqueous potassium hydroxide have been determined, with results as follows. (i) For XC₆H₄NHSiEt₃ compounds in MeOH (5 vol) + aq. alkali (2 vol) at 50°: (X =) H, 1.0;p-Me, 0.80;p-OMe, 0.83;m-Me, 0.90; o-Me, 0.87; p-SMe, 1.90; p-F, 1.7; p-Cl, 2.8; o-Cl, 14; m-Cl, 4.2; m-NO₂, 18; p-CN, ca. 43; p-NO₂, ca. 120. (ii) For PhNHSi(C₆H₄Y)₃ compounds in MeOH (10 vol) + aq. alkali (1 vol) at 50°: (Y =) H, 1.0; p-OMe, 0.12; p-Cl, ca. 32; m-Cl, ca. 84. (iii) For PhNHSiR₃ compounds in MeOH (5 vol) + aq. alkali (2 vol) : (R₃ =) Et₃, 1.0; Et₂Me, 18 (at 30°); Me₂-i-Pr, 8 (at 30°);Me₂-t-Bu, 0.012 (at 50°);i-Pr₃, 0.006 (at 50°). In series (i) the relative rates correlate with σ, or where appropriate σ^?-constants, with a ? value of 1.6. It is suggested that in the transition state of the rate-determining step the OSi bond is fully formed, or almost so, the SiN bond approximately 20—50% broken, and the bond between the nitrogen atom and a proton from the solvent ca. 10—30% formed.     

The chemistry of hetero-allene and -allylic derivatives with rhodium and iridium III. Elimination of hetero-allene molecules from rhodium(I)-hetero-allylic-phosphine complexes. The first complex with η2-coordinated Ph2PS−

Carbon monoxide causes elimination of the hetero-allene molecules ptolNNptol and PhNCO in Rh(PPh₃)₂[Ph₂PC(Nptol)Nptol] and Rh(PPh₃)₂[Ph₂PC(NPh)O], respectively. The resulting complex in both cases is [Rh(CO)₂(PPh₂)(PPh₂)]_n.In the reaction of RhCl(PPh₃)₃ with Ph₂P(S)C(Nptol)NHptol or Ph₂P(S)C(O)NHPh in the presence of a base, a similar elimination occurs yielding the liberated heterocumulene and Rh(PPh₃)₂(SPPh₂). This complex is the first example of a specieswith a side-on coordinated Ph₂PS-moiety. We have also prepared this compound and other species, containing η₂SPPh₂, via direct interaction of RhCl(PPh₃)₃ and IrCl(PPh₃)₂(C₈H₁₄) with Ph₂P(S)H. Upon reaction with CO, the chelating PPh₂ group is displaced by CO to give complexes with an end-on coordinated Ph₂PS^? ligand.Finally, Rh(PPh₃)₂(SPPh₂) incorporates three moles of PhNCS, one by insertion and two by disproportionation, to yield Rh(PPh₃)(PhNC)(PhNCS₂)[Ph₂P(S)C(S)NPh].     

Coordination chemistry of sulfines : I. Synthesis and characterization of the complexes Pt(PPh3)2(XYCSO) (X,Y = aryl,S-aryl,S-alkyl,Cl). Coordination via the CS-π-bond

Reactions of Pt(PPh₃)₄ with the sulfines, XYCSO, (X, Y = aryl, S-aryl, S-alkyl, Cl) yield coordination compounds of the type Pt(PPh₃)₂(XYCSO). Infrared, ³¹P and ¹H NMR spectra reveal that in all cases the sulfine ligand is coordinated side-on via the CS π-bond (Pt—η²-CS). Reactions of Pt(PPh₃)₄ with either the E- or Z-isomer of (p-CH₃C₆H₄)(CH₃S)CSO yields the corresponding E- or Z-coordination compound, Pt(PPh₃)₂[E-(p-CH₃C₆H₄)(CH₃S)CSO] or Pt(PPh₃)₂[Z-(p-CH₃C₆H₄)(CH₃S)CSO], indicating that the configuration of the sulfine ligand is retained upon coordination to the Pt(PPh₃)₂ unit. The compounds Pt(PPh₃)₂(XYCSO), containing reactive CX and/or CY bonds (X, Y = S-aryl, S-alkyl, Cl), undergo a rearrangement in solution to give complexes of the type PtX(PPh₃)₂(YCSO).     

Dicyclopentadienyl-niobium(iii) and -niobium(iv) complexes

The reduction of (η-C₅H₅)₂NbCl₂ (I) under various conditions gives the dimer (η-C₅H₅)₄Nb₂Cl₃ (II) containing niobium(III) and niobium(IV). Reaction of II with AgClO₄ gives [(η-C₅H₅)₄Nb₂Cl₂]⁺ ClO₄^- (III). FeCl₃ and (C₆F₅)₂ TlBr displace I from II to give (η-C₅H₅)₂Nb(μ-Cl)(μ-X)MY₂, where MFe, XYCl(IV) and MTl, XBr, YC₆F₅ (V). Reactions of I with metal halides MXY₂ give (η-C₅H₅)₂ClNb(μ-Cl)MXY₂ where XYCl, MAl (VI), Fe (VII), Tl (VIII) and XBr, YC₆F₅, MTl (IX). The chemical behaviour of all these compounds is described.     

The reaction of organotin compounds with derivatives of triarylmethane in CH2Cl2

The reaction of RSnMe₃ with the triarylmethyl salts Ph₃CBF₄, (C₆Cl₅)₃CSbCl₆ and (p-NO₂C₆H₄)₃CBr was studied. It was shown that the reaction of RSnMe₃ (R  CH₃, CH₂CHCH₂, C₁₃H₉ (9-fluorenyl), C₉H₇ (indenyl), PhCC and CN) with Ph₃CBF₄ is an electrophilic substitution process and that Ph₃CR is formed quantitatively. The reactions of PhSnMe₃ with Ph₃CBF₄ and RSnMe₃ (R  CH₃, CH₂CHCH₂, Ph and PhCC) with (C₆Cl₅)₃SbCl₆ are redox processes. (p-NO₂-C₆H₄)₃CBr only reacts with RSnMe₃ when R is a strong electron withdrawing group (R  9-fluorenyl, indenyl and cyclopentadienyl) and (p-NO₂C₆H₄)₃CR and (p-NO₂C₆H₄)₃C^. are formed. It is assumed that the reactions which give (p-NO₂C₆H₄)₃CR and (p-NO₂C₆H₄)₃C^. are independent.     

Vinyliden-Übergangsmetallkomplexe: II. Die Protonierung der Vinyliden-Komplexe C5H5Rh(CCHR)(PPri3) und ihre stufenweise Umwandlung in Vinyl- und α-Halogenalkyl-Rhodiumverbindungen

The protonation ofC₅H₅Rh(CCH₂)(PPrⁱ₃) (I) by CF₃CO₂H, HCl and HI gives the vinylrhodium compounds C₅H₅Rh(CHCH₂)(PPrⁱ₃)X (II-IV). The reaction of III (X = Cl) and IV (X = I) with a second molecule of HCl leads to the formation of the α-chloroethyl complexes C₅H₅Rh(CHClCH₃)(PPrⁱ₃)X (VII, VIII). The stereochemistry of these products allows us to propose a mechanism for HCl addition to the CC double bond of the vinyl ligand. C₅H₅Rh(CCHPh)(PPrⁱ₃) (XII) reacts with CF₃CO₂H and HI to give the kinetically preferred compounds C₅H₅Rh(Z-CHCHPh)(PPrⁱ₃)X (XIVa, XVa) of which XIVa (X = CF₃CO₂) in4bpolar solvents rearranges smoothly to form the thermodynamically more stable E isomer C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)OCOCF₃ (XIVb). C₅H₅Rh(E-CHCHPh)(PPrⁱ₃)I (XVb) is obtained from XIVb and NaI. The protonation reactions of C₅H₅Rh(CCHMe)(PPrⁱ₃) (XIII) with CF₃CO₂H, HCl and HI always produce mixtures of isomers of the complexes C₅H₅Rh(CHCHMe)(PPrⁱ₃)X (XVI-XVIII). The ratio of Z to E isomers (≈ 62/38) is not dependent on the anion X and is also not influenced by the polarity of the solvent.     

Geometry and conformation of dimethyl sulphate as investigated by electron diffraction and dipolometry

Electron diffraction data of dimethyl sulphate are interpreted by a 2:1 mixture of the C₂ and C_2v rotamers. This finding is also in agreement with the dipole moments of dimethyl sulphate and diethyl sulphate in benzene solution. The SO bond length and OSO bond angle are in agreement with the previously described empirical relationships. The variations in the O ?O distances in the different moieties OSO , OS-O, O-S-O, deserve special attention.     

Weitere Evidenz für die mikroskopische Gleichzeitigkeit des Bruches zweier Bindungen bei einer E2-Reaktion: H-Isotopeneffekte und Substituentenwirkungen bei der Reaktion von 2,2-Diphenyläthyl-benzolsulfonat mit Methoxid-Ion

Second order rate constants are determined for the E2 reactions of 2,2-diphenyl-ethyl benzenesulfonates Ph₂C^xHCH₂O · O₂S–C₆H₄–X with CH₃ONa in methyl cellosolve solution (^xH = H or D, X = p-CH₃O, p-CH₃, H or p-NO₂). The HAMMETT ? values are of the same order of magnitude as those found in the first order solvolyses of methyl, ethyl or isopropyl benzenesulfonates. The primary deuterium isotope effects k_H/k_D are 5.27, 5.42 and 6.70 for X = p-CH₃O, H and p-NO₂. The ? values as well as the increase of k_H/k_D with introduction of p-NO₂ supply evidence for simultaneous C_αO and C_βH bond cleavages also in the E2 reactions of these compounds.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden : VII. Trimethylphosphoranylidenmethyl(trimethylsiloxy)carben-komplexe von chrom,molybdän und wolfram: aufbau einer metallvinyl-einheit durch c(carbanion)c(carben)-π-wechselwirkung und photochemische e/z-isomerisierung

The treatment of the hexacarbonylmetal compounds M(CO)₆ (M = Cr. Mo, W) with two equivalents Me₃PCH₂ yields the phosphonium acylmetalphosphorus ylides Me₄P[(CO)₅MC(O)CHPMe₃] 1a–1c. Their reaction with Me₃SiOSO₂CF₃ leads via O-silylation to formation of the neutral “siloxy(ylidecarbene) complexes” (CO)₅MC(OSiMe₃)CHPMe₃2a–2c, which are protonated by HX (X = Cl, CF₃SO₃) to give the thermolabile carbene complexes [(CO)₅MC(OSiMe₃)H₂CPMe₃]X, 3a, 3b. ¹H, ¹³C NMR and IR data suggest, that delocalization of the ylidic charge to the carbene carbon generates a metal-coordinated vinyl group in the case of 2a–2c. In addition this fact is proved by the X-ray analysis of 2c, for which a C(ylide)C(carbene) bond distance of 133 pm is found. 2a–2c are obtained as pure E-isomers but can be converted to the Z-isomers 2a′–2c′ upon photolysis.     

Dipole moment measurements on metal complexes of monothio-β-diketones

Dipole moments have been reported for over 200 monothio-β-diketone complexes, Met(RCSCHCOR′), (n  2, 3). The data show that the nickel(II), palladium(II), platinum(II), and copper(II) complexes are cis-square-planar, the zinc(II) complexes are tetrahedral, and the chromium(III), iron(III), ruthenium(III), cobalt(III), and rhodium(III) complexes are facial (cis)-octahedral. Measurements of the dipole moments of a considerable number of the metal complexes by both the static polarization and dielectric relaxation methods have shown that atomic polarization is ca. 0.3 D in square-planar, 0.5 D in tetrahedral, and 0.9 D in octahedral complexes.A large number of complexes, Met(RCSCHCOR?_n (R  phenyl or X-substituted phenyl, R′ CF₃) have been studied. The difference in the values of the dipole moments depend upon: (a) the magnitude and vector direction of the PhX bond moments; (b) the inductive effect arising from the difference in electron density of the C¹ and C⁵ carbon atoms of the ligand moiety — this is affected by the nature and position of the substituent X on the phenyl ring; (c) the change in moment brought about by the mesomeric effect of the substituent X.