The photodecomposition of platinacycloalkanes in solution.: I. 1,3-propanediylplatinum(IV) compounds

The gaseous products of the photolysis at 25°C of the platinacyclobutane compounds [X₂$\text{PtCH}{}_2\text{CH}{}_2\text{C}$H₂(N-N)] where X = Cl, Br and N-N = 1,10-phenanthroline, 2,2′-bipyridine, (CH₂NMe₂)₂, (C₅H₅N)₂ in several solvents, in the absence and presence of various additives, have been determined. With solvents of relatively low dielectric constant (e.g. CH₂Cl₂), over 85 mol % of the hydrocarbon products was propene, the formation of which appears to involve a direct transfer of a hydrogen atom between neighbouring groups in the ring. With solvents of relatively high dielectric constant (MeCN, Me₂SO) in the presence of species, e.g. I^?, SbPh₃, having a high trans effect, cyclopropane is the main volatile product. The effect of added halide ion and of the mixed solvents Me₂SO/PhMe and Me₂SO/PhSH indicates that ionisation of the platinacyclobutane and the formation of platinum substituted propyl ion-radicals precede the formation of cyclopropane (and the small amounts of ethylene produced).The photolysis of [X₂$\text{PtCH}{}_2\text{CH}{}_2\text{C}$H₂(MeCN)₂] in methyl cyanide solution in the presence of Et₃RNX′ (X′ = Cl, R = H; X′ = Br, R = Et) gives appreciable amounts of ethylene in the products (up to 25 mol %). It is suggested that the halide ions add to the platinum to give negatively charged platinacyclobutane species, the photodecomposition of which may give C₂H₄.     

The photodecomposition of platinacycloalkanes in solution: II. 1,4-butanediylplatinum(II) and (IV) compounds

The products of the photolysis of a number of platinacyclopentanes in solution at 25°C under a variety of conditions have been determined. With [I₂P$\text{tCH}{}_2\text{CH}{}_2\text{CH}{}_2\text{C}$H₂(L₂)] (L = PMe₂Ph, PPh₃) in CH₂Cl₂, CH₂Br₂ and (CH₃)₂SO the hydrocarbon products are exclusively ethylene and but-1-ene. Formation of the latter through a 1,3-hydrogen shift is preceded by phosphine ligand dissociation. The photolysis of [ICH₃P$\text{tCH}{}_2\text{CH}{}_2\text{C}$H₂(L₂)] gave methane, ethylene, but-1-ene and n-pentane together with a little n-butane, the methane being formed from internal hydrogen abstraction by the CH₃ group in the excited reactant molecule. Photodecomposition of the platinum(II) compounds [P$\text{tCH}{}_2\text{CH}{}_2\text{CH}{}_2\text{C}$H₂(L₂)] (L = (PMe₂Ph)₂, (PPh₃)₂, Ph₂PCH₂CH₂PPh₂) gave ethylene, but-1-ene, pent-1-ene (with the halogenated solvents) and with some systems appreciable yields of n-butane, the latter being the results of internal abstraction of two hydrogen atoms by the C₄H₈ moiety. The formation of pentene is probably preceeded by the addition of CH₂Cl₂ or CH₂Br₂ to the excited reactant molecule. Addition of diphenylphosphine promotes the production of n-butane.     

Reactions of hydridosilacyclobutanes with low-valent complexes of iron or platinum

Unstable transition metal compounds formed from hydridosilacyclobutanes are described: 1-methyl-1-silacyclobutane reacts with nonacarbonyldiiron to give the complexes [Fe(CO)₄(H){$\text{Si(Me)CH}{}_2\text{CH}{}_2\text{C}$H₂}] and [$\text{Fe{CH}{}_2\text{CH}{}_2\text{CH}{}_2\text{Si}$(H)Me}(CO)₄], and with bis(triphenylphosphine)(ethylene)platinum(0) to give [Pt(H)(PPh₃)₂{$\text{Si(Me)CH}{}_2\text{CH}{}_2\text{C}$H₂}].     

Reactions and properties of some trimethyleneplatinum(IV) complexes: V. The kinetics and mechanism of formation from arylcyclopropanes

The kinetics of the reaction of arylcyclopropanes (4-XC₆H₄C₃H₅, X = H, Me, EtO) with either [Pt₂Cl₂(μ-Cl)₂(C₂H₄)₂] or [{$\text{PtCl}{}_2\text{(CH}{}_2\text{CH}{}_2\text{C}$H₂)} in tetrahydrofuran to give in each case [{$\text{PtCl}{}_2\text{(CHArCH}{}_2\text{C}$H₂)}₄] and ethylene or cyclopropane, respectively, have been studied. The reactions are essentially first order in both arylcyclopropane and platinum complexes. The order of reactivity follows the series X = EtO > > Me > H, and [Pt₂Cl₂(μ-Cl)₂(C₂H₄)₂]> [{$\text{PtCl}{}_2\text{(CH}{}_2\text{CH}{}_2\text{C}$H₂)}4] and the rate is accelerated in polar solvents. Mechanisms in which the arylcyclopropane first coordinates to platinum and then undergoes ring opening reactions are proposed.     

Darstellung und eigenschaften von und reaktionen mit metallhaltigen heterocyclen: XXV. Synthese und eigenschaften neuer platina- und rhodacycloalkane durch substitution und oxidative addition einer CCl-bindung

The platinacyclopentane derivative [Cl(CH₂)₃R₂P](Cl)$\text{PtPR}{}_2\text{CH}{}_2\text{CH}{}_2\text{CH}{}_2$ is formed by action of Cl(CH₂)₃PR₂ on Pt(COD)₂ in n-hexane via the not isolable Pt[PR₂(CH₂)₃Cl]₂ (R  C₆H₁₁) by oxidative addition of a CCl bond to platinum. [μ-CIRh(CO)₂]₂ reacts in benzene with Cl(CH₂)₃PR₂ under partially CO substitution to give the stable intermediate Cl(OC)Rh[PR₂(CH₂)₃Cl]₂. In boiling toluene oxidative addition of a CCl bond to rhodium occurs under formation of the phospharhodacyclopentane [CI(CH₂)₃R₂P] Cl₂(OC)-$\text{RhPR}{}_2\text{CH}{}_2\text{CH}{}_2\text{CH}{}_2$ (R  C₆H₅). The ³¹P{¹H}-NMR spectra of the rhodium compound is characterized by an ABX system, that of the platinum by superposition of an ABX pattern with an AB spectrum.     

Reactions and properties of some trimethyleneplatinum(IV) complexes: VII. Kinetics and mechanism of displacement of cyclopropane by alkenes

The kinetics of the reaction of alkenes (e.g. cis-pent-2-ene, hex-1-ene, cyclopentene) with [$\text{PtX}{}_2\text{(CH}{}_2\text{CH}{}_2\text{C}$H₂)(THF)₂] (X = Cl or Br, THF = tetrahydrofuran) or with [$\text{PtCl}{}_2\text{(CHPhCH}{}_2\text{C}$H₂)(THF)₂] in THF solution have been studied. The reactions occur with displacement of cyclopropane or phenylcyclopropane to give [PtCl₂(olefin)(THF)], and follow essentially second order kinetics, first order in both platinum complex and olefin. The mechanism of reaction is discussed.     

The formation of grignard compounds—V: The reaction of iodomethane with magnesium in allyl phenyl ether. A second-order cidnp spectrum

Analysis of product formation reveals that in the reaction of iodomethane and magnesium in anyl phenyl ether ethane and 1-butane are the major side products. The latter product is formed mainly by addition of methyl radicals to the terminal CH₂ group of allyl phenyl ehter, followed by β-scission under extrusion of a phenoxy radical. This mechanism_f is confirmed by an analysis of the CIDNP spectra during the reaction; CH₃ radicals escaping from $\text{CH}{}_3\text{CH}{}_3$ pairs and adding to allyl phenyl ether give rise to a very clear example of a second order CIDNP spectrum in the product 1-butane, while polarization in $\text{CH}{}_3\text{C}{}_6\text{H}{}_5\text{O-CH-CHCH}{}_2$ pairs, formed after α-H abstraction from allyl phenyl ether, leads to net effects in the products ethane (E) and 1-methylallyl phenyl ether (A).     

Transition metal complexes of hexaphenylcarbodiphosphorane

The displacement of tetrahydrofuran (THF) from W(CO)₅(THF) with hexaphenylcarbodiphosphorane yields a compound with a carbon-metal bond (CO)₅W C[P(C₆H₅)₃]₂. The in situ photolysis of tungsten hexacarbonyl and hexaphenylcarbodiphosphorane, however, yields a product (CO)₅W^?CC ⁺P(C₆H₅)₃. Ethylenebis(triphenylphosphine)platinum and hexaphenylcarbodiphosphorane in benzene yield a platinum containing heterocycle [(C₆H₅)₃P]₂$\text{PtC[ P(C}{}_6\text{H}{}_5\text{)}{}_3\text{]P}$-(C₆H₅)₃.     

Isomerisation in the chemistry of platinacyclobutane complexes

The platinacyclobutane complexes PtCl₂L₂(C₃H₅Me)], L  pyridine, CD₃CN, or tetrahydrofuran, exist as mixtures of isomers containing P$\text{tCH}{}_2\text{CHMeC}$H₂ or P$\text{tCHMeCH}{}_2\text{CH}{}_2$ groups in rapid equilibrium. Decomposition occurs in some cases to give [PtCl₂L(CH₃CH₂CHCH₂)]. Stereospecific skeletal isomerisation also occurs in metallocyclobutanes containing the groups P$\text{tCHRCHRC}$H₂  P$\text{tCHRCH}{}_2\text{C}$HR, when R  aryl further decomposition gives ν-allylplatinum complexes.     

Transition metalcarbon bonds: XL. Palladium(II) complexes of [(dimethylamino)methyl]-ferrocene

C₅H₅FeC₅H₄CH₂NMe₂ reacts with sodium chloropalladate(II) in the presence of sodium acetate to give the internally metallated binuclear species [$\text{Pd}{}_2\text{X}{}_2\text{{C}{}_5\text{H}{}_5\text{FeC}{}_5\text{H}{}_3\text{CH}{}_2\text{N}$Me₂}₂] (X = Cl). The corresponding iodide was prepared as were mononuclear species [$\text{Pd(acac) {C}{}_5\text{H}{}_5\text{FeC}{}_5\text{H}{}_3\text{CH}{}_2\text{N}$Me₂}] and [$\text{Pd-{C}{}_5\text{H}{}_5\text{FeC}{}_5\text{H}{}_3\text{CH}{}_2\text{N}$Me₂}L] L = PMe₂Ph, AsMe₂Ph, P(OMe)₃ or PPh₃. ¹H NMR data are given.     

Unusual route to and rearrangement of four-membered ring complexes C5H5Fe (CO) [ (C6H5)2PN(R)CH (C6H5) ]

The amine substituted phosphines (C₆H₅)₂PN(H)CH₂CH₃ and (C₆H₅)₂PN(H)CH₂C₆H₅ react with C₅H₅Fe(CO)₂CH(C₆H₅) (OCH₃) photolytically to give moderate yields of the four-membered chelate ring complexes C₅H₅$\text{Fe (CO) [(C}{}_6\text{H}{}_5\text{)}{}_2\text{PN (CH}{}_2\text{CH}{}_3\text{) C}$H (C₆H₅)] and C₅H₅$\text{Fe (CO) [(C}{}_6\text{H}{}_5\text{)}{}_2\text{PN (CH}{}_2\text{C}{}_6\text{H}{}_5\text{)C}$H(C₆H₅)], respectively. Photolysis of C₅H₅Fe(CO)₂CH(C₆H₅) (OCH₃) in the presence of (S)-(?)-diphenyl(1-phenylethylamino)phosphine leads to the isolation of C₅H₅Fe(CO)[(C₆H₅)2PNC(CH₃) (C₆H₅)]CH₂C₆H₅ which is proposed to arise from a formally 1,3-hydrogen shift rearrangement of an intermediate four-membered chelate ring complex.     

Cyclometallation reactions of N-(benzylidene)benzylamines with palladium compounds

The cyclometallation of p-RC₆H₄CHNCH₂C₆H₂, (R = H, Cl, NO₂) by PdX₂ (X = Cl, AcO) has been studied.In every case the cyclometallation occurs with formation of a five-membered ring containing the methine group. The structure of these compounds [$\text{PdX(}\text{p}\text{-RC}{}_6\text{H}{}_3\text{CHN}$CH₂C₆H₅)]₂, derived from ¹H NMR spectra, are different from those reported previously. Reaction of these compounds with PEt₃ gives the compounds [PdX(p-RC₆H₃CHNCH₂C₆H₅)(PEt₃)₂] but with an excess of PPh₃ only the complexes [$\text{PdX(}\text{p}\text{-RC}{}_6\text{H}{}_3\text{CHN}$CH₂C₆H₅)(PPh₃)] are formed.     

Darstellung und eigenschaften von und Reaktionen mit metallhaltigen Heterocyclen: X. Untersuchungen über den Ablauf der heterolytischen Spaltung der ReRe-Bindung bei der Darstellung von Rhenacycloalkanen; Grenzen ihrer Stabilität und SO2-Insertion in die ReC-σ-Bindung

The six- and seven-membered rhenacycloalkanes (OC)₄R$\text{ePR}{}_2\text{OCH}{}_2\text{XC}$H₂ (R = CH₃, C_oH₅; X = CH₂, CH₂CH₂) are obtained by reaction of the binuclear anions [(OC)₄RePR₂O]₂^2? with the alkanediylbis(triflouromethanesulfonates) X(CH₂Y)₂ (Y = CF₃SO₂O) in dimethoxyethane. In the Reσ bond of (OC)₄R$\text{ePPh}{}_2\text{OCH}{}_2\text{CH}{}_2\text{C}$H₂SO₂ can be inserted under ring expansion. The rhenacycloheptanes (OC)₄R$\text{PR}{}_2\text{OCH}{}_2\text{CH}{}_2\text{CH}{}_2\text{C}$H₂ (R = CH₃, C_oH₅) are thermally unstable and decompose by cleavage of the α-CC bond. The heterolytic cleavage of the ReRe bond in [(OC)₄RePR₂O]₂^2? results in the open chain, ionic intermediate products [R₂(O)PRe(CO)₄CH₂XCH₂Y]^?, which in competition with the cyclisation, are liable to a β-hydrogen transfer. The mechanisms which are responsible for the formation of the hdrido complexes [HRe(CO)₄PR₂O]^? and HRe(CO)₄PR₂OCH₂XCH₃, are discussed.     

On the possibility of a carbenium ion structure for the complexes [Os3H3(CO)9CCR2]+. Further application of the 187Os nucleus

In the ¹H NMR spectrum of the complex [Os₃H₃(CO)₉C$\text{C(CH}{}_2\text{C}$H₂]⁺ at 30°C, under conditions of rapid exchange, the single hydride resonance has two sets of satellites of equal intensity (separated by 32.0 and 28.8 Hz) caused by ¹⁸⁷Os¹H spin—spin coupling. The spectral data rule out the upright carbenium ion structure for the complex, and are consistent with the fluxional process involving hydrocarbon ligand rotation about the C$\text{C(CH}{}_2\text{)}{}_2\text{C}$H₂ axis in a tilted structure, with concomitant rotation of the Os₃H₃(CO)₉ moiety.     

An unusual oxidation/metallation of 2-vinylpyridine

The vinyl group in rans-[PtBr₄{2-(CH₂CH)py}(PEt₃)] undergoes oxidation/metallation metallation ind amp solvents to give [$\text{PtBr}{}_3\text{[2-(C}$H₂·CO)py}(PEt₃)]; the mechanisms of this reaction is discussed. Attempts to prepare this unusual complex from platinum(II) and platinum(IV) complexes containing 2-acetylpyridine were unsuccessful.     

Metallorganische verbindungen des iridiums und rhodiums: XXVI. CH-metallierung und hydridbildung im system Ir2Cl2(C8H14)4/PR3(PR3 = P(CH2CMe3)3, t-BuP(CH2CMe3)2, t-Bu2PCH2CMe3; i-Pr3P

Treatment of Ir₂Cl₂(C₈H₁₄)₄ with the phosphines t-Bu_3?nP(CH₂CMe₃)_n (n = 3,2,1) in hot toluene followed by crystallization of the products from C₇H₈/ EtOH mixtures gave the cyclometallated hydrides (C₈H₁₄)₂Ir-μ-Cl₂$\text{IrH[CH}{}_2\text{CMe}{}_2\text{CH}{}_2\text{P}$(CH₂CMe₃)₂][P(CH₂ (I) [t-BuP(CH₂CMe₃)₂]₂H₂Ir-μ-Cl₂$\text{IrH[CH}{}_2\text{CMe}{}_2\text{CH}{}_2\text{P}$Bu^t(CH₂CMe₃)][t-BuP(CH₂CMe₃)₂] (II), and [(t-Bu₂$\text{PCH}{}_2\text{CMe}{}_2\text{CH}{}_2\text{)HI}$rCl]₂ (III). The dihydrides IrH₂Cl[t-BuP(CH₂CMe₃)₂]₂ (IIa) and IrH₂Cl(t-Bu₂PCH₂CMe₃)₂ (IIIa) were also isolated; these species were, however, more conveniently obtained by bubbling hydrogen through the solution of Ir₂Cl₂ (C₈H₁₄)₄ and the respective phosphine in toluene. i-Pr₃ reacted with the olefiniridium(I) precursor in C₇H₈/EtOH to yield the carbonyl complexes (i-Pr₃P)₂H₂Ir-μ-Cl₂Ir(CO)(PPrⁱ₃)₂ (IV) and IrCl(CO)(PPⁱ₃)₂ (IVa), no cyclometallated product being detected. The stereochemistries of the complexes were deduced from IR, ¹H, ³¹P, and ¹³C NMR data. The crystal structures of IIIa and IVa were also determined.     

Cyclometallation reactions XII. On the effect of various leaving groups on internal metallation reactions with alkylmanganese complexes

The interaction of azobenzene and MnR(CO)₅ (R  Me, Et, CH₂Ph, CH₂-C₆Me₅, COCF₃, COCH₂C₆F₅, COCH₂OPh, Ph or C₆F₅) affords M$\text{n(C}{}_6\text{H}{}_4\text{NN}$Ph)-(CO)₄, together with a binuclear complex Mn₂(CO)₆(C₁₂H₁₀N₂) in some cases. The metallation reaction is shown to proceed most readily with Mn-(CH₂Ph)(CO)₅; with this reagent, the metallated complexes M$\text{n(C}{}_6\text{H}{}_4\text{CH}{}_2\text{P}$Me₂)-(CO)₃[PMe₂(CH₂Ph)] (two isomers) and M$\text{n(C}{}_6\text{H}{}_4\text{CH}{}_2\text{A}$sMe₂(CO)₄ have been obtained on treatment with EMe₂(CH₂Ph) (E  P and As, respectively).     

A dynamic nuclear magnetic resonance study of 1,3-intramolecular shifts in pentacarbonyl-chromium(O) and -tungsten(O) complexes of β-2,4,6-trimethyl-1,3,5-trithian, 1,3,5-trithian, 1,3-dithian and 2-methyl-1,3-dithian: the x-ray crystal structure of [W(CO)5{SCH(Me)SCH(Me)SCH(Me)}]

Variable temperature ¹H NMR spectroscopy has been used in the study of 1,3-intramolecular shifts of the M(CO)₅ moiety in complexes of the general formula [M(CO)₅L], (M = Cr or w), L = $\text{SCH}{}_2\text{SCH}{}_2\text{SC}$H₂, $\text{SCH}{}_2\text{SCH}{}_2\text{CH}{}_2\text{C}$H₂ and $\text{SCH(Me)SCH}{}_2\text{CH}{}_2\text{C}$H₂. For the 1,3,5-trithian complexes precise energy barriers for the process have been obtained by detailed computer simulation of the static and dynamic spectra. Our results suggest that the magnitude of ΔG^≠ (298.15 K) for the 1,3-shift is largely dependent upon the skeletal flexibility of the ligand system. In this context we have investigated the X-ray crystal structure of the highly substituted trithian complex [W(CO)₅{β-$\text{SCH(Me)SCH(Me)SC}$H(Me)}].     

1-[(π-Cyclopentadienyl)dicarbonyliron]-1-methylsilacyclobutane and related iron-substituted silacyclobutanes

Silicon-transition metallic silacyclobutanes CpFe(L₂)$\text{Si(Me)CH}{}_2\text{CH}{}_2\text{C}$H₂ [L = CO or Ph₂MeP; or L₂ = (CO)(Ph₂MeP)] have been prepared and their reactions (substitution at Si or Fe, Si—Fe cleavage, or ring-opening) studied.     

Die thermische reaktion von C5H5(CO)2FeNa mit benzimidchloriden C6H5(Cl)CNR

η⁵-C₅H₅(CO)₂FeNa reacts with the benzimide chlorides C₆H₅(Cl)CNR (R  CH(CH₃)₂, C₆H₅) in boiling THF to give the η¹-iminoacyl complexes η⁵-C₅H₅ (CO)₂Fe[η¹-C(C₆H₅)NR]. Alternatively, the new Fe complexes [η⁵-C₅H₅(CO)Fe$\text{C(C}{}_6\text{H}{}_5\text{)N(CH}{}_3\text{)C(C}{}_6\text{H}{}_5\text{)N}$CH₃PF₆ (IV) and [η⁵-C₅H₅(CO)₂FeC(C₆H₅)N(CH₃)C(C₆H₅)NCH₃]PF₆ (V) are formed under the same conditions, if R  CH₃. Hudrolysis of the CN single bond of the ligand in V, not stabilized by a chelate effects as in IV, results in the formation of [η⁵-C₅H₅(CO)₂FeC(C₆H₅)NHCH₃]PF₆ (VII). Reaction of η⁵-C₅H₅(CO)₂ with N-benyzylbenzimido chloride yields η⁵-C₅H₅(CO)₂FeCH₂C₆H₅ as the only isolated product.