Synthesis of platinum-iodo-alkyl/aryl complexes in ligand-exchange reactions: Determination of the structure of Pt{(S,S)-bdpp}(X)I complexes (X = Me, I) by X-ray crystallography

Pt{(S,S)-bdpp}(R)I (bdpp = 2,4-bis(diphenylphosphino)pentane; R = Me, Ph, Bz, 2-Tioph) complexes were formed in alkyl/aryl ligand - iodide ligand-exchange reactions by reacting the corresponding Pt{(S,S)-bdpp}R₂ complexes with methyl iodide. The Pt{(S,S)-bdpp}(Me)I complex was isolated and fully characterised. The influence of the X ligand on the platinum-bdpp chelate conformation was investigated in Pt{(S,S)-bdpp}(X)I (X = I, SnCl₃, Me) complex series by means of X-ray crystallography.     

The formation of dimetallocycles from reactions of alkynes with (η-C5Me5)2Rh2(CO)2; X-ray structure of [(η-C5Me5)2Rh2(η-CO) {μ-η2,η2-C(O)C2-(CF3)2}]

The complexes (η-C₅Me₅)₂Rh₂(μ-CO) {μ-η²,η²-C(O)CRCR} are obtained from reactions between (η-C₅Me₅)₂Rh₂(CO)₂ and the alkynes RCCR (R  CF₃, CO₂Me, or Ph) at 25°C. The molecular geometry of the complex with R  CF₃ has been established by X-ray diffraction; the bridging 'ene-one' unit adopts a μ-η²,η² conformation. Other complexes isolated from these reactions include (η-C₅Me₅)Rh(C₆R₆) (R  CF₃, CO₂Me), (η-C₅Me)₂Rh₂(C₄R₄) (R  CO₂Me) and (η-C₅Me₅)₂Rh₂(CO₂C₂R₂) (R  Ph). The reaction between (η-C₅Me₅)₂Rh₂(CO)₂ and C₆F₅CCC₆F₅ gives (η-C₅Me₅)₂Rh₂(CO)₂(C₆F₅C₂C₆F₅). Mononuclear complexes such as (η-C₅Me₅)Co(C₄R₄CO) are the major products isolated from reactions between (η-C₅Me₅)₂CO₂(CO)₂ and alkynes at 25°C.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden: XII. Eisenkomplexe mit η1-koordinierter vinylgruppe: spontane zweif achmethylierung des β-kohlenstoffs mit methyliodid oder methylfluorsulfonsäureerster

The reaction of vinyl complexes Cp(CO)(R₃P)FeC(OMe)CH₂ (R  Me, R  Ph) with the methylating reagents MeX (X  OSO₂F, I) in the molar ratio 1/1 affords a mixture of the carbene complexes [Cp(CO)(R₃P)FeC(OMe)R]X (R  Me, Et, i-Pr). Their formation is explained via a series of acid/base equilibria established between vinyl and carbene complexes.     

Phosphinsubstituierte chelatliganden I. Mangan- und rheniumcarbonyl-komplexe mit phosphino-(thio)formamid- und -dithioformiat-liganden

A series of new tetracarbonyl and tricarbonyl complexes of manganese and rhenium with heteroallylic phosphine chelate ligands L  [XC(Y)PPh₂]^? and HXC-(Y)PPh₂ (X, Y  NR, O, S) were prepared by reaction of the appropriate metal carbonyl halides with the free ligands or their silyl intermediates. The silyl method yields both cis-(CO)₄ML and fac-(CO)₃M(X)L (X  Cl, Br) complexes by controlled addition of water. Analytical, spectroscopic and crystallographic data of the ambidentate thioformamide ligands result in a P,S-coordination in all complexes. The ¹³C NMR spectra of several selected compounds were recorded and reveal some unexpected features.     

Neue Synthesen von Me2SbX (X = Cl,I) und Kristallstrukturen von Me2SbI und [(Me3Si)2CH]2SbCl

Novel Syntheses of Me₂SbX (X = Cl, I) and Crystal Structures of Me₂SbI and [(Me₃Si)₂CH]₂SbCl The crystal structures of Me₂SbI (Me = CH₃) and [(Me₃Si)₂CH]₂SbCl have been determined by X‐ray methods. Both molecules are pyramidal. The Me₂SbI molecules are associated to chains through short intermolecular Sb…I distances (366,7(1) pm) with linear I–Sb…I units (171,87(4)°) and bent Sb–I…Sb bridges (116,83(3)°).     

Metallorganische Lewis-Säuren. XLII. Carbonyl- und Nitrosyl-Komplexe von Mangan und Rhenium mit schwach koordinierten Anionen (Ph3P)2(ON)2MnX, (Ph3P)n(OC)5–nMX (M = Mn,Re; n = 1, 2; X = FBF3, OSO2CF3, OSO2F,OCORf)

Organometallic Lewis Acids. XLII. Carbonyl- and Nitrosyl Complexes of Manganese and Rhenium of Weakly Coordinated Anions (Ph₃P)₂(ON)₂MnX, (Ph₃P)_n(OC)_5–nMX (M = Mn, Re; n = 1, 2; X = FBF₃, OSO₂CF₃, OSO₂F, OCOR_f) The complexes (Ph₃P)₂(ON)₂MnX (X = FBF₃, OSO₂CF₃, OSO₂F, OCOCF₃, OCOC₃F₇) and (Ph₃P)_n(OC)_5–nMX (M = Mn, Re; n = 1, 2; X = FBF₃, OSO₂CF₃) have been obtained by reaction of (Ph₃P)₂(ON)₂MnH and (Ph₃P)_n(OC)_5–nMeMe with the corresponding acids HX or from (Ph₃P)_n(OC)_5–nReBr (n = 1, 2) with silver salts AgX, respectively. The compounds have been characterized by their IR and partially by ¹⁹F-NMR data. An efficient method for the preparation of the hydride (Ph₃P)₂(ON)₂MnH is reported.     

Protonation of 3-Arylpropynoic Acid Derivatives in Superacids

According to the ¹H and ¹³C NMR data, 3-arylpropynoic acids and their esters XC₆H _n -C≡C-CO₂R (R = H, Me, Et) having electron-withdrawing substituents in the benzene ring (X = NO₂, CN, COMe, CO₂Me) exist in HSO₃F at ?80 to 0°C as XC₆H _n -C≡C-C⁺(OH)OR ions. Derivatives with other substituents (X = H, F, Me, MeO) in HSO₃F or CF₃SO₃H above ?40°C undergo protonation at the acetylenic carbon atom neighboring to the acid group to give unstable vinyl-type XC₆H _n -C⁺=CH-CO₂R cations which are then transformed into mixtures of stereoisomeric (Z and E) fluorosulfonates or triflluoromethanesulfonates XC₆H _n -CY=CH-CO₂R (Y = OSO₂F, OSO₂CF₃), the E isomer prevailing.     

Cleavage of the carbon-silicon bonds in trimethylsilylacetylenes by trans[(PR3)2PtX(R′OH)]PF6 cations and formation of cationic alkoxycarbene complexes of platinum(II)

Cationic alkoxycarbene complexes of platinum(II) have been isolated in the reactions of trans-[(PR₃)₂PtX(R′OH)]PF₆ (X  H or Me; R′  Me or Et) with Me₃SiCCR′′ (R′′  H, Me or SiMe₃). In these reactions cleavage of the carbon-silicon bond by the nucleophilic attack of alcohol has been observed. These carbene complexes have been characterized by elemental analyses and by IR, ¹H and ¹³C NMR spectral data. ¹³C NMR chemical shift data for carbene carbon atoms suggest that the carbene carbon may be very positively charged.     

Structural study of iron carbonyl derivatives: IV. Synthesis and crystal and molecular structure of syn-[μ-(SCH3)Fe(CO)2P(CH3)3]2

Dimeric palladium(I) complexes of the type [μ-(η³-C₅H₅)-μ-XPd₂(PR₃)₂](X  Br, R  i-Pr, Ph, Cy; X  Cl, I, R  i-Pr) have been prepared by reduction of the complexes [(ν⁵-C₅H₅)(PR₃)PdX] with a variety of reducing agents (Mg,Na/Hg, LiAlH(t-BuO)₃, LiAlH₄, NaBH₄, n-BuMgBr). PMR and IR data and some properties of the new complexes are reported.     

Dinuclear formamidino and triazenido compounds [{2,6-(Me2NCH2)2C6H3} (p-tolylNYNR)PtHgBrCl] (Y  CH,N) containing a platinum-to-mercury donor bond

Complexes [{2,6-(Me₂NCH₂)₂C₆H₃} (p-tolylNYNR)PtHgBrCl] (Y  CH, N; R  Me, Et, i-Pr) have been prepared by the reaction of [{2,6-(Me₂NCH₂)₂C₆H₃}-PtBr] with [Hg(p-tolylNYNR)Cl]. Similar complexes were obtained, although in lower yields, from exchange reactions of [{2,6-(Me₂NCH₂)₂C₆H₃} (RCO₂)-PtHg(O₂CR)Br] with p-tolylNNN(H)-p-tolyl and p-tolylNC(H)N(H)Et.The proposed structure for these heterodinuclear compounds involves a Pt-to-Hg donor bond which is bridged by a triazenido (Y  N) or a formamidino (Y  CH) group, the five-membered ring thus formed acting as a stabilizing factor. The absence of a subsequent electron transfer reaction is ascribed to the constraints of the terdentate 2,6-(Me₂NCH₂)₂C₆H₃ ligand, which fixes the N-donor atoms in mutual trans-positions.The use of p-tolylNYNR, where R is an alkyl group, results in the formation of two isomers of [{2,6-(Me₂NCH₂)₂C₆H₃} (p-tolylNYNR)PtHgBrCl] with p-tolyl-N and alkyl-N sites bonded either to Pt or Hg. The relative abundance of these isomers varies systematically with the nature of the group R. It is suggested that the ratio is determined during the formation of the complexes and that both steric and electronic factors are important.     

Atran-analoge Verbindungen III. Atran-analoge Verbindungen des Typs Me2DCH2CH2OSi(Me) (OCH2CH2)2D′ Me (I) und Me2DCH2CH2OSi(Me) (OCH2CH2D′Me2)OCH2CH2D″ Me2 (II) (MeCH3; D,D′, D‴N,P, As)

Atrane-analogous Compounds. III. Atrane-analogous Compounds of the Type Me₂DCH₂CH₂OSi(Me)(OCH₂ CH₂)₂ D′Me (I) and Type Me₂DCH₂CH₂OSi(Me) OCH₂CH₂₂D″Me₂ (II) (Me?CH₃; D, D′, D″?N, P, As) Atrane analogous compounds I and II (Abb. 1) have been prepared by condensation reactions of trifunctional silanes RSiX₃ (X?Cl, OEt, NMe₂) with N-methyldiethanolamine, ß-chloroethanol, ß-dimethylaminoethanol, and ß-dimethylarsanoethanol according to eqn. (1) to (3) and reaction schemes of Figs. 2 and 3, respectively. For compounds of type I weak N→Si adduct bonding is indicated for the MeN-donor of the eight-membered ring by significant shifts of the MeNCH₂ and OCH₂ proton n.m.r. signals. For compounds of type II there is no n.m.r. evidence for D→Si interactions. In spite of equal Lewis acidity of the Si atoms differences in adduct formation are observed for cage, ring, and acyclic podand systems, which can be explained mainly by entropy effects connected to the formation of five-membered rings.     

The cis-Re(Ph2PCH2CH2PPh2)2)+ metal centre. Synthesis and molecular structure of the dinitrile complex cis-[Re(NCC6H4Me-4 2(Ph 2 PCH 2 CH 2 PPh 2 2 ][BF4]

Reaction of NCC₆H₄X-4 (X  Me, OMe, or Cl) with trans-[ReCl(N₂)(dppe)₂] (dppe  Ph₂PCH₂CH₂PPh₂), at room temperature, in the presence of Tl[BF₄], gives the corresponding complexes cis-[Re(NCC₆H₄X-4)₂(dppe)₂][BF₄] (1); the crystal structure of 1 (X  Me) has been determined by single crystal X-ray diffraction analysis.     

The addition of small molecules to (η-C5H5)2Rh2(CO)(CF3C2CF3) : I. The coordinative-addition of CO,CNR, and some group V donor ligands

Treatment of the μ(η¹)-alkyne complex (η-C₅H₅)₂Rh₂(CO)₂(CF₃C₂CF₃) with trimethylamine-N-oxide results in mono-decarbonylation to give the μ(η²)- alkyne complex (η-C₅H₅)₂Rh₂(μ-CO)(CF₃C₂CF₃). Coordinative addition of a variety of ligands L to the monocarbonyl complex has been achieved at room temperature, and stable adducts (η-C₅H₅)₂Rh₂(CO)L(CF₃C₂CF₃) (L  CO, CNBu^t, PPh₃, PMePh₂, P(OMe)₃, AsPh₃, PF₃ and PF₂(NEt₂)) have been fully characterized by infrared and NMR spectroscopy. In each complex, there is a μ(η¹)-attachment of the hexafluorobut-2-yne and a trans-arrangement of CO and L. The spectroscopic data establish that there is rapid scrambling of CO and L when L  CNBu^t. An unstable adduct is formed when (η-C₅H₅)₂Rh₂(μ-CO)(CF₃C₂CF₃) is dissolved in pyridine.     

The reaction of (trifluoromethyl)dialkylaminoboranes with HF,HCl and HBr. X-Ray structure investigation of the amineboranes (CF3)2B(X)NHMe2, X  F and OH

The reactions of CF₃B(NMe₂)₂ (I) and (CF₃)₂BNMe₂ (II) with HX (X  F, Cl and Br) have been investigated. Additions with preservation of the BC bonds to yield species with tetracoordinate boron, along with some BN cleavage, were observed. While I formed boronium salts CF₃B(X)(NHMe₂)₂⁺X⁻ with X  Cl and Br, CF₃BF₂ · NHMe₂ (V) was obtained with HF. On the other hand, reactions of II with HX yielded the 1 : 1 adducts (CF₃)₂B(X) · HNMe₂ in each case. Of these, the species with X  F (VI) and X  OH (IX) (obtained by hydrolysis) were examined by single crystal X-ray diffraction. Surprisingly, no difference was found between the average BC bond lengths of these borates (VI 1.612(8), IX 1.624(4) Å) and that of II. The implications of this observation for BCF₃ bonding are discussed.     

Deactivation of I(52P1/2) by CF3I,CH3I,C2H5I,and CH4

The technique of laser photolysis of alkyl and perfluoroalkyl iodides at 266 nm followed by time-resolved detection of the 1.3-μm emission from I^*(²P_1/2) has been used to measure the rate constants for deactivation of I^* by CH₃I, C₂H₅I, CF₃I, and CH₄. The recommended values are (2.76± 0.22) × 10^?13, (2.85 ± 0.40) × 10^?13, (3.5 ± 0.5) × 10^?17, and (7.52 ± 0.12) × 10^?14, respectively, in units of cm³ molecule^?1 S^?1.     

SiSi-Kopplungskonstanten symmetrischer disilane

²⁹Si²⁹Si-one bond coupling constants for a series of symmetric disilanes XH₂SiSiH₂X, X = Ph, I, Tf (Tf = OSO₂CF₃) and X₂HSiSiHX₂, X = Ph, I, Br, Me, tBu and Tf have been measured using a modified INADEQUATE pulse sequence. Correlations between SiSi coupling constants, force constants and SiH coupling constants are discussed.     

Hydrochalcogenide and hydride-hydrochalcogenide complexes of rhodium with the tripodal tetraphosphine pp3

The stable hydrochalcogenide [(pp₃)Rh(XH)] complexes (pp₃ = tris(2-diphenylphosphinoethyl)phosphine; X  S (1), Se (2)) have been prepared by treatment of [RhCl(cod)]₂ with hydrochalcogenide solutions in the presence of pp₃. The two compounds react with CF₃SO₃H to yield the rare cis-hydride-hydrochalcogenide [(pp₃)Rh(H)(XH)]CF₃SO₃ compounds (X  S (3), Se (4)), which appear to be formed through an internal oxidative addition.     

Bond energies and thermal decomposition of [Pt(X)(CH3)(P(C2H5)3)2] complexes

The thermal decomposition of the complexes trans-[Pt(X)(CH₃)L₂] (L  P(C₂H₅)₃; X  Cl, Br, I, CN) in decalin at 170 and 200°C affords methane platinum metal and [Pt(X)₂L₂]. The kinetics of the decomposition of the complexes were determined by monitoring the appearance of methane by GLC. The observed first-order rate constant was found to be independent on the nature of the ligand X. The thermal decomposition of the trideuteriomethyl complexes [Pt(X)(CD₃)L₂] (X  I, CN) in decalin-d₁₈ at 170 and 200°C was studied by GLC/MS. The thermolysis affords CD₃H and CD₄ in ratios which are independent of the nature of X and of the temperature used. The mass spectra of the complexes were also examined. A relative scale of platinum-to-methyl bond dissociation energies has been established by measuring the appearance potential of the fragment ion [Pt(X)L₂]⁺ and the ionization energies in the series [Pt(X)(CH₃)L₂]. Ionization potentials and PtCH₃ bond energies show a clear dependence on the nature of X which is not reflected in corresponding changes in the decomposition rates.     

Trifluoromethanesulfonato complexes of (1,4,8,11-tetraazacyclotetradecane)cobalt(III) and ruthenium(III) with trans geometry

Reaction of trans-[M(cyclam)Cl₂]Cl (M = Co, Ru; cyclam = 1,4,8,11-tetra-azacyclotetradecane) with anhydrous CF₃SO₃H at elevated temperatures formed initially trans-[M(cyclam)Cl(OSO₂CF₃)](CF₃SO₃), with trans-[M(cyclam)(OSO₂CF₃)₂](CF₃SO₃) formed after extended reaction time. The complexes were characterized by spectroscopy, and rate constants for the rapid aquation of the bound CF₃SO₃⁻ determined. In the case of the cobalt(III) complexes, derivatives were prepared by substitution of the CF₃SO₃⁻ ligand by the neutral ligands acetonitrile and dimethylformamide.     

Darstellung,Charakterisierung und Struktur funktionalisierter Fluorphosphaalkene des Typs R3E–P=C(F)NEt2 (R/E = Me/Si,Me/Ge,CF3/Ge,Me/Sn)

Preparation, Characterization, and Structure of Functionalized Fluorophosphaalkenes of the Type R₃E–P=C(F)NEt₂ (R/E = Me/Si, Me/Ge, CF₃/Ge, Me/Sn) P‐functionalized 1‐diethylamino‐1‐fluoro‐2‐phosphaalkenes of the type R₃E–P=C(F)NEt₂ [R/E = Me/Si ( 2 ), Me/Ge ( 3 ), CF₃/Ge ( 4 ), Me/Sn ( 5 )] are prepared by reaction of HP=C(F)NEt₂ ( 1 , E/Z = 18/82) with R₃EX (X = I, Cl) in the presence of triethylamine as base, exclusively as Z‐Isomers. 2–5 are thermolabile, so that only the more stable representatives 2 and 4 can be isolated in pure form and fully characterized. 3 and 5 decompose already at temperatures above –10 °C, but are clearly identified by ¹⁹F and ³¹P NMR‐measurements. The Z configuration is established on the basis of typical NMR data, an X‐ray diffraction analysis of 4 and ab initio calculations for E and Z configurations of the model compound Me₃Si–P=C(F)NMe₂. The relatively stable derivative 2 is used as an educt for reactions with pivaloyl‐, adamantoyl‐, and benzoylchloride, respectively, which by cleavage of the Si–P bond yield the push/pull phosphaalkenes RC(O)–P=C(F)NEt₂ [R = tBu ( 6 ), Ad ( 7 ), Ph ( 8 )], in which π‐delocalization with the P=C double bond occurs both with the lone pair on nitrogen and with the carbonyl group.