Alternativ-Liganden. XXII. Rhodium(I)-Komplexe mit Donor/Akzeptor-Liganden des Typs Me2PCH2CH2SiXnMe3−(X = F,Cl, OMe)

Alternative Ligands. XXII. Rhodium(I) complexes with Donor/Acceptor Ligands of the Typs Me₂PCH₂CH₂SiX_nMe_3?n(X = F, Cl, OMe) Donor/acceptor ligand of the type Me₂PCH₂SiX_nMe_3?n react with [Rh(CO)₂Cl]₂ ( 1 ) to give the mononuclear complexes RhCl(CO)(PMe₂CH₂CH₂SiX_nMe_3?n)₂ ( 2-6 , Table 1) with planar geometry of the donor atoms, one exception being Me₂PCH₂CH₂CH₂SiCl₃, yielding the crystalline Rh^III-complex RhCl₂(CO)(PMe₂CH₂CH₂SiCl₂)(PMe₂CH₂CH₂SiCl₃) ( 7 ) by oxidative addition of one of the SiCl bonds to the Rh¹ precursor. Structures with Rh → Si interaction between the basic central atoms and the acceptor group SiX_nMe_3?n could be detected in the isolated products neither spectroscopically nor by X-ray diffraction of the two representatives RhCl(CO)(PMe₂CH₂CH₂SiF₃)₂ ( 2 ) and RhCl(CO)[PMe₂CH₂CH₂siF₃]₂ ( 2 ) and RhCl(CO) [PMe₂CH₂CH₂Si(OMe₃]₂ ( 6 ). The presence of such acid/base adducts in the reaction mixture is indicated for the more acidic acceptor groups SiX_nMe_3?n byv_co values near 1990cm^?1, (see Table 3). The complex RhCl(CO)PMe₃)(PMe₂CH₂CH₂SiF₃ ( 8 ) is obtained by the reaction of RhCl(CO)(PMe₃)₂ ( 9 ) with Me₂PCH₂SiF₃ and has been identified spectroscopically in a mixture with 2 and 9 .     

Alternativ-Liganden. XXI. Neue Donor/Akzeptor-Liganden Me2PCH2CH2SiFnMe3-n,Me2PCH2CH2SiR(C6H4F)2 und (2-Me2PC6H4)SiXMe2

Alternative Ligands. XXI. Novel Donor/Acceptor Ligands Me₂PCH₂CH₂SiF_nMe_3-n, Me₂PCH₂CH₂SiR(C₆H₄F)₂, and (2-Me₂PC₆H₄)SiXMe₂ Donor/acceptor ligands of the type Me₂PCH₂CH₂SiX₃ [X = Cl ( 1 ), F ( 2 ), Me ( 3 ), OMe ( 4 )], (Me₂PCH₂CH₂)₂SiX₂ [X = Cl ( 6 ), F ( 7 )], Me₂PCH₂CH₂SiX(C₆H₄F)₂ [X = F ( 5 ), Me ( 8 )], and Me₂PCH₂CH₂SiX_nMe_3-n[n = 1; X = Cl ( 10 ), F ( 11 ); n = 2; X = F ( 9 )] are prepared in yields between 42 and 95% by photochemical addition of Me₂PH to the corresponding vinylsilane precursors. In case of the halogen containing representatives formation of solid polyadducts, due to Lewis acid/base interaction between P-donor and Si-acceptor function, reduces the yields. Ligands of the type (2-Me₂PC₆H₄)SiXMe₂ [X = NMe₂ ( 12 ), Cl ( 13 ), F ( 14 )] are obtained by two different routes (Abb. 3), using 2-chlorobromobenzene as the starting material. New compounds have been characterized by analytical (C, H) and spectroscopic (NMR, MS) investigations. In order to elucidate the associative properties compounds 2 and 9 were used for the following experiments:

• – Study of the influence of dissolution on the proton and fluorine resonances of 2 and 9 ,
• – investigation of the adduct equilibrium (–H₂CF₃Si←PMe₂CH₂–)n + nBF₃ → n[F₃B←PMe₂CH₂CH₂SiF₃],
• – cleavage of the polyadduct of 2 using [NH₄]F and [Me₄N]F, respectively, for the formation of hexacoordinate complex anions [Me₂PCH₂CH₂SiF₅]^2?.

The results obtained confirm the assumption that oligo- and polymerisation are due to P→Si interaction.     

Alternativ-Liganden. XXIII. Rhodium(I)-Komplexe mit Donor/Akzeptor-Liganden des Typs (Me2PCH2CH2SiX2 und (2-Me2PC6H4)SiXMe2 (X = F,Cl)

Alternative Ligands. XXIII Rhodium(I) Complexes with Donor/Acceptor Ligands of the Type (Me₂PCH₂CH₂)₂SiX₂ and (2-Me₂PC₆H₄)SiXMe₂ (X = F, Cl) Donor/acceptor ligands of the type (Me₂PCH₂CH₂)₂SiX₂ and (2-Me₂PC₆H₄)SiXMe₂ (X = F, Cl) react with [Rh(CO)₂Cl]₂ (₁) to give the mononuclear complexes RhCl(CO)(Me₂PCH₂CH₂)₂SiX₂ [X = F( 4 ), Cl ( 5 )] and RhCl(CO)[2-Me₂PC₆H₄)SixMe₂]₂ [X = F ( 8 ), Cl ( 9 )], respectively. In case of the ligands (Me₂PCH₂CH₂)₂SiCl₂ ( 3 ) and (2-Me₂PC₆H₆)SiClMe₂ ( 7 ) the Rh(I) complexes formed in the first step partly undergo oxidative addition reactions of SiCl bonds yielding rhodium(III) compounds of low solubility. Only for 8 the coordination shifts Δδ = δ(complex)?δ(ligand) and coupling constants give some indication to possible Rh→Si interactions. However, the molecular structure of 8 determined by X-ray diffraction does not show RhSi or RhF bonding contacts. The new compounds were characterized by analytical (C, H) and spectroscopic investigations (MS, IR,-NMR).     

Pentabenzylcyclopentadienyl molybdenum and tungsten hydrides: Syntheses, structures and electrochemistry of [MHCp(CO)2(L)] (L = CO, PMe3, PPh3)

Complexes [MHCp^Bz(CO)₂(PR₃)] (R = CH₃, M = Mo (1); M = W (2); R = Ph, M = Mo (3); Cp^Bz = C₅(CH₂Ph)₅) were prepared by thermal decarbonylation of the corresponding [MHCp^Bz(CO)₃] in the presence of trimethyl- or triphenyl-phosphine. In solution the NMR spectra of all compounds show the presence of cis and trans isomers that interconvert at room temperature. In the solid state the molecular structures obtained for compounds 1 and 2 correspond to the trans isomers, while for 3 the cis isomer is present.The electrochemistry of [MoHCp^Bz(CO)₂(PMe₃)] (1), [MoHCp^Bz(CO)₃] (5), [WHCp^Bz(CO)₃] (6), [WCp^Bz(CO)₃]₂ (7), and [MCp^Bz(CO)₃(CH₃CN)]BF₄ (8), is described. The cleavage of M-H bonds takes place upon oxidation or reduction. Cations [MCp^Bz(CO)₂L(CH₃CN)]⁺ form in solvent-assisted M-H bond breaking upon oxidation of [MHCp^Bz(CO)₂L] (L = PMe₃, CO). Reduction of [MHCp^Bz(CO)₃] gives [MCp^Bz(CO)₃]⁻ and H₂. The presence of one PMe₃ ligand lowers the reduction potential and precludes the observation of reduction waves.     

The preparation and molecular structure oftrans-[MoCl2(PMe2Ph)4]

Summary The compoundtrans-[MoCl₂(PMe₂Ph)₄] has been prepared by the reduction of MoCl₅ (by Mg) or of [MoCl₃(PMe₂Ph)₃] (by LiBuⁿ) in the presence of PMe₂Ph in tetrahydrofuran (THF). It has _eff=2.84 B.M. and crystallises in space group P1 witha=11.591(3),b=12.931(3),c=12.703(3) Å, = 95.28(2), =105.97(2), =103.54(2)°. Refinement of the structure gave R=0.036. The Mo-Cl and Mo-P distances average 2.443(6) and 2.534(8) Å, respectively.Low-valent phosphine complexes of the Group VI metals continue to attract much attention because of their involvement in studies of the catalytic activation of dinitrogen⁽¹⁾, dihydrogen(^{2, 3}), alkenes and alkynes(⁴). As a by-product during our studies of dinitrogen(¹) and hydride(²) complexes of molybdenum and tungsten, we obtainedtrans-[MoCl_2- (PMe₂Ph)₄] as yellow, paramagnetic crystals (_eff= 2.84 B.M.). We first obtained the compound during the attempted synthesis ofcis-[Mo(N₂)₂(PMe₂Ph)₄] by reduction of MoCl₅ with Mg in the presence of PMe₂Ph (see Experimental). Upon identification of the compound we found that it could be readily synthesised by treatment of [MoCl₃(PMe₂Ph)₃]⁽⁵⁾ with LiBuⁿ in THF in the presence of PMe₂Ph (experimental).The complex was shown to have thetrans structure by x-ray analysis (Figure). Analogues oftrans-[MoCl₂(PMe₂Ph)₄] have been prepared, namely [CrCl₂(Me₂PCH₂CH₂PMe₂)₂]⁽⁶⁾,trans- [MoCl₂(PMe₃)₄]⁽⁷⁾, [WCl₂(PMe₂Ph)₄]⁽⁸⁾ and [WCl₂(PMe₃)₄]⁽⁴⁾, of which onlytrans-[MoCl₂(PMe₃)₄] has been examined by X-rays⁽⁷⁾. Its principal structural parametersi.e. d(Mo-Cl)= 2.420(6), d(Mo-P)_av=2.496(3) Å⁽⁶⁾ are close to those found here fortrans-[MoCl₂(PMe₂Ph)₄].     

Reactions of Cyclopalladated Benzylidene-aniline Schiff's Base Complexes. Selective Synthesis of 2′-Substituted Schiff's Base Derivatives and the X-Ray Crystal Structure of the Dimer [Pd(μ-OAc)(5′-OCH3?C6H3CHNC6H4-4-CH3)]2

The 2′-cyclopalladated imine complex , reacts with CO in MeOH to afford the 2′-substituted aryl imine 2′-CO₂CH₃-5′-OCH₃? C₆H₃CH?NTol (Tol = C₆H₄-4-CH₃). The product of this reaction can be altered by changing the bridging ligand from AcO to Cl, in which case only the 5-membered ring heterocyclic compound is obtained. [Pd(μ-OAc)( 1a )]₂ with 2 equiv. of Ph₃P and CO (1 atm) gives the heterocyclic which arises from two CO insertion reactions, whereas [PdX( 1a )]₂ (X = AcO, Cl) with 4 equiv. of C?NBu^t and 4 equiv. of Ph₂PCH₂CH₂PPh₂ affords the heterocyclic ketenimine [PdCl( 1a )]₂ reacts with CH₂?CHCO₂CH₂CH₃ to afford 2′(? CH?CHCO₂CH₂CH₃)-5′-OCH₃C₆H₃CHO, and [Pd(μ-OAc)( 1a )]₂ with I₂ to give 2′-I-5′-OCH₃C₆H₃CHO. Excess CH₃O₂CC?CCO₂CH₃ reacts with various substituted cyclopalladated Schiff's bases in MeOH to afford which we formulate as possessing two Pd? C bonds, and one coordinated ester O atom. The X-ray crystal structure of [Pd(μ-OAc)( 1a )]₂ has been determined; relevant bond lengths [Å] and bond angles [°] are: Pd? O(1), 2.139(6), Pd? O(2), 2.026(6), Pd? N, 2.039(6), Pd? C(2′), 1.951(8), Pd? Pd, 3.113(1), N? Pd? C(2′), 80.9(3), N? Pd? O(1), 97.5(2), C(2′)? Pd? O(2), 91.7(3), O(1)? Pd? O(2), 89.2(2).     

Metal Ions in Biological Systems,Volume 4. Metal Ions as Probes; : edited by Helmut Sigel,Marcel Dekker,New York, 1974, xii + 261 pages, $24.75.

Trends in ³¹P NMR coordination shifts for the complexes M(CO)₃BrL₂, [M(CO)₃L₂(NCMe)]⁺, MeC₅H₄Mn(CO)L₂ and [MeC₅H₄Mn(CO)₂]₂L₂ (M = Mn and Re;L₂ = Ph₂PCH₂PPh₂, Ph₂PCH₂CH₂PPh₂ and Ph₂PCH₂CH₂AsPh₂) are discussed.     

Bis(cyclopentadienyl)methan-verbrückte Zweikernkomplexe. VIII. Zweikernige Cobaltkomplexe mit dem Dianion des Bis(cyclopentadienyl)methans und des Bis(tetramethylcyclopentadienyl)dimethylsilans als Brückenliganden

Bis(cyclopentadienyl)methane-bridged Dinuclear Complexes. VIII. Dinuclear Cobalt Complexes with the Dianion of Bis(cyclopentadienyl)methane and Bis(tetramethylcyclopentadienyl)dimethylsilane as Bridging Ligands The dinuclear cobalt complex [CH₂(C₅H₄)₂][Co(CO)₂]₂ ( 4 ) which is obtained from [Co(CO)₄I] ( 2 ) and Li₂[CH₂(C₅H₄)₂] ( 3 ) in 75% yield reacts with PMe₃, PiPr₃, P₂Me₄, Me₂PCH₂CH₂PMe₂ and (EtO)₂POP(OEt)₂, to the compounds 5–9 substituting one CO ligand per cobalt atom. Oxidative addition of CH₃I to [CH₂(C₅H₄)₂][Co(CO)(PMe₃)]₂ ( 5 ) leads to the formation of the dinuclear cobalt(III) complex [CH₂(C₅H₄)₂][Co(COCH₃)(PMe₃)I]₂ ( 11 ). The reaction of 4 with iodide generates [CH₂(C₅H₄)₂][Co(CO)I₂]₂ ( 12 ) which with PMe₃, P(OMe)₃, P(OiPr)₃, and CNMe reacts under CO substitution to [CH₂(C₅H₄)₂][Co(L)I₂]₂ ( 13–16 ) and with PMe₂H to {[CH₂(C₅H₄)₂][Co(PMe₂H)₃]₂}I₄ ( 17 ). The electrophilic addition reactions of NH₄PF₆ and CH₃I to [CH₂(C₅H₄)₂][Co(PMe₃)₂]₂ ( 20 ) produce the complex salts {[CH₂(C₅H₄)₂][CoR(PMe₃)₂]₂}X₂ ( 21 : R = H; 22 : R = CH₃). From 22a (X = I) and LiCH₃ the dinuclear tetramethyldicobalt compound [CH₂(C₅H₄)₂] · [Co(CH₃)₂(PMe₃)]₂ ( 23 ) is obtained which further reacts, via the intermediate 24 , to the chiral complex {[CH₂(C₅H₄)₂] · [CoCH₃(PMe₃)P(OMe)₃]₂}(PF₆)₂ ( 25 ). The reaction of 20 with C₂(CN)₄ and E- or Z-C₂H₂(CO₂Me)₂ gives the olefin(trimethylphosphine) cobalt(I) derivatives 26 und 27 . The synthesis of the dinuclear compounds 31–38 with [Me₂Si(C₅Me₄)₂]^2? as the bridging unit is also described.     

Alternativ-Liganden VII: Chelatkomplexe des typs (Me = CH3; X = CH3, Cl)

Chelate complexes of the type (CO)₄M iX₂ (X = Me, Cl) have been prepared from Na[Mn(CO)₅] and HMn (CO)₅, respectively, by two-step reactions with the ligands Me₂PCH₂CH₂SiX₂R′ using alkali salt, amine or HCl elimination. (CO)₄M iCl₂ is also obtained by cleavage of Mn₂(CO)₁₀ with Me₂PCH₂CH₂SiCl₃. IN the case of HMn (CO)₅ the intermediates (CO)₄Mn (H) L [L = Me₂PSiMe₃, Me₂PCH₂CH₂SiMe₂ (NMe₂), Me₂PCH₂CH₂SiCl₂ (NMe₂] can be isolated. The new compounds were identified by analytical and spectroscopic (IR, PMR, MS) methods.     

Alternativ-Liganden. XXIV. Rhodium(I)-Komplexe mit P-Donor-und Sn- bzw. B-Akzeptor-Liganden

Alternative Ligands. XXIV. Rhodium(I) Complexes with P-Donor and Sn- or B-Acceptor Ligands Donor/acceptor ligands of the type Me₂PCH₂CH₂SnMe₃ (1) , (Me₂PCH₂CH₂)₂SnMe₂ (2) , and Me₂PCMe=CMeBMe₂ (3) , respectively, have been prepared by hydrostannlation of Me₂PVi with Me₃SnH or Me₂SnH₂ and by a multistep synthesis via Na[Me₃BH], Na[Me₃BC?;CMe] using Me₂PCI as partner, respectively. The new ligands were used to produce the Rh(I) complexes RhCI(CO)(Me₂PCH₂CH₂SnMe₃)₂ (5) , RhCI(CO)(Me₂PCH₂CH₂)₂SnMe₂ (7), and RhCI(CO)(Me₂PCMe=CMeBMe₂)₂ (8) by reactions of Rh(CO)₂CH₂ (4) with the corresponding ligands. In addition, the VASKA type compounds RhCI(CO)(Me₂PVi)₂ (6) and RhCI(CO)(PMe₃)₂ were prepared in order to test an alternative route to 5 or to from the known adduct RhCI(CO)(PMe₃)₂. BBr₃ (9) . RhBr(CO)(PMe₃)₂ (10) and the binuclear system [RhBr(CO)PMe₃]₂ (11) were identified spectroscopically after working up the 1:1 reaction mixture of RhCI(CO)(PMe₃)₂ and BBr₃. Reasonable pathways are suggested for their formation. ?Metallbase”?/acceptor interaction show up, on the one hand, in following reactions in case of the ligands with Sn acceptors, on the other hand, in significant changes of spectroscopic data for 8 . New compounds of sufficient stability were characterized by analytical (C, H) and spectroscopic (MS, IR. NMR) investigations.     

Synthesen zweizähniger P‐Donor/Sn‐Akzeptor‐Liganden: Koordinationsstudien mit Cp*Rh(CO)2 und CpRh(C2H4)2

Alternative Ligands. XXXV. Syntheses of Bidentate P‐Donor/Sn‐Acceptor Ligands: Coordination Experiments with Cp*Rh(CO)₂ and CpRh(C₂H₄)₂ Donor/acceptor ligands Me₂Sn(CH₂CH₂PMe₂)₂ ( 1 ) and Me₂Sn(OCH₂PMe₂)₂ ( 2 ) have been prepared by radical reaction of Me₂PVi with Me₂SnH₂ and by substitution of chlorine in Me₂SnCl₂ or of ethoxy groups in Me₂Sn(OEt)₂ by MOCH₂PMe₂ (M = Li, Na) and HOCH₂PMe₂, respectively. 2 cannot be isolated in pure form from the product mixture because, due to condensation reactions, the “ladder structure” [Me₂Sn(OCH₂PMe₂)₂OSnMe₂]₂ ( 3 ) is formed. The molecular structure of 3 was determined by X‐ray diffraction studies of single crystals. Attempts to produce the thiophosphoryl derivative of 3 result in the degradation of the ladder structure giving the thermally labile phosphane sulfide Me₂Sn(OCH₂P(S)Me₂)₂. Ligands 1 and 2 besides Me₂PCH₂CH₂SnMe₃ ( 4 ) have been used for the preparation of rhodium(I) complexes from Cp*Rh(CO)₂ ( 5 ) or CpRh(C₂H₄)₂ ( 10 ) as educts. The thermal reaction of 5 with 4 yields Cp*Rh(CO)PMe₂CH₂CH₂SnMe₃ ( 6 ), that of 5 with 1 a mixture of the mononuclear derivative Cp*Rh(CO) · PMe₂CH₂CH₂SnMe₂CH₂CH₂PMe₂ ( 7 ) and the binuclear complex [Cp*Rh(CO)PMe₂CH₂CH₂]₂SnMe₂ ( 8 ). The related system [Cp*Rh(CO)PMe₂CH₂O]₂SnMe₂ produced by reaction of 5 with 2 can only be detected in solution but, because of some side‐products, was not fully characterized. From 10 and 4 a mixture of mono‐ and disubstituted products, CpRh(C₂H₄)PMe₂CH₂CH₂SnMe₃ ( 11 ) and CpRh(PMe₂CH₂CH₂SnMe₃)₂ ( 12 ), is obtained. Reaction of 1 with 10 yields a mixture of the complexes CpRh(C₂H₄)PMe₂CH₂CH₂SnMe₂CH₂CH₂PMe₂ ( 13 ) and CpRh(Me₂CH₂CH₂)₂SnMe₂ ( 14 ). Some of the NMR data (¹³C, δδ_Sn) of 14 can be interpreted in terms of the expected Rh → Sn interaction. A definite proof by X‐ray diffraction on single crystals, so far, was not possible.     

Transition Metal Complexes with Bidentate Ligands Spanning trans-Positions. VIII. The reactions of the nucleophile trans-[RuCl(NO)(1)] (1 = 2,11-bis(diphenylphosphinomethyl)benzo[c]-phenanthrene) with carbon monoxide and the phosphite ligand (2) (2 = 1-ethyl-3,5,8-trioxa-4-phosphabicyclo (2.2.2)octane)

The preparation of the nucleophile trans-[RuCl(NO)( 1 )], where 1 is the bidentate ligand Ph₂PCH₂C₁₈CH₂PPh₂, and of the five-coordinate species [RuCl(CO)(NO)( 1 )], [RuCl(CO)(NO)(Ph₂PCH₂Ph)₂] and [RuCl(NO)( 2 )( 1 )] are reported. The crystal structure of [RuCl(CO)(NO)( 1 )] shows that the coordination around the metal atom is distorted trigonal bipyramidal with the phosphorus atoms in axial positions. The Ru? N? O bond angle is 142.8°. ¹H- and ³¹P-NMR. and \documentclass{article}\pagestyle{empty}\begin{document}$ \tilde \nu $\end{document}_NO IR.-data for the above complexes are reported and related to the coordination geometry.     

Studien zur CH-aktivierung: II. Der einfluss der liganden auf die bildung von aryl(hydrido)ruthenium(II)- und -osmium(II)-komplexen aus aromaten

The complexes trans-MCl₂(PMe₃)₄ (M = Ru, Os) react with CO and P(OMe)₃ to give the mono- and disubstituted derivatives trans,mer-MCl₂(PMe₃)₃L (L = CO, P(OMe)₃) and all-trans-MCl₂(PMe₃)₂[P(OMe)₃]₂, respectively. On reaction of trans-RuCl₂[P(OMe)₃]₄ with CO and PMe₃, the compounds trans,mer-RuCl₂[P(OMe)₃]₃(CO) and trans,cis,cis-RuCl₂(PMe₃)₂[P(OMe)₃]₂ are synthesized. The reduction of MCl₂(PMe₃)₂[P(OMe)₃]₂ with Na/Hg in benzene or toluene via {M(PMe₃)₂[P(OMe)₃]₂} as an intermediate leads to subsequent intermolecular addition of the arene and to the aryl(hydrido)metal complexes cis,trans,cis-MH(C₆H₅)(PMe₃)₂[P(OMe)₃]₂ (M = Ru, Os) and MH(C₆H₄CH₃)(PMe₃)₂[P(OMe)₃)₂ (M = Os). For M = Ru, in the presence of P(OMe)₃, the ruthenium(0) compound Ru(PMe₃)₂(P(OMe)₃]₃ is formed. The hydrido(phenyl) complexes react with equimolar amounts of Br₂ or I₂ by elimination of benzene to produce the dihalogenometal compounds cis,trans,cis-MX₂(PMe₃)₂[P(OMe)₃]₂. The reaction of trans-RuCl₂(PMe₃)₄ with Na/Hg in the presence of PPh₃ leads to the ortho-metallated complex fac-RuH(η²-C₆H₄PPh₂)(PMe₃)₃, which reacts with CH₃I, CS₂, COS and HCl to give the compounds mer-RuI(η²-C₆H₄PPh₂)(PMe₃)₃, fac-Ru(SCHS)(η²-C₆H₄PPh₂)(PMe₃)₃, fac-Ru(S₂CO)(CO)(PMe₃)₃ and RuCl₂(PMe₃)₃, respectively. The paramagnetic 17-electron complexes [MCl₂(PMe₃)_nL_4-n]PF₆ are obtained on oxidation of MCl₂(PMe₃)_nL_4-n with AgPF₆. Their UV spectra exhibit a characteristic CT band. [RuCl₂(PMe₃)₄]PF₆ and [OsCl₂(PMe₃)₄]PF₆ react with CO and P(OMe)₃ by reduction to form the corresponding ruthenium(II) and osmium(II) compounds MCl₂(PMe₃)_nL_4-n.     

New cationic palladium (II) and rhodium (I) complexes of [Ph2PCH2C(Ph)N(2,6-Me2C6H3)]

Treatment of the bulky iminophosphine ligand [Ph₂PCH₂C(Ph)N(2,6-Me₂C₆H₃)] (L) with [M(CH₃CN)₂(ligand)]⁺ⁿ, where for M = Pd(II): ligand = η³-allyl, n = 1, and for M = Rh(I), ligand: 2(C₂H₄), 2(CO) or cod, n = 0, yields the mono-cationic iminophosphine complexes [Pd(η³-C₃H₅)(L)][BF₄] (1), [Rh(cod)(L)][BF₄] (2), [Rh(CO)(CH₃CN)(L)][BF₄] (3), and cis-[Rh(L)₂][BF₄] (4). All the new complexes have been characterised by NMR spectroscopy and X-ray diffraction. Complex 1 shows moderate activity in the copolymerisation of CO and ethene but is inactive towards Heck coupling of 4-bromoacetophenone and n-butyl acrylate.     

Alternativ-Liganden. XXX [1] Neue Tripod-Liganden XM' (OCH2PMe2)n(CH2CH2PMe2)3−n (M' = Si; Ge; n = 0–3) für Käfigstrukturen

Alternative Ligands. XXX Novel Tripod Ligands XM' (OCH₂PMe₂)_n(CH₂CH₂PMe₂)_3?n (M' = Si, Ge; n = 0–3) for Cage Structures Attempts to prepare new tripod ligands XSi(OCH₂PMe₂)₃ [X = CF₃ ( 15 ), C₆F₅ ( 16 ), NMe₂ ( 17 ), Cl ( 18 ), F ( 19 ), H ( 20 ), OEt ( 21 ), OMe ( 22 )] prove to be unsuccessful in spite of using different pathways, because the groups X undergo following reactions giving insoluble solids (polyadducts) or form inseparable mixtures, e. g. (RO)_nSi(OCH₂PMe₂)_4?n (R = Me, Et). In many cases Si(OCH₂PMe₂)₄ ( 13 ) can be isolated from the reaction mixture. The syntheses of the ligands XSi(CH₂CH₂PMe₂)₃ [X = NMe₂ ( 6 ), Cl ( 7 ), F ( 8 ), OMe ( 9 ), Vi ( 12 )], Si(OCH₂PMe₂)₄ ( 13 ) und Me₃GeOCH₂PMe₂ ( 14 ) are successful. The compounds MeSi(OCH₂PMe₂)₂CH₂CH₂NMe₂ ( 10 ) and MeSi(OCH₂PMe₂)₂CH₂CH₂P(CF₃)₂ ( 11 ) with different donor groups are obtained in good yields. The preparative program includes the synthesis of the known representatives MeSi(OCH₂PMe₃)₃ ( 1 ), MeSi(OCH₂PMe₂)₂CH₂CH₂PMe₂ ( 2 ), MeSi(OCH₂PMe₂)(CH₂CH₂PMe₂)₂ ( 3 ), MeSi(CH₂CH₂PMe₂)₃ ( 4 ) and MeGe(OCH₂PMe₂)₃ ( 5 ). Important preparative steps are the substitution of M'Cl (M' = Si, Ge) by Me₂PCH₂O groups and the photochemically induced or base catalyzed addition of HNMe₂, HPMe₂ or HP(CF₃)₂ to SiVi functions. The novel compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations.     

Alternativ-Liganden. XXXI. Nickelcarbonylkomplexe mit Tripod-Liganden des Typs XM′(OCH2PMe2)n(CH2CH2PR2)3–n (M′ = Si,Ge; n = 0–3)

Alternative Ligands. XXXI. Nickelcarbonyl Complexes of Tripod Ligands of the Type XM′(OCH₂PMe₂)_n(CH₂CH₂PR₂)_3–n (M′ = Si, Ge; n = 0–3) The coordinating properties of the tripod ligands RM′(OCH₂PMe₂)_n(CH₂CH₂PMe₂)_3–n (M′ = Si, Ge) ( 1–7 ), MeSi(OCH₂PMe₂)₂CH₂CH₂P(CF₃)₂ ( 8 ), MeSi(OCH₂PMe₂)₂CH₂CH₂NMe₂( 10 ) as well as of the tetradentate representative Si(OCH₂PMe₂)₄ ( 9 ) have been investigated by the preparation of the novel nickel carbonyl complexes LNiCO ( 11–18 ), Si(OCH₂PMe₂)₄[Ni(CO)₂]₂ ( 19 ) and (HOCH₂PMe₂)₂Ni(CO)₂ ( 20 ). They are obtained in moderate to good yields by the reaction of Ni(CO)₄ with the corresponding ligands in toluene (20–111°C) (see Table 1). The new compounds have been characterized by analytical (C, H) and spectroscopic investigations (IR; ¹H-, ¹³C-, ¹⁹F, ³¹P-NMR, MS). The ligand properties are discussed on the basis of spectroscopic data [in particular coordination shifts Δδ = δ(complex)—δ(ligand)] leading to the conclusion that the high electron density on Ni gives rise to a weak, but significant Ni→Si interaction. An important indication comes from the large low field shift Δδ_F = 34.5 ppm for the SiF acceptor bridge in 17 . This result is supported by an X-ray diffraction study of 11 giving an NiSi distance of 3.941(2) Å. With the exception of O2…?P3 (Abb. 7) all other O…?P through-cage contacts are longer than the NiSi distance. An additional release from the high charge density on Ni is obtained via π-backbonding to the neighbouring groups OCPMe₂, CCPMe₂ and CO.     

Basische metalle: LII. Synthese von carbenoid- und ylidcobalt(III)-komplexen aus substitutionslabilen cobalt(I)-vorstufen

The cyclopentadienylcobalt(I) compounds C₅H₅Co(PMe₃)P(OR)₃ (R = Me, Et, Prⁱ) and C₅H₅Co(C₂H₄)L (L = PMe₃, P(OMe)₃, CO) are prepared by ligand substitution starting from C₅H₅Co(PMe₃)₂ and C₅H₅Co(C₂H₄)₂. Whereas the reaction of C₅H₅Co(PMe₃)P(OMe)₃ with CH₂Br₂ mainly gives [C₅H₅CoBr(PMe₃)P(OMe)₃]Br, the dihalogenocobalt(III) complexes C₅H₅CoX₂(PMe₃) (X = Br, I) are obtained from C₅H₅Co(CO)PMe₃ and CH₂X₂. Treatment of C₅H₅Co(CO)PMe₃ or C₅H₅Co(C₂H₄)PMe₃ with CH₂ClI at low temperatures produces a mixture of C₅H₅CoCH₂Cl(PMe₃)I and C₅H₅CoCl(PMe₃)I, which can be separated due to their different solubilities. The same reaction in the presence of ligand L gives the carbenoidcobalt(III) compounds [C₅H₅CoCH₂Cl(PMe₃)L]PF₆ in nearly quantitative yields. If NEt₃ is used as the Lewis base, the ylide complexes [C₅H₅Co(CH₂PMe₃)(PMe₃)X]PF₆ (X = Br, I) are obtained. The PF₆ salts of the dications [C₅H₅Co(CH₂PMe₃)(PMe₃)L]²⁺ (L = PMe₃, P(OMe)₃, CNMe) and [C₅H₅Co(CH₂PMe₃)(P(OMe)₃)₂]²⁺ are prepared either from [C₅H₅Co(CH₂PMe₃)(PMe₃)X]⁺ and L, or more directly from C₅H₅Co(CO)PMe₃, CH₂X₂ and PMe₃ or P(OMe)₃, respectively. The synthesis of C₅H₅CoCH₂OMe(PMe₃)I is also described.     

Carbonyl complexes of manganese(I) with chelating phosphino-alkyl or -acyl ligands. Crystal and molecular structure of [Ph2PCH2CH2(O)CMn(CO)2(dppm)l

The phosphine Ph₂PCH₂CH₂Cl reacts with fac-[XMn(CO)₃(dppm)] (X = Cl or Br) in refluxing toluene to give the complexes cis,cis-[XMn(CO)₂(dppm)(Ph₂PCH₂CH₂Cl)] (I). Treatment of those species with Na amalgam in THF leads to the alkyl complex [Ph₂$\text{PCH}{}_2\text{CH}{}_2\text{M}$n(CO)₂(dppm)] (II), which does not react with CO under normal conditions but can be converted into cis,cis-[ClMn(CO)₂(dppm)(PPh₂Et)] by reacting with HCl (g) in ether. If the reduction of I with Na/Hg is carried out in the presence of CO the compound cis-[Ph₂$\text{PCH}{}_2\text{CH}{}_2\text{(O)CM}$n(CO)₂(dppm)] (III) is obtained. The latter has also been prepared directly from fac-[BrMn(CO)3(dppm)], Ph₂PCH₂CH₂Cl, and Na/Hg in THF, and characterized by X-ray crystallography. The crystals are monoclinic, space group P2₁/n; refinement gave R = 0.053 for 2593 reflections with I ? 2.5σ(I). The reaction of the complex fac-[O₃ClOMn(CO)₃(dppm)] with Ph₂PCH₂CH₂Cl in Cl₂CH₂ gives the salt fac-[Mn(CO)₃(dppm)(Ph₂PCH₂CH₂Cl)]ClO₄ which isomerizes to mer-[Mn(CO)₃(dppm)(Ph₂PCH₂CH₂Cl)]ClO₄ in boiling butanol. Both cationic carbonyl complexes give the acyl species III upon reduction with Na amalgam.     

Haloalkyl complexes of the transition metals : II. Some new chloromethyl and methoxymethyl complexes of manganese,rhenium and ruthenium

The reactions of Na[Mn(CO)₅] or Na[Mn(CO)₄(PPh₃)] with CH₂ClI yield the new chloromethyl complexes Mn(CO)₅CH₂Cl and Mn(CO)₄(PPh₃)CH₂Cl. Reaction of Na[Re(CO)₅] or Na[CpRu(CO)₂] with ClCH₂OMe yields Re(CO)₅CH₂Cl and CpRu(CO)₂CH₂Cl respectively, in addition to the corresponding methoxymethyl complexes (Cp = η⁵-C₅H₅). Reaction of CpRu(CO)₂CH₂OMe with HCl yields the corresponding chloromethyl complex.