首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The chloro complexes trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4, react with 1-alkynes HC---C---R in the presence of NEt3 to afford the corresponding acetylide derivatives trans-[Pt(Me) (C---C---R) (PPh3)2] (R = p-tolyl (1), Ph (2), C(CH3)3 (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH2)nCl (n = 2, 3) in the presence of 1 equiv. of HBF4 to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH2)nCl](CH2R) } (PPh3)2][BF4] (R = p-tolyl, N = 2 (4), N = 3 (5); R=Ph, N = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(C---C---Ph)2(PMe2Ph)2] with 2 equiv. HBF4 and 3-chloro-1-propanol affords trans-[Pt(C---CPh) {C(OCH2CH2CH2Cl)(CH2Ph) } (PMe2Ph)2][BF4] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH2CH2Cl)(CH2Ph) } (PPh3)2][BF4] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh3)2], after treatment with AgBF4 in HOCH2CH2Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe2Ph)]2 with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl2{C(OCH2CH2CH2Cl)(CH2C6H4-p-Me}(PMe2Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna21, with a = 11.785(2), B = 29.418(4), C = 15.409(3) Å, V = 4889(1) Å3 and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) Å and the short C(carbene)-O bond distance of 1.30(1) Å suggests extensive electronic delocalization within the Pt---C(carbene)---O moietry.  相似文献   

2.
Lewis acid adducts of the hydrides cis- and trans-Re(CO)(PMe3)4H (1) and (2), mer-Re(CO)2(PMe3)3H (3), fac-Re(CO)2(PMe3)3H (4) and trans-Re(CO)3(PMe3)2H (5) were studied with BH3 and 9-borabicyclo[3,3,1] norbonane (BBNH). Using BH3·THF and (BBNH)2 1 and 2 afforded Re(CO)(PMe3)3(η2-BH4) (6) and Re(CO)(PMe3)3(η2-BBNH2) (7) as stable and isolable products. VT IR studies established for the reaction to 7 that BBNH first attaches in a pre-equilibrium to the OCO atom of 1 or 2. At higher temperatures ReH adduct formation occurs with instantaneous transformation to 7 and elimination of PMe3·BBNH. In a similar way, the hydrides 3 and 4 were converted with BH3·THF and (BBNH)2 to yield the stable complexes Re(CO)2(PMe3)2(η2-BH4) (8) and Re(CO)2(PMe3)2(η2-BBNH2) (9). The intermediacy of the η1-BH4 adducts mer-/fac-Re(CO)2(PMe3)3(η1-BH4) was confirmed by VT 1H, 31P NMR and VT IR experiments. The conversion of 5 with BH3·THF led to equilibria with adducts at the OCO terminus in trans position to H and with HRe as revealed by VT IR studies. Temperature dependent 31P equilibrium studies allowed to calculate ΔH=−4.9 kcal mol−1 and ΔS=+0.034 e.u. for this reaction. These adducts could not be isolated. Compound 5 does not react with (BBNH)2 even at elevated temperatures. DFT calculations were carried out to support the structures of the BH3 adducts of 5. In addition a vibrational analysis helped to unravel the IR band assignments of the involved compounds. DFT calculations on 8 confirmed its C2v structure. X-ray diffraction studies were carried out on single crystals of 6 and 7.  相似文献   

3.
The solution of [RhCl(PPh3)3] in acidic 1-ethyl-3-methylimidazolium chloroaluminate(III) ionic liquid (AlCl3 molar fraction, xAlCl3=0.67) was investigated by 1H and 31P{1H} NMR. One triphenyl phosphine is lost from the complex and is protonated in the acidic media, and cis-[Rh(PPh3)2ClX], (2), where X is probably [AlCl4]−, is formed. On, standing, 2 is converted to trans-[Rh(H)(PPh3)2X], (3). The reaction of 2 and H2 also produces trans-[Rh(H)(PPh3)2X], (3). 1H and 31P{1H} NMR support the suggestion that a weak ligand such as [AlCl4]−, present in solution may interact with the metal centre. When [RhCl(PPh3)3] is dissolved in CH2Cl2/AlCl3/HCl for comparison, two exchanging isomers of what is probably [RhH{(μ-Cl)2AlCl2}{(μ-Cl)AlCl3}(PPh3)2], (6) and (7), are formed.  相似文献   

4.
From a mixture of cis- and trans-Ru(SH)2(dppm)2 (4), formed from reaction of H2S with trans-Ru(H)Cl(dppm)2 (2), a crystal of cis-4 has been isolated and its structure determined by X-ray analysis. The mercapto protons are located within the centrosymmetric structure, although the S-atoms are partially disordered (S–H1.06 Å). The thiolate complexes, trans-Ru(H)SR(dppm)2 (R=Ph, 5a; C6F5, 5b), have been isolated from reaction of trans-2 with 1 equiv. of RSH. trans-Ru(H)SH(dppm)2 (3) has been isolated from reaction of H2S with a mixture of cis- and trans-Ru(H)2(dppm)2 (1). An improved synthetic route for 1 is presented.  相似文献   

5.
The reaction of TiCl4 with Li2[(SiMe2)2(η5-C5H3)2] in toluene at room temperature afforded a mixture of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] in a molar ratio of 1/2 after recrystallization. The complex trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] was hydrolyzed immediately by the addition of water to THF solutions to give trans-[(TiCl2)2(μ-O){(SiMe2)2(η5-C5H3)2}] as a solid insoluble in all organic solvents, whereas hydrolysis of cis-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] under different conditions led to the dinuclear μ-oxo complex cis-[(TiCl2)2)(μ-O){(SiMe2)2(η5-C5H3)2}] and two oxo complexes of the same stoichiometry [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 as crystalline solids. Alkylation of cis- and trans-[(TiCl3)2{(SiMe2)2(η5-C5H3)2}] with MgCIMe led respectively to the partially alkylated cis-[(TiMe2Cl)2{(SiMe2)2(η5-C5H3)2}] and the totally alkylated trans-[(TiMe3)2{(SiMe2)2(η5-C5H3)2}] compounds. The crystal and molecular structure of the tetranuclear oxo complex [(TiCl)2(μ-O){(SiMe2)2(η5-C5H3)2}]2(μ-O)2 was determined by X-ray diffraction.  相似文献   

6.
The PMe2Ph ligands in the aquo-cations mer- [MCl2(H2O)(PMe2Ph)3][ClO4] rapidly exchange on the NMR time-scale giving coalescence in the 1H and 31P NMR spectra. Dissociation of the H2O ligand which is trans to PMe2Ph leads to a five- coordinate intermediate. This intermediate (M = Rh) is believed to be involved in the rapid reaction of [RhCl2(H2O)(PMe2Ph)3] [ClO4] with mer- [RhCl3(PMe2Ph)3] by a chloride transfer mechanism leading to total exchange of the PMe2Ph ligands.  相似文献   

7.
A novel five-coordinate rhenium(III)-thiolato complex, Re(SCH2C6H4OCH3-p)3(PPh3)2 has been isolated during the reaction of trans-ReOCl3(PPh3)2 with p-methoxybenzyl mercaptan. In the unexpected structure that was acquired, the central metal has undergone a reduction from Re(V) to Re(III). The five-coordinate Re(III) complex has been characterized by spectroscopic methods, elemental analysis and X-ray crystallography. X-ray crystallographic studies showed the coordination geometry around rhenium to be that of a trigonal bipyramid. The basal plane is defined by three sulfur atoms of the monodentate ligand, while the two apical positions are occupied by two phosphines of the precursor.  相似文献   

8.
The dinuclear Pt---Si complex {(Ph3P)Pt{μ-η2-H---SiH(IMP)]}2 (trans-1a–cis-1b=3:1; IMP=2-isopropyl-6-methylphenyl) reacted with basic phosphines such as 1,2-bis(diphenylphosphino)ethane (dppe) and dimethylphenylphosphine (PMe2Ph) to afford different dinuclear Pt---Si complexes with loss of H2, {(P)2Pt[μ-SiH(IMP)]}2 [P=dppe, trans-2a (major), cis-2b (trace); PMe2Ph, 3 (trans only)]. Complexes 2 and 3 were characterized by multinuclear NMR spectroscopy and X-ray crystallography (2a). In contrast, the reaction of 1a,b with the sterically demanding tricyclohexylphosphine (PCy3) afforded {(Cy3P)Pt{μ-η2-H---SiH(IMP)]}2 (trans-4a–cis-4b 2:1) analogous to 1a,b where the central Pt2Si2(μ-H)2 core remains intact but the PPh3 ligands have been replaced by PCy3. Complexes 4a and 4b was characterized by multinuclear NMR and IR spectroscopies.  相似文献   

9.
The complex [Ru(H2)(H)(PMe2Ph)4]PF6 (1) has been prepared by reaction of [Ru(H)(PMe2Ph)5] FP6 (2) in THF with 1 atm H2 and characterised by variable temperature 31P and 1H NMR. It undergoes four distinct fluxional processes listed in order of decreasing activation energy: (i) exchange of H2 in solution with the dihydrogen ligand above 273 K; (ii) isomerisation of cis and trans isomers of 1 above 230 K; (iii) exchange of H atoms between H2 and hydride in trans-1 above 180 K; (iv) rapid H2/hydride exchange in cis-1 to below 180 K. A single crystal X-ray diffraction study of 1 at 173 K shows that the complex has the cis geometry in the solid state but does not clearly reveal the positions of the hydrogen ligands. Complex 1 starts out as a catalyst of high activity for the selective hydrogenation of 1-alkynes to 1-alkenes (RC≡CH; R=11Bu, Ph) but it is rapidly deactivated, possibly because of formation of the enynyl complex [Ru(η3RC3CHR)(PMe2Ph)4]+. Complex 1 efficiently catalyzes the hydrogenation of internal alkynes (3-hexyne, 2-pentyne) to internal cis-alkenes with little deactivation, although some isomerisation of the alkene produced is observed. These observations are consistent with those of Nkosi, Coville, Albers and Singleton who reported that complex 2 must dissociate one PMe2Ph ligand to produce the species active for alkyne hydrogenation. Complex 2 catalyses these hydrogenations with slower initial rates than complex 1 but deactivates less readily. In contrast to 1, complex 2 does not appear to cause the isomerisation of internal alkenes.  相似文献   

10.
The potential in preparative chemistry of the precursors trans-[Ru(NH3)(CC---R1)(Ph2PCH2CH2PPh2)2]PF6 (3) has been studied. They offer a convenient access, by NH3 displacement, to new functional alkynyl-ruthenium derivatives. Complexes 3 react with alkynes HCC---R2 to give unsymmetrical trans-Ru(---CC---R1)(---CC---R2)(dppe)2 compounds 4a-c, and with sodium methoxide in methanol they open the route to a variety of mixed hydride complexes 5a-c, trans-Ru(H)(---CC---R1)(dppe)2. In contrast, with carbon monoxide or isocyanides CN---R3 (R3:CH2Ph, C6H11, Me3C) they allow the preparation of cationic derivatives trans-(Ru(CO)(---CC---R1)(dppe)2]PF6 (6a-c) or trans-[Ru(CNR3)(---CC---R1)(dppe)2]PF6 (7a-d).  相似文献   

11.
The metal binding properties of trans-Cl2Pd(glyglyOH)2 and trans-Cl2Pd(glynvalOH)2 towards the oligonucleotide dodecamer [d(CGCGAATTCGCG)]2 duplex, have been studied by 1D and 2D 1H NMR spectroscopy. A selective binding of the metal with G4, followed by G2 was observed with both complexes. This indicates that an intrastrand GNG(G2C3G4)(N7-N7) chelation of Pd(II) with the dodecamer duplex may have taken place. The Pd(II)-duplex interaction is less aggressive with trans-Cl2Pd(glynvalOH)2, than with trans-Cl2Pd(glyglyOH)2. NOE connectivities in the first case show a through space hydrophobic ligand–ligand interaction of the dipeptide and oligonucleotide protons.  相似文献   

12.
It is shown that the reaction of RhCl3·3H2O with acetonitrile normally produces mixtures of mer- and fac-[RhCl3(CH3CN)3] (1a and 1b, respectively). The IR and 1H NMR spectra of these isomers were re-investigated. Their two-dimensional (103Rh,1H) NMR spectra were also recorded. Equilibrium and exchange studies of 1a and 1b in CD3C were performed. It was found that in 1a the exchange rate of the nitrile molecule trans to Cl is much faster than those of mutually trans nitriles. Also the nitrile molecules in 1b underwent fast exchange in CD3CN; however, their rate was slightly faster than that of the more labile CH3CN in 1a. The X-ray crystal structure of mer-[RhCl3(CH3CN)3]·CH3CN (1c) was determined. Crystal data: triclinic space group

Full-size image
.  相似文献   

13.
Two novel tetracopper(I) and tetrasilver(I) complexes [Cu4(atdz)6](ClO4)4·2CH3OH (1) and [Ag4(atdz)6](ClO4)4 (2), have been prepared using 2-amino-1,3,4-thiadiazole (atdz), and their crystal structures and properties have been determined. On each tetranuclear complex, two Cu or Ag atoms (M) are bridged by two atdz ligands to form a six-membered N2M2N2 framework. The two N2M2N2 frameworks are in parallel linked by another atdz ligand to provide the tetranuclear structure with a rectangular M4 core. The four Cu or Ag atoms possess a trigonal-square geometry. The two adjacent MM separations are (3.096(1) and 3.412(1) Å) and (3.316(2) and 3.658(2) Å) for 1 and 2, respectively. On both tetranuclear complexes there are two species of hydrogen bonds between the ClO4 − anions and the NH2 group of atdz ligands. It is proposed that the hydrogen bonds are related to the stabilization of the tetranuclear structure during the crystallization process.  相似文献   

14.
Cobalt(III) complexes with a thiolate or thioether ligand, t-[Co(mp)(tren)]+ (2), t-[Co(mtp)(tren)]2+ (1Me) and t-[Co(mta)(tren)]2+ (2Me), (mp = 3-mercaptopropionate, MA = 3-(methylthio)propionate and MTA = 2-(methylthio)acetate) have been prepared in aqueous solutions. The crystal structures of 1, 2, 1Me and 2Me were determined by X-ray diffraction methods. The crystal data are as follows, t-[Co(mp)(tren)]ClO4 (1CIO4): monoclinic, P21/n, A = 10.877(8), B = 11.570(4), c = 12.173(7) Å, β = 92.20(5)°, V = 1531(1) Å3, Z = 4 and R = 0.060; t-[Co(ma)(tren)]Cl·3H2O (2Cl·3H2O): monoclinic, P21/n, a = 7.7688(8), B = 27.128(2), C = 7.858(1) Å, β = 100.63(1)°, V = 1627.7(3) Å3, Z = 4 and R = 0.066; (+)465CD-t-[Co(mtp)(tren)](ClO4)2 ((+)465CD-1Me(ClO4)2): orthorhombic, P212121, A = 10.6610(7), B = 11.746(1), C = 15.555(1) Å, V = 1947.9(3) Å3, Z = 4 and R = 0.068; (+)465CD-t-[Co(mta)(tren)](ClO4)2 ((+)465CD-2Me(ClO4)2): orthorhombic, P212121, a = 10.564(1), B = 11.375(1), C = 15.434(2) Å, V = 1854.7(4) Å3, Z = 4 and R = 0.047. All central Co(III) atoms have approximately octahedral geometry, coordinated by four N, one O, and one S atoms. All of the complexes are only isomer, of which the sulfur atom in the didentate-O,S ligands are located at the trans position to the tertiary amine nitrogen atom of tren. 1 and 1Me contain six-membered chelate ring, and 2 and 2Me do five-membered chelate ring in the didentate ligand. The chirality of the asymmetric sulfur donor atom in (+)465CD-1Me is the S configuration and that in (+)465CD-2Me is the R one. The 1H NMR, 13C NMR and electronic absorption spectral behaviors and electrochemical properties of the present complexes are discussed in relation to their stereochemistries.  相似文献   

15.
The labile cations [Cu(F-BF3)(PCy3)2] and [Cu(OTf)(PCy3)2] are versatile precursors for the formation of [Cu(X)(PCy3)2] (X = Br, I, SCN, N3) complexes by metathesis with NaX. The azide [Cu(N3)(PCy3)2] is triclinic, space group , a = 9.755(4), B = 22.78(1), C = 9.284(6) Å, = 96.76(3), β = 115.36(3), γ = 94.20(5)°, Z = 2.  相似文献   

16.
The kinetics of the displacement reactions of the bromide ligands of trans-[FeBr2(depe)2] (depe = Et2PCH2CH2PEt2) by the organonitrile NCCH2C6H4OMe-4, in tetrahydrofuran (either in the absence or in the presence of added Br−), to give the corresponding mono- and dinitrile complexes trans-[FeBr(NCCH2C6H4OMe-4)(depe)2]+ and trans-[Fe(NCCH2C6H4OMe-4)2(depe)2]2+, have been investigated by stopped-flow spectrophotometry. The substitution reaction occurs by a mechanism involving rate-limiting dissociation of bromo ligands to form the unsaturated intermediates [FeBr(depe)2]+ (k1 = 1.52 ± 0.02 s−1) and [Fe(NCR)(depe)2]2+ (k3 = 0.063 ± 0.008 s−1) which add the nitrile ligand to form those nitrile complexes. The competition between the nitrile and Br− for such metal centres has also been investigated and a stronger inhibiting effect of added Br− is observed for the substitution of the second bromo ligand relative to the first one. The kinetic data are rationalized in terms of π-electronic effects of these unsaturated metal centres and of the bromide and nitrile ligands.  相似文献   

17.
A series of cuboidal iron-sulfur clusters [Fe4S3(NO)4(PR3)3]0,1+ (R = Et, Pri, Cy) were synthesized by two routes: reductive desulfurization of [Fe4S4(NO)4] by tertiary phosphines, and substitution of triphenylphosphine in [Fe44S3(NO)4(PPh3)3] by a more basic phosphine. The structures of 3[Fe4S3(NO)4(PEt3)3] · 0.5Et2O, [Fe4S3(NO)4(PEt3)3] [Fe4S3(NO)7] and partially substituted [Fe4S3(NO)4(PPh3)2− (PPri3)] have been determined by X-ray diffraction in order to define the cuboidal Fe4S3 core, previously known only in Roussin's black anion and its reduced form, [Fe4S3(NO)77]1−,2−, and as a part of the iron-molybdenum cofactor of nitrogenase.  相似文献   

18.
Reactions of RhCl(cod)(THP) (cod = 1,5-cyclooctadiene; THP = P(CH2OH)3) with PMePh2 or PCyPh2 (Cy = cyclohexyl) in acetone/MeOH solution under H2 surprisingly form the complexes cis, mer-Rh(H)2Cl(PRPh2)3 (R = Me or Cy); both complexes are characterized by crystallography (the first structures in which the hydride ligands of such dihydrido-chloro-trisphosphine complexes have been located), and by detailed 1H and 31P NMR spectroscopy. The key role of the THP in the observed chemistry is discussed.  相似文献   

19.
Analogy with the isolable oxo cluster [Fe3(CO)9(μ3-O)]2−, which is structurally interesting and synthetically useful, prompted the present attempt to synthesize its ruthenium analog. Although the high reactivity of [Ru3(CO)9(μ3-O)]2− (I) prevented its isolation, the reaction of this species with [M(CO)3(NCCH3)]+, where M = Mn or Re, yields [PPN][MRu3(CO)12(η2-μ3-NC(μ-O)CH3]−. The high nucleophilicity of the oxo ligand in [Ru3(CO)9(μ3-O)]2− (I) appears to be responsible for the conversion of acetonitrile to an acetamidediato ligand and for the instability of I. The crystal structure of [PPN][MnRu3(CO)12(η2-μ3-NC(μ-O)CH3)]] reveals a hinged butterfly array of metal atoms in which the acetamidediato ligand bridges the two wings with μ3-N bonding to an Mn and two Ru atoms, and μ-O bonding to an Ru atom.  相似文献   

20.
The 16-electron complex (CO)4W=C(NMe2)SiPh2Me (1) was photochemically prepared from (CO)5W=C- (NMe2)SiPh2Me. Reactions with selected nucleophiles, having different ligand properties, were performed to test the strength of the intramolecular agostic interaction of one of the phenyl groups, by which 1 is stabilized. The stable complexes cis-(CO)4LW=C(NMe2)SiPh2Me were formed with L=P(OMe)3, P(OEt)3 or 2,6-Me2C6H3NC. The substituted complexes had no tendency for ligand elimination. Addition of acetonitrile or pyridine to an ether solution of 1 resulted in the formation of cis-(CO)4(MeCN)W=C(NMe2)SiPh2Me or cis-(CO)4(C5H5N)- W=C(NMe2)SiPh2Me, respectively. These reactions were reversed on evaporation of the solutions. No reaction was observed with triethylamine.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号