Podcasts about coordination chemistry

Tue, 21 May 2013 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/16190/ https://edoc.ub.uni-muenchen.de/16190/1/Steinborn_Martin.pdf Steinborn, Martin ddc:540, ddc:500, Fakultät f

Fri, 9 Oct 2009 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/11562/ https://edoc.ub.uni-muenchen.de/11562/1/Haque_Nadera.pdf Haque, Nadera ddc:540, ddc:500,

Dichloroethyne ClCECCl reacts with Pt(PPh3)2(C2H4) or Pt(PPh& to give the a-complex Pt(PPh3)2(+21C=CC1) (l),w hich can be isomerized by prolonged refluxing in toluene to trans- (Ph3P)zC1Pt-C==CC1 (2). 2 easily undergoes exchange reactions with alkylphosphines and with halide anions to yield trans-(R3P)2ClPt-C=CCl (R = Et (3)) Bu (4)) and trans-(Ph3P)z- (X)Pt-C=CCl (X = F (5a), Br (5b), I (5c)), respectively. The alkylphosphine complexes 3 and 4 can also be obtained by reaction of Pt(PR3)4 (R = Et, “Bu) with ClCECCl or from 1 and the corresponding phosphine. When Pt(PPh&(CzH4) is added to a solution of 3, a dinuclear complex 6 is formed, in which the C=C-Cl group acts as a a,a-bridging ligand. Upon standing, oxidative addition of the remaining C-C1 bond occurs and the p-ethynediyl complex trans- C1(R3P)2Pt-C=C-Pt(PPh3)2C1-Cis (R = Et (7a)) can be obtained. The corresponding p-ethynediyl complex 7b (R = Ph) is formed directly from 2 and Pt(PPh&(CzH4). 7b isomerizes upon heating in toluene to the symmetrical all-trans isomer 8. The molecular structures of 1 and 8 were determined by X-ray diffraction (1: C ~ ~ H ~ ~ C ~ Z P ~ Pa ~=C 10H.3Z11C(3~) AZ,, b = 10.392(4) A, c = 33.675(16) A, P = 90.17(3)’, monoclinic, P21/n, 2 = 4. 8: C74H&1zP4Ptz9 a = 12.938(2) A, b = 19.964(3) A, c = 24.844(3) A, P = 96.14(1)’, monoclinic, C2/c, 2 = 4).

[C5Br5]Mn(CO)3 reacts with butyl lithium and one equivalent of SiMe2Cl2 to yield [C5Br4SiMe2Cl]Mn(CO)3 (1). The reaction of 1 with [C5X4Li]Mn(CO)3 (X=Br, Cl) gives the bimetallic compounds (OC)3Mn(C5Br4--- SiMe2---C5X4)Mn(CO)3 (X=Br (2), Cl (3))·2 can also be obtained by reaction of two equivalents of [C5Br4Li]- Mn(CO)3 with one equivalent of SiMe2Cl2· [C5Cl4Li]Mn(CO)3 reacts with Cp2TiCl2, depending on the reaction conditions, to yield the bi- and trimetallic compounds [C5Cl4TiCp2Cl]Mn(CO)3 (4) and (OC)3Mn(C5Cl4--- TiCp2---C5Cl4)Mn(CO)3 (5). The molecular structures of 2 and 5 have been determined by X-ray crystallography.

When [C5Br5]Mn(CO)3 (1) is treated with butyllithium and hydrolysed after some time, one can always obtain more than one product, independent of stoichiometry, solvent, temperature and lithiation time. However, the distribution of products strongly depends on the reaction conditions. For example, in THF, with a tenfold excess of butyllithium at −78°C, a conversion of more than 80% into [C5H5]Mn(CO)3 can be achieved. In IC5 Cl4Br]Mn(CO)3 (2) only a maximum of two halogens can be substituted by hydrogen. These results can be explained in terms of the competition between butyl lithium and the lithiated species [C5X4Li]Mn(CO)3 in the halogen-metal exchange reaction.

Coordination Chemistry of Perhalogenated Cyclopentadienes and Alkynes, XV[1]. - Systematic Generation of Fivefold Ring-Silylated Cyclopentadienyl Manganese Complexes from [C5Br5]Mn(CO)3. Molecular Structure of [C5Br3(SiMe3)2]Mn(CO)3 [C5Br5]Mn(CO)3 reacts in a sequence of alternate bromine-lithium exchange reactions and electrophilic silylations by SiMe3Cl or SiMe3OSO2CF3 to give [C5Br5-n(SiMe3)n]Mn(CO)3, where n = 1 (1), 2 (2), or 3 (3). A crystal structure determination of 2 shows the two silyl substituents in the relative 1,3-orientation. Addition of one or two equivalents of BuLi and SiMe2HCl to a solution of 3 yields [C5Br2-n(SiMe3)3-(SiMe2H)n]Mn(CO)3 with n = 1 (4) and 2 (5), respectively. If 1 is treated twice with 2 eq. of BuLi and then 2 eq. of SiMe2HCl, a further pentasilylated compound, [C5(SiMe3)(SiMe2H)4]-Mn(CO)3 (6), is obtained. In situ chlorination of [C5(SiMe2H)5]Mn(CO)3 or 6 with PdCl2, followed by addition of MeMgCl, yields after chromatography an inseparable mixture of [C5(SiMe3)4X]Mn(CO)3 compounds, where X = H (7a), SiMe2H (7b), and SiMe3 (7c).

Fri, 1 Jan 1993 12:00:00 +0100 http://epub.ub.uni-muenchen.de/5438/ http://epub.ub.uni-muenchen.de/5438/1/Suenkel_Karlheinz_5438.pdf Sünkel, Karlheinz; Hofmann, Julian Sünkel, Karlheinz und Hofmann, Julian (1993): COORDINATION CHEMISTRY OF PERHALOGENATED CYCLOPENTADIENES AND ALKYNES, XII. SYNTHESIS AND MOLECULAR STRUCTURE OF TRICARBONYL(TETRAKIS(TRIMETHYLSILYL)- CYCLOPENTADIENYL)MANGANESE. In: Journal of

Coordination Chemistry of Perhalogenated Cyclopentadienes and Alkynes, X[1]. - Synthesis and Molecular Structure of a Cyclopentadienyl-1,3-dithiol Complex, [C5Cl3(SH)2]Mn(CO)3 The reaction of [C5Cl4Li]Mn(CO)3 with elemental sulfur leads to [C5Cl4SLi]Mn(CO)3 (1), which is easily oxidized by air to the disulfide (OC)3Mn[C5Cl4S-SCl4C5]Mn(CO)3 (2). Addition of one equivalent of BuLi, followed by an excess of S8 produces the dithiolate [C5Cl3(SLi)2]Mn(CO)3 (3), which yields the dithiol [C5Cl3(SH)2]Mn(CO)3 (5) upon hydrolysis. The molecular structures of 2 and 5 have been determined by X-ray diffraction.

Starting from [q5-C5Br5]M n(CO),, the first r-complex of a cyclopentadienyl ligand with five silyl substituents, [q 5-C5(SiMe2H)5M] n(CO),, was prepared by a series of halogen-lithium exchange reactions, followed by silylation with SiMe2HCI. The crystal structure determination of this compound shows a highly symmetrical "paddle wheel" orientation of the five silyl groups around the cyclopentadienyl ring.

Coordination Chemistry of Perhalogenated Cyclopentadienes and Alkynes, VII1). - Synthesis of Several Tetrachlorometalloles of Cobalt, Rhodium, and Iridium; Structure of a Iridacyclopentadiene Derivative The reaction of dichloroethyne with CpCo(PPh3)2, RhCl(EPh3)3 (E = P, As, Sb), and IrCl(N2)(PPh3)2 leads to the formation of complexes containing a tetrachloro-1-metallacyclopentadiene unit. The crystal-structure determination of (Ph3P)2(Cl)- is reported.

Coordination Chemistry of rr-Bonded Cyclopentadienyl Chalcogeno Ethers, I. - Chelate Complexes of Pentakis(methylthio)cymantrene with Metal Carbonyls [C5(SMe)5]Mn(CO)3 (1) reacts with W(CO)5(THF), Mo(CO)4(C7H8), Cr(CO)3(NCMe)3, and Re(CO)4(-C3H5)/HBF4 to yield the monochelate complexes [[C5(SMe)5]Mn(C0)3][M(CO)4] (M = W: 2; M = Mo: 3) and the dichelate complexes [[C5(SMe)5]Mn(CO)3][M(C0)4]2 (M = W: 4; M = Cr: 5; M = Re BFF4 : 6). The reaction with Mo(CO)3(p-xylene) in THF leads via unstable intermediates, which contain coordinated THF, to a mixture of 3 and [[C5(SMe)5]Mn(CO)3][Mo(CO)4]2 (7). The structures of 3 and 4 in the crystal have been determined by X-ray diffraction methods.

Coordination Chemistry of Perhalogenated cyclopentadienes and Alkynes, I. - metalation of (C5Cl4Br)Mn(CO)3 and Reactions with Electrophiles Lithiation of (C5Cl4Br)Mn(CO)3 with n-butyllithium gives the isolable, but very air-sensitive (C5Cl4Li)Mn(CO)3 (2), which reacts with a series of electrophiles to yield (C5Cl4Br)Mn(CO)3 (3), where E = H, Me, SiR3, CO2R or SR.