Koordinationschemie Perhalogenierter Cyclopentadine und Alkine, XV

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)

Koordinationschemie perhalogenierter Cyclopentadiene und Alkine, X

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

Coordination chemistry of perhalogenated cyclopentadienes and alkynes. 8. Pentakis(dimethylsilyl)cymantrene

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

Komplexchemie perhalogenierter Cyclopentadiene und Alkine, VII

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

Metallkomplexe mit biologisch wichtigen Liganden, LXVIII

The trischelate complexes of the dianion of aspartic acid and -methylaspartic acid (5-C5Me5) (R = H, Me) form adducts with alkali iodides MI (M = Li, Na, K). The polymeric structure of (5-C5Me5)Co(L-asp.-2H+)KI (1c) was determined by X-ray diffraction. In the crystal of 1c the potassium ions are surrounded by five oxygen atoms of the carboxylate groups whereby two oxygen atoms form bridges between two K+ ions. Similarly, trischelate complexes 4 and 5 have been obtained from (5-C5Me5)Co(CO)I2 and 2,3-diaminopropionic, 2,4-diaminobutyric acid, and asparagine, respectively

Coordination Chemistry of Perhalogenated Cyclopentadienes and Alkynes. 17. Reaction of Dichloroethyne With Platinum(0) Phosphine Complexes: Formation of a .pi.-Complex, Isomerization to .beta.-Chloroethynyl Complexes, and Syntheses of Diplatinioethyne Derivatives. Molecular Structures of (Ph3P)2Pt(.eta.2-ClC.tplbond.CCl) and Cl(Ph3P)2PtC.tplbond.CPt(PPh3)2Cl

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)