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

Die Reaktion von (η5-C5H5)Co(CO)2 mit ClCCCl ergibt neben Hexachlorbenzol mindestens sechs verschiedene Produkte, von denen drei durch Röntgenstrukturanalyse charakterisiert werden konnten: Der erste π-Komplex von Hexachlortropon, (CpCo)(η4-C7Cl6O) weist η4-Koordination zweier nicht benachbarter Doppelbindungen auf, was bisher in anderen Komplexen mit Cycloheptatrienon-Liganden nicht beobachtet wurde. Ebenfalls zum erstenmal wird die Struktur eines 1,2-Dikobaltacycloheptadienons beschrieben. Schließlich konnte die Struktur eines bimetallischen Tetrahchlorocobaltacyclopentadienons kristallographisch bestätigt werden

Komplexchemie perhalogenierter Cyclopentadiene und Alkine

Die Reaktion von Dichlorethin mit Pd(PPh3)4 oder RhCl(PPh3)3 führt zu Komplexen mit einem Phosphoniumacetylid-Liganden, Ph3P+ CC−. Ein Platin-Komplex mit demselben Liganden kann durch Reaktion von Pt(PPh3)2(C2H4) mit[Ph3PCCCl]+Cl− dargestellt werden. Die Molekülstruktur des Palladium-Komplexes wurde durch Kristallstrukturanalyse bestimmt

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)