Dichloroethyne ClCECCl reacts with Pt(PPh3)2(C2H4) or Pt(PPh& to give the a-complex Pt(PPh3)2(+21C=CC1) (l), which 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~P~C H Z C~Z , a = 10.311(3) A, 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).

No abstract

No abstract

No abstract

No abstract

No abstract

181 und Alkine [C,Cl,Br]Mn(CO), reacts with butyllithium and Mn(CO),Br or Au(PPhJC1 to give the bimetallic cyclopentadienyl-bridged complexes [C.&l,Mn(CO),]Mn(CO), (1) and [C,Cl,Au(PPh,l]Mn(CO), (2), respectively. The molecular structures of 1 and 2 show no or very weak interactions between the metal centers. 1 reacts with BuLi and Au(PPh,)Cl in a formal substitution reaction to give 2. PPh, replaces one CO ligand in 1 to yield [C,CldMn(CO),(PPh,)nMn(CO), (3). Zusammenfassung [C,Cl,Br]Mn(CO), reagiert mit Butyllithium und Mn(CO)sBr oder Au(PPh&l zu den bimetallischen Cyclopentadienylverbriickten Komplexen [C,Cl,Mn(CO)$4n~CO), (1) bzw. [C,Cl,Au(PPh,)]MdCO), (2). Die Molekiilstrukturen von 1 und 2 zeigen keine oder nur sehr schwache Wechselwirkungen zwischen den Metallzentren. 1 reagiert mit BuLi und Au(PPh$l in einer formalen Substitutionsreaktion zu 2, w&end durch PPh, ein Carbonylligand ersetzt wird und [C,Cl,[Mn(CO),(PPh,IIlMn(CO), (3) gebildet wird.

No abstract