XIII. Synthese und Eigenschaften von [Li(TMEDA)] 2Pt(CH 2CMe 2CMe 2CH 2 ) 2( 1) ; Vergleich der Zersetzungstemperaturen von Metallacyclopentan-Komplexen des Pt(II) und Ni(II) des Typs ( 1) mit und ohne β-Wasserstoff; Kristallstruktur von (COD) PtCH 2SiMe 2SiMe 2CH 2 ( 8)

Abstract

The air-sensitive complex [Li(TMEDA)] 2 Pt(CH 2CMe 2CMe 2C H 2 (1) was synthesized in 50% yield by treatment of (COD)PtCl 2 with LiCH 2CMe 2CMe 2CH 2 Li. This “at-complex” was characterized by elementary analysis as well as by 1H and 13C NMR spectroscopy. DTA investigations showed the following thermal decomposition temperature: T dec. = 163° C. This decomposition temperature is significantly lower than those of the complexes [Li(TMEDA)] 2 Pt(CH 2CHRCHRC H 2) 2 (R=H ( 5), (R = HT dec. = 249°C; R = CH 3 ( 6), [Li(TMEDA)] 2 Ni(CH 2CMe 2CMe 2C H 2) 2 (R = H ( 3), T dec. = 182°C; R = CH 3 ( 4), T dec. = 172°C). Attempts to prepare an “at-complex” containing heteroatoms in the metallacyclic ring adding diethyl ether solution of LiCh 2SMe 2SMe 2CH 2Li ( 7) to CODPtCl 2 unsuccessful. The reaction gave (COD) PtCH 2SiMe 2PtCH 2SiMe 2C 2 ( 8) (yield: 80%). The complex was characterized by mass spectroscopy and X-ray diffraction. The crystal data and the final R values are as follows: crystal system: monoclinic, space group P2 1/ n with cell parameters a = 6.369(1) A ̊ , b = 20.016(2) A ̊ , c = 12.913(2) A ̊ , β = 94.42(1)°, Z = 4, R = 0.039, R w = 0.047. The average distance PtC (in the 1-platina-3,4-disilacyclopentane ring) is 2.063(7) Å and the angle CH 2PtCH 2 is 86.2(3)°.