EPR‐ und Ligandenfeld‐Spektren von Chlorovanadaten(IV). Die Kristallstruktur von PPh₄[V_xTi_2–xCl₉] (x = 0,15)

Abstract

Schwarze, feuchtigkeitsempfindliche Kristalle von PPh4[VxTi2–xCl9] (x = 0,15) entstehen durch Einwirkung von Titantetrachlorid auf PPh4[VCl5] in Dichlormethanlösung. Ihre EPR‐ und Ligandenfeld‐Spektren sowie diejenigen der Vergleichsverbindungen PPh4[VCl5] und (PPh4)2[V2Cl9][VCl5] · CH2Cl2 wurden registriert. In den Mischkristallen PPh4[V0,15Ti1,85Cl9] kann die Existenz flächenverknüpfter [VTiCl9]⊖‐Doppeloktaeder mit trigonal verzerrten Einzeloktaedern EPR‐ und ligandenfeld‐spektroskopisch nachgewiesen werden. Bei den Verbindungen mit [VCl5]⊖‐Anionen indessen lassen sich die spektroskopischen Ergebnisse nur dann verstehen, wenn man auch beim (PPh4)2[V2Cl9][VCl5] · CH2Cl2 — abweichend vom Strukturbefund — eine deutliche Jahn‐Teller‐Verzerrung der trigonalen Bipyramiden annimmt. Die Kristallstruktur von PPh4[V0,15Ti1,85Cl9] wurde durch Röntgenbeugung bestimmt; (2588 unabhängige, beobachtete Reflexe, R = 4,4%). Kristalldaten: triklin, Raumgruppe P1, a = 1090,4; b = 1217,4; c = 1287,7 pm; α = 73,19°; β = 69,87°; γ = 82,15°; Z = 2. Die Verbindung besteht aus PPh4⊕‐Kationen und Anionen [V0,15Ti1,85Cl9]⊖ mit statistischer Ti/V‐Verteilung. Die Metallatome des Anions sind wie in den Ionen [V2Cl9]⊖ und [Ti2Cl9]⊖ über drei Chlorobrücken zu einem Doppeloktaeder verknüpft.

Planar Tetracoordination of Carbon in Groups 4 and 5 Organometallic Chemistry

“…We were able to prepare and characterize dimetallic complexes of groups 4 and 5 containing two ptCs . This result was obtained in our group rather incidentally as our primary goal was then the synthesis of dimetallic vanadium−titanium complexes for use as molecular precursors in the organometallic chemical vapor deposition of carbonitride ceramics containing both these metals. , In many heterodimetallic complexes, an electron-poor metal (Ti, Zr) is associated with an electron-rich metal (Rh, Ru). , The association in a single molecule of two electron-poor metals is more unusual, and indeed, very few heterodimetallic compounds of groups 4 and 5 elements have been described. − The reaction behavior of alkyne triple bonds in substituted titanocene and zirconocene compounds has recently been extensively studied. ,,− In particular, the preparation by oxidative addition of titanium−silver and titanium−copper heterodimetallic compounds from [(C 5 H 4 (SiMe 3 )] 2 Ti(C⋮CSiMe 3 ) 2 and MCl 2 (M = Fe, Co, Ni) or M‘X (M‘ = Ag, Cu; X = Cl, R) has been reported by Lang et al (Scheme ) …”

Synthesis and Characterization of [Cp2V(μ-η2:η4-butadiyne)ZrCp‘2] Heterodimetallic Complexes (Cp‘ = C5H4t-Bu, C5H4Me). Formation Mechanism and Theoretical (ELF) Evidence for the Existence of Planar Tetracoordinate Carbon (ptC)

“…Quite often, an electron-poor metal (Ti, Zr) is associated with an electron-rich metal (Rh, Ru; Ni; Fe, Co, Ni, Cu, Ag 4 ). The association in a single molecule of two electron-poor metals is more unusual, and indeed, a limited number of heterodimetallic compounds of group IV−V elements have been described. − …”

[Cp2V(μ-η2:η4-butadiyne)MCp2′] (M=Ti, Zr; Cp′=C5H5, C5H4SiMe3): Heterodimetallic Complexes from a Bis(alkynyl)metallocene and Vanadocene—Unexpected Structure of [Cp2V(μ-η2:η4-butadiyne)Zr(C5H4SiMe3)2] Containing Two Planar-Tetracoordinate Carbon Atoms

“…[4] The combination of two electron-poor metals in a single molecule is more unusual, and indeed, very few heterodimetallic compounds containing elements from Groups 4 and 5 have been described. Among the known compounds are the [Cl 3 TiCl 3 VCl 3 ](PPh 4 ) salt, [5] the oxygen-bridged [(Cl)(acacen)V-O-TiCl 3 (thf) 2 ] compound (acacen N,N'-bis(acetylacetone)ethylenediamine), [6] and the [(tBuh 5 -C 5 H 4 ) 2 Zr(h 1 -1,h 1 -1')(h 6 -C 6 H 5 ) 2 V] complex. [7] A number of possible synthetic routes towards titanium ± vanadium organometallic complexes have been previously explored in our group without much success.…”