New Mono- and Polynuclear Alkynyl Complexes Containing Phenylacetylide as Terminal Or Bridging Ligand. X-Ray Structures of the Compounds NBu 4[Pt(CH2C6H4P(o-Tolyl) 2-kC,P)(C=CPh)2], [Pt(CH2C 6H4P(o-Tolyl)2-kC,P)(C=CPh)(CO)], [{Pt(CH2C6H4P(o-..

Casas, J. M. (Universidad de Zaragoza) ; Fornies,J. (Universidad de Zaragoza) ; Fuertes,S. (Universidad de Zaragoza) ; Martin,A. ; Sicilia,V. (Universidad de Zaragoza)

Resumen: This work describes the synthesis of the compounds Q[Pt(CP)(CCPh)2] (Q = Li+ (1), NBu4+ (2). CP = CH2C6H4P(o-tolyl)2-κC,P) and their use as precursors for the preparation of homo- and heteropolynuclear complexes by reactions with Lewis acid species of transition metals, M (M = Cu(I), Ag(I), Tl(I), Pd(II), Pt(II)). These reactions give rise to heteropolynuclear complexes that exhibit different bonding patterns for the bridging alkynyl ligands, depending on M. The reaction of 2 with readily available M+ (M = Cu, Ag) species affords the discrete tetranuclear clusters [{Pt(CP)(CCPh)2M}2] (M = Cu (3), Ag (4)). The X-ray structure of 3 shows that in this complex both “Pt(CP)(CCPh)2” fragments are connected by two d10 metal centers and are stabilized by alkynyl bridging ligands, showing the stronger preference of the MI centers (MI = Cu, Ag) for the electron-rich alkynyl units than for the basic Pt(II) center. However, the reaction of 2 with TlPF6 rendered the tentatively tetranuclear complex [{Pt(CP)(CCPh)2Tl}2] (5), containing Pt→Tl dative bonds, which shows the higher affinity of thallium for the electron density of platinum(II) than for the alkynyl units. Moreover, the reaction of (NBu4)[Pt(CP)(CCPh)2] (2) with the neutral complex [Pd(C6F5)2(THF)2] yields the compound (NBu4)[Pt(CP)(CCPh)2Pd(C6F5)2] (11), in which the two alkynyl ligands are η2-bonded to Pd(II) in such a way that the “cis-Pt(CCPh)2“ fragment acts as a chelate ligand toward Pd(II). Meanwhile the reactions with the cationic and neutral Pt(II) complexes [Pt(CP)(THF)2]+ and [Pt(C6F5)2(THF)2] produce the complexes [{Pt(CP)(μ-CCPh)}2] (6) and (NBu4)[Pt(CP)(μ-CCPh)2Pt(C6F5)2] (12), both containing the double μ2-η2(σ,π)-alkynyl bridging system “Pt2(μ-CCPh)2” as a consequence of an alkynylating process. This bridging system “Pt2(μ-CCPh)2” can be broken by neutral ligands, L, to give mono(σ-alkynyl) complexes of Pt(II). Thus, the complexes [Pt(CP)(CCPh)L] (L = CO (7), py (8), tht (9), PPh3 (10)) have been obtained by reaction of 6 with L in a 1:2 molar ratio. When L = PPh3, the substitution reaction takes place with stereoretention, but not when L = CO, py, tht, as was conclusively established by an X-ray study on the complex [Pt(CH2C6H4P(o-tolyl)2)(CCPh)(CO)] (7). The cis or trans disposition of the two σ-C-donor ligands (C(CP), σ-CCPh) around the Pt center in complexes 6−10 and 12 seems to depend as much on the transphobia of pairs of trans ligands (T) as on the steric requirements of those in the cis configuration.

Idioma: Inglés

Año: 2007

Publicado en: Organometallics 26, 7 (2007), 1674-1685
ISSN: 0276-7333

Factor impacto JCR: 3.833 (2007)

Categ. JCR: CHEMISTRY, ORGANIC rank: 10 / 56 = 0.179 (2007) - Q1 - T1
Categ. JCR: CHEMISTRY, INORGANIC & NUCLEAR rank: 6 / 43 = 0.14 (2007) - Q1 - T1

Tipo y forma: Article (Published version)

Área (Departamento): Área Química Inorgánica (Dpto. Química Inorgánica)