Über Trifluorphosphinkomplexe von Palladium(0) und Platin(0)

Abstract

InhaltsiibersichtGegtniiber den Chloriden von Pd(II), Pt(I1) nnd Pt(1V) fungiert Trifluorphosphin als Kednktionsmittel und Komplexligand. PF,-Druckumsetzungen dieser Chloride liefern mit quantitativer Ausbeute die Tetrakis(trifluorph0sphin)-Komplexe der nullwertigen Metalle, M(PF3)4; es sind farblose, LuBerst fluchtige Blussigkeiten (Zers.-P. 130" (Pt) bzw. -20" (Pd)). Ihre tetraedrische Struktur wird an Hand der IR-Spektren sowie der 19F-und 31P-Kernresonanzmessungen aufgezeigt. Bereits unter sehr milden Bedingungen bilden diese Elementkomplexe mit Phosphordonatoren farblose, kristalline Substitutionsprodukte M(PF3)4-n(PR3)n (R = C,H,: n = 1 und 2; R = OC,H,: n = 4), deren PF,-Gruppen unter CO-Druck teilweise bis vollig durch Kohlenmonoxid auspetauscht werden konnen. Sum rnaryIf reacted with the chlorides of PdII, PtII, and PtIv, trifluorphosphine behaves as a reducing agent and a ligand. These chlorides react under PF, pressure to yield quantitatively the tetrakis(trif1uorphosphine) complexes of the zerovalent metals, M(PF,),, which are colourless, extremely volatile liquids (dec. 130" (Pt), -20" (Pd) respectively). Their tetrahedral structure is deduced from their I R spectra as well a8 from 19F and alp NMR spectra. These metal(0) complexes give already under mild conditions with phosphorus donors colourless crystaline substitution products M(PF3)4-,,(PR3)n (R = C,H,: n = 1 and 2; R = OC,H,: n = 4). Under CO pressure the PF, groups of these derivatives may be exchanged partially to completely by carbonmonoxide.

MOCVD of Platinum (100) Films on Random Hastelloy C276

“…[7] Thin platinum films have been deposited using several metal-organic precursors such as Pt(CH 3 )RL 2 (R = methyl, allyl vinyl or tertiarybutynyl and L = CH 3 NC or 1,5-cyclooctadiene), [8] Pt(hfa) 2 (Hhfa = 1,1,1,5,5,5-hexafluoroacetylacetone), [9] cis-bis(h 2 ,h 1 -pent-4-en-1-yl)platinum, [10] CpPt(CH 3 ) 3 (Cp = cyclopentadienyl), [11] CH 3 CpPt(CH 3 ) 3, [11d,12] and from other precursors such as Pt(CO) 2 Cl 2 [13] and Pt(PF 3 ) 4 . [13,14] All of them require, however, the combined use of H 2 as reducing agent to deposit pure platinum films. Most of them, unfortunately, show low volatility and, in addition, in most cases are not commercially available.…”

Unexpected Direct Iron‐Fluorine Bonds in Trifluorophosphane Iron Complexes: An Alternative to Bridging Trifluorophosphane and Difluorophosphido Groups

“…However, multinuclear NMR studies in the À70 8C to+ 80 8C temperature range suggest two interconverting isomers. In addition, the Mçssbauer spectrum at À70 8C has been interpreted as a mixture of cis and trans isomers, which could correspond to IIIa and IIIb, 8 ] Both structures are genuine minima without any imaginary frequencies ( Figure 5, Table 4). The lower energy Figure 5 and Table 4) at 9.4 kcal mol À1 (B3 LYP) or 23.5 kcal mol À1 (BP86) above IVa has two bridging PF 3 groups and represents the www.chemeurj.org first example of a metal trifluorophosphane structure with bridging PF 3 groups.…”

“…A second much higher energy structure (VIb in Figure 8) is found for [Fe 2 A C H T U N G T R E N N U N G (PF 3 ) 9 ] with an intact bridging PF 3 group, and having a distorted trigonal bipyramidal phosphorus atom. However, unlike the related [Os 2 (CO) 9 ] (or [Os 2 (CO) 8 A C H T U N G T R E N N U N G (m-CO)]) with a single bridging carbonyl group, [59,60] the iron atoms in VIb are too far apart ( % 4 ) for the formal iron-iron single bond required to give both iron atoms the favored 18-electron configuration. The dissociation energies summarized in Table 7 (Table 7).…”

“…[2] However, [Ni(CO) 4 ] was subsequently found to be almost the only binary metal carbonyl that can be synthesized efficiently at atmospheric CO pressure. Thus reactions in autoclaves at high CO pressures were found to be necessary for the synthesis of other metal carbonyls including the very important [Fe(CO) 5 ], [Mo(CO) 6 ], and [Co 2 (CO) 8 ], discovered about a century ago and now commercially available for many years. Analogously, the first homoleptic metal trifluorophosphane complex was [NiA C H T U N G T R E N N U N G (PF 3 ) 4 ], which was first reported in 1951 by Irvine and Wilkinson, [3,4] 9 ] one of the iron atoms has inserted into a P À F bond of one of the PF 3 ligands to give a structure [(F 3 P) 4 Fe !…”

“…The trifluorophosphane ligand in metal trifluorophosphane complexes is recognized as being a strong acceptor ligand like carbon monoxide, undoubtedly because of the electron withdrawing properties of the three highly electronegative fluorine atoms. [12][13][14][15][16][17][18][19][20][21] Thus PF 3 ligands, like CO ligands, stabilize low formal oxidation states so that zerovalent metal derivatives, such as [22] [7,8,23] , and [Pt 4 A C H T U N G T R E N N U N G (PF 3 ) 8 ] [24] .…”