Phosphido ligand

Metallacycle fomiation has also been observed in bis-Cp complexes. Heating Cp 2UR[P(Si(CH2)2)2] (R = Cl [146840-37-17, CH [146840-39-3]) results in the metaHation of the phosphido ligand. These complexes are stmcturaHy similar to the group 4 and 6 transition-metal metallacycle complexes, but show a dramatically reduced reactivity. 

Examples of "very tnixed"-metal cluster-assisted C-heteroatom bond formation are still rare, with both literature extant examples involving coupling of bridging phosphido ligand with a C-ligand. Phosphido, hydrido, and alky tie were assembled stereospecilically to afford PPh2(( /.v-CR=CHR) (Fig. 29),-" while an unusual... 

The mononuclear mechanism is similar to the one proposed for platinum-catalyzed hydrophosphination of formaldehyde (Scheme 5-3), but also includes a second P-C bond-forming pathway nucleophilic (Michael) attack of the phosphido ligand on coordinated acrylonitrile. The binuclear mechanism is similar, but P-C bond formation is proposed to occur by cooperative action of two Pt centers, with complexes 4 - 6 as possible intermediates [8]. 

Complexes with mono- and oligodentate phosphines and phosphido ligands 502... 

One of the first isolated and structurally characterized phosphido complexes [(t-Bu Ph"N)3Mo=P] (la) was obtained from the reaction of a molybde-num(III) complex with P4 in 79% yield (Eq. 1) [8]. The molybdenum starting material [(f-Bu Ph"N)3Mo] is planar, and the three unpaired electrons are localized on the Mo atom [10], engendering an ideal environment for the reduction of white phosphorus and formation of the triple bond, la can transfer the phosphido ligand to another complex [(t-BuPhN)3Moj via a het-erocumulene intermediate to give [(t-BuPhN)3Mo=Pj (lb) [11] (Eq. 2). 

Trialkoxy complexes of tungsten with terminal phosphido ligands could not yet be isolated. They were postulated to be very reactive intermediates in different transformation reactions, e.g., during the metathesis reaction of [W2(0R)6] with phosphaalkynes [6, 14]. However, we were able to characterize the complex [(t-BuO)3W=P] (3c) by P-NMR spectroscopy by monitoring the metathesis reaction of [W2(Ot-Bu)6] with MesC=P in the tempera-... 

Structure and Bonding of Terminal Phosphido Ligand Complexes... 

Table 2 M=E bond lengths and P-NMR data of asymmetric coordinated phosphido ligand complexes ...

In Fig. 3 the MO schemes and the structural parameters of 3e and 21c are compared using B-P86/SVP density functional theory and RI-J approximations [39]. In general the phosphido ligand complexes of types A and B... 

Another example of partial degradation of the Fe3(CO)i2 triangle is furnished by its reactions with phosphino-acetylenes which lead to complicated open Fe structures bridged by phosphido ligands and resulting acetylene dimers (79, 311). 

Phosphorus magnetic shielding tensors, general phosphido ligands in transition metal complexes, 1, 472 Phosphorus(III) mercury compounds, preparation, 2, 425-426 Phosphorus—metal complexes, characteristics, 2, 34 Phosphorus—nitrogen-containing rings, chromium carbonyl link, 5, 225... 

The only well-characterized amides and phosphides of the Group 2 metals, with the exception of the carbazoles, are those containing the bis(trimethylsilyl)amido(phosphido) ligand. This ligand has been successfully used to produce soluble, low-nuclearity, and low-coordination-num-... 

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