Phosphido ligand complexes

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... 

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. 

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-... 

It is also pertinent to mention the occurrence of bridging phosphido and arsenido selenide ligands (Scheme 4).32 The phosphido selenide complexes (1 Scheme 4) were found to be very reactive and readily gave the six-membered heterocyclic complexes (3). In contrast the arsenido selenide systems gave both the four-membered ring intermediates (1 M = Mn, Re) and the six-membered heterocycles (3). 

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... 

Phosphine-phosphido ligands can be made, for example, from R2P(CH2) PRH, and give complexes such as the following ... 

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