Aryloxo complexes

H NMR data has been reported for the ethylzinc complex, Zn(TPP—NMe)Et, formed from the reaction of free-base N-methyl porphyrin H(TPP—NMe) with ZnEti. The ethyl proton chemical shifts are observed upheld, evidence that the ethyl group is coordinated to zinc near the center of the porphyrin. The complex is stable under N2 in the dark, but decomposed by a radical mechanism in visible light.The complex reacted with hindered phenols (HOAr) when irradiated with visible light to give ethane and the aryloxo complexes Zn(TPP—NMe)OAr. The reaction of Zn(TPP—NMe)Et, a secondary amine (HNEt2) and CO2 gave zinc carbamate complexes, for example Zn(TPP—NMclOiCNEti."" ... 

Tungsten aryloxo complexes have been shown to catalyze the intramolecular metathesis reactions of di- and tri-substituted co-unsaturated glucose and glucosamine derivatives to yield bicyclic carbohydrate-based compounds containing 12- and 14-membered rings [108,214,215]. An example is shown in Eq. 37. The tolerance for amides and esters is noteworthy, as are the yields and the size of the rings that are formed. 

Bis(aryloxo) complexes, with mono-Cp Ti(IV), 4, 474 Bis(aiyloxo) titanacyclopent-2-ene, synthesis, 4, 358 Bis(A7-azain do Mi methane-coordinated complexes, with platinum(II), 8, 475... 

B-C bonds, 3, 97 B-N bonds, 3, 97 B-O bonds, 3,94 B-P bonds, 3, 97 B-Si bonds, 3, 97 oxo acid anion complexes, 3, 96 Borates, alkoxo-, 3, 94 Borates, amidotrihydro-, 3,92 Borates, aryloxo-, 3, 94 Borates, carboxylato-, 3,96 Borates, catechol, 3,95 Borates, chlorosulfato-, 3,97 Borates, dicarboxylato-, 3,96 Borates, dipyrazol-l-yl-, 3, 92 Borates, halogeno-, 3,92 Borates, halogenohydro-, 3,90 Borates, hydro-, 3,90 Borates, hydrohydroxo-, 3,90 Borates, hydropyrazol-l-yl-, 3, 92 Borates, hydroxo-, 3,94 Borates, hydroxycarboxylato-, 3,96 Borates, inositol, 3, 95 Borates, monoalkyl-, 3, 92 Borates, monophosphido-, 3, 92 Borates, peroxohydroxo-, 3, 94 Borates, polyol, 3, 95 Borates, pyrrol-l-yl-, 3, 92 Borates, sulfato-, 3, 97 Borates, tetrabromo-, 3, 92 Borates, tetrachloro-, 3, 92 Borates, tetrafluoro-, 3, 92 minerals, 6, 847 Borates, tetrahalogeno-mixed, 3, 93 nB NMR, 3, 92 Borates, tetraiodo-, 3, 92 Borates, tetranitrato-, 3, 96 Borates, tetraperchlorato-, 3, 97 Borates, tripyrazol-l-yl-, 3, 92 Borax, 3,101 Borazines... 

Gold(III) alkoxo complexes are stabilized by a variety of ancillary ligands. Some of them, as with [Au2(/u-OTMS)2Me4] which was synthesized some time ago178"1 have found recent applications as precursor for CVD.1785 Thermally stable aryloxo and fluoroalkoxo complexes of the type... 

Fonetal. dialkylated a tantalum(aryloxo)(amido) trichloride with 2equiv. diethylzinc to furnish the corresponding diethyltantalum complex 25, as shown in Scheme 22.62... 

The aryloxo(chloro)neopentylidenetungsten complex developed by Basset and coworkers (Scheme 2) has also been employed as an initiator in ROMP reactions [165,166]. 

The quasi living polymerization of ethene and norbornene has been reviewed, among other topics in living polymerization of alkenes (19). Specifically, arylimido-aryloxo-vanadium(V) complexes with methylaluminoxane or Et2AlCl as co-catalyst have been used as catalyst systems. The polymers exhibit a low polydispersity and a high molecular weight (20). 

W. Wang and K. Nomura, Remarkable effects of aluminum cocatalyst and comonomer in ethylene copolymerizations catalyzed by (arylim-ido)(aryloxo) vanadium complexes efficient synthesis of high molecular weight ethylene/norbomene copolymer, Macromolecules, 38(14) 5905-5913, July 2005. 

Some examples have been reported of tethered r 6-arene complexes of molyb-denum(II) and tungsten(II) that incorporate oxygen as the auxiliary donor atom.37 40 Reaction of neat 2,6-diphenylphenol with [MH4(PMePh2)4] (M = Mo, W) at 150 °C gives the tethered hydrido(aryloxo)metal(II) complexes 30 and 31.36 A metal-hydride bond is probably first cleaved by the phenolic oxygen with loss of H2 coordination of the pendant arene then induces loss of another equivalent of H2. 

The transamination of the anionic amido ytterbium complex LiYb (N Pr2)4 with aryloxo-functionalised NHC imidazolium salt precursors affords bis-aryloxo-NHC monoamido ytterbium(III) complexes (Scheme 32)71 The complexes are isostructural with one another in the solid state and exhibit average ytterbium-NHC bond distances of 2.487 A (R = Me) and 2.535 A (R = Pr). These are comparable to the monodentate lanthanide(III)-NHC bond lengths where the ligand possesses and amido tether, though a direct comparison with like-for-like metal centre is not possible. The longer ytterbium-NHC bond length where R = Pr is likely as a result of the increased bulk of the ligand. 

Scheme 32 Synthesis of bis-aryloxo-NHC monoamido ytterbium complexes.

A novel intermolecular type of trimer formation occurs with 2-hydroxy-5,10,15,20-tetraphenylporphyrinatoiron(lll). Deprotonation of the 2-hydroxy group creates an anionic aryloxo ligand for another Fe center, and the cyclic trimer thus forms. The metal ions are weakly coupled high-spin Fe centers (/Xeff = 5.4 0.2/xb), and the 3-H NMR resonances of this low-symmetry trimer are uniquely found at very negative chemical shifts (-89.8, -94.7 and -99.3 ppm at 291 K) and are very broad (670-690 Hz), while all other /3-pyrrole protons resonate in the +82 to +62 ppm region typical of high-spin Fe in monomeric complexes.The structure of the trimeiic complex has also been reported. ... 

These ligands can be tuned both electronically and sterically via ring substitution. Consistently larger MOC bond angles are found in aryloxo relative to alkoxo complexes as ligand oxygen in the... 

The synthesis and characterization of a family of mono-Gp dichloro complexes with disubstituted aryloxo ligands has been reported, and their molecular structures provide some means of quantifying the number of electrons donated to the metal center by an aryloxide ligand. These complexes can be reduced by Grignard reagents or LiBu11 in the presence of enynes. The formation of metallacyclic derivatives (Scheme 348) was observed for the Cp but not for the Cp complexes, as deduced by NMR spectroscopy. The complexes have been investigated as catalysts... 

Scheme 350 shows the structures of a number of mono-Cp titanium complexes with more elaborately substituted aryloxo ligands. The compounds are formed by the reaction of Cp TiCl3 with 1 equiv. of the substituted phenol in the presence of an excess of pyridine or by treatment of the lithium phenoxide with Cp TiCl3 some of them have been... 

Mono-Cp chloro titanium complexes containing a sulfide-bridged chelating bis(aryloxo) ligand have been synthesized and characterized (Scheme 383). The complex Ti(tbmp)Gl2 reacts with LiCp (Cp =Cp, Cp, G5H4SiMe3) to... 

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