4-hydroxyphenyl complex with

Most complexes with catalytic properties are tetradentate derivatives of salen but other ligands, e.g., A-(hydroxyphenyl)salicyldimine and A-(hydroxyphenyl)pyridine-2-carboxaldimine, form ternary complexes with bipy and CU ((14) and (15), respectively) that are catalytically competent. 

C27H23Cl2N03PRe, Rhenium(V), dichloro(2-(2 -hydroxyphenyl)-2-oxazoline)(triphenyl-phosphine) 0x0-, 34 58 C27H50P2, dcpp, l,3-bis(dicyclohexylphosphi-no)propane, complex with copper(I), 34 177... 

A number of complexes of dioxouranium(VI) compounds with thioureas have been reported (Table 85) but little is known about them. In addition to those listed in the table, a number of complexes with dioxouranium(VI) nitrate formulated as [U02Lx(N03)](N03), with x = 4 and L = o-chlorophenyl thiourea, jc = 3 and L = o- or p-hydroxyphenyl thiourea, and x = 2 and L = o-methoxyphenylthiourea, as well as [U02L(N03)2] with L = benzylthiourea, have also been recorded. 37... 

Schiff s bases formed from o-hydroxyaldehydes often form reagents of service in analysis. For example, the base formed with ethylenediamine forms an insoluble complex with nickel (14) which has been used for its gravimetric determination. 2-(o-Hydroxyphenyl)benzoxazole (15a) has been... 

The effects of a-, (3-, y-, and 2,6-di-o-methyl-(3-CDs on the ground- and excited-state properties of 2-(2 -hydroxyphenyl)benzoxazole (HBO), 2-(2 -hydrox-yphenyl)benzothiazole (HBT), and 2-(2 -hydroxyphenyl)benzimidazole (HBI) (42) in aqueous media have been investigated using fluorescence [184], The molecules form 1 1 complexes with a reasonably high association constant, and they enter the cavity axially from the wider-rim side of (3-CD with the benzazole... 

Technetium(V) complexes with /u,v(ohydroxyphenyl)phenylphosphine and (o-hydroxyphenyl)diphenylphosphine ligands were prepared by metathesis reactions with the appropriate Tc(V) precursor and/or by reduction/ligand-exchange reactions with ammonium pertechnetate [530]. It was expected that the combination of one soft phosphine P-donor and two hard phenolate O-donors in the chelate should stabilize Tc centers in intermediate oxidation states. 

Fig. 3. Relationship between width at half-height (AH1/2) of the low-field component of the ESR spectrum of copper complex with poly(hydroxyphenyl-benzoxazolterephthalamide) and the ratio [Cu]/[L] at -196 °C...

Scheme 10 Complexes with bis(o-hydroxyphenyl)phenylphosphine and bis (2-hydroxy-5-methylphenyl)phenylphosphine...

As Section IV will be mostly devoted to 2,4-pentanedione, acacH, it is worthwhile to dwell on this well studied species. The rate of interconversion between the keto and the enol form of acacH is rather slow at room temperature , thus they can be simultaneously detected by NMR spectroscopy it has been observed that the lower the polarity of the solvent, the higher the percentage of the enol tautomer . Electron diffraction studies indicate that in the gas phase acacH adopts the enol configuration with a keto/enol ratio of 8/92. More recently, an X-ray analysis of acacH, carried out at 110 showed that it exists as a mixture of the two enol forms 86 and 87, with the enolic hydrogen atom equally distributed over two positions close to the oxygen atoms as in 88. It should be noted that inclusion compounds containing different host molecules show different ratios of acacH in the enol form. For example, acacH exists as a dynamically averaged 1 1 mixture of 86 and 87 in an inclusion complex with l,T-binaphthyl-2,2 -dicarboxylic acid as host , while l,l-bis( >-hydroxyphenyl)cyclohexane and (4R,5R)-trawi-4,5-bis(hydroxydiphenylmethyl)-2,2-dimethyl-l,3-dioxolane include acacH in pure enolic form. ... 

The absolute stereo-preference in the Diels-Alder reaction can be easily understood in terms of the most favorable transition-state assembly 5, in which an attractive donor-acceptor interaction favors coordination of the dienophile at the face of boron which is cis to the 2-hydroxyphenyl substituent. At this time, the conformation of a,y3-enal has a strong s-trans preference. We believe that the coordination of a proton of the 2-hydroxyphenyl group with an oxygen of the adjacent B-O bond in complex 5 plays an important role in asymmetric induction this hydrogen-bonding interaction via a Brpnsted acid would cause the Lewis acidity of boron and the jr-basicity of the phenoxy moiety to increase, and the transition-state assembly 5 would be stabilized. The jr-basic phenoxy moiety and the jr-acidic dienophile could then assume a parallel orientation at the ideal separation (3 A) for donor-acceptor interaction. In this conformation, the hydroxyphenyl group blocks the si face of the dienophile, leaving the re face open to approach by diene. 

The phosphine oxide exo-exo cages (30) and (31) and exo-endo cages (32) and (33) have been prepared from tris(4-hydroxyphenyl)phosphine oxide (29) and in two cases, (30) and (33), X-ray structural analyses were carried out.l i Compounds (30 to 33) all form 1 2 complexes with p-nitrophenol. 

The synthesis of mono-Gp triphenoxo titanium complexes with the chelating tris(2-hydroxyphenyl)amine and tris(2-hydroxy-3,5-dimethylbenzyl)amine has been reported (Scheme 378). Electrochemical experiments provide useful information on the reduction potentials of the compounds, from which it is clear that tris(2-hydroxy-3,5-dimethylbenzyl)amine is a stronger donor than tris(2-hydroxyphenyl)amine. The chelate ring size is also important while the reduction of complex containing tris(2-hydroxyphenyl)amine is largely reversible, the reduction of the tris(hydroxybenzyl)amine derivative is irreversible. In the presence of MAO these compounds show high activity and appreciable selectivity for the preparation of syndiotactic polystyrene.909... 

A formazan dye (l,5-bis[3,5 dichloro-2-hydroxyphenyl]-3-formazan carbonitrile) forms a complex with magnesium at alkaline pH, which has been measured at 630 nm by thin-film reflectance photometry. N,hf -[l,2-ethanediyibis[oxy-2,l-phenylene]bis(N-carboxymethyl)] glycine is used to chelate calcium. This thin-film reflectance method shows relatively little interference from icteric, Upemic, and hemolyzed specimens. Elevated calcium concentrations cause a measurable but small overestimation. 

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