Tris compounds

The tris compounds are highly bridged three-dimensional polymers. Photoreduction of aqueous Ti(IV)-containing alcohols or glycols, but not of ethylene glycol, yields Ti(III) and the aldehyde or ketone corresponding to the alcohol (191,192). A possible mechanism is... 

The tris and bis complexes of acetylacetone (2,4-pentanedione) (167) with chromium(III) have been known for many years (168,169).739 The tris compound is generally prepared by the reaction of an aqueous suspension of anhydrous chromium(III) chloride with acetylacetone, in the presence of urea.740 Recently a novel, efficient synthesis of tris(acetylacetonato)chromium-(III) from Cr03 in acetylacetone has been reported.741 The crystal structure of the tris complex has been determined.744 A large anisotropic motion was observed for one of the chelate rings, attributed to thermal motion, rather than a slight disorder in the molecular packing. 

Since Amadori compounds are secondary amines, the question of the formation and reactivity of /V-nitroso derivatives arises. Accordingly, Pool el al 22 tested those derived from glucose with Ala, Asp, Phe, Gly, Ser, and Try in five strains of S. typhimurium with and without S9. The first three compounds were not mutagenic, the next two showed low but reproducible increases in the number of his+ revertants in TA1535 (without S9), but the last, containing indolyl-nitrosamine-D-fructose-L-tryptophan, was mutagenic in all five strains, with and without S9. When separated, the Try compound was mutagenic in three strains, without S9. 

Compound 12 is a tetra-antennary oligosaccharide that was isolated from the urine of a patient with GM,-gangliosidosis.52,64 64a This structure can be conceived of as an extension of the tri- (compound 10) or tri -antennary (compound 11) oligosaccharide with an N-acetyllactos-amine unit. The 500-MHz, H-n.m.r. spectrum of 12 is presented in Fig. 12, and its n.m.r. data are given in Table IV. 

Structure of Halonitrides.—On account of their stability towards heat and hydrolysing agents, as wrell as the requirements of valency, cyclic formulas have been assigned to the halonitrides in which the rings are composed either of >N—PC12 or of >N and >PC12 alternately.2 Thus the tri-compounds may be represented by... 

Tris compounds have been proposed only in [py2H][MnBr3py3] (which could be instead [MnBr2py4]-pyHBr) and [R4N][MnBrCl2py3] (R = Me, Et) and a 4-picoline analogue, but even their formulation as discrete species needs X-ray confirmation. 

Except perhaps for the special case of the n = 4 species, the values of n seem invariably to define the number of bidentate ligands bonded to Mn tris compounds are octahedral cations (one salt, the ethylxanthate, has been shown123 to be isomorphous with the octahedral Fe, Co and Ni salts) bis... 

Among the many rare earth complexes of / -diketones that have been described (i, 12, 15, 16), the tris compounds generally have the most... 

The emissions of both compounds are composed of two components having lifetimes similar to those of the parent tris compounds. 

Another series of luminescent rhodlum(III) complexes which have been investigated are cis-Rh(bipy)2X2 hd cis-Rh(phen)9X9 where X = Cl , Br and I. Instead of the highly structured, relatively long-lived "ligand type" emission shown by the parent tris compounds, these systems have a broad, structureless, and short-lived emission (Table 8) which is located in the near... 

Bis(polyfluorophenyl)thallium(III) bromides with aryl groups containing two ortho-fluorine atoms undergo reductive symmetrization with Cu powder in 1,4-dioxane to produce adducts of the corresponding tris compound" ... 

The crude pyridine complex is sublimed, then treated with 1,4-dioxane to yield the tris compounds as dioxane complexes in 20-60% yield. The ease of decarboxylation is R = CgFj p-MeOCgF > p-HCgF4 = m-HCgF4 > o-HCjF4. Two ortho-fluorine atoms are required for the reaction to proceed. 

Clonidine reduces blood pressure by acting on the central nervous system, but it also contracts blood vessels in the peripheral nervous system, and this leads to an increase in blood pressure. The biological activity of a series of related compounds on the central nervous system was found to correlate with the partition coefficient between octanol and water and the biological activity on the peripheral nervous system. The study indicated that there was an optimum value for the partition coefficient, and that central and peripheral nervous system activity could not be separated, suggesting that to find a drug that only acts on the central nervous system it would be necessary to try compounds unrelated to clonidine. Clonidine attaches to the same type of receptor in both the central and peripheral nervous systems — hence the correlation between central and peripheral nervous system biological activity. To attach to the receptor in the central nervous system, however, it has to cross the blood-brain barrier and thus must dissolve in lipids to reach its target. This leads to the correlation of central nervous system activity with lipid solubility. 

Using various rat-paw oedema tests, Piccinini, Marazzi-Uberti and Lugaresi found that l,2-diphenylpyrazolidine-3,5-dione (XXXII, R = R = H) is inactive but that the bi- and tri- compounds (XXXII, R = H, R = XXXIII, and XXXII, Ri = R2 = XXXIII) are 1-2 and 3-5 times respectively, more active than phenylbutazone. 

Most of the data for this section come from the reactions of MnClj with uni-, bi- and ter-dentate ligands (Table 45). The green monopyridine compound (214) is not at all robust, but reacts further to give a more stable, brown tris compound [MnCljpyj] (215). Compounds of the latter class generally are sensitive to moisture (although the NEtj compound is distinctly less so), but the py compound is stable up to 100°C under N2. No physical measurements were reported, but the related terpy compound (219) is a typical, high spin, octahedral species. 

Triphenylantimony tris compound precursor Tris (trimethylsilyl) silane tritium mfg. 

As shown in Fig. 3.33, starting from the Diels-Alder product, reduction for removal of acetoxyl group by samarium diiodide was first tried. Compound 3.68 was obtained in 90 % yield. Using CCLj as the solvent and benzoyl peroxide as the... 

The final rule listed bismuth vanadate, as a vanadium compound, as a TRI compound for annual reporting . The rulemaking did not include a reasonable argument for the bioaccumulation of either cobalt or vanadium metals included in insoluble compounds. Nor was there any mention of cobalt blue or vanadium yellow pigments. 

S Die Swell As resin molecular weight increases, die swell will decrease. Die swell is generally not a desirable characteristic, since it makes the fabrication of profile dies more difficult. The lower the die swell of a particular compound, the more easily a die can be fabricated on the first (or second) try. Compounds with lower die swell can also be extruded into complex profiles more easily than those with higher die swell. 

Of special interest are the emission properties of [Ru(bpy-h8)2(bpy-d8)]. While the homoleptic tris compounds were found to occupy one specific site in [Zn(bpy-hg)3] (0104)2, partially deuterated complexes have the tendency to occupy different sites. This is expected, when taking the considerations in Section 3.2.2 into account Thus, the spectrum of [Ru(bpy-h8)2(bpy-d8)] (Fig. 19b) is registered for the site of lowest energy. Its electronic origin, lying at 17684 cm" , is identified similarly as described above (e.g., see Sect. 3.3.1). The transition energy is expected to be somewhat blue-shifted compared to that of the per-protonated compound due to the deuteration of one ligand, but this effect seems to be canceled by the interaction with the crystalline environment. As expected, partial deuteration leads to an increase in the emission decay time (at T = 1.5 K) of state j I) to r= (253 5) ps [85] compared to 230 ps for the per-protonated compound. 

The satellite structure of [Ru(bpy-h8)2(bpy-d8)] is assigned (1) to phonon satellites with the same energies as found for the tris compounds (e. g., 33,47, 66, 78 cm ) (2) to metal-ligand (M-L) vibrations (most modes between 100 and = 500 cm ) and (3) to ligand modes (above 500 cm ). The M-L modes cannot be directly correlated with those of the tris compounds, since this would require a complete normal coordinate analysis for each of the complexes, which, however, are not as yet available. 

It is emphasized that the excitation spectrum of [Ru(bpy-hg)2(bpy-dg)] does not exhibit any additional electronic transition compared to tixe tris compounds. Note that the occurrence of two additional and distinct origins would be required to support the localized model proposed by Riesen and Krausz [162]. These authors investigated a spectral range (of line-narrowed excitation spectra) being too small to give support for their model. Moreover, they interpreted the overlapping phonon satellites to state III) of 23,33,40, and 46 cm as an additional electronic origin required by their model [162]. Thus, Fig. 20b shows directly that this model [162] breaks down (see also Sect. 3.8.1). 

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