Tris complexes structure

Cobalt, tris(l,2-propanediamine)-complexes structure, 1, 25 conformation, 1,25 nomenclature, 1, 129 stereonotation, 1,129... 

Ethane, (K)-l-cyclohexyl-L2-bis(diphenylphosphino)-rhodium complexes asymmetric hydrogenation, 6,253 Ethane, tetracyano-metal complexes, 2,263 Ethane, tetrakis(aminomethyl)-metal complexes, 2, 56 Ethane, tris[l, 1, l-(trisaminomethyl)]-complexes structure, 1,26... 

Germanium, eyclopentadienyl-, 3, 218 Germanium, tris(acetyiacetone)-structure, 1, 65 Germanium alkoxides physical properties, 2, 346 Germanium complexes, 3,183-223 acetylacetone isomerization, 2,383 bivalent... 

Iron, tris(hexafluoroacetylacetone)-structure, 1,65 Iron, tris(oxalato)-chemical actinometer, 1,409 photoreduction, 1,471 relief-image-forming systems, 6,125 Iron, tris(l,10-phenanthroline)-absorptiometry, 1,549 racemization, 1,466 solid state, 1,467 structure, 1, 64 lron(III) chloride amino acid formation prebiotic systems, 6,871 Iron complexes acetonitrile. 4,1210 acetylacetone, 2,371 amidines... 

Molybdenum, tris(phenylenedithio)-structure, 1,63 Molybdenum alkoxides physical properties, 2,346 synthesis, 2,339 Molybdenum blue liquid-liquid extraction, 1,548 Molybdenum cofactor, 6,657 Molybdenum complexes acrylonitrile, 2,263 alkoxides, 3,1307 alkoxy carbonyl reactions, 2,355 alkyl, 3,1307 alkyl alkoxy reactions, 2,358 alkyl peroxides oxidation catalyses, 6,342 allyl, 3,1306... 

Niobium, tris(diethyldilhiocarbamato)oxy-stereochemistry, 1,82 structure, 1, 83 Niobium, tris(oxa ato)oxy-stereochcmistry, 1, 82 Niobium, tris(phcnylcncdirhio)-structure, 1, 63 Niobium alanate, 3, 685 Niobium complexes alkyl alkoxy reactions, 2, 358 amides, 2,164 properties, 2, 168 synthesis, 2, 165 applications, 6,1014 carbamicacid, 2, 450 clusters, 3, 672,673,675 hexamethylbenzene ligands, 3, 669 cyanides synthesis, 2, 9 p-dinitrogen, 3, 418 fluoro... 

Tris(bipyridyl) complexes structure, 1, 63 Tris(diketonate) complexes structure, 1,65 Trisdithiolencs metal complexes synthesis, 2, 597... 

These principles of macromolecular organization replaced the naive vision of some of the early molecular biologists, who tried to reduce each complex structure and function of organisms directly to one (or a limited number of) proteins or other macromolecules. The best example of this simplistic reductionist approach was the efforts aiming in the sixties at discovering the molecules of memory - molecules that allegedly encoded the memories or behaviors. Many articles and books1 were devoted to this search, without any success. 

Figure 12.15 Gangliosides. The prefix mono-, di, tri- or tetra- denotes the number of sialic acid W-acetyl neuraminic acid, NANA) residues present in the molecule. The many different gangliosides have complex structures and for convenience shorthand notations are used. The two commonest were introduced by Svennerholm, who named the parent compound GM1, and Wiegnandt, who named it Ggnti. The latter system gives enough information for the structures to be worked out from the shorthand form once the symbols have been learnt. GalNAc represents N-acetyl galactosamine in the above structure.

As in the case of o-dioxolenes, the diimine derivatives also form tris-complexes. Figure 38 for instance shows the molecular structure of the benzoquinone diimino dication [Osn(bqdi)3]2 +. 50c... 

Among the other structurally characterized tris-complexes ([Fen(bqdi)3]2 +, 64 [Rum(bqdi)2(opda)]2 + 65) of known electrochemical behaviour,66 the only case we know in which structural data are available for redox couples is concerned with [Re o-C6H4(NH)2 3] + /[Re 0-C6H4(NH)2 3].67 Figure 39 shows the trigonal prismatic geometry of the monocation. 

Dithiolenes also form tris complexes of octahedral geometry. Limiting to M(dmit)3 complexes we can cite as a typical example the dianion [W(dmit)3]2-, the molecular structure of which is illustrated in Figure 44.81... 

Analogous methyl compoimds are iU-characterized and appear to be polymeric [129). The air-sensitive phenyl derivatives when first obtained from THF are soluble in benzene, but when dried completely are no longer soluble — apparently due to pol5unerization. The homoaryl complexes of the smaller scandium, and yttrium ions form only the tris complexes Sc(CeH5)3 and Y(C6H5)3 [129) It is apparent that the structure and stabihty of the homoaryls are dependent on the metal ionic radii and the steric bulkiness of the phenyl group. 

Attempts to prepare adducts directly from [VO(oxme)2] (138) were unsuccessful and a trigonal bipyramidal structure was suggested for this compound as for [VO(2-Me-oxine)2] (139).825 The [VO(oxine)2X] compounds were prepared by addition of V0S04 to an aqueous solution containing 8-hydroxyquinoline and the base X. For the adducts [VO(oxine)2X], a correlation was found between v(V=0) and the pK of the X ligand, except with bases with substituents where steric hindrance may be operating, and no evidence was obtained for the existence of both cis and trans isomers, unlike the case of [VO(acac)2] adducts (Section 33.5.5.4.ii). For the tris complexes [VO(oxine)3] , an octahedral structure in which one oxine ligand is unidentate and bonded to V was proposed.825... 

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. 

The closely related tris complex of malonaldehyde (170) has been synthesized by the reaction of 1,1,3,3-tetramethoxypropane with anhydrous CrCl3 in an ether slurry.745 The complex was purified by sublimation and contains the simplest structural unit capable of enolizing to form a /3-ketoenolate chelate. 

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