P-complex

Olefin-CO coploymers Olefin p-complexes Olefin Fibers Olefin hydroformylation Olefin hydrogenation Olefimc alcohols Olefin isomerization Olefin metathesis Olefin oligomers Olefin oxides... 

The bioflavanoids (vitamin P complex) are substances which maintain the small blood vessel walls. The substances are widely distributed among plants, eg, all citms fmits, and have been used medicinally to decrease capillary permeability and fragility. 

However, high spin (P and (P species, which possess 4, 5, and 4 unpaired electrons, respectively, are labile, as are (P through (P octahedral complexes. In addition to the inert (P systems, low spin (P and (P complexes are inert to rapid substitution. The (P species are the least labile of the configurations classed as labile. 

The chlorination of phosphonic and phosphinic acids and esters are of considerable importance. PCI5 can also act as a Lewis acid to give 6-coordinate P complexes, e.g. pyPClf, and pyz-PCI5, where py = C5H5N (pyridine) and pyz = cyclo-1, 4-C4H4N2 (pyrazine). ... 

Bunz UHF (1999) Carbon-Rich Molecular Objects from Multiply Ethynylated p-Complexes. 201 131-161... 

CTien contraction of muscle is stimulated (via events involving Ca +, troponin, tropomyosin, and actin, which are described below), actin becomes accessible and the S-1 head of myosin finds it, binds it, and forms the actin-myosin-ADP-P complex indicated. 

Phosphorus (P) is one of the major limiting factors for plant growth in many soils. Plant availability of inorganic phosphorus (Pi) can be limited by formation of sparingly soluble Ca phosphates, particularly in alkaline and calcareous soils by adsorption to Fe- and Al-oxide surfaces in acid soils and by formation of Fe/ Al-P complexes with humic acids (94). Phosphorus deficiency can significantly alter the composition of root exudates in a way that is, at least in some plant species, related to an increased ability for mobilization of sparingly soluble P sources (29,31,71). 

The Cr(CN-[P])g and Ni(CN-[P]) complexes of 2 have been prepared as well under macroscale conditions. 100 - 200 mg of metal were deposited typically into a blend of 2 in a poly(dimethylsilox-ane) at 270 K [normally - 10 ml of 2 in 40 ml of diluent]. The products for each metal were dark orange, viscous oils which gave IR and uv-visible spectra in good agreement with those obtained from the matrix experiments. 

Caubere, P. Complex Bases and Complex Reducing Agents. New Tools in Organic Synthesis. 73, 49-124(1978). 

This complex then acts as the active centre. The monomer is then attracted towards the Ti-C bond (C from the alkyl group R) in active centre, when it formes a p complex with the Ti ion as under ... 

The active catalyst formed then has an octahedral structure, with the four Cl attached to the latice and the ethyl group attached to the Ti through a s bond, and leaving a vacant orbital at the position where originally the fifth chlorine was attached. Once the active catalyst is formed, the monomer is attracted towards the vacant d-orbital which then forms a transition p complex with the Ti, as shown below ... 

It was only in 1959 that Guy Ourisson renovated the study of organic chemistry by organizing the Groupe d Etudes de Chimie Organique (GECO), to facilitate contact with chemists abroad and to rethink the theoretical foundations of modern organic chemistry. 89 That this was a project sorely needed is indicated by Micheline Charpentier-Morize s reflections on her doctoral thesis defense in 1958. Prevost presided over the jury. When she referred to the possible existence of a "p-complex" to explain reactivity, Prevost exclaimed, "Madame, if I have one reproach for you, it is that you know the modem theories too well. "90... 

Under these prevailing circumstances the reduction in (A - P) complex concentration taking place may be predicted as follows ... 

Sinha, S.P. Complexes of the Rare-Earths. Oxford Pergamon Press 1966... 

Fig. 13 shows the B3LYP/6-31- -- -G -calculated optimized structures of neutral diastereomeric [E j-P ] and [E -P ] complexes. Two structures have been predicted for both the homochiral (Ihomo and IIhomo) and heterochiral (Ihetero and IIhetero) complexes. Their electrostatic parameters, binding energies and computed dipole-bound electron affinities EAdb are reported in Table 5. 

Compounds 81 and 83-86 were linked to P-CD, the ruthenium p-complexes prepared in situ and reductions carried out with the standard substrate 63 (Fig. 26). Comparing the results of ruthenium complexes with ligands 87-91 reveals that any substituent adjacent to the tosyl group leads to modest to good ee values but reduces the reactivity of the catalyst considerably, see 87-89 (Fig. 26), improvement of the 5delds between 33% and 53% was only achieved at elevated temperatures (50°C). In contrast, ruthenium complexes with ligands... 

The crystal structures of D-AspRS-tRNA P complexes show interaction of the LI loop with determinant C36 of Three residues of the extended loop of the T. thermophilus D-AspRSl (Asn82,... 

Boronic esters have been used in a wide range of transformations. These useful reagents have been transformed into numerous functional groups and are essential reagents for several C-C bond-forming reactions. Transition metal-catalyzed hydroboration of olefins often leads to mixtures of branched and linear products. Several groups have reported asymmetric reductions of vinyl boronic esters [50-52] with chiral rhodium P,P complexes however, the first iridium-catalyzed reduction was reported by Paptchikhine et al (Scheme 10) [53]. 

A.J., and Yang, R.T. (2004) Selective adsorption of organosulfur compounds from transportation fuels by p-complex-ation. Sep. Set. Technol., 39, 1717. 

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