P. species

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. 

Bis(p -octadienediyl-Ni11 species are shown (i) to be thermodynamically highly unfavorable, thus indicating them to be sparsely populated, and (ii) not to be involved as reactive intermediates along any viable path either for allylic isomerization or for reductive elimination. This leads to the conclusion, that bis(p ) species play no role within the catalytic reaction cycle. 

Note that by definition XK — 1 and thus Xp is the cumulative mass fraction of the first P species. The inverse transformation corresponding to Eq. (93) is... 

Consistently with the discussion in Section 4.7.5, we can describe the entire reaction profile from reactant (R) to product (P) species,... 

Exudation occurs in response to environmental constraints, especially P deficiency (e.g., Jones 1998 Hinsinger et al. 2003) and differs depending on the P-form (Lambers et al. 2002) and plant species (Nuruzzaman et al. 2006). Banksia grandis exuded citrate, malate, and trans-aconitate when supplied with aluminium-phosphate. It exuded less of these tricarboxylates and dicarboxylates, but instead lactate and acetate, when supplied with iron-phosphate (Lambers et al. 2002). Plant species differ in their abilities to use various P species (van Ray and van Diest 1979), which can be due to differences in their exudation behavior (Nuruzzaman et al. 2006) and acidification of the root zone (Haynes 1992). This can influence the interspecific competition and coexistence of species, as we will discuss later. 

On the other hand, the mono-, bis- and trishomoaromatic (N, O, P) species are formally derived from the triborirane dianion M by successive incorporation of methylene bridges into the ring. 

Introduction of mesityl groups at the porphyrin ring can prevent the formation of the dimeric products and the reaction with dioxygen now leads to ruthenium(VI)-dioxo complexes of TMP (tetramesitylporphyrin) [35], The tram-Ru(VI)02-TM P species can catalyse the epoxidation of alkenes as well as whole range of other oxidation reactions. After transfer of one oxygen atom to an organic substrate Ru(IV)0-TMP is formed, which disproportionates to an equilibrium of Ru02 and llu ). 

The main goal was to produce CDPG on a large scale. Tetrazole activation was not investigated because acceptable yields were observed when pyridi-um hydrochloride was employed (step a). Cumene hydroperoxide was used as a useful oxidant (step b). To be successful, deprotection by catalytic hydrogenolysis (step c) must proceed in the absence of P species. Otherwise the efficiency of catalytic hydrogenolysis is severely diminished. 

Aldenberg, T., Jaworska, J.S., Traas, T.P. (2002). Normal species sensitivity distributions and probabilistic ecological risk assessment. In Posthuma, L., Suter II, G.W. and Traas, T.P., Species Sensitivity, Distributions in Ecotoxicology Boca Raton CRC Press, USA. 

Figure 9.2 E-pH diagram for P species. Soluble species concentrations (except H+) = 10 -° M. Soluble species and most solids are hydrated. No agents producing complexes or insoluble compounds are present other than HOH and OH. ...

Bis adducts of Et3P with In2Br4 and In2I4 have been prepared vibrational spectra showed these to be P(X2)InIn(X2)P species, with a staggered conformation in the solid state.26... 

More detailed investigations [38,39] have shown the kinetics of low-temperature electron transfer reaction (1) in bacteria to have a biphase character, i.e. to consist of two sections, one with a faster and the other with a slower decay of the Pf centres. Also, the type of kinetics of reaction (1) in bacteria at low temperatures has been found to depend on the conditions of sample preparation. The region of fast (t 50 ms) charge recombination at T < 230 K was observed only for the samples frozen in the dark. The extent of P decay was observed to decrease upon freezing the samples in the light. These results were explained by the presence of two channels for the decay of P+ centres by reactions with particles A and Q". The faster decay of P+ was assumed to be due to its reaction with A and the slower decay of P4 to its reaction with Q . The relative amounts of A and Q particles (i.e. the extent of electron transfer from the reduced form of the primary acceptor A to the secondary acceptor Q) was assumed to depend on temperature. This assumption explains why the character of P decay depends on whether P+ species are formed after or in the process of freezing the sample. 

Given that the Fe and P bound to the DOM in humic lakes are probably not directly available to organisms, the DOM-Fe-P complex would have to undergo some form of transformation to yield bioavailable Fe and P species. In terms of biological uptake, in general it can be said that Fe is preferred in the dissolved free ionic form and P as orthophosphate (P04). Several known processes result in the transformation of Fe and P from the DOM-Fe-P complex into biologically available species. Two of the mechanisms are physical-chemical processes (1) UV-mediated photoreduction and (2) DOM-mediated chemical reduction or dark reduction. Other mechanisms are... 

An interesting relationship between the structure of the [RhH(CO)2(P - P)] species and their enantio-discriminating performance has been found for several series of diphosphite ligands. In general, enantioselectivities were highest for ligands with a strong bis-equatorial (ee) coordination preference, and they were considerable reduced by equilibrium of species with bis-equatorial (ee) and equatorial-axial (ea) coordination modes (Scheme 5a) [22, 37,49],... 

The bonding in P species can be expressed by their bond valence b, which corresponds to the number of P-P bonds. Let g be the total number of valence electrons in P . When a covalent bond is formed between two P atoms, each of them gains one electron in its valence shell. In order to satisfy the octet rule for P , j(<8n — g) electron pairs must be involved in bonding between the P atoms. The number of these bonding electron pairs is defined as the bond valence b of the P species ... 

Decomposition of the Pd M P species via /1-hydrogen elimination is unfavourable, since both /1-hydrogen atoms, H3 and Hi, are not easily accessible for a Pd-H bond forming process. The suppression of /1-hydrogen abstraction is a prerequisite for the monomer undergoing m-insertion polymerisation, leading, in this case, to poly(2,3-bicyclo[2.2.1]hept-2-ene) [10]. 

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