Ligand response equations

In these equations, MR3 4, MR, and MR4 are the molar refractivities of 3- and 4-substituents, of R-, and of 4-substituents, respectively. All the equations exhibited positive coefficients of the MR terms. This suggests that the dispersion forces of substituents are actually responsible for the binding of ligands to cyclodextrin. Eq. 14 shows that the stability of a-cyclodextrin-RCOO complexes increases linearly up to MR = 4.0 and then falls off linearly. 

Because the reaction requires energy from light, it is known as photosynthesis. The equation looks simple but photosynthesis is anything but that. The structures that are responsible for absorption of light in order for its energy to be used are the chlorophylls, which contain porphyrin-type ligands. The porphyrin structure is derived from the basic unit known as porphin, shown in Figure 22.16. 

Warshel and coworkers have recently examined the LIE method and different versions of what they call the LRA (linear response approximation) method for the binding of a set of cyclic urea compounds to HIV protease.34 The key features of their LRA scheme is that both averages of Equation 2 are evaluated, thus requiring two extra simulations of the non-polar states (see above), that the ligand intramolecular electrostatic terms are included in the averages, and that the non-polar contribution is calculated with the PDLD method. Results of similar quality were reported with the different methods.34 However, it should be noted that the value Vi of the electrostatic coefficient was used in Ref. 34, which, as discussed above, has been shown... 

The selectivity for hydrogenation of dienes in the presence of monoolefins arises from the exceptional stability of jr-ally 1 complexes. In the case of Pt catalysts the reactions shown can compete with one another (equation 6)14. The second pathway is favored, especially when the olefin or diene must compete with excess ligands (phosphine, CO, SnCp ) for a coordination site. This is why the diene is almost completely hydrogenated before the concentration of olefin increases to the point that the olefin gains access to the catalyst. A similar phenomenon can be responsible for selectivity in hydrogenation of dienes with heterogeneous catalysts. 

Substituting this expression into the equation above yields a new expression relating the MS response to four variables the total ligand concentration [S]q, which is the known, independent variable in a titration experiment the fCj, which is the dependent variable of interest the total receptor concentration [ ]q and the MS response calibration factor Cms ... 

Therefore, plotting the ALIS MS response from a titration series versus the total ligand concentration yields a saturation binding curve that can be fit to this equation by nonlinear regression analysis to yield the of the ligand of interest. 

The biological or functional response to receptor activation can be assumed to be directly proportional to the number of receptors (R) occupied by a given ligand (L) at equilibrium. This assumption is termed the occupancy theory of drug response. The equation describing this phenomenon was proposed as ... 

In 1993, Jacobsen and Evans simultaneously reported that [7V-(p-tolylsulfonyl)imino]phenyliodinane (TsN=IPh, 195) is an efficient asymmetric nitrene transfer reagent to alkenes in the presence of a catalytic amount of a copper(i) salt and a chiral diimine ligand or a chiral bis(oxazoline) ligand (Equation (31)). Mechanistic study by Jacobsen and co-workers suggests that a discrete copper(iii) nitrene complex is an intermediate responsible to the reaction. ... 

In liquid ammonia, hexacyanochromates(II) can be reduced to the diamagnetic chromium(O) complexes M6[Cr(CN)6] by the appropriate alkali metal. The K salt was earlier obtained by reduction of K3[Cr(CN)6], Greater metal-ligand jt bonding is presumably responsible for the lower CN stretching frequencies of M6[Cr(CN)6]. The potassium salt is oxidized to K3[Cr(CN)6] by ammonium cyanide in liquid ammonia (equation l).12... 

Most of the reported photochemical reactions of lanthanide complexes involve some type of redox behavior.147 Photolysis (254—405 nm) of Eu2+ in acidic aqueous solution, for example, results in photooxidation of the metal and generation of H2 (equation 50).148 While the excited states responsible for this reaction nominally arise from 4/ -+ 5d transitions localized on the metal, strong mixing of the 5rf-orbital with ligand orbitals endows these states with appreciable CTTL character. Photoreduction of aquated Eu3+ can also be driven with UV ( 254 nm) light149 and forms the... 

Many more recent stoichiometric studies of cobalt(III) complexes have been responsible for most of the developments in this area of research. Cobalt(III) ammine complexes effect hydrolysis of ethyl glycinate in basic conditions via intramolecular attack of a coordinated amide ion hydrolysis by external hydroxide ion attack also occurs (equation 74).341 Replacement of ammonia ligands by a quadridentate or two bidentate ligands allows the formation of aquo-hydroxo complexes and enables intramolecular hydroxide ion attack on a coordinated amino ester, amino amide... 

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