Complex, persistent

The [ArH, TNM] complexes persist for prolonged periods at room temperature if the solutions are carefully protected from adventitious light. 

Heterometallic alkali metal phosphide complexes with transition metals have also been reported. The complex [(Cy2P)3Hf(ju.-PCy2)2Li (DME)] results from the reaction of LiPCy2 with HfCl4(THF) (98). This complex persists in solution. Jones et al. have reported the synthesis and reactivity toward a range of electrophiles of a series of lithium di-t-butylphosphido(alkyl)cuprates [RCu(PBu2)Li] (R = Me,... 

Cote, J., Peterson, C.L., and Workman, J.L. (1996) Perturbation of nucleosome core structure by the SWI/SNF complex persists after its detachment, enhancing subsequent transcription factor binding. Proc. Natl. Acad. Sci. USA 95, 4947 952. 

This example shows that use of the van der Waals technique brings out important features on the potential surface, in the differences in reactivity, and in energy distribution upon the symmetry of the entrance channel. It would be very interesting to see if the orbital specificity observed in the complex persists in the collisional regime. 

Fig. 2. Summary of regulatory GTPase cycle in photoactivation of cGMP-specific phosphodiesterase (PDE) in retinal rod cells. T, transducin (Gt) Rho, rhodopsin Rho, photoactivated Rho. PDE is represented as a heterotrimeric peripheral membrane protein, as is T. This regulatory cycle differs from that in Fig. 1 mainly in that the activation of PDE entails the dissociation of an inhibitory y subunit (PDEy) under the influence of activated Ta-GTP complex leading to formation of intermediary soluble Ta-GTP/PDEy complex. This complex persists until GTP is hydrolyzed to GDP, at which moment the inhibited PDEa/3y heterotrimer reforms. Dark adapted - non-activated - Rho is then required for reassociation of Ta-GDP to T/3y and release of GDP.

From the optical properties of the solutions it is clear that the blue color is associated with cobalt complexing (Table XI and Figure 11). At low concentrations of AlEt2Cl the blue color of the cobaltamine complex persists, but at the higher concentrations of AlEt2Cl when the color is yellow it is reasonable... 

Plots of AG, AH, and AS for the consecutive addition of 1 and 2 hiba ligands to the lanthanide cations are shown in fig. 13a. It is clear in this figure that the consistent interval in the free energy of the lanthanide-hiba complexes persists for the 1 1 and 1 2 complexes. For the 1 1 hiba complexes, the steady variation in complex stability across the lanthanide series is primarily related to the increasing contiibution of a favorable entropy superimposed on a nearly constant exothermic enthalpy. For the 1 2 complexes, the steady change in AG correlates most strongly with the trend for AH. 

The NOE generated in the complex is observed in the free form. This is possible since the relaxation time of the free small molecule is long, and therefore the effect generated in the complex persists after the molecule has dissociated from the complex. In addition, the experiment benefits from the sharp lines and simple spectra of small molecules. 

Investigating the reaction between hydroxylammonium chloride and iodine Weigh out accurately about 0.86 g of purest HO.NH3.CI and make up to 250 cm in a volumetric flask. Pipette 25.0 cm aliquot of the solution into a conical flask and dilute to about 150 cm Warm the solution on a hot plate, fitted with a magnetic stirrer. Add 0.15 g purest MgO (used to avoid acidity of the solution) and add slowly (standardised) 0.05 M iodine solution from a burette keeping the suspension warm. When the colour of iodine fades slowly, add 2 cm of freshly prepared starch solution to the conical flask and continue the titration slowly until the blue colour of the starch/iodine adsorption complex persists for 30 seconds. From the average of two concordant titres, deduce the molar ratio I2 to (HO.NH3) and hence an equation representing the reaction, based on changes in oxidation numbers. 

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