Structural pathway

In a continuation of their earlier work,1 Hathaway and co-workers investigated crystal structures, electronic properties, and structural pathways for a series of five-coordinate complexes with two 1,10-phenanthroline (phen) ligands and axial ligands [(phen)2CuCl]Y [Y BF4 -0.51120 (269), PF6-(270), CF3S03--H20 (271) or BPh4 (272)],243 [(phen)2Cu(H20)][Y]2... 

Comparison of rates in the gel and liquid state of the membrane. In the case of channel mechanism, ions can pass through a structured pathway which is more or less similar to the bulk aqueous phase, while carriers encapsulate ions and transfer in the membrane. Therefore, the former is insensitive to gel-liquid phase transition of the membrane, while the gel state inhibits the carrier transport. 

Figure 21 Structural pathways for some oopper(II) stereochemistries...

Figure 25 (a) Copper(II) stereochemical structural pathways and (b) the normal modes of vibration of an elongated tetragonal octahedral complex of copper(II), e g. [Cu(NH3)4(SCN)2]... 

Figure 82 Structural pathway for the CuCl system and some calculated AOM coefficients1085,1108...

Figure 102 The structural pathway connecting the compressed tetrahedral copper(II) geometry and the trigonal planar copper(I) geometry, and the relationship with the type I copper geometry...

Local description of the arrangement around cations concludes unambiguously for [Cu-Cr-Cl] in a cationic ordering. The evidence of similar ordering for [Zn-Cr-Cl] was only obtained by a combined EXAFS and UV-Vis study of the formation of this LDH in solution [18], The structural pathway so-reported involves the heterocondensation between hexa-aquo zinc(II) complexes and deprotonated chromium monomers. 

Lossinsky AS, Shivers RR. Structural pathways for macromolecular and cellular transport across the blood-brain barrier during inflammatory conditions. Review. Histol Histopathol 2004 19(2) 535-64. 

As a consequence of the non-spherical symmetry of the copper(II) ion, d9 configuration, and of the influence of the Jahn-Teller, and pseudo Jahn-Teller effect on six-coordinate geometries, the stereochemistries of the copper(II) ion are characterized by non-rigid geometries (fluxional behaviour), and ranges of distorted geometries (Plasticity Effect). The latter may be connected by a series of Structural Pathways, which may be characterised by an Electronic Criterion of Stereochemistry for a related series of complexes, e.g. the [Cu(bipy)2X] [Y] complexes. 

The question7 must now be asked how far do the arrows of Fig. 35 represent continuous transitions from one type of coordination to another (i.e. square coplanar to tetrahedral) with Structural Pathways861 not only between the regular static stereochemistries of Fig. 35, but between the intermediate distorted structures. Each structural pathway is... 

Fig. 37. The structural pathways for the distortion of the CuN4C1 square pyramid involving three alternative routes chromophore of the [Cu(bipy)2Cl] complexes, from trigonal bipyramid to...

Fig. 40. a The structural pathways for the CuN2N2 OO chromophore of the [Cu(bipy)2(OXO)]+ cation for distortion from regular cif-distorted octahedral to distorted square pyramid (route E and F) and to bicapped... 

In this way a wide range of stereochemistries of the copper(II) ion may be understood if they are first separated in terms of fluxional behaviour and basic static stereochemistries and then the static structures linked by the normal modes of vibration to yield Structural Pathways connecting the regular structures via the alternative tetrahedral and trigonal distorted structures. The full potential and consequences of the Jahn-Teller effect are then realised in the Plasticity Effect and the Fluxional Behaviour in copper(II) stereochemistry as a whole. 

Fig. 45. Correlation of electronic spectral energies and g-values for [Cu(bipy)2X] Y complexes in a Structural Pathway (see Fig. 41)93)...

Transition metals mainly form n complexes with enynes. Nearly all the metal-mediated enyne cycloisomerization reactions occur via this structural pathway (11). In some cases, it has been shown (Scheme 36) that transition... 

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