Propylenediamine metal complexes

Propionohydroxamic acid metal complexes, 506 Propylenediamine metal complexes, 34 Protactinium complexes cupferron, 510 Proteins... 

Propionohydroxamic acid metal complexes, 506 Propylenediamine metal complexes, 34 Protactinium complexes cupferron, 510 Proteins electron transfer active sites, 525 metal complexes, 759-774 binding sites, 769,771 naturally occurring, 974 occurrence, 962 Proton exchange amine ligands, 24 Protonolysis metal alkoxides, 352 Prussian blue, 7, 8 Pseudocubanes structure... 

Fig. 12.30 The oh contbi mcr of the A or i. isomer of tris(clianiine)metal complexes. The hatched circles represent the positions of the methyl groups in the propylene-diapiine complex. For propylenediamine this represents the A555 or l65S isomer. [Modified from Corey, E. J. Bailar. J. C., Jr. J. Am. Chem. Soc.

Another class of mda/edf transitions that has been extensively studied are the d-d transitions of transition metal complexes (Figure 12). A particularly successful empirical sector rule for this system is as follows the CD of the E band of tris-chelate complexes such as [Co(propylenediamine)3] is larger than that of the A2 band, and the sign of the E band of the A enantiomer is negative Figure 13). As the A2 and E bands of d-d transitions lie very close in energy (these D3... 

Figure 12 A-Enantiomer tris-chelate transition metal complexes illustrating the geometry of the fee and mer Isomers adopted by [Co(propylenediamine)3) and the lei and ob conformers of [Co(ethylenediamlne)3] . (Source Circular dichroism and linear dichroism, A. Rodger and B. Nord6n, 1997, by permission of Oxford University Press.)...

Optical activity may be achieved in at least three ways (a) by the asymmetric arrangement of ligands about the central metal ion (b) by the use of a ligand which is itself optically active and (c) by the use of a ligand in which an atom (or atoms) becomes chiral upon attachment to the metal. The second of these is illustrated by propylenediamine and the tetradentate (7) and the last by (8) and by (9). Neither the nitrogen atoms nor the arsenic atoms in these last two ligand molecules are chiral, but the ones near the centers of their respective molecules become so when they are coordinated to a metal ion. In each case, they can be of the same or of opposite chirality. Thus complexes with a six-coordinate metal can theoretically exist in a large number of isomeric forms these differ in stability and not all of them have been isolated. 

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