Triamines metal complexes

Bismuth ligands, 2,989-1061 bonding, 2,1030-1041 7i bonding, 2, 1033-1039 trigonal bipyramidal complexes, 2,1036 Bismuth line, 3,294 Bismuthotungstates, 3, 1042 Bismuth pentafluoride, 3, 292 Bismuth tribromide, 3, 291 Bismuth trichloride, 3, 290 Bismuth trifiuoride, 3, 290 Bismuth triiodide, 3,292 Bismuth trioxide, 3,284 2,2 -Bisphenol metal complexes color photography, 6,109 Bis(trimethylene)triamine metal complexes, 2, 49 4,4 -Bi-l, 2,4-triazolyl metal complexes, 2, 89 polymers... 

Cyclodextrins classification, 920 Cyclohexane-1,2-diamine metal complexes, 34 C.yclohexanc-l,2-dione monooxime metal complexes, 273 Cyclohexane-1,3,5-triamine metal complexes, 50 Cyclohexanone oxime... 

Sarcophaginates can also be prepared by template condensation of bis-triamine metal complexes with formaldehyde and nitromethane or ammonia. Macrotricyclic and macrotetracyclic complexes of different structures have simultaneously been formed [148, 149],... 

I6A related phenomenon has been observed in (octahedral) metal complexes, where rates of exchange at the metal centres of hexaaquo-complexes of Ru and Fe(II) and Fe(III) are faster for longer M-OH2 distances (Bernard et al., 1982). Similarly, exchange is faster for the longer bonds at the Ni(II) centres of triamine/aquo-complexes when more nitrogen ligands are present (Schwarzenbach et al., 1983). 

Recently, Bunton et al. synthesized the Ci6H33-attached triamine copper(II) complex 8b [26], which promoted the hydrolysis of diphenyl 4-nitrophenyl phosphate (DNP) at alkaline pH. The catalytic activity was almost the same as that for Menger s previously reported comicellar system with 3b. The active species was proposed to be the hydroxide-bound copper(II) complex 8b. The pvalue of the copper(II)-bound water molecule was speculated to be about 8 from the fact that the nonalkylated and tetradecyl homologous copper(II) complexes have a pvalue of 8 (determined by DNP hydrolysis kinetics). Since the micellar metal complex 8b was not fully characterized either in the solid state or in a micellar solution, its hydrolysis mechanism remains to be elucidated. 

Silver(I) complexes with macrocyclic nitrogen ligands are also very numerous. Mono- or homodi-nuclear silver-containing molecular clefts can be synthesized from the cyclocondensation of functionalized alkanediamines or triamines with 2,6-diacetylpyridine, pyridine-2,6-dicarbalde-hyde, thiophene-2,5-dicarbaldehyde, furan-2,5-dicarbaldehyde, or pyrrole-2,5-dicarbaldehyde in the presence of silver(I).486 97 The clefts are derived from bibracchial tetraimine Schiff base macrocycles and have been used, via transmetallation reactions, to complex other metal centers. The incorporation of a range of functionalized triamines has provided the conformational flexibility to vary the homodinuclear intermetallic separation from ca. 3 A to an excess of 6 A, and also to incorporate anions as intermetallic spacers. Some examples of the silver(I) complexes obtained are shown in Figure 5. 

An example of the above mentioned cascade complexation of carboxylates by macrocyclic receptors containing metal ionic centers is the inclusion of oxalate by the dien dicobalt complex 9 (Martell, Mitsokaitis) [12]. Similarly, the -cyclodextrin (jS-CD) 10, modified with a zinc cation bound by a triamine side chain, encapsulates anions like 1-adamantylcarboxylate in its cavity, fixing them by combined electrostatic and hydrophobic interactions [13], Zinc s group achieved the enantioselective transport of the potassium salts of N-protected amino acids and dipeptides by making use of the cation affinity of... 

Zn complexes with the cyclic triamines (6) have also been investigated.216 Formation of the 1 1 complex occurs in a single step, but with some of the larger ligands loss of a proton occurs before any noticeable metal-ligand interaction occurs. Some hydrolysis of the [ZnL]2+ complexes is observed the stability increases as the ring size decreases, in agreement with predictions from molecular models. 

All the linear triamines (27)-(31) are commerically available and there are others, such as 6,6-tri, which, as yet, do not appear to have been used in the preparation of coordination complexes. These linear polyamine ligands can coordinate in either meridional or facial topology and both bis(tri-amine) and mono(triamine) complexes are possible for octahedral central metal ions. 

Pyridine-2,6-dicarbaldehyde and 2,6-diacetylpyridine have been widely used in the template synthesis of imine chelates ranging in complexity from linear tridentates, such as (17),38 39 to macrocyclic structures with a range of ring sizes, such as (18).40-42 The in situ formation of macrocyclic ligands of this type depends upon the ring size and the strength of complexation of the triamine by the metal ion at the pH of the reaction. Related complexes with an additional donor atom attached to R2 have been synthesized also.43 44... 

The N,N-, N,0-, and 0,0-metal-cyclic structures can be found in these chelates. The first structures are characteristic for di- and triamine ligands (430a, 431), the second and third ones are formed in the complexes of all three types of ligand systems described above (429-431). In principle, the same situation as mentioned before (Sec. 2.2.4.2), for di- and triamine chelates, is observed for N,N-coordination. The 0,0-coordination is mostly present in structures formed only by carboxyl groups (compare with the data of Sec. 2.2.4.4). Here the most propagated structures in coordination compounds are 277, 279, and 280, for example, in complexonates of the triamine series [764], In the case of N,0-metal-binding, the most propagated structures are those with five (432) and six-member (433) metal-cycles [756-760,762-767] ... 

The second approach involves the addition of a chelated form of the transition metal, for example, Ci2-dien plus zinc(II) (where Ci2-dien is 4-dodecyldiethylenediamine), into the mobile phase (Fig. 2.7). In this example, the triamine chelate binds strongly to the metal ion, forming a complex cationic counterion. The metal chelate represents a conformationally semirigid structure with a local polarized charge center. As such, not only is there the typical electrostatic attraction of anions for the positively charged... 

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