Calcium complexes Schiff bases

Calcium-binding proteins, 6, 564, 572, 596 intestinal, 6, 576 structure, 6, 573 Calcium carbonate calcium deposition as, 6, 597 Calcium complexes acetylacetone, 2, 372 amides, 2,164 amino acids, 3, 33 arsine oxides, 3, 9 biology, 6, 549 bipyridyl, 3, 13 crown ethers, 3, 39 dimethylphthalate, 3, 16 enzyme stabilization, 6, 549 hydrates, 3, 7 ionophores, 3, 66 malonic acid, 2, 444 peptides, 3, 33 phosphines, 3, 9 phthalocyanines, 2,863 porphyrins, 2, 820 proteins, 2, 770 pyridine oxide, 3,9 Schiff bases, 3, 29 urea, 3, 9... 

In a more recent report, a novel dinuclear N,N,0-donor Schiff base-calcium complex [(DAIP)2Ca]2 where DAIP = 2-[2(-dimethylamino-ethylimino)methyl] phenol 76 (Fig. 12) was shown to initiate ROP of L-lactide in a controlled fashion in the presence of benzyl alcohol giving a 96% conversion within 30-60 min at room temperature, yielding polymers with high molecular weight and low PDIs [89]. Taking into account the dimeric molecular structures of hexa- and hepta-coordinated Ca" in the solid state and the kinetic results gained from this study (first order dependency on [LA] a first order dependency on [BnOH] with d[LA]/ df = prop[LA] [BnOH] and a p op constant of 1.95 s ), a coordinatio-... 

Darensbourg and coworkers reported a systematic investigation of ROP catalyst performance along with kinetic and mechanistic studies for the polymerization of L- and rac-lactide using calcium complexes derived from tridentate Schiff base ligands (Fig. 13) [90, 91]. With calcium catalysts 77a-d, used in melt and solution polymerization of L-lactide, it was found that calcium salen catalyst 77d with bis (phosphoranylidene)ammonium azide as a co-catalyst is much less active than the calcium complexes with tridentate Schiff base ligands, as reflected in the monomer L-lactide conversions of 59-80% for 77a-c but only 35% for 77d as initiator. 

Fig. 13 Calcium complexes supported by N,0-donor Schiff base ligands Table 4 Ca complexes in rac-lactide and L-lactide polymerization...

Calcium complexes amino acids, 33 arsine oxides, 9 bipyridyl, 13 crown ethers, 39 dimethylphthalate, 16 hydrates, 7, ionophores, 66 peptides, 33 phosphines, 9 pyridine oxide, 9 Schiff bases, 29 urea,9 Calixarenes... 

Reaction of dff with l,5-diaminopentan-3-ol in the presence of calcium(II), strontium(II), or barium(II) perchlorates yields either the complexes of the (2 - - 2) macrocycle L810 or of the open-chain (1 +2) condensation product L811 (Eq. 3.80). In the absence of a template centre one fails to obtain macrocyclic or open-chain Schiff bases by using these ligsons [197]. 

The above mentioned Schiff base (I) forms with metal ions colored inner complex salts. Solutions of calcium, barium and strontium salts when... 

Fig. 29 Structure of calcium complexes supported by tridentate Schiff base ligand (89-94) by Darensbourg and coworkers [104, 105]...

Table 6 Chiral Box-calcium complexes-catalyzed 1,4-addition reactions of glycine Schiff bases with a,p-unsaturated carbonyl compounds...

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