SYNTHESIS OF A NEW POTENTIALLY SEXIDENTATE PENDANT-ARM MACROCYCLIC POLYAMINO ACID AND COORDINATION TO COBALT(III)
Hambley, TW; Lawrance, GA; Maeder, M; Wilkes, EN
| HERO ID | 4935955 |
|---|---|
| In Press | No |
| Year | 1992 |
| Title | SYNTHESIS OF A NEW POTENTIALLY SEXIDENTATE PENDANT-ARM MACROCYCLIC POLYAMINO ACID AND COORDINATION TO COBALT(III) |
| Authors | Hambley, TW; Lawrance, GA; Maeder, M; Wilkes, EN |
| Journal | Journal of the Chemical Society. Dalton Transactions |
| Issue | 7 |
| Page Numbers | 1283-1289 |
| Abstract | From reaction of bis(ethane-1,2-diamine)copper(II) with formaldehyde and diethyl malonate then formaldehyde and nitroethane in turn the pendant-arm macrocyclic complexion (hydrogen 13-methyl-13-nitro-1,4,8,11-tetraazacyclotetradecane-6-carboxylat e)copper(II) was prepared. Reduction with zinc in aqueous acid yields the free pendant-arm beta-polyamino acid macrocycle hydrogen 13-amino-13-methyl-1,4,8,11-tetraazacyclotetradecane-6-carboxylate (L3) as the hydrochloride salt. Co-ordination to cobalt(III) was achieved following reaction with cobalt(II) ion and air, yielding the chloro(hydrogen 13-amino-13-methyl-1,4,8,11-tetraazacyclotetradecane-6-carboxylat e)cobalt(III) ion, as well as its aqua analogue. The chlorocobalt(III) complex crystallized as the perchlorate salt in the space group Pbca, a = 10.256(4), b = 12.689(5), c = 3.08(2) angstrom, Z = 8, with the co-ordinated chloride in a cis disposition relative to the pendant amine, the four secondary amines co-ordinated in a folded geometry with uncommon RRRR stereochemistry, and the pendant carboxylic acid group not coordinated. Equilibration of the reaction mixture from this synthesis at pH 8 over activated carbon yielded almost exclusively the complex with the ligand bound as a sexidentate ligand where the pendant amine and carboxylate groups occupy trans sites. This complex crystallized as the perchlorate salt in the space group P2(1)/n with a = 10.939(2), b = 13,355(2), c = 14.596(2) angstrom, beta = 102.17(1)-degrees and Z = 4. Metal-donor distances [Co-O 1.899(2), Co N (pendant) 1.956(2), average Co-N (secondary) 1.95(1) angstrom] are at the short end of the range for saturated polydentate amino acid ligands, presumably influenced by the sterically efficient ligand. |
| Doi | 10.1039/dt9920001283 |
| Wosid | WOS:A1992HP10000026 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |