X-Ray structure and stereoselective intramolecular synthesis of a novel quadridentate complex

Bell, John D.; Gainsford, A. R.; Golding, Bernard T.; Herlt, Anthony J.; Sargeson, Alan M.

doi:10.1039/c39740000980

Cited by 13 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While monodentate, N-bound aminoacetone cobalt(III) complexes have been reported, the pendant carbonyl functionality always condensed in basic conditions with a coordinated amine group of another ligand to produce extended chelate structures linked by carbinolamine or imine units. 7,29,30 This study has emphasized the greatly enhanced reactivity that a chelated 2-amino ketone moiety may experience at a metal centre. In this way the study lends credibility to proposals 2,3 that imply similar chelation of the A-site ALA substrate in the action of Zn 2+ -dependent ALAD.…”

Section: Discussionmentioning

confidence: 99%

First aminoacetone chelate: [Co(tren){NH2CH2C(O)CH3}]3+—a substrate binding and activation model for zinc(ii)-dependent 5-aminolaevulinic acid dehydratase

et al. 2007

View full text Add to dashboard Cite

The complex p-[Co(tren){NH(2)CH(2)C(O)CH(3)}](ClO(4))(3).H(2)O was produced stereoselectively from [Co(tren)(O(3)SCF(3))(2)]O(3)SCF(3) () and 2-(aminomethyl)-2-methyl-1,3-dioxolane. The structure of was determined by X-ray crystallography. The complex is the first aminoacetone chelate to be reported and the first structurally characterized example of a non-conjugated ketone moiety coordinated to cobalt(iii). The robust complex was stable to aquation in strong acid and behaved as an acid with pK(a) = 4.99(1) indicative of a strong activation of the aminoacetone ligand towards deprotonation. The complex constitutes a structural model for a proposed substrate binding mode relevant for substrate activation of the zinc(ii)-dependent enzyme 5-aminolaevulinic acid dehydratase.

show abstract

Section: Discussionmentioning

confidence: 99%

First aminoacetone chelate: [Co(tren){NH2CH2C(O)CH3}]3+—a substrate binding and activation model for zinc(ii)-dependent 5-aminolaevulinic acid dehydratase

et al. 2007

View full text Add to dashboard Cite

show abstract

“…15 Torr) in a Büchi rotary evaporator using a water aspirator and water bath (ca. (14), 118 (18), 116 (16), 86 (86) and 75 (100).…”

Section: Experimental Generalmentioning

confidence: 99%

“…Only a single band was observed and this eluate was collected and evaporated to dryness. The glassy residue (3.0 g) was suspended in absolute EtOH, evaporated and dried in vacuo (Found: C, 29.0; H, 7.28; N, 16…”

Section: S-[co(tren-tngly)]zncl 4 •H 2 Omentioning

confidence: 99%

“…12,15- 23 For coordinated primary amines the initially formed aminal 18 may react further by eliminating water to form a N-bound imine provided this is stereochemically feasible so that the imine moiety can achieve near planarity. 16,22 Regio-and stereoselectivity may be invoked by appropriate choice of transoid ligands. 18 Thus, intramolecular condensation of an amine and the pendant aldehyde in the [Co(tren)Cl(NH 2 CH 2 CHO)]2 + complex to form the imine complex [Co(tren-enim)Cl] 2+ (tren-enim = 1,8-diamino-6-(2aminoethyl)-3,6-diazaocta-2-ene) occurs regioselectively with the primary amine trans to the chloride ligand.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Facile cobalt(iii) template synthesis of novel branched hexadentate polyamine monocarboxylates

et al. 2005

Self Cite

View full text Add to dashboard Cite

New hexadentate polyamine monocarboxylate ligands, 11-amino-9-(2-aminoethyl)-3,6,9-triazaundecanoate (tren-engly-), 12-amino-10-(2-aminoethyl)-3,7,10-triazadodecanoate (tren-tngly-) and 13-amino-11-(2-aminoethyl)-3,8,11-triazatridecanoate (tren-bngly-), were synthesized by intramolecular coupling of tetradentate tris(2-aminoethyl)amine (tren) and didentate N-([small omega]-formylalkyl)glycinates, OCH(CH2)nNHCH2CO2-, in easily and stereoselectively assembled cobalt(III) templates, p-[Co(tren){(RO)2CH(CH2)nNHCH2CO2}](O3SCF3)2, n = 1-3 (R = Me or Et). The reaction sequences comprised assembly of the template from [Co(tren)(O3SCF3)2]O3SCF3 (1) and (RO)2CH(CH2)nNHCH2CO2Et, deprotection of the pendant acetal in acid, intramolecular condensation of the resulting aldehyde with a coordinated primary amine at intermediate pH to form the imine and reduction of this by NaBH4. For n= 1, imine formation occurred exclusively at the primary amine trans to the carboxylate producing the hexadentate 11-amino-9-(2-aminoethyl)-3,6,9-triazaundeca-5-enoato (tren-enimgly-) complex, i-[Co(tren-enimgly)]Cl2.3.5H2O. In all instances, subsequent imine reduction gave the s isomer complex, exclusively. Complexes p-[Co(tren){(MeO)2CHCH2gly}](O3SCF3)2 (3), i-[Co(tren-enimgly)]ZnCl4.H2O (5), s-[Co(tren-engly)]ZnCl(4)(s-6), s-[Co(tren-tngly)]ZnCl4.H2O (s-7) and s-[Co(tren-bngly)ZnCl3]2ZnCl4 (s-8) were structurally characterized by X-ray crystallography. Charcoal-catalyzed equilibration of s-[Co(tren-engly)]Cl(2).2H(2)O dissolved in water produced the s- (s-6), p- (p-6) and t-[Co(tren-engly)]2+ (t-6) isomers in comparable amounts. p-6 and t-6 were also structurally characterized as their tetrachlorozincate and chloride salts, respectively. In base-catalyzed reactions, s-6 and t-6 each also formed p-6. Reduction of s-[Co(tren-engly)]Cl2.2H2O with (NH4)2S and acidification liberated the pentaamino carboxylic acid ligand which was isolated as the hydrochloride salt.

show abstract

“…(~)5S9'[Co(en)2(NH2CH2CN)Br]Br2 was obtained by dissolving the combined diastereoisomer fractions in water (pH 3), passing the solution through Dowex AG-X1 (Br™ form) anion-exchange resin, reducing the eluate to a small volume, and adding NaBr. Anal.…”

mentioning

confidence: 99%

Intramolecular hydration of nitriles coordinated to cobalt(III). Formation of five- and six-membered chelated amides

Buckingham¹,

Morris²,

Sargeson³

et al. 1977

Inorg. Chem.

View full text Add to dashboard Cite

X-Ray structure and stereoselective intramolecular synthesis of a novel quadridentate complex

Cited by 13 publications

References 0 publications

First aminoacetone chelate: [Co(tren){NH2CH2C(O)CH3}]3+—a substrate binding and activation model for zinc(ii)-dependent 5-aminolaevulinic acid dehydratase

First aminoacetone chelate: [Co(tren){NH2CH2C(O)CH3}]3+—a substrate binding and activation model for zinc(ii)-dependent 5-aminolaevulinic acid dehydratase

Facile cobalt(iii) template synthesis of novel branched hexadentate polyamine monocarboxylates

Intramolecular hydration of nitriles coordinated to cobalt(III). Formation of five- and six-membered chelated amides

Contact Info

Product

Resources

About