1,4,7-Triazacyclononane

changed 477205742 1,4,7-Triazacyclononane 1,4,7-triazacyclononane.svg 150px 1,4,7-Triazacyclononane 1,4,7-Triazacyclononane-3D-balls.png 160 TACN molecule 1,4,7-Triazonane correct chemspider correct EBI 37405 163681 188318 637-157-5 1650628 773877 2614 1/C6H15N3/c1-2-8-5-6-9-4-3-7-1/h7-9H,1-6H2 ITWBWJFEJCHKSN-UHFFFAOYAS C1CNCCNCCN1 correct chemspider 1S/C6H15N3/c1-2-8-5-6-9-4-3-7-1/h7-9H,1-6H2 correct chemspider ITWBWJFEJCHKSN-UHFFFAOYSA-N correct CAS 4730-54-5 correct FDA 2UIF93C5H3 C6H15N3 129.2046 g/mol 05 Danger 314 260 264 280 301+330+331 303+361+353 304+340 305+351+338 310 321 363 405 501 1,4,7-Triazacyclononane, known as "TACN" which is pronounced "tack-en," is an aza-crown ether with the formula (C2H4NH)3.Chaudhuri P. Wieghardt K. 1987 Lippard Stephen J. The Chemistry of 1,4,7-Triazacyclononane and Related Tridentate Macrocyclic Compounds Progress in Inorganic Chemistry Hoboken, NJ, USA John Wiley & Sons, Inc. 35 329–436 10.1002/9780470166369.ch4 9780470166369 TACN is derived, formally speaking, from cyclononane by replacing three equidistant CH2 groups with NH groups. TACN is one of the oligomers derived from aziridine, C2H4NH. Other members of the series include piperazine, C4H8(NH)2, and the cyclic tetramer 1,4,7,10-tetraazacyclododecane. Synthesis The ligand is prepared from diethylene triamine as follows by macrocyclization using ethyleneglycol ditosylate.Wieghardt Karl Schmidt Wilfried Nuber Bernhard Weiss Johannes 1979 Darstellung und Struktur des trans-Diaqua-di-μ-hydroxo-bis[(1,4,7-triazacyclononan)cobalt(III)]-Kations; Kinetik und Mechanismus seiner Bildung Chemische Berichte de 112 6 2220–2230 10.1002/cber.19791120629 H2NCH2CH2NHCH2CH2NH2 + 3 TsCl → Ts(H)NCH2CH2N(Ts)CH2CHH2N(H)Ts + 3 HCl Ts(H)NCH2CH2N(Ts)CH2CH2N(H)Ts + 2 NaOEt → Ts(Na)NCH2CH2N(Ts)CH2CH2N(Na)Ts Ts(Na)NCHH2CH2N(Ts)CH2CH2N(Na)Ts + TsOCH2CH2OTs + → [(CH2CH2N(Ts)]3 + 2 NaOTs [(CH2CH2N(Ts)]3 + 3 H2O → [CH2CH2NH]3 + 3 HOTs Coordination chemistry TACN is a popular tridentate ligand. It is threefold symmetric and binds to one face of an octahedron of metalloids and transition metals. The (TACN)M unit is kinetically inert, allowing further synthetic transformations on the other coordination sites. A bulky analogue of TACN, is the N,N′,N″-trimethylated analogue trimethyltriazacyclononane. Illustrative complexes Although TACN characteristically coordinates to metals in mid- and high oxidation states, e.g. Ni(III), Mn(IV), Mo(III), W(III), exceptions occur. To illustrate, 1,4,7-triazacyclononane reacts readily with Mo(CO)6 and W(CO)6 to produce the respective air-stable tricarbonyl compounds, [(κ3 -TACN)Mo(CO)3] and [(κ3-TACN)W(CO)3]. Both have an oxidation state of zero. After further reacting with 30% H2O2, the products are [(κ3-TACN)MoO3] and [(κ3-TACN)WO3]. Both of these oxo complexes have an oxidation state of 6. The macrocyclic ligand does dissociate in the course of this dramatic change in formal oxidation state of the metal. The complex [κ3-TACN)Cu(II)Cl2], a catalyst for hydrolytic cleavage of phosphodiester bonds in DNA,Sibbons Kevin F. Shastri Kirtida Watkinson Michael 2006 The application of manganese complexes of ligands derived from 1,4,7-triazacyclononane in oxidative catalysis Dalton Transactions 2006 5 645–661 10.1039/B511331H 16429167 is prepared as follows from TACN trihydrochloride: TACN·3HCl + CuCl2·3H2O + 3 NaOH → [(κ3-TACN)CuCl2] + 6 H2O + 3 NaCl Mn-TACN complexes catalyze epoxidation of alkenes such as styrene using H2O2 as an oxidant in a carbonate buffered methanol solution at a pH of 8.0. These reagents are considered environmentally benign,Deal Kim A. Burstyn Judith N. 1996 Mechanistic Studies of Dichloro(1,4,7-triazacyclononane)copper(II)-Catalyzed Phosphate Diester Hydrolysis Inorg. Chem. 35 10 2792–2798 10.1021/ic951488l [(κ3-TACN)Mn] + H2O2 + NaHCO3 + (C6H5)C2H3→ [(κ3-TACN)Mn] + 2H2O + CO2 +  (C6H5)C2H2O Chromium (II) sources, e.g. created by heating CrCl3.6H2O in DMSO react with TACN to form both 1:1 Cr:and 2:1 complexes,Wieghardt Karl Schmidt Wilfried Endres Helmut Wolfe C. Robert 1979 Neue μ-Hydroxo-Übergangsmetallkomplexe, II. Darstellung mehrkerniger Komplexe des Chroms(III) mit dreizähnigen Amin-Liganden. Struktur des μ[cis-Dihydroxo(O,O′)-hydroxo(1,4,7-triazacyclononan)chrom(III)]-di-μ-hydroxobis[(1,4,7-triazacyclononan)chrom(III)]-Kations Chemische Berichte de 112 8 2837–2846 10.1002/cber.19791120810 e.g. yellow [(TACN)2Cr]3+.Wieghardt K. Schmidt W. Hermann W. Küppers H.-J. 1983 Redox potentials of bis(1,4,7-triazacyclononane complexes of some first transition series metals(II,III). Preparation of bis(1,4,7-triazacyclononane)nickel(III) perchlorate Inorg. Chem. 22 20 2953 10.1021/ic00162a037 References Category:Ethyleneamines Category:Chelating agents Category:Macrocycles Category:Secondary amines Category:Tridentate ligands Category:Nine-membered rings