1,4,7-Triazacyclononane, l-

GFP hopo ICBP IP3 Ln3+ mal memal MLCK nota oxine par pdta pmea py quin-2 green fluorescent protein hydroxypyridinon(at)e intestinal calcium-binding protein inositol 1,4,5-triphosphate a lanthanide(III) cation malonate methylmalonate myosin light chain kinase 1,4,7-triazacyclononane-l,4,7-triacetate 8- hydroxyquinoline pyridine-2-azo-4 -dimethylaniline propylene-1,2-diaminetetraacetate 9- [2-(phosphonomethoxy)ethyl] adenine pjrridine pjrridyl 8-amino-2- [(2-amino-5-methylphenoxy )methyl] -6-methoxyquinoline-ATJV -tetraacetate 2- [ [2-[his(carboxymethyl)amino]-5-methyl-phenoxy] methyl] -6-methoxy-8- [bis(carboxymethyl) amino] quinoline]... 

Numerous other polyamido ligands that feature three or more nitrogen donor sites are known. In these, the nitrogens can be incorporated as part of a ring as they are in 1,4,7 triazacyclononanes (L)," cyclams (M) or the tris(aminobenzyl)-1,4,7-triazacyclono-nane species (N). ... 

NiL2]2+-type sandwich complexes of tacn ligands bearing one or three pendent alkyne arms (L = /V,/V, /V"-tris(3-prop-1 -yne)-1,4,7-triazacyclononane or 7V-(4-but-2-yne)-1,4,7-triazacyclo-... 

In 1988 a powdered material believed to be [PdL 2](PF6)3 (L = 1,4,7-triazacyclononane), which behaved electrochemically in accord with that formula, was prepared.76... 

Pendent arm 1,4,7-triazacyclononane macrocycles (91) and (92) have been used to stabilize the zinc-to-phenoxyl bond allowing characterization of these compounds.477 The interest in the zinc complexes comes from the wide potential range in which it is redox stable allowing observation of the ligand-based redox processes, this allows study of the radical by EPR and the electronic spectra is unperturbed by d-d transitions. Macrocycles of the type l,4,7-tris(2-hydroxybenzyl)-1,4,7-triazacylononane form a bound phenoxyl radical in a reversible one-electron oxidation of the ligand. The EPR, resonance Raman, electronic spectra, and crystal structure of the phenoxide complexes were reported. This compound can be compared to a zinc complex with a non-coordinated phenoxyl radical as a pendent from the ligand.735... 

In a new twist on this subject, electrochemical activation parameters have been obtained for two series of redox couples that undergo coupled spin-state change and electron transfer (28). One series is [M(tacn)2]3+/2+ where M = Fe, Co, Ni, and Ru, and tacn = 1,4,7-triazacyclononane. The other is [Fe(pzb)2]+/0, where pzb-= hydrotris(pyrazol-l-yl)borate... 

The monoammonium salt of l,4,7-triazatricyclo[5.2.1.04 10]decane 72 when treated with water led to the desired substituted 1,4,7-triazacyclononane 73 in 92% yield (Equation 30) <20010L2855>. 

L Ligands containing an 1,4,7-triazacyclononane backbone and one, two, or three phenol pendent arms. 

The first successful isolation of a mononuclear uranium-tacn complex was achieved by treatment of the free l, 7-tris(3,5-di-fert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (( ArOH)3tacn) (4 - ) (25) with one equivalent of [U(N(SiMe3)2)3] (35) in cold pentane... 

Me3-TACN - 1,4,7-trimethyl-l,4,7-triazacyclononane bipy - 2,2 -blpyrldine py - pyridine ImH = imidazole... 

Photolysis of the monoazido species [Mn L (acac)L]BPh4 (where L is 1,4,7-triazacyclononane, is its N-methylated derivative, and acac is pentane-2,4-dionate) in the solid state has been demonstrated to yield the six-coordinate nitrido species [Mn L(N)(acac)]BPh4. ... 

Cohydrolysis of MnLCls (L= 1,4,7-triazacyclononane) and RuL Cl3 H20 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane) in equimolar amounts in methanol containing an excess of sodium acetate gives rise to the asymmetric heterodinuclear species [L Ru(/i-0)(/u-CH3C00)2MnL]PFg on addition of sodium hexafluorophosphate. A model to interpret the strong spin-exchange coupling in this complex was presented." ... 

Tris-N-functionalization of 1,4,7-triazacyclononane has yielded a variety of sexadentate ligands, which form stable complexes with manganese(II). For example, the l,4,7-tris(2-pyridyl-methyl) derivative gives a complex of type [MnL](C104)2 in which the manganese ion has a... 

The A,A A"-tris(carboxymethyl) derivative of the 12-membered macrocycle 1,5,9-triazacyclo-dodecane yields a complex of type [MnL] in aqueous solution which is approximately two orders of magnitude less stable than the corresponding complex of l,4,7-tris(carboxymethyl)-1,4,7-triazacyclononane, as might be expected for the substitution of three six-membered chelate rings in the former for three five-membered chelate rings in the latter. " ... 

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