Tren group

As another example, we prepared disubstituted cyclodextrin 35 in which one substituent was a metal-binding tren group while the other was an imidazole [122]. Zn2+ complexed to the tren group gave good rate acceleration in the hydrolysis of bound catechol cyclic phosphate 36, which was fastest when the two catalytic groups were attached to opposite sides of the cyclodextrin so they could not bind each other. The geometry of the complex led to the selective formation of product 37 rather than 38 both are formed equally by ordinary hydrolysis without the catalyst. 

Fig. 12. Non-catecholate donor group TREN family of synthetic siderophore mimics.

Resch, G., Berger, M. and Kranzl, L. (2001). Database for the Model ElGreen. Report of the European Research Project ElGreen—Funded by the European Commission, DG TREN. Vienna Energy Economics Group (EEG), Vienna University of Technology. 

Use of the tripodal ligand Saltren creates a tetranuclear complex [Mn402(Sal-tren)2][MnCl4] 2CH3CN (172) having a fused open cubane structure without a carboxylate group. At 300 K the value of the effective magnetic moment for (172) is 5.1 /Ub, which decreases to 2.0 /iB at 4.2 K. The redox properties of (172) in propylene carbonate have been studied by cyclic voltammetry. Two oxidation responses are observed at = —0.32V and 0.43 V vs. SCE. 

In contrast to the TREN template, 75 with the NTA template preferred the h-cis configuration . This could be caused either due to the inverse directionality of the hydroxamate group, or, more plausibly, because the tripeptide is connected through the amino end, leading to opposite orientation of the hydrogen-bonding network. ... 

Martell et al. (33g) while studying the complex equilibria of a new octaaza macrobicyclic cryptand, (MX)3(tren)2 (containing two tren moieties and three m-xylyl groups) reported the synthesis and... 

The p3-bridged carbonato complex posseses a pseudo-3-fold molecular symmetry. Each of the Cu atoms is five coordinate with the four nitrogen atoms of tren and one oxygen atom of the carbonate ligand (C). The coordination polyhedron of the Cu atom can be described as almost (TBP), the copper ions being slightly out of the plane (0.15 A) of the three primary amine groups (Fig. 5). 

The tetradentate ligand tren usually forms 1 1 six-coordinate complexes with two additional ligands in cis positions750 as in the complex [Ni(NCS)2(tren)],724 as well as dinuclear complexes of general formula [NiX(tren)]2(BPh4)2 where two X groups are bridging the Ni(tren)2+ moieties.725"728 A common feature of both NJ and NCO- complexes is the marked asymmetry... 

An increase of the bulkiness of the donor groups, with respect to tren, as in the ligand Me6tren, reduces the coordination number from six to five and a number of high-spin five-coordinate [NiX(Metrigonal bipyramidal coordination with Cj site symmetry (98).731,732 The trigonal bipyramidal coordination is retained in the complexes dissolved in solution. 

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