Triamines cyclic

The PE spectra of some cyclic triamines with the nitrogen atoms in 1,3-positions like hexahydro-l,3,5-triazines (59) and tetracyclic derivatives such as 60 and 61 have been studied and interpreted with regard to their conformational properties110. The n ionizations lead to two strongly overlapping bands between 7.5 and 9.5 eV which are consistent with diequatorial-monoaxial nitrogen substituent orientations at the hexahydro-... 

The medium-ring cyclic triamines, 1,4,7-triazacyclononane (tacn), 1,4,7-triazacyclodecane (tacd), 1,4,8-triazacycloundecane (tacud), and 1,5,9-triaza-cyclododecane (tacdd) have been synthesized and the cobalt complexes [Co(tacn)2]Br3, [Co(tacd)2]Br3,H20 and [Co(tacud)BrCl2] isolated. It has been suggested that the structures are of the sandwich type [viz. (95) and (96) "] and, for this reason, the reporter looks forward to publication of X-ray structural analyses. 

Zn complexes with the cyclic triamines (6) have also been investigated.216 Formation of the 1 1 complex occurs in a single step, but with some of the larger ligands loss of a proton occurs before any noticeable metal-ligand interaction occurs. Some hydrolysis of the [ZnL]2+ complexes is observed the stability increases as the ring size decreases, in agreement with predictions from molecular models. 

For the cyclic triamines, Ni11 compounds hydrolyze slowly (e.g. for [12]aneN3 k IO-6 s-1)42 but the Cun compounds react at about the same rate as non-cyclic analogues.43... 

The coordination chemistry of the cyclic triamine 1,4,7-triazacyclononane ([9]aneN3 48h) has been studied by Wieghardt et al. and has proven to be a rich area. In aqueous solution, [9]aneN3... 

Orthoformates have been reacted with secondary aliphatic aminesj- A -alkylanilines, 1,3.5-triaminocyclohexanes and cyclic triamines to afford trisaminomethane derivatives, e.g. (535) and (536) (Scheme 97), usually in unsatisfactory yields. Better results have been reported when ortho-formates were replaced by amide acetals. - ... 

A substituted linear triamine (L-24) is effective for three types of monomers, styrene, MA, and MMA, to give relatively narrow MWDs (MwIMn = 1.1 —1.4), where the polymerizations of styrene and MA are faster than those with L-l.108 A cyclic triamine (L-25) with ethylene linkers is similarly effective.81 A perfluoroalkyl-substituted triamine (L-26) is useful... 

D. E. De Vos, T. Bein, Elighly selective epoxidation of alkenes and styrenes with H2O2 and manganese complexes of the cyclic triamine l,4,7-trimethyl-l,4,7-triazacyclononane, Chem. Commun. (1996) 917. 

As an alternative to porphyrin and phthalocyanine catalysts, complexes of Mn and the cyclic triamine l,4,7-trimethyl-l,4,7-tnazacyclononane (tmtacn) clearly deserve more attention [11]. In acetone and at subambient temperature, the activity of Mn-tmtacn matches that of the more active porphyrins, with 1,000 turnovers within a few hours in the styrene epoxidation [12]. Moreover, Mn-tmtacn is colorless after reaction, and because of its relatively moderate price, it has even been commercialized for a short while in laundry powders [13]. A heterogeneous version of Mn-tmtacn would obviously offer even more advantages. We have proposed an immobilization of Mn-tmtacn based on zeolite... 

Since the titled cyclic triamine, NHCH-C NHO Q NHCl cS (tacn) coordinates facially in an octahedral complex, it isz available for the preparation of the fac(A)-[Co(A,)(BC)d]-type complexes. Using this ligand, glycinate and a variety of unidentates, various complexes of this type were new synthesized by the present authors, their CD spectral studies being carried out. 

Formation and coordination of H5C5 as a cr-bonded ligand and as a TT-bonded ligand. In the latter mode, the ligand occupies the face of an octahedron in the same way that a conventional cyclic triamine does. 

The peraza macrocycles, in general, form more stable complexes with a variety of metal ions than do the open-chain polyamines containing the same number of amine groups. This characteristic is called the macrocyclic effect. Triaza-crowri macrocycles, in nearly every case, form 1 1 complexes with metal ions that are thermodynamically more stable than those with dieth-ylenetriamine. Only complexes of the open-chain triamine with and Hg- are more stable than those with the cyclic triamines (Bianchi et al., 1991). Triaza-9-crown-3 (23) forms stronger complexes with most cations than the larger triazacyclodecane (24), triazacycloundecane (25), or triazacyclo-dodecane (26) (Bhula et al., 1988 Chaudhuri and Wieghardt, 1987). 

One report in the literature describes the preparation and structural characterization of a compound containing an unusual octaorganotrimagnesate. The compound [Mg2Me3(tacn)2]2[Mg3Mes], 220, is formed upon treatment of dime-thylmagnesium with the cyclic triamine ligand tacn (tacn = N,N, N"-trimethyl-... 

Therefore, the investigation of the effect of cyclic triamine TMT on the MMA polymerization and properties of the polymer obtained is interesting. The stmcture of this compound is shown by scheme 1. In the stmcture the lutrogen atoms and the geminal methylene groups are These groups and atoms are most active in formation of redox iiutiating systems (ROX) for complex-radical polymerization. 

Perspective view of an unexpected Sm(II) reduction product [L2Sm Al(CH3)4 2] of the reaction of Sm(III)[Al(CH3)4]3 with a cyclic triamine ligand L = cyclo-(cyclohexyl-NCH2)3 [1]. The figure shows the experimental atom positions and the links between atoms represent chemical bonds, to facilitate identification of the components. The positions of the many hydrogen atoms have been omitted to clarify the picture. 

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