1,1,4,7,7-pentamethyldiethylenetriamine

Certain multidentate ligands also provide for better solubility. Cu1 complexes formed with tctramcthylcthylcncdiaminc (TMEDA), N,N,N ,N ,N -pentamethyldiethylenetriamine (PMDETA, 140) and 1,1,4,7,10,10-hcxamethyltricthylcnctctraminc (HMTETA, 144) and Mc6TREN (145) have been found effective.311 Transfer to ligand during MMA polymerization has been reported as a side reaction when PMDETA is used. 12 313... 

In the presence of N,N,N, N",N"-pentamethyldiethylenetriamine ( = PMDETA), monomeric lithium complexes of bulky formamidinate ligands can be isolated. The compounds (Scheme 12) comprise a Li(PMDETA) center coordinated by a bulky formamidinate in either the E-syn- or E-anti-isomeric form. Two of the structures display coordination of the pendant amidinate imine, and can therefore be considered the first examples of if. r -C = N,N metal amidinate coordination. ... 

TMEDA changes into the dimeric [PhLi(TMEDA)]2. Monomeric phenyllithium PhLi(PMDTA) is observed if the tridentate donor ligand PMDTA (PMDTA = N,N,N, N, N"-Pentamethyldiethylenetriamine) is utilized.13... 

The reaction (a Schlenk dimerization) between the phosphine-borane-substituted alkene nPr2P(BH3) (Me3Si)C=CH2 and elemental lithium in THF yields the complex [(pmdeta)Li Prn2P(BH3) (Me3Si)CCH2]2 123 which in the solid state has a lithium bound to the BH3 hydrogens of the ligand, and no Li-C(carbanion) contact (pmdeta = N,N,N, N",N"-pentamethyldiethylenetriamine).85... 

Well-defined monomeric derivatives could be obtained by reacting 85 (Ln = Y, La, Yb) with (Me2NCH2CH2)2NMe (PMDTA) (PMDTA = N,N,N, N",N"-pentamethyldiethylenetriamine) in a 1 1 molar ratio in THF solution. The products... 

Another system that has been investigated by C CP/MAS NMR spectroscopy as a function of different ligands is a-(dimethylamino)benzyllithium (2, Scheme 1) . The DEE complex was proven to exist in the solid state as an rf coordinated dimer . All the studied complexes are of an tf type according to comparison to solution NMR data. However, the actual structure varies as reflected by the shift difference between the two orf/zo-carbons. This difference ranges from 4.4 ppm for the N, N, N, N, N"-pentamethyldiethylenetriamine (PMDTA) complex to 20.3 ppm for the TMEDA complex. 

Related work was done with variously substituted acrylates in an ionic liquid 87). It was found that the solubility of both monomers and polymers depends on the chain length of the alkyl group linked to the ester. Methyl acrylate and its polymer are soluble in [BMIMJPF. However, butyl acrylate (BA) is only partially soluble, and the corresponding polymer is insoluble in the ionic liquid. The ATRP of BA in the ionic liquid proceeded under biphasic conditions with the catalyst, CuBr/pentamethyldiethylenetriamine, dissolved in the ionic liquid phase. Relatively low-molecular-weight polymer was formed. In this case, as the polymer was insoluble in the ionic liquid, it was spontaneously separated from the ionic liquid phase free of copper contamination. Furthermore, an undesirable side-reaction was significantly reduced in the ionic-liquid-phase ATRP 87). 

Data acquired at ambient temperature. Ligand abbreviations diglyme = bis(2-methoxyethyl) ether tmeda = tetramethylethylenediamine pmdta = pentamethyldiethylenetriamine teed = tetraethylethylenediamine OAr =... 

A 10-ml Schlenk flask was charged with CuBr (0.10 mmol), CuBr2 (0.005 mmol), N,N,N, N",N"-pentamethyldiethylenetriamine (0.105 mol), 5-methylene-2-phenyl-... 

The dimethylaurate(I) anion was more readily isolated (9) when the lithium ion was complexed with pentamethyldiethylenetriamine (PMDT) [Eq. (2)]. The greater thermal stability of these complexes compared with their phosphine analogs was explained in terms of less-ready ligand dissociation and complexation of the lithium ion, preventing its attack at the gold center. 

Scheme 3. A summary of routes to [HMo(CO)j]J . Yields of the tetramer are in parentheses PMTA = 1,1,4,7,7-pentamethyldiethylenetriamine.

Crassous et al.177) studied the polymerization of ethylene using n-butyllithium in conjunction with the tertiary diamines TMEDA, TEEDA (tetraethylethylenedi-amine) and PMDT (pentamethyldiethylenetriamine). In contrast to the situation with TMEDA the rate of polymerization was found to show a first order dependence upon the complexed chain end concentration. Steric hindrance seems to prevent the dimerization of the chain ends. Examination of the n-BuLi. TEEDA complex by -NMR shows that the displacement to high field of the protons a to the lithium induced by complexation is much smaller with TEEDA than with TMEDA or PMDT. With [TEEDA] < [RLi] time-averaged signals were obtained showing that the exchange process... 

Controlled grafting via heterogeneous ATRP of polymethyl methacrylate onto poly(ethylene-co-styrene) is one of the most significant advancements in the surface modification of PE [199]. The grafting of PMMA was carried out in presence of CuBr and pentamethyldiethylenetriamine as a catalyst via the well-known ATRP mechanism, as shown in Scheme 13. 

PMDETA N,N,N, N",N"-pentamethyldiethylenetriamine PMMA Poly(methyl methacrylate)... 

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