Pentamethyldiethylenetriamine PMDETA

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. ... 

The adducts of (Me3Si)3H2CjLi with the nitrogen bases quinuclidine [N(CH2CH2)3CH], tetramethylethylenediamine (tmeda, Me2NCH2CH2N-Me2), and pentamethyldiethylenetriamine [pmdeta, Me2NCH2CH2N-... 

The first stannyl-alkali metal compound with a covalent Sn-M bond to be identified crystallographically was the pentamethyldiethylenetriamine (PMDETA) complex of Ph3SnLi (19-4), with rSnLi av. 281.7 pm, slightly greater than the sum of the two covalent radii (274 pm), and CSnC 96.1(2)°.30 This structure is preserved in solution, and, at -90 °C, the 7Li NMR spectrum shows (SnLi) = 412 Hz. Similarly the toluene complex... 

Several ligands were used with allyl-type and vinyl-type initiators, such as 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMDETA), NJJyN JJ jN -pentamethyldiethylenetriamine (PMDETA), or compound 7 in Scheme 66. Zeng et al. showed that the combination of initiator 1 in Scheme 66 with BA6TREN or initiator 4 in Scheme 66 with BA6TREN gave the best control of the molar mass for the ATRP of 2-(dimethylamino)ethyl methacrylate. These allylic macromonomers are then able to copolymerize with acrylamide. 

Materials. All chemicals and solvents where purchased from Sigma-Aldrich, Acros and Fluka at the highest available purity and used as received unless otherwise noted. NIPAAm (99%, Acros) was purified by two reciystallizations in a mixture of u-hexane and benzene (4 1 v v). CuBr (98%, Aldrich) and CuCl (97%, Aldrich) were purified by stirring with acetic acid overnight. After filtration, they were washed with ethanol and ether and then dried in vacuum oven. N,N,N ,N ,N -pentamethyldiethylenetriamine (PMDETA 99%, Aldrich) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (HMTETA 97%, Aldrich) were distilled before use. Tris(2-dimethylaminoethyl)amine (MeeTREN) was prepared as described in the literature. Water was obtained from a Milli-Q PLUS (Millipore) apparatus. 

Styrene (S, 99%, stabilized), 2-ethylhexylaciylate (EHA, 99-i-%, stabilized), copper(l) cUoride (CuCl), copper(l) bromide (CuBr, 98%) and ethyl-2-bromopropionate (99%) were purchased from Acros. 2-Bromopropionyl bromide (97%), ethylene glycol (99%), l,l,l-tris(hydroxymethyl)propane (97%), pentaerythritol (99%), 2,2 -bipyridine (bpyr, 99 +%) and N,N,N, N",N -pentamethyldiethylenetriamine (PMDETA, 99 %) were purchased from Aldrich. Tris(2-(dimethylamino)ethyl) amine (Mce-TREN) (18-19) and alkylated linear amine ligands (ALAL) (20-22) were synthesized according to literature procedures. All other solvents and chemicals were reagent grade, and were used as received. 

Typically, phosphoms-based ligands are used to complex no-copper transition metals. Whereas, nitrogen-containing ligands have been used in copper-and iron-mediated ATRP, including 1,1,4,7,10,10-Hexamethyltriethylenetetramine (HMTETA), 2,2 -bipyridine (Bipy), NJ l,N d l ,N -pentamethyldiethylenetriamine (PMDETA), and tris[2-(dimethylamino)ethyl]amine (MceTREN) [26, 27], The activation rate constants for these ligands in copper bromide mediated ATRP and the proposed reaction mechanism of copper/2,2 -bipyridine are shown in Fig. 3.5. 

Biedron and co-workers (39) reported heterogeneous ATRP in [BMIMJPFe. Alkyl acrylates (methyl, butyl, hexyl, and dodecyl) are either soluble, partly soluble, or completely insoluble in this RTIL depending on the length of the alkyl substituent. For the heterogeneous systems, the alkyl acrylate formed an upper monomer phase while the CuBr/pentamethyldiethylenetriamine (PMDETA) catalyst remained in the lower RTIL phase. Methyl acrylate (MA) and poly(methyl acrylate) (PMA) are miscible with [BMIMJPFe and form a homogeneous polymerization system, therefore, all reactions proceed in one phase. For the three other acrylates, the growing macromolecular chains react with the monomer at the... 

Problem 11,6 Styrene (St) was polymerized by ATRP using a copper(I) bromide (CuBr) catalyst, com-plexed with A, A, A, A, iV"-pentamethyldiethylenetriamine (PMDETA) ligand, and methyl 2-bromopropion-ate (MBrP) as initiator. Experiments were performed in 1 E mixed vessel at 110°C with excellent temperature control using a monomer to solvent (toluene) ratio of 70 30 wt% and molar ratios of 50 1 1 1 for St/MBrP/CuBr/PMDETA. Under these reaction conditions, only a portion of the catalyst species was soluble and 90% monomer conversion was obtained in 6 h. Calculate a theoretical molecular weight (MW) of the polymer obtained. How would you explain if the experimental MW is found to be higher than the theoretical... 

A bromine-terminated monofunctional poly(rerr-butyl acrylate) resulting from ATRP of rBA catalyzed by the CuBr/At, At,At, iV, lV"-pentamethyldiethylenetriamine (PMDETA) system (initial mole concentration ratios tBA methyl bromopropionate (MBrP) CuBr PMDETA CuBr2 = 50 1 0.5 0.525 0.025, 25% acetone, 60°C conversion = 96% after 6.5 h) was used as macroinitiator for block copolymerization with styrene (St) with the initial mole concentration ratios of St P(rBA) CuBr PMDETA = 100 1 1 1 at 100°C (conversion 94%). The monofunctional bromo-terminated copolymer P(rBA)-A-P(St) formed was subsequently used as a macroinitiator for a further copolymerization with methyl acrylate (MA). The polymerization was also catalyzed by CuBr/PMDETA (initial concentration ratios MA P(rBA-i>-P(St) CuBr PMDETA = 392 1 1 1), under high dilution in toluene and reached 23% monomer conversion after 3.5 h at 70°C. The experimental molecular weight (M ) of the resulting triblock copolymer P(tBA)-fo-P(St)-fr-P(MA) was 24,800 with a PDI = 1.10. Calculate the theoretical M to compare with the experimental value. 

Alkynyl Amino Alcohols. Compound 1 can be used to prepare alkynyl amino alcohols when the alkyllithium reagent used is sec-BuLi (3 equiv) a mixture of the TV-protected alkynyl amino alcohol and the TV-protected amino alcohol is obtained (21 and 55%, respectively, eq 13). It is noteworthy that the authors of this article were able to optimize the yield of the alkynyl amino alcohol by the addition of pentamethyldiethylenetriamine (PMDETA) and the use of TV-2,4,6-triisopropylbenzenesulfonyl over the TV-toluenesulfonyl nitrogen protecting group. ... 

The copper-catalyzed azide/alkyne click reaction has found the broadest application in the modification of ROMP polymers, with the first reported example in 2004 by Binder and Kluger [13]. Since then, the copper-catalyzed click reaction has been used for the preparation of block copolymers [24, 29, 37], stars [18, 26], cycles [23], networks [25], and graft copolymers [27, 28, 38, 56, 57], as well as for end- [16] and side-chain-functionalized polymers [13, 17, 19-22, 48]. The most often used catalysts and bases for the azide/alkyne click reaction include copper(l) iodide, copper(l) bromide, trisftriphenylphosphine) copper(l) bromide, or copperfll) sulfate/sodium ascorbate as catalyst and diisopropylethylamine (DIPEA), pentamethyldiethylenetriamine (PMDETA), or 2,2 -bipyridine (bPy) as base. 

Lacerda et al. [63] prepared novel nanostructured composite materials from bacterial cellulose membranes (BC) and acrylate polymers by in-situ atom transfer radical polymerization (ATRP). The BC membranes were first functionalized with initiating sites by reaction with 2-bromoisobutyryl bromide (BiBBr), and then polymerization of methyl methacrylate (MMA) and n-butylacrylate (n-BA) was carried out in presence of catalysts copper (I) bromide and N, N, N, N", N"-pentamethyldiethylenetriamine (PMDETA), shown in Figure 5.8. 

Figure 12 illustrates that while the Cu7N,N,N, N", N"-pentamethyldiethylenetriamine (PMDETA) complex is active, it disproportionates in aqueous ATRP. On the other hand, ligands such as bpy, HMTETA, and TPMA can be used in aqueous media, although with rather different activities. If necessary, catalyst disproportionation in water can be suppressed by using an appropriate cosolvent or by addition of a pseudoligand that will stabilize Cu versus Cu , such as pyridine, which allows... 

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