Carboxylate, nitrate, sulfonate, and phosphate catalysts for living radical polymerization via oxygen–iodine halogen bonding catalysis

Abstract

Oxyanions, i.e., carboxylate, nitrate, phosphate, and sulfonate, were used for halogen-bonding-catalyzed living radial polymerization, giving low-dispersity polymethacrylates, polystyrene, and polyacrylonitrile homopolymers and block copolymers.

Air‐Tolerant Reversible Complexation Mediated Polymerization (RCMP) Using Aldehyde

“…The addition of a small amount of I 2 (0.0125 equiv with respect to CP−I) led to a lower Đ value of 1.26 with keeping a relatively high monomer conversion (86%) for 20 h (Table 2 (entry 2) and Figure 3 (squares)). I 2 worked as a deactivator of the propagating radical and prevented the addition of many monomers to the propagating radical in an activation–deactivation cycle, [ 48 ] enabling more uniform polymer growth (narrow molecular weight distribution). Thus, the results demonstrate an efficient catalytic activity of the generated RCOO − and successful air‐tolerant two‐step polymerizations of MMA.…”

“…[ 47 ] Recently, we studied oxyanions (carboxylate (COO – ), nitrate (NO 3 – ), phosphate (PO 4 – ), and sulfonate (SO 3 – ) anions) as the catalysts, showing that carboxylate anions are particularly efficient catalysts and amenable to a range of monomers including functional methacrylates, styrene, and acrylonitrile. [ 48 ]…”

Recent development in halogen-bonding-catalyzed living radical polymerization

“…Our research group found the reversible reactions using alkyl iodides, enabling the use of XB catalysis to LRP. Since our first report in 2011, we have developed several types of RCMP catalysts, including amines, 40,49 iodide anion (I − ), [50][51][52][53][54] organic superbases, 55 pseudohalide anions, 56 pyridine N-oxides, 57 and oxyanions 58 (Fig. 3).…”

“…50 The free radical nature of the propagating species was supported by a radical trap experiment in low-mass model systems. [49][50][51][52][55][56][57][58] For example (Fig. 6a), an alkyl iodide CP-I (10 mM), an I − catalyst (80 mM), and a radical trap 2,2,6,6tetramethylpiperidinyl-1-oxy (TEMPO) (20 mM) were heated in a solvent at 60°C.…”

“…3)) and non-toxic solvents such as ethyl lactate, ethanol, and water were also developed, being attractive for sustainable society. 52,58 Hunter et al reported that the stability of XB is relatively insensitive to the solvent polarity. 69 The association constant ) is a model of MMA medium (ε = 7.9).…”