Synthesis of a new diglycidylic Meldrum acid derivative and study of the curing with lanthanide triflates as initiators

A new epoxy resin derived from Meldrum acid (DGMA) was synthesized by a two steps synthetic procedure and structurally characterized by the usual spectroscopic techniques and elemental analysis. Ytterbium and lanthanum triflates were tested as cationic initiators to cure this resin and its mixtures with diglycidylether of bisphenol A (DGEBA) in several proportions. By FTIR‐ATR spectroscopy the evolution of the groups, which participate in the curing was followed. The evolution of the curing and the T_g of the materials were studied by differential scanning calorimetry and the kinetic parameters were calculated applying isoconversional procedures. Ytterbium triflate led to a quicker curing than lanthanum. The thermal stability of the materials obtained was evaluated by thermogravimetry and the higher thermal degradability of the materials containing DGMA was confirmed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3088–3097, 2008     

Anionic lanthanide phenoxide complexes as novel single‐component initiators for the polymerization of ε‐caprolactone and trimethylene carbonate

The anionic lanthanide‐sodium‐2,6‐di‐tert‐butyl‐phenoxide complexes [Ln(OAr)₄][Na(DME)₃]·DME (Ln = Nd 1 (neodymium), Sm 2 (samarium), or Gd 3 (gadolium); DME = dimethoxyethane) were synthesized by the reaction of anhydrous LnCl₃ with 4 equiv of sodium‐2,6‐di‐tert‐butyl‐phenoxide NaOAr in high yields and structurally characterized. These complexes showed high catalytic activity in the ring‐opening polymerizations of ?‐caprolactone (?‐CL) and trimethylene carbonate (TMC). The catalytic activity profoundly depended on the lanthanide metals. The active order of Gd < Sm < Nd for the polymerization of ?‐CL and TMC was observed. The polymers obtained with these initiators all showed a unimodal molecular weight distribution, indicating that the [Ln(OAr)₄][Na(DME)₃]·DME anionic complexes could be used as single‐component initiators. The anionic complex was more efficient than the corresponding neutral complex, Ln(OAr)₃(THF)₂. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1210–1218, 2007     

Cationic copolymerization of diglycidyl ether of bisphenol A with phthalide or 3,3′‐diphtalide catalyzed by lanthanide triflates

Mixtures of the diglycidylether of bisphenol A (DGEBA) and phthalide (PT) or 3,3′‐diphthalide (DPT) were cured using ytterbium or lanthanum triflate as catalyst. The curing was studied by differential scanning calorimetry (DSC) and Fourier transform infrared in attenuated‐total‐reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and quantify the evolution of the epoxide and lactone groups. The T_g of the crosslinked materials increased when the proportion of lactone in the curing mixture decreased. The kinetics was studied with DSC experiments and isoconversional procedures. The differences in the reactivity of the systems were related to the Lewis acidity of the lanthanide salt used as initiator. The increase in the proportion of lactone leads to an increase in the reaction rate. The shrinkage was determined from the densities before and after curing and its evolution was studied by thermomechanical analysis. The materials obtained were characterized by thermogravimetry and dynamic mechanical thermal analysis. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1711–1721, 2006     

Convenient synthetic route to tetraarylphosphonium polyelectrolytes via palladium‐catalyzed P–C coupling of aryl triflates and diphenylphosphine

A series of eight tetraarylphosphonium polyelectrolytes (TPELs) has been successfully synthesized by polymerization of diphenylphosphine and bis(aryl triflate)s. The bis(aryl triflate)s are readily prepared from bisphenols, some of which are commodity feedstocks such as bisphenol A. The polymerization via palladium catalyzed P–C bond formation produces degrees of polymerization up to 65. All polymeric triflates have reasonable thermal stability in the range of 350–450 °C. The stability of the TPELs to alkaline solution is strongly depending on the spacer between adjacent phosphonium sites. Polymers with electron‐releasing and bulky substituent para‐ to the phosphonium site have improved stability while those with electron‐withdrawing substituent para‐ to phosphonium site have decreased alkaline stability due to decomposition via a nucleophilic aromatic substitution pathway. These findings have important ramifications for the design of ionomers for alkaline exchange membrane fuel cells and related electrochemical energy conversion devices. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 1984–1990     

Ring-Opening Polymerization of Cyclic Monomers with Aluminum Triflate

A green method for the controlled synthesis of aliphatic polymers is presented. The ring-opening polymerizations of cyclic monomers including several lactones, such as caprolactone (CL) or pentadecalactone (PDL), and cyclic anhydride monomers, such as succinic anhydride (SUC) and tetrahydrofuran (THF), catalyzed by a series of metal triflates (trifluoromethanesulfonate) were studied. Aluminum triflate was found to be an advantageous candidate to catalyze the ring-opening polymerization of cyclic monomers. The details of the ring-opening polymerization of CL catalyzed by aluminum triflate were studied. The maximum number average molecular weight (M_n), polydispersity (M_w/M_n) and yield of the obtained poly(-caprolactone) (PCL) at 60 °C for 6 hours were 18,400, 1.94 and 89 wt%, respectively. Those of poly(pentadecalactone) (PPDL) at 100 °C for 6 hours were 12,400, 2.24 and 49 wt%, respectively. The M_n, M_w/M_n and yield of the obtained poly(butylene succinate) (PBS) from SUC and THF at 100 °C for 48 hours were 4,900, 2.03 and 84 wt%, respectively. Furthermore, the mechanism of the polymerization was discussed based on the relationship between the conversion of CL and time. The molecular weight buildup of PCL was linear with a conversion in 50 min before the conversion reached 100 % and with M_w/M_n stabilized at about 1.5. The M_w/M_n of PCL then gradually increased. From these data, a living polymerization with a small transesterification was suggested from the PCL polymerization by aluminum triflate.     

Novel functional initiators for oxazoline polymerization

The initiating behavior of the functional tosylates 1 – 4 and triflates 5 and 6 for the cationic ring‐opening polymerization of 2‐methyl‐1,3‐oxazoline was investigated. The emphasis was directed at tosylates and triflates with 2,2‐dimethyl‐1,3‐dioxolane‐, 2,3‐epoxypropyl‐, 2,3‐didodecanoyl‐glycerol‐, and cholest‐5‐en‐moieties that allow the construction of amphiphilic polyoxazoline conjugates. The tosylates were prepared by a simple reaction of the corresponding alcohols with p‐toluenesulfonyl chloride, whereas the preparation of the corresponding triflates required low temperature and the use of 2,6‐di‐tert‐butylpyridine as a sterically hindered base. Among the initiators tested, 2,2‐dimethyl‐(4‐trifluoromethanesulfonyloxymethyl)‐1,3‐dioxolane 6 gave the best results in respect to molecular weight and polydispersity. Starting from the corresponding functional oxazoline polymers obtained with 6 as an initiator, amphiphilic lipid‐polyoxazoline conjugates with a diacylglycerol backbone could be prepared. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2821–2831, 2001     

Poly(ε‐caprolactone) by combined ring‐opening polymerization and azeotropic polycondensation—the role of cyclization and equilibration

Using three different catalysts, water‐initiated polymerizations of ε‐caprolactone were conducted in bulk with variation of the monomer/water ratio. The resulting CH₂OH and CO₂H‐ terminated polylactones were subjected in situ to azeotropic polycondensations. With Bi‐triflate and temperatures, the polycondensations were not much successful and involved side reactions. With ZnCl₂, and especially SnCl₂, considerably higher molar masses were achieved. The substitution of toluene for chlorobenzene for refluxing gave better results. The polycondensations broadened the molar mass distribution of the ROP‐based prepolymers, and polydispersities between 1.4–1.8 were obtained. The MALDI–TOF mass spectra revealed that the polycondensations significantly enhanced the fraction of rings due to efficient “end‐biting” reactions. By comparison with copolymerization experiments and Sn methoxide‐initiated polymerizations, it was demonstrated that equilibration reactions, such as the formation of rings by “back‐biting,” did not occur. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Influence of lanthanide triflate compounds on formation of networks from DGEBA and γ‐butyrolactone

Diglycidylether of bisphenol A (DGEBA) was cured with γ‐butyrolactone (γ‐BL) using different lanthanide triflates as catalysts. Fourier transform infrared spectroscopy was used to study the different evolutions of the four elemental processes that took place during curing with lanthanum and ytterbium triflates. The greatest differences among the lanthanides were in oxophilicity and Lewis acidity. Differences in the coordination ability of the metal to the monomers were shown and according to the Pearson theory, were related to their different characteristics. Differences in the reactivity of the systems were related to the differences in the Lewis acidity of the initiators. The evolution of the contraction during curing using different lanthanide triflates was monitored by thermomechanical analysis. All systems showed that contraction took place in two stages and that there was an intermediate region, associated with gelation, with no contraction. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3782–3791, 2004     

Sulfonic acids as water‐soluble initiators for cationic polymerization in aqueous media with Yb(OTf)3

Aqueous sulfonic acids (HOSO₂R; R = CH₃, Ph‐p‐CH₃, and Ph‐p‐NO₂), coupled with a water‐tolerant Lewis acid, ytterbium triflate [Yb(OTf)₃; OTf =  OSO₂CF₃], initiate the cationic suspension polymerization of p‐methoxystyrene (pMOS) in heterogeneous aqueous media. They induce controlled polymerization of pMOS at 30 °C, and the molecular weights of the polymers (weight‐average molecular weight/number‐average molecular weight ∼ 1.7) increase with conversion. These suspension polymerizations are initiated by the entry of sulfonic acid from the aqueous phase into the organic phase and proceed via reversible activation of the sulfonyl terminus by the Lewis acid. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2728–2733, 2000     

Polycondensation of activated L‐valine and L‐leucine esters with various lewis acids

To develop a novel polycondensation method for the preparation of poly (amino acid)s, we screened a transition metal or a rare‐earth triflate as a Lewis acid for the polycondensation of activated amino acid esters in N,N‐dimethylformamide solutions at room temperature. The polymerizations of 4‐nitrophenyl L ‐leucinate ( 1a ) and 4‐nitrophenyl L ‐valinate ( 1b ) scarcely proceeded without any Lewis acid at room temperature. In the presence of 5 mol % metal triflates, especially scandium(III) trifluoromethanesulfonate, the polymerizations of both monomers were promoted effectively. The products, which were collected by the reaction mixture being poured into water, were recognized as poly(L ‐valine)s by Fourier transform infrared spectroscopy, gel permeation chromatography analysis, and ¹H NMR spectroscopy. These results showed that a metal triflate as a Lewis acid could coordinate to a carbonyl oxygen of activated L ‐valinate and L ‐leucinate even in a highly polar solvent, such as N,N‐dimethylformamide; therefore, the polymerizations of activated L ‐valinate and L ‐leucinate were promoted. Because steric hindrance derived from the isobutyl group in 1b was less than that of the isopropyl unit in 1a , the effect of the metals was not as sensitive for the polymerization of 1b . © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 543–547, 2007     

Synthesis and ring‐opening polymerizations of novel S‐glycooxazolines

A new 2‐oxazolines containing S‐galactosyl substituents linked to alkyl chains of different lengths; (S‐glycooxazoline) were prepared relatively in high yields. By using a 1:1 adduct of 2‐methyl‐2‐oxazoline and methyl triflate, as the initiator, the monomer was polymerized via ring‐opening polymerization (ROP) to give products with relatively narrow molecular weight distributions. Homo‐ and copolymerization were performed, and the kinetics of these new S‐glycooxazolines in the ROP are investigated. After a quantitative deprotection, poly(2‐oxazoline)s having pendant carbohydrate were obtained. The interaction of the poly(S‐glycooxazoline) with RCA₁₂₀ lectin was investigated, the binding constant between glycopolymer and lectin was increased by 10² times compared with that of the monosaccharide (D ‐galactose). The in vivo expression of green fluorescent protein using the synthesized poly(S‐glycooxazoline)s as polymeric inducers in Escherichia coli host were performed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Bidentate coordination effect on polycondensation of amino acid esters between metal triflates and methoxy groups

To study the bidentate coordination effect on the polycondensation of L ‐valinates between metal triflates as a Lewis acid and methoxy groups, we carried out the polycondensation of 2‐methoxy‐4‐nitrophenyl L ‐valinate ( 1a ) and 2‐methoxyphenyl L ‐valinate ( 1b ) in the presence of the various kinds of rare‐earth triflates in DMF solution at room temperature. The polymerizations of 1a did not proceed without any metal triflates. In the presence of 5 mol% triflates, especially Sc(OTf)₃, the polymerization proceeded effectively. After the reaction mixture was poured into water, the product was collected, which was recognized as poly(L ‐valine)s by FTIR spectrum and GPC measurement. The yield of the product from the polymerization of 1a with Sc(OTf)₃ was higher than that from the polymerization of 4‐nitrophenyl L ‐valinate ( 1c ) with Sc(OTf)₃. This result indicates that the polymerization of 1a was promoted to introduce the methoxy group on the o‐position of the phenyl ring at the ester group with the aim of the bidentate coordination effect between metal triflates and L ‐valinate. As a control experiment, we carried out the polycondensation of 1b in the presence of 5 mol% metal triflates; however, any polymerization did not proceeded. That reason is from the lower activity of activated L ‐valinate ( 1b ). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2864–2868, 2008     

The degradation of new thermally degradable thermosets obtained by cationic curing of mixtures of DGEBA and 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione)

The thermal degradation of thermosetting materials prepared by cationic copolymerization of mixtures of different proportions of diglycidylether of bisphenol A (DGEBA) with 6,6-dimethyl (4,8-dioxaspiro[2.5]octane-5,7-dione) (MCP) initiated by ytterbium or lanthanum triflate or using a conventional initiator, BF₃·MEA was investigated. To study the thermal degradation, several techniques were used such as thermogravimetry (TGA), infrared spectroscopy (FTIR) and calorimetry (DSC) and the volatiles evolved during degradation were identified by mass spectrometry. The materials prepared possess the characteristics of thermally degradable thermosets, due to the presence of ester groups in the polymer chain, which are broken at the beginning of degradation. The degradability increased when lanthanide triflates were used in the curing, especially the ytterbium salt and when the proportion of MCP in the material increased.     

Cationic polymerizations of 2‐alkyloxazolines catalyzed by bismuth salts

Acidic bismuth salts, such as BiCl₃, BiBr₃, BiJ₃, and Bi‐triflate catalyzed the ring‐opening polymerization of 2‐methoxazoline (MOZ) in bulk at 100 °C, whereas less acidic salts such as Bi₂O₃ or Bi(III)acetate did not. Bi‐triflate‐catalyzed polymerizations of 2‐ethyloxazoline (EtOZ) were performed with variation of the monomer–catalyst ratio (M/C). It was found that the molecular weights were independent of the M/C ratio. The formation of cationic chain ends and the absence of cycles was proven by reactions of virgin polymerization products with N,N‐dimethyl‐4‐aminopyridine or triphenylphosphine. The resulting polymers having modified cationic chain ends were characterized by ¹H NMR spectroscopy and MALDI‐TOF mass spectrometry. The polymerization mechanism including chain‐transfer reactions is discussed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4777–4784, 2008     

Slow Reactant–Water Exchange and High Catalytic Performance of Water‐Tolerant Lewis Acids

³¹P nuclear magnetic resonance (NMR) spectroscopic measurement with trimethylphosphine oxide (TMPO) was applied to evaluate the Lewis acid catalysis of various metal triflates in water. The original ³¹P NMR chemical shift and line width of TMPO is changed by the direct interaction of TMPO molecules with the Lewis acid sites of metal triflates. [Sc(OTf)₃] and [In(OTf)₃] had larger changes in ³¹P chemical shift and line width by formation of the Lewis acid–TMPO complex than other metal triflates. It originates from the strong interaction between the Lewis acid and TMPO, which results in higher stability of [Sc(OTf)₃TMPO] and [In(OTf)₃TMPO] complexes than other metal triflate–TMPO complexes. The catalytic activities of [Sc(OTf)₃] and [In(OTf)₃] for Lewis acid‐catalyzed reactions with carbonyl compounds in water were far superior to the other metal triflates, which indicates that the high stability of metal triflate–carbonyl compound complexes cause high catalytic performance for these reactions. Density functional theory (DFT) calculation suggests that low LUMO levels of [Sc(OTf)₃] and [In(OTf)₃] would be responsible for the formation of stable coordination intermediate with nucleophilic reactant in water.     

Influence of the addition of erbium and ytterbium triflates in the curing kinetics of a DGEBA/<Emphasis Type="Italic">o</Emphasis>-tolybiguanide powder mixture

Solid bisphenol-A epoxy resin (DGEBA) of medium molecular mass was cured using o-tolylbiguanide (TBG) as cross-linking agent. In order to improve the kinetics of the reactive system, two Lewis acid catalysts (erbium(III) and ytterbium(III) trifluoromethanesulfonates) were added in proportions of 1 phr. The kinetic study was performed by dynamic scanning calorimetry (DSC) and the complete kinetic triplet (E, A and g(α)) determined. The kinetic analysis was performed with an integral isoconversional procedure (model-free), and the kinetic model was determined by the Coats-Redfern method and through the compensation effect (IKR). All the systems followed the m=1.5/n=0.5 isothermal curing model simulated from non-isothermal experiments. The addition of a little proportion of ytterbium or erbium triflates accelerated the curing process. In order to extract further information about the role of the lanthanide triflates added to epoxy/TBG systems, the kinetic results were compared with our previous kinetic studies made on DGEBA/lanthanide triflates initiated systems.     

Solvolysen von 4-Alkylidenbicyclo[3.2.0]hept-2-en-6-olen. Synthese von 1-Vinylfulvenen und 8,8-Diphenylheptafulven

Solvolysis of 4-Alkydenbicyclo[3.2.0]hept-2-en-6-oles. Synthesis of 1-Vinylfulvenes and 8,8-Diphenylheptafulvene Four 4-alkylidenebicyclo[3.2.0]hept-2-en-6-ones 2–5 , obtained via ketene cycloaddition to fulvenes, were reduced to separated mixtures of the ‘endo’ -alcohols ‘endo’- 6 to ‘endo’- 9 (68–73%) and ‘exo’- 6 to ‘exo’- 9 (3–20%). Treatment of some of these alcohols with (CF₃SO₂)₂O in CH₂Cl₂/pyridine caused a spontaneous solvolysis to yield unsaturated 7-membered rings as pyridinium triflates 10–12 or 1-vinylfulvenes 13 and 14 , a new class of reactive tetraenes: Both ‘endo’- 9 and ‘exo’- 9 , having two methyl groups at C(7), were converted into the vinylfulvene 13 (≈ 80%). The alcohols with two H-atoms at C(7) exhibited a stereochemically controlled reaction selectivity, inasmuch as ‘endo’- 6 to ‘endo’- 8 afforded only the corresponding 7-membered-ring pyridinium salts 10–12 (66–79%), while ‘exo’- 6 produced only the vinylfulvene 14 (77%). A stereoelectronic control argument explains the C(1), C(5)-bond cleavage with ‘endo’- B and ‘endo’– 6 -‘endo’- 8 , as well as the C(1), C(7)-bond cleavage with ‘exo’- B , ‘exo’- 6 , and with both ‘endo’- and ‘exo’- 9 . Thermolysis (120°) of the pyridinium triflates 10 and 11 yielded the 3-isopropenyl-cycloheptatrienes 18 and 19 , respectively (≈90%); similar conditions (145°) applied to the triflate 12 produced the doubly cyclized fluorene derivative 21 (60%). When the iodide 22 derived from the triflate 12 with Nal was heated in refluxing toluene, 8,8-diphenylheptafulvene ( 23 , 86%) was obtained.     

Aqueous solution and solid state interactions of lanthanide ions with a methacrylic ester polymer bearing pendant 15‐crown‐5 moieties

The interaction between trivalent lanthanide ions and poly(1,4,7,10,13‐pentaoxacyclopentadecan‐2‐yl‐methyl methacrylate), PCR5, in aqueous solution and in the solid state have been studied. In aqueous solution, evidence of a weak interaction between the lanthanides and PCR5 comes from the small red shift of the Ce(III) emission spectra and the slight broadening of the Gd(III) EPR spectra. From the Tb(III) lifetimes in the presence of H₂O and D₂O the loss of one or two water coordinated molecules is confirmed when Tb(III) is bound to PCR5. An association constant of the order of 200 M^?1 was obtained for a 1:1 (lanthanide:15‐crown‐5) complex from the shift of the polymer NMR signals induced by Tb(III). A similar association constant is obtained from the differences of the molar conductivity of Ce(III) solution at various concentrations in presence and absence of PCR5. When Tb(III) is adsorbed on PCR5 membranes, lifetime experiments in H₂O and D₂O confirm the loss of 5 or 6 water coordinated molecules indicating that in solid state the lanthanide(III)‐PCR5 interaction is stronger than in solution. The adsorption of Ce(III) in PCR5 membranes shows a Langmuir type isotherm, from which an equilibrium constant of 39 M^?1 has been calculated. SEM shows that the membrane morphology is not much affected by lanthanide adsorption. Support for lanthanide ion–crown interactions comes from ab initio calculations on 15‐crown‐5/La(III) complex. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1788–1799, 2007     

Synthesis and characterization of poly(L‐lactic acid)–poly(ε‐caprolactone) multiblock copolymers by melt polycondensation

An Erratum has been published for this article in J. Polym. Sci. Part A: Polym. Chem. (2004) 42(22) 5845 New multiblock copolymers derived from poly(L‐lactic acid) (PLLA) and poly(ε‐caprolactone) (PCL) were prepared with the coupling reaction between PLLA and PCL oligomers with ? NCO terminals. Fourier transform infrared (FTIR), ¹³C NMR, and differential scanning calorimetry (DSC) were used to characterize the copolymers and the results showed that PLLA and PCL were coupled by the reaction between ? NCO groups at the end of the PCL and ? OH (or ? COOH) groups at the end of the PLLA. DSC data indicated that the different compositions of PLLA and PCL had an influence on the thermal and crystallization properties including the glass‐transition temperature (T_g), melting temperature (T_M), crystallizing temperature (T_c), melting enthalpy (ΔH_m), crystallizing enthalpy (ΔH_c), and crystallinity. Gel permeation chromatography (GPC) was employed to study the effect of the composition of PLLA and PCL and reaction time on the molecular weight and the molecular weight distribution of the copolymers. The weight‐average molecular weight of PLLA–PCL multiblock copolymers was up to 180,000 at a composition of 60% PLLA and 40% PCL, whereas that of the homopolymer of PLLA was only 14,000. A polarized optical microscope was used to observe the crystalline morphology of copolymers; the results showed that all polymers exhibited a spherulitic morphology. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5045–5053, 2004     

The effects of counter anions on the dynamic mechanical response in polymer networks crosslinked by metal–ligand coordination

Metal–ligand coordination has been proven to be an attractive strategy to tune a polymer network's dynamic mechanical properties, such as self-healing ability. Nonetheless, the role of counter anions is often overlooked. To address this, a series of polydimethylsiloxane (PDMS) films crosslinked through lanthanide metal cations (Eu³⁺, Tb³⁺)–bipyridine interactions have been prepared and studied. Neutral 2,2'-bipyridine ligands were embedded into the linear polydimethylsiloxane (PDMS) chain through polycondensation. With nitrate ( ) as the coordinating anions, metal salts Eu(NO₃)₃ and Tb(NO₃)₃ were found to be ineffective crosslinkers. With noncoordinating anions, such as triflate (OTf^-: CF₃ ), metal salts Eu(OTf)₃ and Tb(OTf)₃ showed improved interaction strength with bipyridine ligands. Surprisingly, the addition of Eu(OTf)₃ and Tb(OTf)₃ salts also increased the d-spacing distances of the phase-segregated domains between metal–ligand complexes and the PDMS polymer backbone. For the Eu(OTf)₃-, Tb(OTf)₃-PDMS films, the much-improved self-healing abilities are attributed to the crosslinker dynamics and the enhanced chain mobility. This work underlines the importance of counter anions on the mechanical properties, and provides further guidance on the future design of self-healing metal−ligand crosslinked polymers.) © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3110–3116