Imine Functionality Research Articles

Amide/urea-based simple fluorometric receptors for iodide and Hg2+ ions in aqueous medium: Aggregation induced emission and DFT studies

Herein, we report pyrene-tagged amide and urea-based sugar derivatives 1 and 2 in a simple synthetic pathway to recognize I− and Hg2+ ions. Both molecules showed absorbance and fluorescence selectivity towards iodide ions in THF/H2O (7/3, v/v) medium. The selectivity and sensitivity of 2 for iodide ions are superior to 1 due to more H-bond donors in 2. Interestingly, fluorometric receptor 2 exhibited aggregation-induced emission (AIE) at higher pH with a remarkable fluorometric color change. The AIE phenomenon might be explained by the self-association of 2 after forming imine functionality in the alkali medium. The Stern-Volmer plot showed the fluorescence quenching constant of each receptor with an iodide ion and indicated the quenching pathway. The LODs of 1 and 2 for iodide ions were evaluated as 0.84 and 0.17 µM, respectively. The 1:1 binding stoichiometry of 1 or 2 with iodide was found from the Job plot and verified by measuring the complex mass.Further, the complexes of each receptor with I− ions can detect Hg2+ ions selectively by fluorescence turn-on method with low sensitivities (LODs: 0.008 µM for 1 and 0.01 µM for 2). DFT results were used to understand the binding mode of receptors 1 and 2 with iodide ions and the quenching process in the aqueous THF medium. The real application of the receptors was established for the recovery of iodide and Hg2+ ions from natural water samples.

Rheological and mechanical comparison of di-and tri-block copolymer imine vitrimers

Vitrimers’ tendency to creep over time under stress poses a significant challenge to their widespread industrial use. Recently, nanoscale self-assembly has emerged as a promising route to control creep in vitrimers; however, mechanical robustness of such phase-separated materials requires further enhancement and investigation. Herein, we explored how the prepolymer architecture influences the structure-property relationships in vitrimers made of statistical copolymers, AB hard-soft diblock copolymers, and ABA hard-soft-hard triblock copolymers. Reversible addition fragmentation chain-transfer (RAFT) polymerization was employed to control the length, sequence, and morphology of the precursors. Dynamic imine functionalities were localized within the soft segment, which consisted of a bio-based copolymer of long-chain alkyl methacrylate and aldehyde-functional vanillin methacrylate. Compared to the statistical vitrimers, the triblock copolymer vitrimers exhibited approximately 60 % improved creep resistance, a 400 % increase in hardness, a higher tensile modulus, and ∼ 57 % higher stress at break. In contrast, vitrimers derived from diblock copolymers exhibited much weaker tensile properties with approximately 30 % lower stress at break. Our findings suggest that by controlling the chain architecture in block copolymers and optimizing the order–disorder transition, we can enhance vitrimers’ creep resistance and tune their viscoelastic properties while tailoring their mechanical strength.

Selective C3- or C5-Borylation of furfural derivatives: Enabling the synthesis of tri- and tetra-substituted furan Analogues

A strategy of C3/C4 and C5/C4 bis-C–H functionalization of furfural and 5-hydroxymethylfurfural is presented. This task has been accomplished by the initial iridium-catalyzed C–H borylation of furfural, equipped with an appropriate imine function. Depending on the nature of the ligand employed, the borylation takes place selectively at C3 or C5, the products serving in turn as partners in Suzuki-Miyaura cross-couplings. After aldehyde function regeneration, some of the resulting heterobiaryl compounds underwent a, C3- or C5-directed, C4-selective Pd-catalyzed Fujiwara-Moritani olefination. These hitherto unknown serial C3/C4 and C5/C4 bis C–H functionalization strategies allow the straightforward conversion of the bio-sourced platform molecules furfural and 5-hydroxymethylfurfural into tri- and tetra-substituted furaldehyde derivatives.

Synthesis and Experimental Structure of a Multifunctional Catechol‐Azomethinebenzoic Acid, DFT/DMol3 Calculations, and Molecular Docking with Hsp90

AbstractThe multifunctional catechol‐azomethine‐benzoic acid derivative 4‐[(E)‐[(2,3‐dihydroxyphenyl)methylidene]amino]benzoic acid (1) was prepared and the structure were confirmed by EI‐MS and 1H and 13C NMR spectroscopy. A Single‐crystal X‐ray diffraction study revealed coplanarity of the two aromatic rings within the imine function, supported by intramolecular N−H⋯O hydrogen bonds. In the crystal structure intermolecular O−H⋯O hydrogen bonds form chains, propagating along [010]. FT‐IR and Hirshfeld surface analysis confirms the multiple hydrogen bonding. DFT/DMol3 calculations localized the highest occupied molecular orbital (HOMO) on the o‐catechol unit, while the lowest unoccupied molecular orbital (LUMO) is delocalized over the entire molecule. The calculated map of electrostatic potential (MEP) showed relatively low values for both electrophilic and nucleophilic susceptibility. A molecular docking study of 1 in comparison with the established inhibitor geldanamycin (G) using the protein structure of the heat shock protein 90 co‐crystallized with G (Hsp90⋅G) showed that 1 occupies the same binding pocket as G in the Hsp90⋅G structure, indicating that the title structure might be a suitable inhibitor. The Swiss ADME approach showed promising general drug‐likeness properties for 1 with a relatively high lipophilicity (logP=1.68) and a logS value of −2.99 which lies in the middle of the logS distribution of traded drugs.

Covalent Adaptable Networks with Tailorable Material Properties Based on Divanillin Polyimines.

Covalent adaptable networks (CANs) are being developed as future replacements for thermosets as they can retain the high mechanical and chemical robustness inherent to thermosets but also integrate the possibility of reprocessing after material use. Here, covalent adaptable polyimine-based networks were designed with methoxy and allyloxy-substituted divanillin as a core component together with long flexible aliphatic fatty acid-based amines and a short rigid chain triamine, yielding CANs with a high renewable content. The designed series of CANs with reversible imine functionality allowed for fast stress relaxation and tailorability of the thermomechanical properties, as a result of the ratio between long flexible and short rigid amines, with tensile strength (σb) ranging 1.07-18.7 MPa and glass transition temperatures ranging 16-61 °C. The CANs were subsequently successfully reprocessed up to three times without determinantal structure alterations and retained mechanical performance. The CANs were also successfully chemically recycled under acidic conditions, where the starting divanillin monomer was recovered and utilized for the synthesis of a recycled CAN with similar thermal and mechanical properties. This promising class of thermosets bearing sustainable dynamic functionalities opens a window of opportunity for the progressive replacement of fossil-based thermosets.

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Azepine ring is a prominent structural scaffold in biologically significant molecules. This study demonstrates a Ni(II)‐catalyzed alkyne functionalization/cyclization cascade reaction of alkyne‐tethered malononitriles, involving intermolecular regioselective arylation of the alkynes and desymmetrizing addition onto the nitrile group, to access azepine derivatives. This strategy introduces an all‐carbon quaternary stereocenter and an unprotected imine functionality simultaneously to the azepine scaffold, showing great promise for subsequent transformations. More details are discussed in the article by Liu et al. on page 873—878.image

Ni‐Catalyzed Enantioselective Difunctionalization of Alkynes to Azepine Derivatives Bearing a Quaternary Center and an Unprotected Imine†

Comprehensive SummaryThe azepine ring is a prominent structural scaffold in biologically significant molecules. In this study, we present a Ni(II)‐catalyzed asymmetric difunctionalization of alkynes, involving intermolecular regioselective arylation and intramolecular nitrile addition, enabling the synthesis of enantioenriched azepine derivatives. This reaction simultaneously installs an all‐carbon quaternary stereocenter and introduces an unprotected imine functionality, showing great promise for subsequent transformations. The reaction exhibits good tolerance toward various functional groups, resulting in high yields and enantioselectivities. The synthetic utility of this methodology is further demonstrated through gram‐scale synthesis and product derivatization. This research offers an efficient approach to the synthesis of seven‐membered nitrogen heterocycles.

Paper-based biomimetic test-strip for CA15-3 with coloured readout

The combination of molecularly-imprinted polymers (MIPs) on paper substrates for capturing a cancer antigen 15–3 (CA15-3) with the traditional coloured transduction scheme of enzyme-linked immunosorbent assay (ELISA) using 3,3′,5,5′-tetramethylbenzidine (TMB), horseradish peroxidase (HRP) and H2O2 is presented here for the first time.Here, the paper surface was modified with a silane derivative containing an amine function that allows subsequent binding of 3-aminophenylboronic acid (3-APBA). The target protein, CA15-3, was then bound via the boronic groups of APBA. The empty space around CA15-3 was filled by polymerization of dopamine. Finally, the CA15-3 template was removed by breaking the imine function to create vacant sites for which CA15-3 has a high affinity. Binding of CA15-3 was detected by oxidation of TMB substrate by HRP in the presence of H2O2.The results showed that the MIP was able to selectively recognize CA15-3 within 3–500 U mL−1, even in complex samples. Quantitative data were extracted by analysing the colour coordinates of images captured with a smartphone using ImageJ. This selective behaviour was confirmed by comparison with a control material (non– polymer, NIP).Overall, the described approach has advantages over conventional ELISA, namely low cost and high stability, which is due to the use of MIP as a trapping element acting as a selective pre-concentration point of CA15-3. To our knowledge, this is the first biomimetic ELISA (B-ELISA) on paper substrate used for macromolecules such as proteins. We believe that this approach has the potential to be applied to other protein disease biomarkers, making it a suitable tool for screening glycoproteins at the point-of-care.

A Journey from Benzoborirene to Benzoborole-Supported 1,2-Diimine and Antiaromatic Borolediide.

The reaction of benzoborirene with one equivalent of isocyanides leads to benzene-fused boretes bearing one imine function, while the reaction with two equivalents of isocyanide affords 2,3-dihydro-2,3-diiminoboroles with perfect regioselectivity. The isocyanide double insertion products represent a novel type of 1,2-diimine with a benzoborole backbone. The reduction chemistry of the benzoborole-supported 1,2-diimine was investigated. Single- and two-electron reduction allow for the isolation and full characterization of a radical anion and a dianion, respectively. In stark contrast to the ordinary boroles, which should turn aromatic by accepting two electrons, the antiaromatic character of the benzoborole backbone is highlighted upon reduction, thus presenting a rare example of antiaromatic borole dianion. Detailed quantum chemical calculations provide a rationale for the observed regioselectivity and the electronic structure of the reduced borole diimine species.

Von Benzoborirenen zu Benzoborol‐basierenden 1,2‐Diiminen und antiaromatischen Boroldiiden

AbstractDie Reaktion von Benzoborirenen mit einem Äquivalent Isocyanid führt zu benzolkondensierten Boreten mit einer Iminfunktion, während die Reaktion mit zwei Äquivalenten Isocyanid 2,3‐Dihydro‐2,3‐diiminoborole mit perfekter Regioselektivität ergibt. Die Isocyanid‐Doppelinsertionsprodukte stellen einen neuen Typ von 1,2‐Diiminen mit einem Benzoborol‐Rückgrat dar. Die Reduktionschemie des Benzoborol‐basierenden 1,2‐Diimins wurde untersucht. Die Reduktion mit einem und zwei Elektronen ermöglicht die Isolierung und vollständige Charakterisierung eines radikalischen Anions bzw. eines Dianions. Im Gegensatz zu gewöhnlichen Borolen, die durch die Aufnahme von zwei Elektronen aromatisch werden sollten, wird der antiaromatische Charakter des Benzoborol‐Rückgrats bei der Reduktion verstärkt und stellt somit ein seltenes Beispiel für ein antiaromatisches Borol‐Dianion dar. Detaillierte quantenchemische Berechnungen liefern eine Erklärung für die beobachtete Regioselektivität und die elektronische Struktur der reduzierten Borol‐Diimin‐Spezies.

Molecular Mechanisms Involved in the Chemical Instability of ONC201 and Methods to Counter Its Degradation in Solution.

Glioblastoma is one of the most common and aggressive forms of brain tumor, a rare disease for which there is a great need for innovative therapies. ONC201, a new drug substance, has been used in a compassionate treatment program where the choice of dosage form and regimen have yet to be justified. The prior knowledge needed to anticipate ONC201 stability problems has recently been partially addressed, by (i) showing that ONC201 is sensitive to light and oxidation and (ii) identifying the molecular structures of the main degradation products formed. The aim of the work presented here was to improve our understanding of the degradation pathways of ONC201 using data from ab initio calculations and experimental work to supplement the structural information we already published. The C-H bonds located αto the amine of the tetrahydropyridine group and those located alpha to the imine function of the dihydroimidazole group exhibit the lowest bond dissociation energies (BDEs) within the ONC201 molecule. Moreover, these values drop well below 90 kcal.mol-1 when ONC201 is in an excited state (S1; T1). The structures of the photoproducts we had previously identified are consistent with these data, showing that they would have resulted from radical processes following the abstraction of alpha hydrogens. Concerning ONC201's sensitivity to oxidation, the structures of the oxidation products matched the critical points revealed through mapped electrostatic potential (MEP) and average local ionization energy (ALIE). The data obtained from ab initio calculations and experimental work showed that the reactivity of ONC201 to light and oxidation conditions is highly dependent on pH. While an acidic environment (pH < 6) contributes to making ONC201 quantitatively more stable in solution in the face of oxidation and photo-oxidation, it nevertheless seems that certain chemical groups in the molecule are more exposed to nucleophilic attacks, which explains the variation observed in the profile of degradation products formed in the presence of certain antioxidants tested. This information is crucial to better understand the stability results in the presence of antioxidant agents and to determine the right conditions for them to act.

Digital Light Processing 3D Printing of Isosorbide- and Vanillin-Based Ester and Ester-Imine Thermosets: Structure-Property Recyclability Relationships.

Four isosorbide-based photocurable resins were designed to reveal correlations between the composition and chemical structure, digital light processing (DLP) three-dimensional (3D) printability, thermoset properties, and recyclability. Especially, the role of functional groups, i.e., the concentration of ester groups vs the combination of ester and imine functionalities, in the recyclability of the resins was investigated. The resins consisted of methacrylated isosorbide alone or in combination with methacrylated vanillin or a flexible methacrylated vanillin Schiff-base. The composition of the resins significantly affected their 3D printability as well as the physical and chemical properties of the resulting thermosets. The results indicated the potential of methacrylated isosorbide to confer rigidity to thermosets with some negative effects on the printing quality and solvent-resistance properties. An increase in the methacrylated vanillin concentration in the resin enabled us to overcome these drawbacks, leading, however, to thermosets with lower thermal stability. The replacement of methacrylated vanillin with the methacrylated Schiff-base resin decreased the rigidity of the networks, ensuring, on the other hand, improved solvent-resistance properties. The results highlighted an almost complete preservation of the elastic modulus after the reprocessing or chemical recycling of the ester-imine thermosets, thanks to the presence of two distinct dynamic covalent bonds in the network; however, the concentration of the ester functions in the ester thermosets played a significant role in the success of the chemical recycling procedure.

Rare Caulamidine Hexacyclic Alkaloids from the Marine Ascidian Polyandrocarpa sp.

Two new caulamidines C (2) and D (4) and three isocaulamidines B, C, and D (1, 3, and 5) along with the known compound caulamidine B (6) were isolated from the marine ascidian Polyandrocarpa sp. Their structures were elucidated by analysis of nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) data. Isocaulamidines have an altered pattern of N-methyl substitution (N-15 vs N-13 in the caulamidines) with a concomitant double-bond rearrangement to provide a new C-14/N-13 imine functionality. Caulamidine C (2) and isocaulamidine C (3) are the first members of this alkaloid family with two chlorine substituents in the core 6H-2,6-naphthyridine ring system.

Theoretical insight into the unexpected initial (3 + 2) cycloaddition reaction of mesitonitrile oxide with 1, 4-diazepine derivatives: A computational study

1,4-Diazepine as an active drug component underlies the potency of most psychotic, anticancer, anticonvulsant, and antibacterial drugs in the market and is, therefore crucial in chemotherapeutic treatment in biomedicine. Proper functionalization of this moiety can afford even more potent drugs. As a result of their therapeutic significance, this study aims at precisely giving a comprehensive computational insight into the unexpected initial reactivity of 1,4-diazepine derivatives and mesitonitrile oxide. The initial reaction between mesitonitrile oxide and 1,4-diazepine derivatives proceeds via a (3 + 2) cycloaddition reaction which leads to the formation of a cycloadduct where the mesitonitrile oxide unexpectedly adds across the imine functionality at the expense of the potential olefinic carbon-carbon double bond. Calculations at the density functional theory (DFT) M06/6-311G (d, p) level of theory indicate that the initial (3 + 2) cycloaddition reaction of mesitonitrile oxide (1,3-dipole) and 1,4-diazepine derivatives (dipolarophile) in all cases proceeds to form the cycloadduct where the 1,3-dipole adds preferentially to the imine functionality at the expense of the potential olefinic carbon-carbon double bond. In light of the parent reaction, the most kinetically favored cycloadductP3A had a rate constant of 5.1 × 106 M−1s−1, which is about 12 manifolds faster than the next competing stereoisomer P1A with a rate constant of 4.1 × 105 M−1s−1 and about 1024 faster than the most favored cycloadduct P3B with a rate constant of 7.2 × 10−19 M−1s−1 in the unfavored pathway (Path B). Irrespective of the electronic and steric nature of the electron-donating (EDG) and electron-withdrawing (EWG) substituents placed on the dipolarophile, the selectivities of the reaction were maintained. Rationalization of the potential energy surface depicts that the 1,3-dipole adds across the dipolarophile via an asynchronous concerted mechanism. Rationalization of the HOMO-LUMO energies of the mesitonitrile oxide (1,3-dipole) and the 1,4-diazepine derivatives (dipolarophile) depict that the EDG-substituted dipolarophile react as nucleophiles, whereas the dipole reacts as an electrophile. Conversely, the HOMO-LUMO interaction between the EWG-substituted dipolarophile indicates that the EWG-substituted dipolarophile react as electrophiles, whereas the dipole reacts as a nucleophile. The electrophilic parr function at various reactive sites of the dipolarophile shows that the 1,3-dipole preferentially adds across the local centers with the largest electrophilic NBO or Mulliken spin densities which is consistent with the energetic trend observed. The reactivity of the 1,4-diazepine derivatives and the mesitonitrile oxide showed poor stereoselectivity.

P-Anisidine release study by hydrolysis of Schiff bases in homogeneous media

ABSTRACT. The objective of this work is to study the release of p-anisidine by the hydrolysis of synthesized Schiff bases N-vinylbenzylidene-p-anisidine (Im) as a monomer and its copolymers (Cp1, Cp2) with N,N-dimethylacrylamide (DMA). The hydrolysis behavior and kinetics are investigated in homogeneous media composed of ethanol/water (80% v/v) at 37 °C and at pH range of 4.0-10.0. The variation of the concentration over time is measured in thermostatically cells using UV-Vis spectroscopy. The results showed that the imine function hydrolysis obeyed to the first order for all compounds; the experimental kinetic constants are determined and the pH–rate diagram profile is established. It is noticed that the hydrolysis of imine function is extremely dependent on its carrier and the pH medium.&#x0D; &#x0D; KEY WORDS: p-Anisidine, Copolymer, Schiff base, Hydrolysis, pH–rate diagram, Controlled release&#x0D; &#x0D; Bull. Chem. Soc. Ethiop. 2023, 37(3), 745-755. &#x0D; DOI: https://dx.doi.org/10.4314/bcse.v37i3.16

Targeted delivery of fenamates with aminated starch.

Aim: To develop controlled-release tablets based on aminated starch. Materials & methods: Aminated starch was characterized with Fourier transform infraredand x-ray diffraction. Thermogravimetric analysis confirmed the preferential oxidation of crystalline region of starch. Results: The tablets achieved an initial fast release of fenamates, which slows down after 12h. Drug release was not completed in the simulated intestinal media, which may be due to the stability of imine bond in aminated starch at weakly acidic pH. Drug release was completed in simulated acidic media due to the hydrolysis of imine functionality at strongly acidic pH. Conclusion: Aminated starch with an imine functionality may serve as intestinetargeted, controlled drug-delivery system. Mucoadhesive potential of tablets further supports this observation.

Nucleophilic substitution reaction as an important tool in the synthetic protocol for selenium donor containing Schiff bases: applications of metal complexes in homogeneous catalysis

Nucleophilic substitution reaction has been used as a tool to incorporate Se in ligands having imine functionality. Metal complexes of such ligands,i.e., Schiff bases, are used as homogeneous catalytic systems for a variety of organic reactions.

Covalent DNA Binding Is Essential for Gram-Negative Antibacterial Activity of Broad Spectrum Pyrrolobenzodiazepines.

It is urgent to find new antibiotic classes against multidrug-resistant bacteria as the rate of discovery of new classes of antibiotics has been very slow in the last 50 years. Recently, pyrrolobenzodiazepines (PBDs) with a C8-linked aliphatic-heterocycle have been identified as a new broad-spectrum antibiotic class with activity against Gram-negative bacteria. The active imine moiety of the reported lead pyrrolobenzodiazepine compounds was replaced with amide to obtain the non-DNA binding and noncytotoxic dilactam analogues to understand the structure-activity relationship further and improve the safety potential of this class. The synthesised compounds were tested against panels of multidrug-resistant Gram-positive and Gram-negative bacteria, including WHO priority pathogens. Minimum inhibitory concentrations for the dilactam analogues ranged from 4 to 32 mg/L for MDR Gram-positive bacteria, compared to 0.03 to 2 mg/L for the corresponding imine analogues. At the same time, they were found to be inactive against MDR Gram-negative bacteria, with a MIC &gt; 32 mg/L, compared to a MIC of 0.5 to 32 mg/L for imine analogues. A molecular modelling study suggests that the lack of imine functionality also affects the interaction of PBDs with DNA gyrase. This study suggests that the presence of N10-C11 imine moiety is crucial for the broad-spectrum activity of pyrrolobenzodiazepines.

Palladacycle versus coordination complex of palladium(II) with a bulky organophosphorus (P,N) ligand: Application in catalysis of allylation of aldehydes

Palladacyclic complex 1 [Pd(L1)Cl] [L1: anthracene–9-yl–CH = N(CH2)2–PPh2 behaving as (P, N, C−) ligand] has been prepared, and characterized using multi-nuclei NMR spectroscopic, high resolution mass spectrometric (HRMS) and single-crystal X-ray diffraction (SC-XRD) techniques. This palladacycle 1 and the 2 [i.e., Pd(L1)Cl2, a square planar Pd(II) complex of the same ligand] have anthracene core, imine functionality and P,N donors. Both the 1 and 2 have been explored as potential catalysts for allylation of aldehydes with allyltributylstannnane. Both the complexes show good efficiency towards this CC coupling reaction. Various aldehydes such as 4–bromobenzaldehyde, 4–chlorobenzaldehyde, 2–bromobenzaldehyde, 2–chlorobenzaldehyde, 4–methoxybenzaldehyde, 4–methylbenzal dehyde, 4–nitrobenzaldehyde pyridine–2–carboxaldehyde and furfural have been explored for this reaction. Effect of presence of Pd–C bond is noticed on the catalytic performance. The palladacyclic complex 1 is more efficient than coordination complex 2 as the Pd-C bond of metallacyclic complex increases the rate of dissociation of Pd-Cl bond and therefore helping in easy participation and increased efficiency of complex 1 in catalysis.

Phenoxy-Amidine Ligands: Toward Lactic Acid-Tolerant Catalysts for Lactide Ring-Opening Polymerization

The replacement of the imine functionality in the ubiquitous phenoxy-imine (FI) ligands by a more robust and donor N,N,N′-trisubstituted amidine function was examined and gave rise to the synthesis of five new phenoxy-amidine (FA) ligands (L1–L5). The solid-state structure of four proligands has been determined by X-ray diffraction analysis and showed that the amidine moiety is in a trans-configuration. The reaction of the phenol-amidine proligands with AlMe3 afforded mononuclear (L1–L5)AlMe2 (1a–5a). A similar alkane elimination route was used from ZnEt2 and led to dinuclear [(L1–L5)ZnEt]2 complexes (1b–5b) or to homoleptic (L2/L4)2Zn complexes (2b′, 4b′) depending on the metal/ligand ratio used. The structure of these complexes has been determined by NMR spectroscopy (1H, 13C, HMBC, HSQC, DOSY, and NOESY experiments) and X-ray diffraction study for seven of them. The crystal structure of the Al complexes showed FA ligands coordinated in a chelate fashion via the O atom of the aryloxy group and the imino-N atom, indicating that the amidine function has undergone trans–cis isomerization upon coordination. A similar chelating coordination mode was observed for the FA ligands with Zn metal ions. These complexes were used as initiators for the ring-opening polymerization of rac-lactide. FA–Zn complexes gave the best performance, affording polylactic acid with a narrow molecular weight distribution and heterotactic bias (Pr up to 0.75). Remarkably, some of these complexes were able to tolerate the presence of a large amount of lactic acid to the point of using it as a co-initiator during the polymerization reaction.