AI for organic and polymer synthesis

Recent years have witnessed the transformative impact from the integration of artificial intelligence with organic and polymer synthesis. This synergy offers innovative and intelligent solutions to a range of classic problems in synthetic chemistry. These exciting advancements include the prediction of molecular property, multi-step retrosynthetic pathway planning, elucidation of the structure-performance relationship of single-step transformation, establishment of the quantitative linkage between polymer structures and their functions, design and optimization of polymerization process, prediction of the structure and sequence of biological macromolecules, as well as automated and intelligent synthesis platforms. Chemists can now explore synthetic chemistry with unprecedented precision and efficiency, creating novel reactions, catalysts, and polymer materials under the datadriven paradigm. Despite these thrilling developments, the field of artificial intelligence(AI) synthetic chemistry is still in its infancy, facing challenges and limitations in terms of data openness, model interpretability, as well as software and hardware support. This review aims to provide an overview of the current progress, key challenges, and future development suggestions in the interdisciplinary field between AI and synthetic chemistry. It is hoped that this overview will offer readers a comprehensive understanding of this emerging field, inspiring and promoting further scientific research and development.

Organoboron chemistry towards controlled and precise polymer synthesis

Organoboron reagents have garnered considerable attention due to their distinct properties. In recent years, boronic acids and boronate esters have been important intermediates for cross-coupling reactions and other functional group construction and are often used to synthesize small organic molecules, drugs, and bioactive substances. In this feature article, we encapsulate the strategy of harnessing the unique properties of organoboron reagents to overcome challenges encountered in conventional polymer synthesis. We delve into the synthesis of boron-containing monomers and polymer materials, unraveling the unique attributes of these newfound polymers while offering innovative insights into their application within recyclable or reprocessable materials. We develop organoboron-based photocatalysts, employing their inner-sphere electron transfer(ISET) mechanisms to initiate controlled radical polymerization. We utilize alkylborane to initiate controlled radical polymerization and further designed B-alkylcatecholboranes to prepare ultra-high molecular weight polymers. Notably, we also propose a liquid-phase synthesis method based on organoboron tags and apply it to the precise synthesis of sequence-controlled conjugated polymers.These advancements open up new frontiers in the realm of polymer science, and the versatility and potential of organoboron reagents in polymer synthesis continue to inspire exciting research endeavors.

Maleimide Chemistry:Enabling the Precision Polymer Synthesis

Herein is presented a compilation of the main characteristics of maleimide chemistry in developing the precisely controlled polymers,including the design of sequence-controlled polymers,topological polymers,and polymeric single-chain nanoparticles.The synthetic methods,relied on the versatilities of the maleimide moieties as a latent monomer which leads to an efficient alternative in various innovative applications,especially in self-healing material,self-reporting materials for real-time monitoring,and also in data storage and anticounterfeiting technologies.The core of the content in this review is focused on the up-to-data advances and publications on the major of maleimide chemistry in our research group.

NOVEL SYNTHESIS OF LONG MULTI-BLOCK HETEROPOLYMER CHAINS WITH AN ORDERED SEQUENCE AND CONTROLLABLE BLOCK LENGTHS

It had very long been a dream in polymer science to synthesize long multi-block polymer chains with an orderedchain sequence and controllable block lengths. Using ionic or living free radical polymerization or furnishing each end ofpolymer blocks with a reactive functional group, one can only prepare heteropolymer chains with few long blocks, such asdiblock and triblock copolymers. The most plausible result so far was a pentablock copolymer. Recently, using a combinationof polymer physics and synthetic chemistry, we have invented self-assembly assisted polycondensation (SAAP). Thiscommunication reports the results of using this novel. method to connect 10-100 triblock polymer chains together to formlong multi-block heteropolymer chains with an ordered sequence and controllable block lengths.

SYNTHESIS AND CHARACTERIZATION OF LIQUID CRYSTAL POLYMERS WITH T-SHAPED TWO-DIMENSIONAL MESOGENIC UNITS (Ⅱ)

A series of liquid crystalline polymers with T-shaped two-dimensional mesogenic unitswere synthesized via low temperature solution polycondensation of 2-(4'-alkoxy-phenyl)hydroquinone with various diacyl dichlorides. The polymers were found to be nematic andshown thermotropic liquid crystalline behaviors through observations using DSC, polarizedmicroscopy and X-ray diffraction. The melting temperature T_m and the isotropizationtemperature T_i of the polymers change regularly with varying of the monomer structures.

Hydrothermal Synthesis, Crystal Structure and Thermal Analyses of Pyrazine-2,3-dicarboxylic Acid Bridged Co(II) Coordination Polymer of _∞~2[Co(phen)(μ-L)_(3/3)]·H_2O (H_2L = Pyrazine-2,3-dicarboxylic Acid)

A novel pyrazine-2,3-dicarboxylic acid bridged Co(II) phen complex 2 ∞ [Co- (phen)(μ-L)3/3]?H2O (H2L = pyrazine-2,3-dicarboxylic acid) has been hydrothermally synthesized, and X-ray single-crystal diffraction analysis shows that it crystallizes in the monoclinic system, space group P21/n with a = 11.480(2), b = 11.885(2), c = 12.939(3) ?, β = 110.55(3)°, V = 1653.1(6) ?3, Mr = 423.25, Dc = 0.425 g/cm3, Z = 4, R = 0.0361 and wR = 0.1011. The title complex consists of 2D 2 ∞ [Co(phen)(μ-L)3/3] layers and crystal water molecules. Each Co atom is octahedrally coordinated by three N atoms and three O atoms to form 2D 2 ∞ [Co(phen)(μ-L)3/3] polymeric layers. Furthermore, such 2D layers are stacked into 3D supramolecular frameworks via Van der Waals’ intermolecular forces, strong and weak hydrogen-bond interactions. The coordination phen and crystal water molecules are resided into cavities of the frameworks.

CONTROLLED ANIONIC SYNTHESIS OF FUNCTIONALIZED AND STAR-BRANCHED POLYMERS

The use of living, alkyllithium-initiated anionic polymerization to prepare chain-end functionalized polymers and heteroarm, star-branched polymers is discussed. The scope and limitations of specific termination reactions with a variety of electrophilic species are illustrated for carbonation, hydroxyethylation, amination, and sulfonation. The methodology of using substituted 1,1-diphenylethylenes to provide a general, quantitative functionalization procedure is outlined and illustrated with examples of amine and phenol end-functionalization. A methodology is described for the synthesis of functionalized, star-branched copolymers with compositionally heterogeneous arms of controlled molecular weight and narrow molecular weight distribution using 1, 3-bis(1-pbenylethenyl) benzene.

Synthesis, Structure and Luminescent Property of a New Zn(Ⅱ) Coordination Polymer Based on 1,3,5-Benzenetricarboxylate and 4,4'-Bipyridine Ligands

A new Zn（II） coordination polymer [Zn3（BTC）2（4,4＇-bpy）（CO）2]n （1, H3BTC = 1,3,5-benzenetricarboxylic acid, 4,4＇-bpy = 4,4＇-bipyridine） has been prepared through urothermal reaction of zinc nitrate hexahydrate with 1,3,5-benzenetricarboxylic acid and 4,4＇-bipyridine, and characterized by elemental analysis, IR spectroscopy, TGA and powder XRD, and its crystal structure was determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in the monoclinic system, space group C2/c, with a = 10.262（3）, b = 18.838（5）, c = 15.083（4）/k, fl = 99.203（4）°, V = 2878.3（14） A3, C30H14Zn3N2O14, Mr= 822.54, Z = 4, Dc = 1.898 g/cm3,μ = 2.561 mm-1,F（000） = 1640, R = 0.0363 and wR = 0.0932 for 2828 observed reflections （I 〉 2σ（I））. X-ray analysis shows that the asymmetric unit of the title compound contains two crystallographically unique Zn（lI） atoms which are connected by BTC3- ligands and 4,4＇-bpy coligands to form a 3D framework with 1D channels. The solid luminescence of ligand and the title complex was also studied at room temperature.

Polymer Supported Synthesis of Multi-substituted Pyrimidine-4-one Derivatives via Pbf-activated Thiourea

Efficient polymer supported synthesis of multi-substituted pyrimidine-4-one derivatives was described. Target products were produced from fluorenylmethoxycarbonyl（Fmoc） protected β-amino acid loaded on hydro- xymethyl resin through deprotection, N-alkylation, guanidine formation, and cleavage of 2,2,4,6,7-pentamethyl dihy-drobenzofuran-sulfonyl（Pbf） by trifluoracetic acid（TFA） followed with cyclization. The procedure has the advantages of easy operation, mild reaction conditions, and forming multiple substituents.

Synthesis and Crystal Structure of a New Zinc(Ⅱ)Coordination Polymer Assembled by 4-Nitrophthalic Acid and Bis(imidazol)Ligands

A new complex [Zn（4-nph）（bib）]（2n）·nH2O（1） has been obtained by the reaction of metal（Zn（Ⅱ））,1,4-bis（imidazol-1-yl）-butane（bib） with 4-nitrophthalic acid（4-H（2nph））.The crystal structure of 1 has been determined by single-crystal X-ray diffraction analysis.Compound 1 is of triclinic system,space group P1 with a = 10.3251,b = 12.4503,c = 16.6497 A,α = 88.487（3）,β = 72.529（3）,γ = 79.991（3）°,V = 2009.8（5）A^3 and Mr = 945.47.Complex 1 shows a three-dimensional（3 D） framework.Moreover,through intermolecular hydrogen bonds,compound 1 is assembled into a supramolecular structure.The thermal stability and luminescent properties of 1 are also investigated.

Solvothermal Synthesis,Crystal Structure and Photoluminescence Property of a 3D Lead(Ⅱ)Coordination Polymer Based on Terephthalic Acid

Solvothermal reaction of Pb（NO3）2·6H2O with rigid linear ligand terephthalic acid（H2pta） in N,N-dimethylformamide（DMF） produced a new three-dimensional（3D） lead（Ⅱ）coordination polymer[Pb2（pta）1.5（μ4-OH）（DMF）]n 1,and its structure was characterized by single-crystal X-ray diffraction analyses.In polymer 1,the μ4-OH bridges the nearby lead（Ⅱ） ions into an infinite one-dimensional（1D） chain,and then the organic ligand pta^2- joins the neighbored chains into a 3D structure by two similar connection modes in different configurations.The solid-state photoluminescent studies revealed that 1 exhibits a strong greenish emission mainly originating from ligand-to-metal charge transfer between the delocalized π bonds of the aromatic carboxylate ligand pta^2- and the p orbitals of the Pb^2＋ centers.

Synthesis and Crystal Structure of an Adipate-bridged Dinuclear Cadmium(Ⅱ)Polymer with 2-Methylpyrazino[2,3-f][1,10]-phenanthroline(mpphen)Terminal Ligands

A metal-organic coordination polymer, [Cd（C15H10N4）（C6H8O4）]2n （1, C15H10N4： 2-methyl-pyrazino-[2,3-f][1,10]-phenanthroline （mpphen）, C6H8O4： adipate）, was synthesized via hydrothermal synthesis. The polymer was characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. X-ray diffraction shows that 1 is a cadmium polymer constructed by adipate-bridged dmuclear clusters, and each adipate connects two clusters to form a two-dimen- sional planar structure. Crystal data for 1： monoclinic, space group C2/c, a = 22.403（9）, b = 16.039（6）, c = 13.808（6） A, β= 125.262（6）°, V = 4051（3） A3, Mr = 502.79, Dc = 1.649 g/eraa, μ（MoKa） = 1.114 mm^-1, F（000） = 2016, Z = 8, the final R = 0.0509 and wR = 0.1054 for 1509 observed reflections （I 〉 2σ（I））.

THE SYNTHESIS AND CHARACTERIZATION OF Ba-CROSSLINKED POLYMER ANTI-RADIATION MATERIALS

Crosslinked poly(methyl methacrylate) and polystyrene with barium dimethacrylate [Ba(MA)_2] as crosslinking agent have been synthesized. The relationship between X-ray absorbability and the content of Ba(MA)_2 in polymers was investigated. TGA and DSC results indicated that the crosslinked polymers containing barium dimethacrylate have a much better heat stability than pure PMMA or PS. The mechanical properties of the polymers containing barium are improved in comparison with the pure PMMA.

SYNTHESIS AND CRYSTAL STRUCTURE OF A ONE-DIMENSIONAL POLYMERIC CLUSTER[Mo(μ-S)_2Ag(μ-S)_2·α-MePyH]_n

Reaction of (NH_4)_2MoS_4 with AgI in α-MePy gives the title com- pound,an X-ray analysis of which shows that the molecule forms a one-dimensional polymeric chain with continuous metal-metal bonds.

STUDY ON AB-CROSSLINKED POLYMERS Ⅰ. THE SYNTHESIS AND MECHANICAL PROPERTIES OF AB-CROSSLINKED POLYMERS BASED. ON PU/PS

The AB-crosslinked polymers (i.e. ABCP) with polystyrene as chain A and vinyl group blocked prepolymers of polyurethanes (PU) as chain B were synthesized and studied. The results of dynamic mechanical spectrometry (DMS) show that the compatibility between the components A and B can be improved greatly through chemical crosslinking during the formation of ABCPs. This effect is especially pronounced when short chain prepolymers is chosen as one of the components. It is apparent that the degree of crosslinking between the two components plays a major role in determining their compatibility. Copolymerizafion of styrene with maleic anhydride in chain A can improve the compatibility and broaden the damping temperature range. Mechanical properties of the sythesized ABCPs were also studied.

CATALYTIC ACTIVITIES OF RARE-EARTH CALIXARENE COMPLEXES IN POLYMER SYNTHESES

The studies of our group on the catalytic activities of rare earth calixarene complexes in polymer syntheses are reviewed. Rare earth calixarene complexes are effect catalysts for the polymerizations of butadiene, isoprene, ethylene, styrene, propylene oxide, styrene oxide, trimethylene carbonate and 2,2-dimethyl-trimethylene carbonate.

A Cd(Ⅱ)Coordination Polymer with cds Topology Constructed by Polycarboxylate and Imidazole-containing Ligand

A new Cd（Ⅱ） coordination polymer,{[Cd（pda）（bimb）]·（H2O）（0.5）}n（1,H2pda=1,3-phenylenediacetic acid,bimb = 4,4-bis（1-imidazolyl）biphenyl）,has been synthesized and characterized by elemental analysis,IR spectroscopy,powder X-ray diffraction（PXRD） analyses and single-crystal X-ray diffraction techniques. Complex 1 shows a 4-connected two-fold interpenetrated three-dimensional（3-D） cds topology. In additional,photoluminescent properties of 1 and its dehydrated product have also been studied.

A New Cd(Ⅱ)Coordination Compound Based on 4-(1,2,4-Triazol-4-yl)phenylacetic Acid:Synthesis,Structure and Photoluminescence Property

A new complex [Cd2（L）2（Cl）2（H2O）]n（1） was synthesized by reacting CdCl2·2.5 H2O with 4-（1,2,4-triazol-4-yl）phenylacetic acid（HL） ligand.The structure of the complex was characterized by single-crystal X-ray diffraction,IR spectroscopy,elemental analysis and PXRD.Complex 1 crystallizes in triclinic,space group P21/c with a = 11.4303（8）,b = 14.1792（10）,c = 14.6857（10） ？,β = 96.3780（10）o,V = 2365.4（3） A^3,Z = 4,C（20）H（16）Cl2N6O5Cd2,Mr = 716.09,Dc = 2.011 g/cm3,μ = 2.069 mm^-1,S = 1.051,F（000） = 1392,the final R = 0.0458 and wR = 0.0949 for 5402 observed reflections（I 〉 2σ（I））.Complex 1 is a two-dimensional（2D） layer structure and non-covalent bonding interactions such as C–H···π and π···π extend the 2D to form a three-dimensional supramolecular polymer.

Two Three-dimensional Supramolecular Polymer Built from Mixed N-Donor and Carboxylate Ligands

Two new complexes, [Mn（L）（mmbda）（H_2O）]（1） and [Co（L）（btc）（H_2O）]·H_2O（2）, were synthesized by reacting the corresponding metal（Ⅱ） salts with rigid ligand 1,4-di（1Himidazol-4-yl）benzene（L） and two different carboxylic acids of 5-methylisophthalic acid（H_2mmbda） and 1,2,4-benzenetricarboxylic acid（H_3btc）, respectively. The structures of the complexes were characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in triclinic, space group P1 with a = 6.9436（4）, b = 9.7306（6）, c = 15.5302（10） ？, α = 73.7430（10）, β = 85.1010（10）, γ = 70.0360（10）o, V = 946.75（10） ？~3, Z = 2, C_（21）H_（20）N_4O_5 Mn, M_r = 463.33, D_c = 1.618 g/cm^3, μ = 0.742-1, S = 1.002, F（000） = 474, the final R = 0.0285 and wR = 0.0600 for 4328 observed reflections（I 〉 2σ（I））. Complex 2 crystallizes in monoclinic, space group P2_1/n with a = 12.5216（12）, b = 7.3312（8）, c = 22.510（2） ？, β = 93.104（2）o, V = 2063.3（4） ？~3, Z = 4, C_（21）H_（18）N_4O_8Co, M_r = 513.31, D_c = 1.646 g/cm^3, μ = 0.892^（-1） mm, S = 1.096, F（000） = 1044, the final R = 0.0673 and wR = 0.1780 for 3594 observed reflections（I 〉 2σ（I））. Both of complexes are one-dimensional（1D） chain structures and rich hydrogen bonds extend such 1D chains to form three-dimensional（3D） supramolecular polymers.