Organometallics最新文献

{"title":"Macrocyclic Ruthenium Ring Expansion Metathesis Polymerization Initiators Exhibit Tether Length-Dependent Behavior","authors":"Meredith N. Pomfret,&nbsp;, ,&nbsp;Lucy P. Miller,&nbsp;, ,&nbsp;Nicholas P. Serck,&nbsp;, ,&nbsp;Ángel Rentería-Gómez,&nbsp;, ,&nbsp;Bob Li,&nbsp;, ,&nbsp;Sarah M. Zeitler,&nbsp;, ,&nbsp;Sebastian M. Krajewski,&nbsp;, ,&nbsp;Werner Kaminsky,&nbsp;, ,&nbsp;Rajan Paranji,&nbsp;, ,&nbsp;Osvaldo Gutierrez*,&nbsp;, and ,&nbsp;Matthew R. Golder*,&nbsp;","doi":"10.1021/acs.organomet.5c00226","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00226","url":null,"abstract":"<p >Polymers with a cyclic architecture are invaluable constructs for a variety of materials science and engineering applications. Due to their macrocyclic nature, these plastics are imbued with enhanced mechanical durability; a single scission event along the backbone keeps the polymer intact, and the molar mass remains unchanged. Hence, polymer topology can be envisioned as a strategy to prolong the useful lifetime of a material before failure. With a growing interest in synthesizing such cyclic polymers using ring-expansion metathesis polymerization (REMP), there remains an unmet need to further understand the structure–activity relationships of the requisite organometallic initiators. While analogous Ru-based initiators for ring-opening metathesis polymerization (ROMP) have been widely studied, this same focus has not been applied to REMP. Herein, we report the synthesis and activity of <b>CBX</b> cyclic Ru-benzylidene initiators (<i>X</i> = number of carbon atoms in the tether, 4–6). Through mechanistic studies, we note a marked difference in REMP molar mass control that is reinforced via analyses using solid-state X-ray crystallography and DFT calculations. Overall, these studies provide insight into the relationship between the <b>CBX</b> tether length and its propensity for productive secondary metathesis, a key mechanistic facet for modulating cyclic polymer molar mass.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 18","pages":"2083–2091"},"PeriodicalIF":2.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Pd–Phosphine Ligands Suitable for Suzuki–Miyaura Polymerization through Intramolecular Catalyst Transfer","authors":"Ryusuke Shimada,&nbsp;, ,&nbsp;Natsuhiro Sano,&nbsp;, ,&nbsp;Yoshihiro Ohta,&nbsp;, and ,&nbsp;Tsutomu Yokozawa*,&nbsp;","doi":"10.1021/acs.organomet.5c00191","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00191","url":null,"abstract":"<p >The suitability of four Pd–phosphine ligands, di(<i>tert</i>-butyl)-4-methoxyphenylphosphine (^<i>t</i>Bu₂PC₆H₄OMe), di(<i>tert</i>-butyl)-3,4,5-trimethoxyphenylphosphine (^<i>t</i>Bu₂PC₆H₂(OMe)₃), di(1-adamantyl)-4-methoxyphenylphosphine (Ad₂PC₆H₄OMe), and di(1-adamantyl)-4-dimethylaminophenylphosphine (Ad₂PC₆H₄NMe₂), for Suzuki–Miyaura nonstoichiometric polycondensation and catalyst-transfer condensation polymerization (CTCP) was investigated. These four phosphine ligands were synthesized by the reaction of the corresponding phenyl lithium with di(<i>tert</i>-butyl)chlorophosphine or di(1-adamantyl)chlorophosphine. To avoid oxidation, we quickly converted the as-obtained phosphines into the corresponding tetrafluoroboric acid salts and purified them by recrystallization. We first conducted a Suzuki–Miyaura coupling reaction of 2.0 equiv of phenylene dibromide <b>1</b> with 1.0 equiv of pinacol phenylboronate in the presence of Pd(OAc)₂/synthesized ligands and CsF/18-crown-6 as a base at room temperature. The use of Ad₂PC₆H₄OMe and Ad₂PC₆H₄NMe₂ resulted in the exclusive formation of the disubstituted products. Accordingly, nonstoichiometric Suzuki–Miyaura polycondensation of 1.3 equiv of <b>1</b> with 1.0 equiv of phenylenediboronate was conducted in the presence of Pd(OAc)₂/Ad₂PC₆H₄OMe or Ad₂PC₆H₄NMe₂. High-molecular-weight poly(<i>p</i>-phenylene) was obtained with Ad₂PC₆H₄OMe, whereas the molecular weight was low when Ad₂PC₆H₄NMe₂ was used. We next investigated CTCP of fluorene AB monomer <b>5</b> with a Pd–Ad₂PC₆H₄NMe₂ initiator. The polymerization of <b>5</b> yielded a high-molecular-weight polymer with a narrow dispersity. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra showed peaks due to the polymer containing the initiator unit, indicating that the polymerization proceeded through the CTCP mechanism.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 18","pages":"2065–2073"},"PeriodicalIF":2.9,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metathesis or Isomerization: Counteranion Directed Reactivity of Grubbs I","authors":"Paul D. Miller,&nbsp;, ,&nbsp;Joe B. Calkins,&nbsp;, ,&nbsp;Craig A. Bayse,&nbsp;, and ,&nbsp;Trandon A. Bender*,&nbsp;","doi":"10.1021/acs.organomet.5c00147","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00147","url":null,"abstract":"<p >Catalytic isomerization of alkenes has garnered interest for many years, but there are remaining challenges when it comes to thermodynamic selectivity and uncontrolled isomerization. Nonbiased substrates, be it sterically or thermodynamically, remain challenging for many catalysts, with a few examples available in the more modern literature. Herein, we present the controlled isomerization of linear alkenes with a cocatalytic mixture of commercially available catalyst and reagents: Grubbs I, tris(pentafluorophenyl)borane, and triethylsilane. DFT calculations indicate that an observed alkylidyne hydride intermediate is in rapid equilibrium with an alkylidene that binds the alkene substrate. This combination results in a π-acidic metal and a hydridic H–B(C₆F₅)₃^– counteranion to provide the controlled monoisomerization of aliphatic alkenes.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 18","pages":"2016–2024"},"PeriodicalIF":2.9,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acs.organomet.5c00147","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unsymmetrical Phosphinoquinoline Iron(II) Complexes with Enhanced Thermal Stability and High Activity for Isoprene Polymerization","authors":"Shengli Jin,&nbsp;, ,&nbsp;Long Liu,&nbsp;, and ,&nbsp;Fei Lin*,&nbsp;","doi":"10.1021/acs.organomet.5c00157","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00157","url":null,"abstract":"<p >Polyisoprene is the most important composition of natural rubber. The green catalytic polymerization of isoprene by earth-abundant metal iron is a promising next-generation manufacturing process in the rubber industry. We now show that a series of unsymmetrical phosphinoquinoline Fe(II) precatalysts can efficiently catalyze isoprene polymerization, producing polyisoprene elastomers with controlled microstructures. The structures of these designed Fe(II) complexes were well-defined by NMR spectra and X-ray single crystal diffraction analysis. Activation with only 5 equiv of dMAO (dry methylaluminoxane) enabled the phosphinoquinoline Fe(II) complexes to catalyze isoprene polymerization with remarkable activity (up to 3431 kg_PI·mol_Fe^–1·h^–1), yielding polyisoprene with a predominantly <i>cis</i>-1,4/3,4 mixed microstructure (ca. 1:1 ratio). The bidentate <i>N,P</i>-ligands, containing strongly coordinating phosphorus atoms, effectively stabilized the iron active centers, offering high monomer conversion and polyisoprene with high molecular weight at approximately 10⁵ Da across a broad temperature range (−10 to 100 °C). Control over polymerization activity and polyisoprene microstructure was achieved by modifying the ligand structures. Aryl-substituted catalysts exhibited high activity (409 kg_PI·mol_Fe^–1·h^–1) and excellent <i>cis</i>-1,4 stereoselectivity (<i>cis</i>-1,4/<i>trans</i>-1,4 &gt; 97:1), highlighting the synergistic effects of ligand electronic and steric properties on catalytic performance and the isoprene coordination–insertion polymerization mechanism.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 18","pages":"2025–2034"},"PeriodicalIF":2.9,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reductive α-Methylation of α,β-Unsaturated Ketones Catalyzed by a Mn(I) PCNHCP Pincer Complex with Methanol as Both H2 and C1–Source","authors":"Kartick Dey,&nbsp;, ,&nbsp;Rohit Kamte,&nbsp;, and ,&nbsp;Graham de Ruiter*,&nbsp;","doi":"10.1021/acs.organomet.5c00183","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00183","url":null,"abstract":"<p >With a growing demand for sustainable and environmentally friendly chemistry, there is an increasing interest in using earth-abundant metals in catalysis, especially when it can be utilized in atom-economical reactions. Here we present such an atom-economical reaction and describe the selective reductive α-methylation of α,β-unsaturated ketones with methanol as both the hydrogen and the C₁-source. The reaction is catalyzed by our previously reported earth-abundant metal catalyst [(PC_NHCP)Mn(CO)₂H] (<b>1</b>) and is compatible with a variety of functional groups that include –halide, –trifluoromethyl, –alkene, –alkyne, –ester, –amide, as well as the heterocycles. Based on literature precedent and our own mechanistic investigations, a plausible mechanism for the reductive α-methylation of α, β-unsaturated ketones is presented, which is further discussed in this report.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 18","pages":"2035–2041"},"PeriodicalIF":2.9,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selenoxanthylium Salts Synthesized from Selenoethers and Their Electronic Structures","authors":"Noriyoshi Nagahora*,&nbsp;Akira Yasuda,&nbsp;Minami Yamasaki and Mana Hotta,&nbsp;","doi":"10.1021/acs.organomet.5c00228","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00228","url":null,"abstract":"<p >A Lewis/Brønsted acid-promoted intramolecular cyclization of diarylselenoethers bearing formyl groups afforded novel selenoxanthylium salts in good yield. The electronic structures of these selenoxanthylium salts were determined using NMR and UV–vis absorption spectroscopy techniques as well as DFT calculations. The obtained results clearly imply effective conjugation of the π-electrons throughout the entire fused selenium-containing heterocyclic framework.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 17","pages":"1876–1880"},"PeriodicalIF":2.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reactivity of Cyclopropenylaluminates","authors":"Marco F. Starostzik,&nbsp;Jakub Kenar,&nbsp;Han-Ying Liu,&nbsp;Mary F. Mahon and Michael S. Hill*,&nbsp;","doi":"10.1021/acs.organomet.5c00272","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00272","url":null,"abstract":"<p >Reactions of the potassium cyclopropenylaluminates, [{SiN^Dipp}Al-η²-(C₂Ph₂)K] and [{SiN^Dipp}Al-η²-(PhC═CSiMe₃)K] with terminal alkynes provide alkynylvinylaluminate derivatives with the silyl-substituted analog providing a level of kinetic discrimination. While this latter behavior results in the regiochemical protonation at Al–C(Ph) and retention of the more sterically congested Al–C(SiMe₃) bond, reactions with CO₂ and phenyl-substituted ketones are complicated by a reduced level of discrimination and a likely tendency toward multiple C═O insertion or loss of coordinated alkyne. This latter process results in reactivity more reminiscent of the Al(I) compounds used to synthesize the cyclopropenylaluminate starting materials. Similar observations are provided by reactions with organic azides and trimethylsilyldiazomethane, which proceed with terminal nitrogen insertion and the generation of azacyclobutenylaluminate structures for [{SiN^Dipp}Al-η²-(C₂Ph₂)K], but with evidence of greater degrees of competitive alkyne elimination from [{SiN^Dipp}Al-η²-(PhC═CSiMe₃)K].</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 17","pages":"1987–1997"},"PeriodicalIF":2.9,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acs.organomet.5c00272","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbodiimide Ring-Opening Metathesis Polymerization and Depolymerization Using Terminal Iridium Imido Initiators","authors":"Samuel W. Kaplan,&nbsp;Matthew C. Satkowiak and Aleksandr V. Zhukhovitskiy*,&nbsp;","doi":"10.1021/acs.organomet.5c00220","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00220","url":null,"abstract":"<p >Carbodiimide ring-opening polymerization (CDI-ROMP) enables chain growth of main-chain poly(CDI)s, which in principle could allow for control over the molecular weight, dispersity, and architecture of these polymers and their derivatives. However, thus far, chain transfer has limited this control. Herein, we describe the use of terminal iridium imido initiators, which reduce chain transfer in CDI-ROMP and improve the polymerization control: dispersities of ∼ 1.3 were achieved at complete monomer consumption, with even lower dispersities (1.1–1.2) at conversions below 85%, and the previously observed undershooting of theoretical molecular weight was avoided. Furthermore, we show that these initiators also enable depolymerization of poly(CDI)s to monomer with conversions of 50–60% under mild reaction conditions.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 17","pages":"1945–1950"},"PeriodicalIF":2.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flash Communication: Crystalline Boron-Centered Radical Cation Stabilized by Diphosphine-Substituted closo-Hexaborate","authors":"Penglong Wang,&nbsp; and ,&nbsp;Rei Kinjo*,&nbsp;","doi":"10.1021/acs.organomet.5c00247","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00247","url":null,"abstract":"<p >By the reduction reaction, a boron-center radical cation (<b>2</b>) stabilized by a diphosphine-substituted <i>closo</i>-hexaborate cluster has been synthesized and fully characterized. Single-crystal X-ray diffraction, electron paramagnetic resonance (EPR) spectroscopy, and density functional theory (DFT) calculations reveal that the unpaired electron in <b>2</b> predominantly resides on the tricoordinate boron center with the high spin density of 0.767.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 17","pages":"1884–1887"},"PeriodicalIF":2.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nucleophilic Substitution vs Ring Opening – Dual Reactivity of Benzo[b]phosphol-3-yl Triflates toward Alkyl Grignard Reagents","authors":"Adrianna Maciąg,&nbsp;Łukasz Ponikiewski,&nbsp;Paweł Kubica and Sylwia Sowa*,&nbsp;","doi":"10.1021/acs.organomet.5c00193","DOIUrl":"https://doi.org/10.1021/acs.organomet.5c00193","url":null,"abstract":"<p >A new method for the synthesis of 3-alkylbenzo[<i>b</i>]phosphole oxides involving nucleophilic substitution through an addition–elimination mechanism has been developed. The reaction proceeds without a metal catalyst and yields a library of previously unavailable 3-alkylbenzo[<i>b</i>]phosphole oxides in yields of up to 90%. This method enables regioselective functionalization at position 3 in the benzophosphole ring, providing the possibility for independent functionalization at both the 3-position and 4–7 positions (benzoring). A competitive ring-opening process that yields 2-ethynylphenyl(alkyl)phosphine oxides and subsequent processes that lead to cyclic side products were also investigated. Mechanistic proposals for all of these processes are presented.</p>","PeriodicalId":56,"journal":{"name":"Organometallics","volume":"44 17","pages":"1906–1919"},"PeriodicalIF":2.9,"publicationDate":"2025-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acs.organomet.5c00193","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}