Appropriately designed catalysts help to minimise the energy required to convert the energy-poor feedstock H2O into energy-rich molecular H2. Herein, two families of pyridazine-based cryptates, mononuclear [MIILi](BF4)2 and mixed metal dinuclear [MIICuILi](BF4)3 (M = Fe, Co, Cu or Zn; Li is the Schiff base cryptand made by 2:3 condensation of tris(2-aminoethyl)amine and 3,6-diformylpyridazine), are investigated as potential electrocatalysts for the hydrogen evolution reaction (HER) in MeCN with acetic acid as the proton source. The synthesis and structures of a new mixed metal cryptate, [ZnIICuILi](BF4)3, and the tetrafluoroborate analogue of the previously reported perchlorate salt of the mono-zinc cryptate, [ZnIILi](BF4)2·0.5H2O, are reported. Electrocatalytic HER testing showed that a deposit forms on the glassy carbon working electrode during electrolysis and it is the active species responsible for the very modest activity observed. The deposits formed by the heterobinuclear cryptates had higher activities (2.0 < TON2hr < 3.5) than the deposits formed by the mononuclear cryptates (TON2hr < 0.75). But unfortunately the control, using CuI(MeCN)4BF4, had a similar TON2hr (2.3) to those seen for the heterobinculear cryptates, which indicates that it is the deposit formed by the CuI cation present in the heterobinuclear cryptates that is likely responsible for the observed, very modest, HER activity.
{"title":"Testing mixed metal bimetallic, and monometallic, cryptates for electrocatalytic hydrogen evolution","authors":"Varinder Singh, Matthew G. Robb, Sally Brooker","doi":"10.1039/d4dt03161j","DOIUrl":"https://doi.org/10.1039/d4dt03161j","url":null,"abstract":"Appropriately designed catalysts help to minimise the energy required to convert the energy-poor feedstock H2O into energy-rich molecular H2. Herein, two families of pyridazine-based cryptates, mononuclear [MIILi](BF4)2 and mixed metal dinuclear [MIICuILi](BF4)3 (M = Fe, Co, Cu or Zn; Li is the Schiff base cryptand made by 2:3 condensation of tris(2-aminoethyl)amine and 3,6-diformylpyridazine), are investigated as potential electrocatalysts for the hydrogen evolution reaction (HER) in MeCN with acetic acid as the proton source. The synthesis and structures of a new mixed metal cryptate, [ZnIICuILi](BF4)3, and the tetrafluoroborate analogue of the previously reported perchlorate salt of the mono-zinc cryptate, [ZnIILi](BF4)2·0.5H2O, are reported. Electrocatalytic HER testing showed that a deposit forms on the glassy carbon working electrode during electrolysis and it is the active species responsible for the very modest activity observed. The deposits formed by the heterobinuclear cryptates had higher activities (2.0 < TON2hr < 3.5) than the deposits formed by the mononuclear cryptates (TON2hr < 0.75). But unfortunately the control, using CuI(MeCN)4BF4, had a similar TON2hr (2.3) to those seen for the heterobinculear cryptates, which indicates that it is the deposit formed by the CuI cation present in the heterobinuclear cryptates that is likely responsible for the observed, very modest, HER activity.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"23 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937125","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}
Shixiong Zhang, Yajun Ji, Pengcheng Zhang, shulei wang, bin Zhang, Peng Zhou
Recently, photo-assisted electrocatalysis as an emerging catalytic approach that combines the technologies of photocatalysis and electrocatalysis attracted great interests among researchers. Under this circumstance, the NiFe-LDH compounded with PbS based (PbS@NFHS) heterojunction with both photoactive and electrocatalytic properties was first time constructed through an ambient etching route and subsequent low-temperature hydrothermal method. The as-prepared catalyst displayed a novel hierarchical 3D open structure based on nanosheets, which offered numerous electrochemically active sites, facilitated the swift diffusion of ions and enhanced both electrical conductivity and catalytic stability, thus significantly improving the catalytic performance. Furthermore, the charge redistribution in the p-n junction leaded to the formation of space-charge regions and a built-in electric field, which benefited the charge transfer and thereby enhanced the intrinsic activity. Under illumination, electrochemical tests exhibited that the overpotential was only 291 mV for OER at 50 mA cm-2 in 1 M KOH solution, which was 50 mV lower than that without illumination. Moreover, the catalyst can maintain stability for 40 hours at a current of 10 mA cm-2 in 1 M KOH. Compared to traditional electrocatalytic OER, this work employed a very promising photo-assisted electrocatalytic strategy, which could further broaden the wide application of NiFe-LDH.
{"title":"PbS@NiFe-LDH Heterojunction: An Efficient Photo-Assisted Electrocatalyst for OER","authors":"Shixiong Zhang, Yajun Ji, Pengcheng Zhang, shulei wang, bin Zhang, Peng Zhou","doi":"10.1039/d4dt03007a","DOIUrl":"https://doi.org/10.1039/d4dt03007a","url":null,"abstract":"Recently, photo-assisted electrocatalysis as an emerging catalytic approach that combines the technologies of photocatalysis and electrocatalysis attracted great interests among researchers. Under this circumstance, the NiFe-LDH compounded with PbS based (PbS@NFHS) heterojunction with both photoactive and electrocatalytic properties was first time constructed through an ambient etching route and subsequent low-temperature hydrothermal method. The as-prepared catalyst displayed a novel hierarchical 3D open structure based on nanosheets, which offered numerous electrochemically active sites, facilitated the swift diffusion of ions and enhanced both electrical conductivity and catalytic stability, thus significantly improving the catalytic performance. Furthermore, the charge redistribution in the p-n junction leaded to the formation of space-charge regions and a built-in electric field, which benefited the charge transfer and thereby enhanced the intrinsic activity. Under illumination, electrochemical tests exhibited that the overpotential was only 291 mV for OER at 50 mA cm-2 in 1 M KOH solution, which was 50 mV lower than that without illumination. Moreover, the catalyst can maintain stability for 40 hours at a current of 10 mA cm-2 in 1 M KOH. Compared to traditional electrocatalytic OER, this work employed a very promising photo-assisted electrocatalytic strategy, which could further broaden the wide application of NiFe-LDH.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"82 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937127","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}
substituents are explored to study their reactivities for an organic transformation in water medium. The ligand backbone of Mo1 and Mo2 are covalently connected to a methyl group and one unit of hydrophobic n-hexadecyl chain, via ether linkage, respectively. The complex Mo3 possesses two units of n-hexadecyl chains connected to the ligand backbone via a secondary amine-N. The complexes Mo2 and Mo3 formed metallomicelle when dispersed in water due to the presence of surfacant in their structures making them capable to uptake organic substrates. The catalytic potential of the complexes was evaluated for the oxidative coupling of benzylamine with 1,2-diaminobenzene to synthesize benzimidazole in neat water using open air as the sole oxidant. The double-chain surfactant-type catalyst Mo3 displayed superior activity compared to the single-chain surfactant type complex, Mo2. A wide variety of benzimidazoles were synthesized in good to excellent yields under environmentally benign conditions using Mo3 as catalyst. The practical utility of the process was validated through multi-gram scale-up reactions and recyclability experiments. A plausible mechanism is proposed based on a few controlled experiments and literature support.
{"title":"A Double Chain Based Metallomicellar Catalyst for Aerobic Oxidative Synthesis of Benzimidazoles in Water","authors":"Pragyansmruti Sunani, Prabaharan Thiruvengetam, Dillip Kumar Chand","doi":"10.1039/d4dt03406f","DOIUrl":"https://doi.org/10.1039/d4dt03406f","url":null,"abstract":"substituents are explored to study their reactivities for an organic transformation in water medium. The ligand backbone of Mo1 and Mo2 are covalently connected to a methyl group and one unit of hydrophobic n-hexadecyl chain, via ether linkage, respectively. The complex Mo3 possesses two units of n-hexadecyl chains connected to the ligand backbone via a secondary amine-N. The complexes Mo2 and Mo3 formed metallomicelle when dispersed in water due to the presence of surfacant in their structures making them capable to uptake organic substrates. The catalytic potential of the complexes was evaluated for the oxidative coupling of benzylamine with 1,2-diaminobenzene to synthesize benzimidazole in neat water using open air as the sole oxidant. The double-chain surfactant-type catalyst Mo3 displayed superior activity compared to the single-chain surfactant type complex, Mo2. A wide variety of benzimidazoles were synthesized in good to excellent yields under environmentally benign conditions using Mo3 as catalyst. The practical utility of the process was validated through multi-gram scale-up reactions and recyclability experiments. A plausible mechanism is proposed based on a few controlled experiments and literature support.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"20 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937124","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}
BiVO4 is considered as one of the important candidate materials for photoelectrochemical water splitting technology. However, the low efficiency of charge separation and poor kinetics of water oxidation limit its performance in the PEC water splitting. In this work, BiVO4/MIL-53(FeNiCo) photoanode was constructed by a facile hydrothermal deposition method, exhibiting excellent water oxidation ability under AM 1.5 G light irradiation, and achieving a photocurrent density of 3.53 mA cm-2 at 1.23 VRHE, which is about 3.2 times that of pure BiVO4. The electrochemical test results demonstrate that the decoration of MIL-53(FeNiCo) could enhance the charge transfer and accelerate the kinetics of water oxidation reaction, thus leading to the excellent PEC water splitting performance. The PEC stability is also significantly improved, indicating that MIL-53(FeNiCo) allows BiVO4 to be used for water oxidation for stable PEC water oxidation.
{"title":"MIL-53(FeNiCo) decorated BiVO4 photoanode for efficient photoelectrochemical water oxidation","authors":"Leiting Si, Jiawei Yang, Guang Liu","doi":"10.1039/d4dt03089c","DOIUrl":"https://doi.org/10.1039/d4dt03089c","url":null,"abstract":"BiVO4 is considered as one of the important candidate materials for photoelectrochemical water splitting technology. However, the low efficiency of charge separation and poor kinetics of water oxidation limit its performance in the PEC water splitting. In this work, BiVO4/MIL-53(FeNiCo) photoanode was constructed by a facile hydrothermal deposition method, exhibiting excellent water oxidation ability under AM 1.5 G light irradiation, and achieving a photocurrent density of 3.53 mA cm-2 at 1.23 VRHE, which is about 3.2 times that of pure BiVO4. The electrochemical test results demonstrate that the decoration of MIL-53(FeNiCo) could enhance the charge transfer and accelerate the kinetics of water oxidation reaction, thus leading to the excellent PEC water splitting performance. The PEC stability is also significantly improved, indicating that MIL-53(FeNiCo) allows BiVO4 to be used for water oxidation for stable PEC water oxidation.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"56 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937128","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}
Hydrogen is a zero-emissive fuel and has immense potential to replace carbon-emitting fuels in the future. The need for the development of efficient H2 sensors are essential for preventing hazardous situations and facilitating its widespread usage. Chemiresistors are popular gas sensors owing to their attractive properties such as fast response, miniaturization, simple integration with electronics and low cost. Traditionally, semiconducting metal oxides (SMOs) and Pd-based materials have been widely investigated for chemiresistive H2 sensing applications. However, issues such as limited selectivity and poor reliability still hinder their use in real-time applications. Recent advancements have explored Metal-Organic Frameworks (MOFs) and Covalent-Organic Frameworks (COFs), offering new perspectives and potential applications in this field. MOFs and COFs belong to crystalline frameworks (CFs), are highly porous, designable materials with tunable pore surfaces with featuring sites for H2 interaction. They exhibit good selectivity with quick response/recovery times towards H2 at relatively low temperatures compared to SMOs. Further, they endeavor additional advantage of sensing H2 in the absence of oxygen and even at high concentrations of H2. In this perspective article, we summarize the recent advancements and challenges in the development of H2 sensors employing MOFs, COFs, and their hybrid composites as sensing elements. Additionally, we have discussed our perspective on hybridizing MOFs/COFs with SMOs and other nanomaterials for the future development of advanced H2 sensors.
{"title":"Advancements in porous framework materials for chemiresistive hydrogen sensing: Exploring MOFs and COFs","authors":"Nany Thokala, Marilyn Esclance DMello, Krishnaveni Valle, Kiran Vankayala, Suresh Babu Kalidindi","doi":"10.1039/d4dt02551b","DOIUrl":"https://doi.org/10.1039/d4dt02551b","url":null,"abstract":"Hydrogen is a zero-emissive fuel and has immense potential to replace carbon-emitting fuels in the future. The need for the development of efficient H2 sensors are essential for preventing hazardous situations and facilitating its widespread usage. Chemiresistors are popular gas sensors owing to their attractive properties such as fast response, miniaturization, simple integration with electronics and low cost. Traditionally, semiconducting metal oxides (SMOs) and Pd-based materials have been widely investigated for chemiresistive H2 sensing applications. However, issues such as limited selectivity and poor reliability still hinder their use in real-time applications. Recent advancements have explored Metal-Organic Frameworks (MOFs) and Covalent-Organic Frameworks (COFs), offering new perspectives and potential applications in this field. MOFs and COFs belong to crystalline frameworks (CFs), are highly porous, designable materials with tunable pore surfaces with featuring sites for H2 interaction. They exhibit good selectivity with quick response/recovery times towards H2 at relatively low temperatures compared to SMOs. Further, they endeavor additional advantage of sensing H2 in the absence of oxygen and even at high concentrations of H2. In this perspective article, we summarize the recent advancements and challenges in the development of H2 sensors employing MOFs, COFs, and their hybrid composites as sensing elements. Additionally, we have discussed our perspective on hybridizing MOFs/COFs with SMOs and other nanomaterials for the future development of advanced H2 sensors.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"101 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936588","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}
Amir Sohel Bulbul, Jhansi Mogilipuri, Venugopal Rao Soma, Muniappan Sankar
Meso-β, β-β’ trifused porphyrins incorporating two distinct active methylene groups (MN = malononitrile and IND = 1,3-indanedione) and their corresponding metal complexes with Cu(II) and Zn(II) have been synthesised with good to excellent yields and characterised by various spectroscopic techniques and spectrometric methods. Single crystal X-ray analysis of the Zn(II) complex, ZnTFPMB(MN)2 (where TFP = trifused porphyrin and MB = monobenzo) revealed a ruffled nonplanar ‘armchair’ type conformation with a twist angle of 24.10°. The absorption spectra showed a significant bathochromic shift in both the B- and Q-bands, extending into the near-infrared (NIR) region, particularly for the π-extended trifused porphyrins. The cyclic voltammograms of MN-appended trifused porphyrins revealed unusual redox behavior, likely due to chemical reactions occurring at the electrode surface during electroreduction. The HOMO-LUMO energy gap for the π-extended porphyrins (MTFPMB(VCN)2) was effectively reduced to ≤1.5 V, compared to ~2.23 V for the parent porphyrins. Additionally, the femtosecond third-order nonlinear optical properties of the synthesized trifused porphyrins and reported Ni(II) complexes were investigated using the Z-scan technique. Most of the studied porphyrins exhibited promising three-photon absorption coefficients and cross-section values, suggesting their potential applications in optical limiting, bio-imaging, and advanced optoelectronics.
{"title":"Meso-β, β-β’ Trifused Porphyrins: Synthesis, Spectral, Electrochemical and DFT Studies and Their Femtosecond Third-Order Nonlinear Optical Properties","authors":"Amir Sohel Bulbul, Jhansi Mogilipuri, Venugopal Rao Soma, Muniappan Sankar","doi":"10.1039/d4dt02930e","DOIUrl":"https://doi.org/10.1039/d4dt02930e","url":null,"abstract":"Meso-β, β-β’ trifused porphyrins incorporating two distinct active methylene groups (MN = malononitrile and IND = 1,3-indanedione) and their corresponding metal complexes with Cu(II) and Zn(II) have been synthesised with good to excellent yields and characterised by various spectroscopic techniques and spectrometric methods. Single crystal X-ray analysis of the Zn(II) complex, ZnTFPMB(MN)2 (where TFP = trifused porphyrin and MB = monobenzo) revealed a ruffled nonplanar ‘armchair’ type conformation with a twist angle of 24.10°. The absorption spectra showed a significant bathochromic shift in both the B- and Q-bands, extending into the near-infrared (NIR) region, particularly for the π-extended trifused porphyrins. The cyclic voltammograms of MN-appended trifused porphyrins revealed unusual redox behavior, likely due to chemical reactions occurring at the electrode surface during electroreduction. The HOMO-LUMO energy gap for the π-extended porphyrins (MTFPMB(VCN)2) was effectively reduced to ≤1.5 V, compared to ~2.23 V for the parent porphyrins. Additionally, the femtosecond third-order nonlinear optical properties of the synthesized trifused porphyrins and reported Ni(II) complexes were investigated using the Z-scan technique. Most of the studied porphyrins exhibited promising three-photon absorption coefficients and cross-section values, suggesting their potential applications in optical limiting, bio-imaging, and advanced optoelectronics.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"43 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936587","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}
Hung-Anh Tran Vu, Trung Pham Duc, Hang Tran Thi My, Anh Duong Duc, Abdullah H. Alshehri, Van Tan Tran, Thi Minh Hien Nguyen, Cong De Pham, Viet Huong Nguyen
Cupric oxide (CuO) is a promising p-type semiconducting oxide for many critical fields such as energy conversion and storage, and gas sensors, attributed to their unique optoelectrical properties and cost-effectiveness. This work successfully deposited amorphous, pinhole-free, ultrathin CuO films using atmospheric pressure spatial atomic layer deposition (SALD) with copper (II) acetylacetonate and ozone as precursors. The growth rate increased from 0.05 Å/cycle at 175 °C to 0.35 Å/cycle at 275 °C. XPS and XRD confirmed the formation of a pure CuO phase, with typical strong satellite shakeup peaks, and tenorite crystalline phase. The films exhibited semiconducting behavior, with temperature-dependent electrical measurements revealing the Fermi level positioned 0.2–0.24 eV above the valence band. Furthermore, p-type CuO was combined with n-type ZnO, both deposited by SALD, to form a high-performance photodiode. This CuO/ZnO heterojunction demonstrated excellent rectifying behavior, with an ION/IOFF ratio of 2.04×103, and functioned as an efficient UV detector, showing fast response and good repeatability. These results highlight the potential of SALD-deposited CuO thin films for optoelectronic applications
{"title":"Atmospheric Pressure Spatial Atomic Layer Deposition of p-type CuO thin films from copper (II) acetylacetonate and ozone for UV detection","authors":"Hung-Anh Tran Vu, Trung Pham Duc, Hang Tran Thi My, Anh Duong Duc, Abdullah H. Alshehri, Van Tan Tran, Thi Minh Hien Nguyen, Cong De Pham, Viet Huong Nguyen","doi":"10.1039/d4dt02689f","DOIUrl":"https://doi.org/10.1039/d4dt02689f","url":null,"abstract":"Cupric oxide (CuO) is a promising p-type semiconducting oxide for many critical fields such as energy conversion and storage, and gas sensors, attributed to their unique optoelectrical properties and cost-effectiveness. This work successfully deposited amorphous, pinhole-free, ultrathin CuO films using atmospheric pressure spatial atomic layer deposition (SALD) with copper (II) acetylacetonate and ozone as precursors. The growth rate increased from 0.05 Å/cycle at 175 °C to 0.35 Å/cycle at 275 °C. XPS and XRD confirmed the formation of a pure CuO phase, with typical strong satellite shakeup peaks, and tenorite crystalline phase. The films exhibited semiconducting behavior, with temperature-dependent electrical measurements revealing the Fermi level positioned 0.2–0.24 eV above the valence band. Furthermore, p-type CuO was combined with n-type ZnO, both deposited by SALD, to form a high-performance photodiode. This CuO/ZnO heterojunction demonstrated excellent rectifying behavior, with an ION<small><sub></sub></small>/IOFF<small><sub></sub></small> ratio of 2.04×10<small><sup>3</sup></small>, and functioned as an efficient UV detector, showing fast response and good repeatability. These results highlight the potential of SALD-deposited CuO thin films for optoelectronic applications","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"12 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936589","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}
Dinuclear aluminum complexes bearing constrained ‘indanimine’ ligand based on a short hydrazine bridge was synthesized. Single-crystal X-ray crystallography reveals bimetallic penta-coordinated aluminum centers having a distorted trigonal bipyramidal geometry. A short Al-Al distance of 4.1 Å was observed due to a highly rigid framework and a short hydrazine bridging moiety. The bimetallic aluminum isopropoxide complex reacted with N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate (DMFB) giving an activated aluminum species via a proton abstraction by isopropoxide. The activated complex was shown to be significantly more active in the ring-opening polymerization (ROP) of ε-caprolactone (CL) and δ-valerolactone (VL) compared to the original non-activated aluminum alkoxide complex. On the other hand, the ROP of L-lactide (LA) by the activated complex completely shut down the polymerization possibly due to a strong coordination of the adjacent ester group to the cationic aluminum center. This unique behavior of LA was then applied as an inhibitor in the ROP of CL. Therefore, the on-going ROP of CL was shown to be switch off immediately when LA was added (OFF mode). The polymerization may resume only when the temperature was increased to 90 °C (ON mode) giving an example of ON/OFF switchable ring-opening polymerization.
{"title":"Bimetallic constrained aluminum alkoxide complex for ring-opening polymerization of cyclic esters: activity enhancement via cationic activation","authors":"Narongchai Kanhanond, Phongnarin Chumsaeng, Supawadee Namuangruk, Khamphee Phomphrai","doi":"10.1039/d4dt02849j","DOIUrl":"https://doi.org/10.1039/d4dt02849j","url":null,"abstract":"Dinuclear aluminum complexes bearing constrained ‘indanimine’ ligand based on a short hydrazine bridge was synthesized. Single-crystal X-ray crystallography reveals bimetallic penta-coordinated aluminum centers having a distorted trigonal bipyramidal geometry. A short Al-Al distance of 4.1 Å was observed due to a highly rigid framework and a short hydrazine bridging moiety. The bimetallic aluminum isopropoxide complex reacted with N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate (DMFB) giving an activated aluminum species via a proton abstraction by isopropoxide. The activated complex was shown to be significantly more active in the ring-opening polymerization (ROP) of ε-caprolactone (CL) and δ-valerolactone (VL) compared to the original non-activated aluminum alkoxide complex. On the other hand, the ROP of L-lactide (LA) by the activated complex completely shut down the polymerization possibly due to a strong coordination of the adjacent ester group to the cationic aluminum center. This unique behavior of LA was then applied as an inhibitor in the ROP of CL. Therefore, the on-going ROP of CL was shown to be switch off immediately when LA was added (OFF mode). The polymerization may resume only when the temperature was increased to 90 °C (ON mode) giving an example of ON/OFF switchable ring-opening polymerization.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"10 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937129","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}
Marcel Geppert, Michelle Müller, Michael Linseis, Rainer R.F. Winter
We present the synthesis, characterization, and photophysical properties of two pyrene-modified (NCN) pincer bismuth complexes, where the pyrenyl residues are either part of the cyclometalating pincer ligand (1) or bound as monodentate ligands to the BiIII ion (2). Both complexes are dually emissive at 77 K. For complex 2, pyrenyl phosphorescence persists at r.t. in degassed CH2Cl2, albeit with reduced intensity. This renders 2 one of only a handful of Bi complexes showing this property.
{"title":"Room-temperature phosphorescence and static excimer excitation of pyrene-modified (NCN) pincer bismuth complexes","authors":"Marcel Geppert, Michelle Müller, Michael Linseis, Rainer R.F. Winter","doi":"10.1039/d4dt03304c","DOIUrl":"https://doi.org/10.1039/d4dt03304c","url":null,"abstract":"We present the synthesis, characterization, and photophysical properties of two pyrene-modified (NCN) pincer bismuth complexes, where the pyrenyl residues are either part of the cyclometalating pincer ligand (1) or bound as monodentate ligands to the BiIII ion (2). Both complexes are dually emissive at 77 K. For complex 2, pyrenyl phosphorescence persists at r.t. in degassed CH2Cl2, albeit with reduced intensity. This renders 2 one of only a handful of Bi complexes showing this property.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"23 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936585","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}
Laura Holzhauer, Vitalii Shekhovtsev, Cecilia Bruschi, Mathis Gunther, Olaf Fuhr, Patrick PH Hodapp, Claudia Bizzarri, Wolfgang Wenzel, Nicole Jung, Stefan Braese
The formation of novel complexes from so far non-investigated ligands and different metal centers is important for the development of new functional materials such as (photo)catalysts or biologically active compounds. Still, promising strategies to quickly and systematically investigate the complexation behavior of selected ligands are rare. We developed an NMR-based screening approach to monitor changes within reaction mixtures containing metals and ligands on a small scale via a simple but reliable protocol. Based on the obtained data, we could draw conclusions on the formation of 2-(1', 2', 3'-triazol-1'yl)quinoxaline-based transition metal complexes. The NMR screening results obtained were confirmed by the repetition of selected experiments on a large scale, and wherever possible, the type of complex obtained was evaluated by crystal structure elucidation. We could show the versatile complexation of the selected ligands with copper, gold, and silver in a bridging, chelating, or monodentate manner. The calculated theoretical properties supported the experimental results and enabled initial in silico predictions of similar compounds before conducting the complexation experiments and structural analyses.
{"title":"Identification of novel triazolylquinoxaline-based metal complexes supported by experimental and virtual screenings","authors":"Laura Holzhauer, Vitalii Shekhovtsev, Cecilia Bruschi, Mathis Gunther, Olaf Fuhr, Patrick PH Hodapp, Claudia Bizzarri, Wolfgang Wenzel, Nicole Jung, Stefan Braese","doi":"10.1039/d4dt02068e","DOIUrl":"https://doi.org/10.1039/d4dt02068e","url":null,"abstract":"The formation of novel complexes from so far non-investigated ligands and different metal centers is important for the development of new functional materials such as (photo)catalysts or biologically active compounds. Still, promising strategies to quickly and systematically investigate the complexation behavior of selected ligands are rare. We developed an NMR-based screening approach to monitor changes within reaction mixtures containing metals and ligands on a small scale via a simple but reliable protocol. Based on the obtained data, we could draw conclusions on the formation of 2-(1', 2', 3'-triazol-1'yl)quinoxaline-based transition metal complexes. The NMR screening results obtained were confirmed by the repetition of selected experiments on a large scale, and wherever possible, the type of complex obtained was evaluated by crystal structure elucidation. We could show the versatile complexation of the selected ligands with copper, gold, and silver in a bridging, chelating, or monodentate manner. The calculated theoretical properties supported the experimental results and enabled initial in silico predictions of similar compounds before conducting the complexation experiments and structural analyses.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"30 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142936586","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}
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