This study presents the direct N-alkylation of aromatic amines using greener primary alcohols as alkyl donors, catalyzed by base metal-derived Co(II) catalysts via the borrowing hydrogen (BH) method. Two well-defined phosphine-free NNN-type pincer ligands (L1 and L2) were synthesized and utilized to prepare cobalt(II) catalysts C1 and C2. The catalysts were well characterized by UV-vis, IR, HRMS, and Single-crystal X-ray diffraction studies. The catalysts C1 and C2 were utilized for the N-alkylation of various aromatic, heteroaromatic as well as aromatic-diamines, and a wide substrate scope total of 30 derivatives was explored with isolated yields up to 95%. Two antihistamine drug precursors for tripelennamine and mepyramine were synthesized on a gram scale for the large-scale applicability of the current protocol. Various control experiments were also performed to explore the possible reaction intermediates and reaction pathway. Cobalt(II) intermediates involved in the catalytic cycle were also characterized by the HRMS study.
{"title":"A well-defined phosphine free metal-ligand cooperative route for N-alkylation of aromatic amines via activation of renewable alcohols catalyzed by a NNN pincer cobalt(II) complexes","authors":"Rahul Saini, Prashant Kukreti, Rahul Chauhan, Abhishek Panwar, Kaushik Ghosh","doi":"10.1039/d4dt03095h","DOIUrl":"https://doi.org/10.1039/d4dt03095h","url":null,"abstract":"This study presents the direct N-alkylation of aromatic amines using greener primary alcohols as alkyl donors, catalyzed by base metal-derived Co(II) catalysts via the borrowing hydrogen (BH) method. Two well-defined phosphine-free NNN-type pincer ligands (L1 and L2) were synthesized and utilized to prepare cobalt(II) catalysts C1 and C2. The catalysts were well characterized by UV-vis, IR, HRMS, and Single-crystal X-ray diffraction studies. The catalysts C1 and C2 were utilized for the N-alkylation of various aromatic, heteroaromatic as well as aromatic-diamines, and a wide substrate scope total of 30 derivatives was explored with isolated yields up to 95%. Two antihistamine drug precursors for tripelennamine and mepyramine were synthesized on a gram scale for the large-scale applicability of the current protocol. Various control experiments were also performed to explore the possible reaction intermediates and reaction pathway. Cobalt(II) intermediates involved in the catalytic cycle were also characterized by the HRMS study.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"210 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526261","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}
Ming Liu, Jingpi Gao, Yang Zhang, Xin Zhou, Yu Wang, Li Wu, Zhiyuan Tian, Jian-Hong Tang
Magnetic resonance (MR) imaging is a non-invasive clinical diagnostic modality that provides anatomical and physiological information with sub-millimetre spatial resolution at the organ and tissue levels. It utilizes the relaxation times (T1 and T2) of protons in water to generate MR images. However, the intrinsic MR contrast produced by water relaxation in organs and tissues is limited. To enhance the sensitivity and specificity of MR imaging, about 30% - 45% of all clinical MR diagnoses need to use contrast media. Currently, all clinically approved MR contrast agents are linear or macrocyclic gadolinium(III) (Gd(III)) complexes, which are not specific to particular biological events. Due to the relatively high potential for releasing toxic free Gd(III), linear Gd(III) complexes raise safety concerns, making macrocyclic Gd(III) probes the preferred choice for clinical MR imaging without acute safety issues. To enhance the capability of MR imaging for detecting dynamic biological processes and conditions, many bioresponsive macrocyclic Gd(III) complexes capable of targeting diverse biomarkers have been developed. This review provides a concise and timely summary of bioresponsive macrocyclic Gd(III) contrast agents, particularly those developed between 2019 and 2024. We focus on three major types of Gd(III) agents that respond specifically to changes in pH, chemicals, and enzymes, highlighting their molecular design strategies, proton-relaxivity responses, and applications in in vitro and in vivo MR imaging for monitoring specific biomedical conditions and therapies.
{"title":"Recent Advances in Bioresponsive Macrocyclic Gadolinium(III) Complexes for MR Imaging and Therapy","authors":"Ming Liu, Jingpi Gao, Yang Zhang, Xin Zhou, Yu Wang, Li Wu, Zhiyuan Tian, Jian-Hong Tang","doi":"10.1039/d5dt00191a","DOIUrl":"https://doi.org/10.1039/d5dt00191a","url":null,"abstract":"Magnetic resonance (MR) imaging is a non-invasive clinical diagnostic modality that provides anatomical and physiological information with sub-millimetre spatial resolution at the organ and tissue levels. It utilizes the relaxation times (T1 and T2) of protons in water to generate MR images. However, the intrinsic MR contrast produced by water relaxation in organs and tissues is limited. To enhance the sensitivity and specificity of MR imaging, about 30% - 45% of all clinical MR diagnoses need to use contrast media. Currently, all clinically approved MR contrast agents are linear or macrocyclic gadolinium(III) (Gd(III)) complexes, which are not specific to particular biological events. Due to the relatively high potential for releasing toxic free Gd(III), linear Gd(III) complexes raise safety concerns, making macrocyclic Gd(III) probes the preferred choice for clinical MR imaging without acute safety issues. To enhance the capability of MR imaging for detecting dynamic biological processes and conditions, many bioresponsive macrocyclic Gd(III) complexes capable of targeting diverse biomarkers have been developed. This review provides a concise and timely summary of bioresponsive macrocyclic Gd(III) contrast agents, particularly those developed between 2019 and 2024. We focus on three major types of Gd(III) agents that respond specifically to changes in pH, chemicals, and enzymes, highlighting their molecular design strategies, proton-relaxivity responses, and applications in in vitro and in vivo MR imaging for monitoring specific biomedical conditions and therapies.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"9 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526262","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}
Felix Meyer, Serhiy Demeshko, Christopher Golz, Oliver Townrow, Malte Fischer
We present the synthesis and characterization of the first isolable monomeric triplet titanocene complex, stabilized by the N-heterocyclic carbene (NHC) IMe4. Investigated by SQUID magnetometry and quantum-chemical calculations, reactivity studies of the titanium precursor [Cp2Ti(btmsa)] (2) with the NHC IiPr2Me2 and the zirconocene complex [Cp2Zr(py)(btmsa)] (1) revealed divergent reactivity patterns, highlighting the role of steric and electronic effects in stabilization.
{"title":"Isolation of the Parent Triplet Titanocene via NHC Stabilisation","authors":"Felix Meyer, Serhiy Demeshko, Christopher Golz, Oliver Townrow, Malte Fischer","doi":"10.1039/d5dt00480b","DOIUrl":"https://doi.org/10.1039/d5dt00480b","url":null,"abstract":"We present the synthesis and characterization of the first isolable monomeric triplet titanocene complex, stabilized by the <em>N</em>-heterocyclic carbene (NHC) IMe<small><sub>4</sub></small>. Investigated by SQUID magnetometry and quantum-chemical calculations, reactivity studies of the titanium precursor [Cp<small><sub>2</sub></small>Ti(btmsa)] (<strong>2</strong>) with the NHC I<small><sup><em>i</em></sup></small>Pr<small><sub>2</sub></small>Me<small><sub>2</sub></small> and the zirconocene complex [Cp<small><sub>2</sub></small>Zr(py)(btmsa)] (<strong>1</strong>) revealed divergent reactivity patterns, highlighting the role of steric and electronic effects in stabilization.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"33 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518275","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}
Youyi Sun, Zhengxin Yang, Weihao Li, Alexey Y. Ganin
Proton exchange membrane (PEM) water electrolysers are considered the most promising devices for hydrogen production when operated in tandem with renewable energy sources. However, their efficiency depends on catalysts used on the anode and cathode but the acidic conditions at the membrane restrict the catalysts to noble metals. Hence, the search for non-noble metal catalysts that are active and stable under acidic conditions is important. In this work we demonstrate that phase pure Co6W6N (prepared by the nitridation of an oxide precursor) remains stable in 0.5 M H2SO4 suggesting it is a suitable electrocatalyst for the hydrogen evolution reaction (HER) in acidic media. Moreover, it shows a comparatively low overpotential of ‒150 ± 8 mV at a benchmark current density of 10 mA cm‒2. Furthermore, two isostructural catalysts with the compositions Co3Fe3W6N and Fe6W6N showed the overpotentials of 225 ± 8 mV and 414 ± 18 mV at 10 mA cm‒2 respectively, suggesting that Co-sites are responsible for the catalytic performance. This was further confirmed by the X-ray photoelectron spectroscopy (XPS) which showed that W-oxidation states in Co6W6N and Fe6W6N are practically identical and hence, cannot be the cause for the overpotential’s increase upon the substitution. In this context, Co6W6N appears an optimal target for future tests in full-scale electrolysis systems.
{"title":"The investigation of Co6-xFexW6N (x =0, 3, 6) as Electrocatalysts for the Hydrogen Evolution Reaction","authors":"Youyi Sun, Zhengxin Yang, Weihao Li, Alexey Y. Ganin","doi":"10.1039/d4dt03005b","DOIUrl":"https://doi.org/10.1039/d4dt03005b","url":null,"abstract":"Proton exchange membrane (PEM) water electrolysers are considered the most promising devices for hydrogen production when operated in tandem with renewable energy sources. However, their efficiency depends on catalysts used on the anode and cathode but the acidic conditions at the membrane restrict the catalysts to noble metals. Hence, the search for non-noble metal catalysts that are active and stable under acidic conditions is important. In this work we demonstrate that phase pure Co6W6N (prepared by the nitridation of an oxide precursor) remains stable in 0.5 M H2SO4 suggesting it is a suitable electrocatalyst for the hydrogen evolution reaction (HER) in acidic media. Moreover, it shows a comparatively low overpotential of ‒150 ± 8 mV at a benchmark current density of 10 mA cm‒2. Furthermore, two isostructural catalysts with the compositions Co3Fe3W6N and Fe6W6N showed the overpotentials of 225 ± 8 mV and 414 ± 18 mV at 10 mA cm‒2 respectively, suggesting that Co-sites are responsible for the catalytic performance. This was further confirmed by the X-ray photoelectron spectroscopy (XPS) which showed that W-oxidation states in Co6W6N and Fe6W6N are practically identical and hence, cannot be the cause for the overpotential’s increase upon the substitution. In this context, Co6W6N appears an optimal target for future tests in full-scale electrolysis systems.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"130 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518274","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}
Milad Moghadasi, Mohammad Abbasi, Mahtab Mousavi, Masoud Mirzaei
An increasing number of studies have demonstrated that polyoxometalate-based materials have biological applications, which means that polyoxometalate species have potential in medicine. The antibacterial, antiviral, and anticancer properties of polyoxometalates make them promising candidates for a new generation of metallodrugs in treating diseases due to their versatile structures, unique physicochemical properties, and easy synthesis processes. Recent studies have focused on the use of these materials as chemotherapeutic and photothermal agents with the capacity to generate reactive oxygen species and on the study of their mechanisms. However, due to the high solubility and long-lasting toxicity effects of pure polyoxometalates, their modification with heterometals, organic molecules, and interactions with biomolecules is an efficient strategy for introducing them into biological media and can be considered a key issue of the bioorthogonal chemistry of polyoxometalates. Here, we summarize and discuss the current status of biomedical applications of polyoxometalate-based materials. Furthermore, the prospect of using these materials for therapeutic purposes is anticipated, indicating promising directions for future research and development.
{"title":"Polyoxometalate-based materials in therapeutic and biomedical applications: current status and perspective","authors":"Milad Moghadasi, Mohammad Abbasi, Mahtab Mousavi, Masoud Mirzaei","doi":"10.1039/d4dt03428g","DOIUrl":"https://doi.org/10.1039/d4dt03428g","url":null,"abstract":"An increasing number of studies have demonstrated that polyoxometalate-based materials have biological applications, which means that polyoxometalate species have potential in medicine. The antibacterial, antiviral, and anticancer properties of polyoxometalates make them promising candidates for a new generation of metallodrugs in treating diseases due to their versatile structures, unique physicochemical properties, and easy synthesis processes. Recent studies have focused on the use of these materials as chemotherapeutic and photothermal agents with the capacity to generate reactive oxygen species and on the study of their mechanisms. However, due to the high solubility and long-lasting toxicity effects of pure polyoxometalates, their modification with heterometals, organic molecules, and interactions with biomolecules is an efficient strategy for introducing them into biological media and can be considered a key issue of the bioorthogonal chemistry of polyoxometalates. Here, we summarize and discuss the current status of biomedical applications of polyoxometalate-based materials. Furthermore, the prospect of using these materials for therapeutic purposes is anticipated, indicating promising directions for future research and development.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"15 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506770","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}
Chrisoula Kakoulidou, Antonios Hatzidimitriou, Konstantina C Fylaktakidou, George L Psomas
A quinazoline derivative containing a properly situated o−phenol ring, namely (E)−2−((2−(quinazolin−4−yl)hydrazono)methyl)phenol (H2L), was synthesized in order to investigate the ability of this novel ligand for metal complexation. The interaction of deprotonated HL− with Zn(II) resulted in the mononuclear complex [Ζn(HL)2]·1.5CH3OH·H2O (complex 1). When doubly deprotonated ligand L−2 reacted with Cu(II), the tetranuclear complex [Cu4(L)4(DMF)4]·8H2O (complex 2) was isolated, which can be described as an azametallacoronate compound. All three compounds were characterized by spectroscopic techniques and single−crystal X−ray crystallography. The biological profile of the compounds was evaluated in regard to their affinity for calf−thymus DNA, the ability to cleave supercoiled circular pBR322 plasmid DNA in the absence or presence of irradiation of various wavelengths (UVA, UVB and visible light), their binding with bovine serum albumin and their capacity to scavenge 1,1−diphenyl−picrylhydrazyl and 2,2'−azinobis−(3−ethylbenzothiazoline−6−sulfonic acid) radicals and to reduce H2O2. The compounds can bind tightly to calf−thymus DNA via intercalation, and do not induce notable cleavage of plasmid DNA. They can bind tightly and reversibly to the albumin and have shown moderate antioxidant activity.
为了研究这种新型配体的金属络合能力，我们合成了一种含有适当位置邻苯酚环的喹唑啉衍生物，即 (E)-2-((2-(喹唑啉-4-基)肼基)甲基)苯酚 (H2L)。去质子化的 HL- 与 Zn(II) 相互作用，生成单核络合物 [Ζn(HL)2]-1.5CH3OH-H2O（络合物 1）。当双去质子化配体 L-2 与 Cu(II) 反应时，分离出了四核络合物 [Cu4(L)4(DMF)4]-8H2O（络合物 2），它可以被描述为偶氮金属硼酸盐化合物。这三种化合物都通过光谱技术和单晶 X 射线晶体学进行了表征。对这些化合物的生物特性进行了评估，包括对小牛胸腺 DNA 的亲和力、在没有或有不同波长（UVA、UVB 和可见光）照射的情况下裂解超卷曲环状 pBR322 质粒 DNA 的能力、与牛血清白蛋白的结合力、清除 1,1-二苯基-苦基肼和 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) 自由基以及还原 H2O2 的能力。这些化合物可通过插层作用与小牛胸腺 DNA 紧密结合，不会引起质粒 DNA 的明显裂解。它们能与白蛋白紧密且可逆地结合，并显示出中等程度的抗氧化活性。
{"title":"A mononuclear zinc(II) complex and a tetranuclear copper(II) azametallacoronate with (E)−2−((2−(quinazolin−4−yl)hydrazono)methyl)phenol: Structure and biological activity","authors":"Chrisoula Kakoulidou, Antonios Hatzidimitriou, Konstantina C Fylaktakidou, George L Psomas","doi":"10.1039/d4dt03518f","DOIUrl":"https://doi.org/10.1039/d4dt03518f","url":null,"abstract":"A quinazoline derivative containing a properly situated o−phenol ring, namely (E)−2−((2−(quinazolin−4−yl)hydrazono)methyl)phenol (H2L), was synthesized in order to investigate the ability of this novel ligand for metal complexation. The interaction of deprotonated HL− with Zn(II) resulted in the mononuclear complex [Ζn(HL)2]·1.5CH3OH·H2O (complex 1). When doubly deprotonated ligand L−2 reacted with Cu(II), the tetranuclear complex [Cu4(L)4(DMF)4]·8H2O (complex 2) was isolated, which can be described as an azametallacoronate compound. All three compounds were characterized by spectroscopic techniques and single−crystal X−ray crystallography. The biological profile of the compounds was evaluated in regard to their affinity for calf−thymus DNA, the ability to cleave supercoiled circular pBR322 plasmid DNA in the absence or presence of irradiation of various wavelengths (UVA, UVB and visible light), their binding with bovine serum albumin and their capacity to scavenge 1,1−diphenyl−picrylhydrazyl and 2,2'−azinobis−(3−ethylbenzothiazoline−6−sulfonic acid) radicals and to reduce H2O2. The compounds can bind tightly to calf−thymus DNA via intercalation, and do not induce notable cleavage of plasmid DNA. They can bind tightly and reversibly to the albumin and have shown moderate antioxidant activity.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"29 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506891","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}
Jorge Labella, Jorge Labrador-Santiago, Daniel Holgado, Tomás Torres
The element hosted within the inner cavity of phthalocyanines (Pcs) dictates the wide functional versatility of these well-known macrocycles. Subphthalocyanines (SubPcs), by contrast, are only known as boron complexes, yet they exhibit a range of emerging properties unattainable with other compounds. The effects of replacing the boron atom in these macrocycles, however, remain unclear. Herein, we present a comprehensive theoretical investigation of non-boron SubPc complexes incorporating various metal and non-metal elements. Specifically, we use density functional theory (DFT) to assess the impact of boron replacement on bowl depth, dipole moment, charge distribution, key frontier molecular orbitals, UV-Vis absorption properties, ionization potential, and electron affinity of SubPcs. Our findings reveal that substituting the boron atom induces significant alterations across these properties, with pronounced variability depending on the group, atomic size, and oxidation state of the central element. Altogether, this study underscores the functional versatility that non-boron SubPcs could introduce within the broader field of porphyrinoid chemistry, paving the way for disruptive materials with tailored electronic and photophysical properties.
{"title":"Effects of Removing Boron from Subphthalocyanines: A Theoretical Perspective","authors":"Jorge Labella, Jorge Labrador-Santiago, Daniel Holgado, Tomás Torres","doi":"10.1039/d4dt03173c","DOIUrl":"https://doi.org/10.1039/d4dt03173c","url":null,"abstract":"The element hosted within the inner cavity of phthalocyanines (Pcs) dictates the wide functional versatility of these well-known macrocycles. Subphthalocyanines (SubPcs), by contrast, are only known as boron complexes, yet they exhibit a range of emerging properties unattainable with other compounds. The effects of replacing the boron atom in these macrocycles, however, remain unclear. Herein, we present a comprehensive theoretical investigation of non-boron SubPc complexes incorporating various metal and non-metal elements. Specifically, we use density functional theory (DFT) to assess the impact of boron replacement on bowl depth, dipole moment, charge distribution, key frontier molecular orbitals, UV-Vis absorption properties, ionization potential, and electron affinity of SubPcs. Our findings reveal that substituting the boron atom induces significant alterations across these properties, with pronounced variability depending on the group, atomic size, and oxidation state of the central element. Altogether, this study underscores the functional versatility that non-boron SubPcs could introduce within the broader field of porphyrinoid chemistry, paving the way for disruptive materials with tailored electronic and photophysical properties.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"49 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506768","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}
Design strategies for chiral iridium (III) complexes with stable circularly polarized luminescent properties have been emerged as important ongoing research tasks in the field of organic photonics. Given the high rigidity, low chemical activity and multi-closed-loop structure, the chirality of R-camphor can not be easily affected. And the introducing of indolo[3,2,1-jk] carbazole is beneficial for narrow emission spectrum. Thus, two yellow-emission chiral iridium(III) isomers, Δ-(mpincz)2Ir(R-camphor) and Λ-(mpincz)2Ir(R-camphor), were designed and systematically investigated towards photophysical properties, chiroptical properties, electrochemistry behaviors, theoretical calculations and electroluminescence. The maximum emission peak of the racemic Δ/Λ-(mpincz)2Ir(R-camphor) in degassed toluene solution is located at 560 nm with the full width at half maximum (FWHM) of 48 nm，which also demonstrated strong circularly polarized photoluminescence (CPPL) in toluene solution with the luminescent dissymmetry factor (gPL) of 1.15 × 10-3 and -1.0 × 10-3, respectively. Based on Δ-(mpincz)2Ir(R-camphor) and Λ-(mpincz)2Ir(R-camphor), the efficient organic light-emitting diodes (OLEDs) were fabricated by vacuum evaporation deposition, with the maximum external quantum efficiency (EQEmax) of 14.65% and 15.58%, respectively and the asymmetry coefficients (gEL) are 1.86 × 10-4 and -2.29 × 10-4, respectively. This work may provide the effective strategy for the preparation of circularly polarized narrowband Ir(III) complexes.
{"title":"Circularly polarized narrowband phosphorescent organic light-emitting diodes","authors":"Guangzhao Lu, Shaohua Wu, Ping Chen, Xiaoyang Xia, Wenya Wang, Qifei Xie, Yanyu Qi, Hua-Bo Han, Liang Zhou","doi":"10.1039/d5dt00337g","DOIUrl":"https://doi.org/10.1039/d5dt00337g","url":null,"abstract":"Design strategies for chiral iridium (III) complexes with stable circularly polarized luminescent properties have been emerged as important ongoing research tasks in the field of organic photonics. Given the high rigidity, low chemical activity and multi-closed-loop structure, the chirality of R-camphor can not be easily affected. And the introducing of indolo[3,2,1-jk] carbazole is beneficial for narrow emission spectrum. Thus, two yellow-emission chiral iridium(III) isomers, Δ-(mpincz)2Ir(R-camphor) and Λ-(mpincz)2Ir(R-camphor), were designed and systematically investigated towards photophysical properties, chiroptical properties, electrochemistry behaviors, theoretical calculations and electroluminescence. The maximum emission peak of the racemic Δ/Λ-(mpincz)2Ir(R-camphor) in degassed toluene solution is located at 560 nm with the full width at half maximum (FWHM) of 48 nm，which also demonstrated strong circularly polarized photoluminescence (CPPL) in toluene solution with the luminescent dissymmetry factor (gPL) of 1.15 × 10-3 and -1.0 × 10-3, respectively. Based on Δ-(mpincz)2Ir(R-camphor) and Λ-(mpincz)2Ir(R-camphor), the efficient organic light-emitting diodes (OLEDs) were fabricated by vacuum evaporation deposition, with the maximum external quantum efficiency (EQEmax) of 14.65% and 15.58%, respectively and the asymmetry coefficients (gEL) are 1.86 × 10-4 and -2.29 × 10-4, respectively. This work may provide the effective strategy for the preparation of circularly polarized narrowband Ir(III) complexes.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"66 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506771","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}
Mohan Paudel, Sanjit Karki, Narayan Acharya, Sashil Chapagain, Johann V. Hemmer, Dillon T. Hofsommer, Gautam Gupta, Robert M. Buchanan, Craig A. Grapperhaus
Green hydrogen, generated through the electrolysis of water using renewable energy sources, is recognized as a highly promising alternative to fossil fuels in the pursuit of net-zero carbon emissions. Electrocatalysts are crucial for reducing overpotentials and enhancing the efficiency of the hydrogen evolution reaction (HER) for the production of green hydrogen. Homogeneous HER serves as a primary method to assess the activity and mechanisms of novel non-precious molecular electrocatalysts in pursuit of replacing precious platinum standards. However, these catalysts can sometimes exhibit instability under reductive and acidic conditions during homogeneous HER. Thus, it is also essential to evaluate catalysts through heterogeneous HER for initial assessment and practical application. In this study, we examine a series of structurally related N2S2 chelated Ni(II) complexes, which are tailored to optimize the basicity of the catalyst for heterogeneous HER activity. These complexes are insoluble in 0.5 M H2SO4, and the films formed after catalyst deposition on glassy carbon electrodes (GCEs) exhibit catalytic currents during HER, demonstrating moderate to good overpotentials, Tafel slopes, and charge transfer resistance. Furthermore, we observe the anticipated structure–activity relationship that arises from tuning the catalyst structure. The complexes maintain stability over extended reductive cycling, as confirmed by various surface characterization techniques, including SEM, EDX, XPS, and XRD. This study highlights the potential of utilizing catalyst basicity to develop efficient and robust heterogeneous HER catalysts.
{"title":"Heterogenous HER activity of Ni(II)N2S2 molecular catalysts","authors":"Mohan Paudel, Sanjit Karki, Narayan Acharya, Sashil Chapagain, Johann V. Hemmer, Dillon T. Hofsommer, Gautam Gupta, Robert M. Buchanan, Craig A. Grapperhaus","doi":"10.1039/d5dt00005j","DOIUrl":"https://doi.org/10.1039/d5dt00005j","url":null,"abstract":"Green hydrogen, generated through the electrolysis of water using renewable energy sources, is recognized as a highly promising alternative to fossil fuels in the pursuit of net-zero carbon emissions. Electrocatalysts are crucial for reducing overpotentials and enhancing the efficiency of the hydrogen evolution reaction (HER) for the production of green hydrogen. Homogeneous HER serves as a primary method to assess the activity and mechanisms of novel non-precious molecular electrocatalysts in pursuit of replacing precious platinum standards. However, these catalysts can sometimes exhibit instability under reductive and acidic conditions during homogeneous HER. Thus, it is also essential to evaluate catalysts through heterogeneous HER for initial assessment and practical application. In this study, we examine a series of structurally related N<small><sub>2</sub></small>S<small><sub>2</sub></small> chelated Ni(<small>II</small>) complexes, which are tailored to optimize the basicity of the catalyst for heterogeneous HER activity. These complexes are insoluble in 0.5 M H<small><sub>2</sub></small>SO<small><sub>4</sub></small>, and the films formed after catalyst deposition on glassy carbon electrodes (GCEs) exhibit catalytic currents during HER, demonstrating moderate to good overpotentials, Tafel slopes, and charge transfer resistance. Furthermore, we observe the anticipated structure–activity relationship that arises from tuning the catalyst structure. The complexes maintain stability over extended reductive cycling, as confirmed by various surface characterization techniques, including SEM, EDX, XPS, and XRD. This study highlights the potential of utilizing catalyst basicity to develop efficient and robust heterogeneous HER catalysts.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"51 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506766","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}
Małgorzata Zienkiewicz-Machnik, Roman Luboradzki, Justyna Mech-Piskorz, Gonzalo Angulo, Wojciech Nogala, Tomasz Ratajczyk, Pavlo Aleshkevych, Adam Kubas
We report structural and physicochemical characterization supported by quantum chemical studies of two novel copper(II) [CuLCl]2[CuCl4] (1) and cobalt(II) [CoLCl][CoL′Cl3] (2) cationic−anionic complexes with N-scorpionate type ligand, N,N,N-tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L), where L′ is 1-methylamine-3,5-dimethylpyrazole. The obtained complexes are the first reported examples of cationic−anionic coordination compounds tested for catecholase activity. Interestingly, only copper complex (1) shows catalytic activity in the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC), which turned out to be solvent dependent. Here, experimental UV-vis spectroscopy of 1 shows that essential features of the solid-state spectrum are maintained in DMSO and MeOH solvents. In contrast, the build-up of a new feature around 465 nm for 1 in CH3CN was noted, along with negligible activity. According to quantum chemical calculations, this feature could be attributed to ligand-to-metal excitations within the [CuCl4]2− fragment disturbed by adjacent [CuLCl]+ species. The band shifts to lower energies compared to solid-state measurements as the two charged fragments get closer due to Coulomb interactions. In DMSO, the solvent molecule serves as an inert ligand in a [CuLCl]+ fragment and blocks the catalytic center, disturbing the formation of the [catalyst–substrate] complex and decreasing activity, while in MeOH, the solvent effectively stabilizes [CuCl4]2−via a H-bond network and the free coordination site is accessible, thus allowing a substrate molecule to bind. The critical advantage of the investigated complexes, in the context of their possible catalytic activity, was the fact that their usage would not introduce any unnecessary counterions.
{"title":"Cationic−anionic complexes of Cu(II) and Co(II) with N-scorpionate ligand – structure, spectroscopy, and catecholase activity","authors":"Małgorzata Zienkiewicz-Machnik, Roman Luboradzki, Justyna Mech-Piskorz, Gonzalo Angulo, Wojciech Nogala, Tomasz Ratajczyk, Pavlo Aleshkevych, Adam Kubas","doi":"10.1039/d4dt03478c","DOIUrl":"https://doi.org/10.1039/d4dt03478c","url":null,"abstract":"We report structural and physicochemical characterization supported by quantum chemical studies of two novel copper(<small>II</small>) [CuLCl]<small><sub>2</sub></small>[CuCl<small><sub>4</sub></small>] (<strong>1</strong>) and cobalt(<small>II</small>) [CoLCl][CoL′Cl<small><sub>3</sub></small>] (<strong>2</strong>) cationic−anionic complexes with <em>N</em>-scorpionate type ligand, <em>N</em>,<em>N</em>,<em>N</em>-tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L), where L′ is 1-methylamine-3,5-dimethylpyrazole. The obtained complexes are the first reported examples of cationic−anionic coordination compounds tested for catecholase activity. Interestingly, only copper complex (<strong>1</strong>) shows catalytic activity in the oxidation of 3,5-di-<em>tert</em>-butylcatechol (3,5-DTBC), which turned out to be solvent dependent. Here, experimental UV-vis spectroscopy of <strong>1</strong> shows that essential features of the solid-state spectrum are maintained in DMSO and MeOH solvents. In contrast, the build-up of a new feature around 465 nm for <strong>1</strong> in CH<small><sub>3</sub></small>CN was noted, along with negligible activity. According to quantum chemical calculations, this feature could be attributed to ligand-to-metal excitations within the [CuCl<small><sub>4</sub></small>]<small><sup>2−</sup></small> fragment disturbed by adjacent [CuLCl]<small><sup>+</sup></small> species. The band shifts to lower energies compared to solid-state measurements as the two charged fragments get closer due to Coulomb interactions. In DMSO, the solvent molecule serves as an inert ligand in a [CuLCl]<small><sup>+</sup></small> fragment and blocks the catalytic center, disturbing the formation of the [catalyst–substrate] complex and decreasing activity, while in MeOH, the solvent effectively stabilizes [CuCl<small><sub>4</sub></small>]<small><sup>2−</sup></small> <em>via</em> a H-bond network and the free coordination site is accessible, thus allowing a substrate molecule to bind. The critical advantage of the investigated complexes, in the context of their possible catalytic activity, was the fact that their usage would not introduce any unnecessary counterions.","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":"1 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506767","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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