Article
Chemistry, Multidisciplinary
Alexa Caise, Liam P. Griffin, Caitilin McManus, Andreas Heilmann, Simon Aldridge
Summary: This study reports the reversible uptake of carbon dioxide by dimetallynes with ancillary hemi-labile pincer ligands. Crystallographic analysis reveals that the coordination of the CO2 fragment depends on the identity of the Group 14 element. The thermodynamics of CO2 uptake/loss are determined through VT NMR and the reversibility of the process is demonstrated by thermodynamically-controlled exchange reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Inorganic & Nuclear
Hai-Jun Li, Rui Feng, Gao-Xiang Wang, Junnian Wei, Zhenfeng Xi
Summary: By reacting semi-rigid PNP ligand with CoBr2, complex PNPCoBr (1) was obtained. The reduction of 1 with excess amounts of KC8 in THE under a N-2 atmosphere yielded binuclear cobalt dinitrogen anion complex [Co(mu-Cy2P)PCyN2](2)K (2) by cleaving the C-P bond of the PNP ligand. Adding 2,2,2-cryptand into complex 2 effectively prepared ion pair Co complex, [Co(mu-Cy2P)PCyN2](2)K(crypt-222) (3). The structures of 1, 2, and 3 were determined by single-crystal X-ray diffraction analysis, and N-2 is moderately activated in complexes 2 and 3. DFT calculations suggest the presence of a Co-Co bond in 2 and 3. Compounds 1 and 2 exhibit catalytic activity for the transformation of N-2 to N(SiMe3)(3).
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Fei Fang, Jia-Xin Kang, Cong-Qiao Xu, Jiarui Chang, Jie Zhang, Shujun Li, Xuenian Chen
Summary: The influence of the pincer platform composition and substitution on the reactivity and physical properties of pincer complexes is easily explored experimentally, with subtle effects on the molecular structures and thermodynamic stability. The bond lengths and strengths of M-C-ipso, M-P, and M-X were discussed, along with thermochemical balances for different types of pincer complexes.
INORGANIC CHEMISTRY
(2021)
Review
Chemistry, Inorganic & Nuclear
Yidan Wang, Bo Zhang, Shuai Guo
Summary: The combination of NHC and pincer framework in transition metal complexes has been widely studied and applied in various fields, including catalysis and optical material chemistry. This minireview focuses on the synthesis, reactivity study and applications of metal pincer NHCs.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Maxym Tansky, Zipeng Gu, Robert J. Comito
Summary: This report introduces a new method for the synthesis of bis(pyrazolyl)alkanes, avoiding common issues in traditional methods and suitable for systematic ligand optimization. Additionally, new reactants including pyrazoles and aldehydes have been explored, providing a new direction for the development of novel catalysts.
JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Inorganic & Nuclear
Man-Man Xue, Jiarui Chang, Jie Zhang, Xuenian Chen
Summary: In this study, two types of platinum thiolate complexes were successfully synthesized and fully characterized. The results showed that these platinum complexes exhibited high catalytic activity in the hydrosilylation of aldehydes and ketones. Additionally, the catalytic system showed good compatibility with the subsequent hydrolysis reaction.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Amy L. Speelman, Kazimer L. Skubi, Brandon Q. Mercado, Patrick L. Holland
Summary: Recent experimental evidence indicates that during N-2 reduction, the FeMoco of nitrogenase undergoes structural rearrangement, leading to the generation of coordinatively unsaturated iron sites. New designed ligands have shown the potential flexibility in structural arrangement of metal complexes, mimicking the resting state of nitrogenase.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Fei Fang, Man-Man Xue, Man Ding, Jie Zhang, Shujun Li, Xuenian Chen
Summary: This study investigated the stability and transformation process of the diphosphino-boryl-based PBP pincer platform in the presence of water, revealing that the PBP pincer backbone can easily be converted into a POP backbone. By analyzing the crystal structures of the resulting palladium complexes, possible pathways for pincer backbone transformation were discussed.
CHEMISTRY-AN ASIAN JOURNAL
(2021)
Article
Chemistry, Inorganic & Nuclear
Qingbing Yuan, Zeming Huang, Weikang Wu, Dongjing Hong, Shan Zhu, Jieding Wei, Shuangliu Zhou, Shaowu Wang
Summary: Novel tetranuclear organocopper(I) clusters with excellent catalytic activities have been synthesized through reactions between Cu(I) halides and lithiated ligands. The structures of these clusters are stabilized by multiple Cu-Cu interactions, with halide anions bridged to the metal centers.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Vasudevan Subramaniyan, Francoise Tibika, Yuri Tulchinsky
Summary: In this study, we investigated the strain effect on the properties of complexes formed by chelating ligands and pincer ligands. We found that ligand strain plays an important role in the overall binding energy and coordination behavior of PSP pincer ligands. Our findings suggest that the internal ligand strain can significantly affect the coordination properties of pincer ligands.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Fanqiang Meng, Shogo Kuriyama, Hiromasa Tanaka, Akihito Egi, Kazunari Yoshizawa, Yoshiaki Nishibayashi
Summary: A series of rhenium complexes with pyridine-based PNP-type pincer ligands are synthesized from rhenium phosphine complexes. These complexes catalyze the conversion of dinitrogen into ammonia and silylation of dinitrogen under mild reaction conditions, demonstrating the successful catalytic nitrogen fixation using rhenium-dinitrogen complexes as catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Inorganic & Nuclear
Diana V. Aleksanyan, Aleksandr A. Spiridonov, Svetlana G. Churusova, Ekaterina Yu. Rybalkina, Anastasia A. Danshina, Alexander S. Peregudov, Zinaida S. Klemenkova, Vladimir A. Kozlov
Summary: The application of thiophosphorylated indoles in the synthesis of new pincer ligands for Pd(II) ions was investigated. Isomeric 1-and 3-thiophosphorylated indoles bearing pyridylmethyl or pyridylcarbonyl donor groups readily underwent cyclopalladation, yielding Pd(II) pincer complexes in high yields. The structures of these complexes were confirmed by various spectroscopic methods and X-ray crystallography. The cytotoxic activity of these complexes on human cancer cell lines was evaluated, and the derivatives with thiophosphoryl and pyridylmethyl arms exhibited high potency and induced cell apoptosis.
INORGANICA CHIMICA ACTA
(2023)
Article
Chemistry, Inorganic & Nuclear
Jia-Xue Mao, Jiarui Chang, Jie Zhang, Xuenian Chen
Summary: The structures and catalytic reactivity of nickel chloride and thiolate complexes supported by benzene-pyridine-based nonsymmetrical PCN pincer ligands were investigated. The composition and substitution of the pincer backbone were found to have a significant influence on the structures and catalytic reactivity.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Sylvain Sudan, Ru-Jin Li, Suzanne M. Jansze, Andre Platzek, Robin Rudolf, Guido H. Clever, Farzaneh Fadaei-Tirani, Rosario Scopelliti, Kay Severin
Summary: The design of structurally defined heteroleptic coordination cages is challenging and only a few examples are known. In this study, a novel hexanuclear Pd cage containing two types of dipyridyl ligands was identified using a selection approach. The structure of the cage was elucidated by single-crystal X-ray diffraction, revealing an unprecedented trigonal-antiprismatic cage structure.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Multidisciplinary
Aathith Vasanthakumar, Jeffrey S. Price, David J. H. Emslie
Summary: A palladium-catalyzed coupling reaction synthesized a stable neutral [XII2] ligand from 4,5-dibromo-2,7-di-tert-butyl-9,9-dimethylxanthene. The reaction of XII2 with YCl3(THF)(3.5) provided [(XII2)YCl3] (1), while the reaction with [Y(CH2SiMe3)(3)(THF)(2)] produced a complex mixture of products. Protonation of XII2 using [H(OEt2)(2)][B(C6F5)(4)] and subsequent reaction with [M(CH2SiMe3)(3)(THF)(2)] directly afforded cationic scandium and yttrium dialkyl complexes.
Article
Chemistry, Inorganic & Nuclear
Victor N. Nemykin, Dustin E. Nevonen, Laura S. Ferch, Michael Shepit, David E. Herbert, Johan van Lierop
Summary: Density Functional Theory (DFT) calculations were used to predict Mossbauer hyperfine parameters of bis-axially coordinated iron(II) phthalocyanine complexes, with MN12L exchange-correlation functional accurately predicting quadrupole splitting trends. Hybrid exchange-correlation functionals underestimated quadrupole splittings while still accurately predicting isomer shifts. The study successfully explained the quadrupole splitting trends using Natural Bond Orbital (NBO) analysis and reported the first X-ray crystal structure of a PcFeL2 complex with axial phosphine ligands.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Yuriy V. Zatsikha, Liliya I. Shamova, David E. Herbert, Victor N. Nemykin
Summary: The newly synthesized compounds exhibit broad absorption in the visible region of the electromagnetic spectrum and have a stable structure. The beta-isoindigo fragment is in a trans-configuration accompanying a planar conjugated core.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Medicinal
Alexander O. Pritchard, Dion B. Nemez, David E. Herbert, Shyamala Dakshinamurti, John L. Sorensen
Summary: This article presents a straightforward purification method of forskolin from commercially available weight loss capsules, addressing ambiguities in the use of the name 'forskolin'. The complete spectroscopic characterization and single crystal X-ray structure of purified forskolin is detailed in this report.
BIOORGANIC & MEDICINAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Inorganic & Nuclear
Baldeep K. Sidhu, Jason D. Braun, David E. Herbert
Summary: The Pd-catalyzed Buchwald-Hartwig amination of 2-bromo-1-iodobenzene with (4-amino-2-tert-butyl)-phenanthridine using 1,1'-bis(diphenylphosphino)ferrocene (dppf) leads to a side reaction involving the activation of dppf's P-C bond and the formation of a unique Pd(II) coordination complex. The study provides a comprehensive characterization of this complex and proposes a mechanism for the rare unstrained P-C-(cyclopentadienyl) bond activation.
Article
Chemistry, Organic
Issiah B. Lozada, Robert J. Ortiz, Jason D. Braun, J. A. Gareth Williams, David E. Herbert
Summary: A series of intramolecular, donor-stabilized BF2 complexes supported by phenanthridinyl-decorated, beta-ketoiminate chelating ligand scaffolds were characterized by spectroscopy and X-ray diffraction. The orientation of the phenanthridinyl arm in solution is fixed, despite not coordinating to the boron center, and a through-space interaction between phenanthridinyl C-H and a single fluorine atom was observed. Methylation of the phenanthridinyl nitrogen restricts rotation, leading to stronger emission in solution.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Christopher B. Larsen, Jason D. Braun, Issiah B. Lozada, Kristjan Kunnus, Elisa Biasin, Charles Kolodziej, Clemens Burda, Amy A. Cordones, Kelly J. Gaffney, David E. Herbert
Summary: Accessing panchromatic absorption and long-lived charge-transfer (CT) excited states is crucial for developing abundant-metal molecular photosensitizers. This study presents an aerobically stable Fe(II) complex with panchromatic absorption and a 3 ns excited-state lifetime, demonstrating the importance of metal-ligand covalency in elongating excited state lifetimes. The findings highlight a novel design principle for extending excited state lifetimes in abundant metal photosensitizers.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Inorganic & Nuclear
Issiah B. Lozada, J. A. Gareth Williams, David E. Herbert
Summary: A series of platinum (II) complexes of benzannulated pincer-type diarylamido ligands were synthesized and characterized, showing strong metal-to-ligand charge-transfer absorptions and phosphorescence at room temperature. Computational modeling revealed efficient population of the lowest-lying triplet state in these complexes. The optical properties were minimally affected by substituents in the phenanthridinyl unit, but emission was significantly quenched by molecular distortions in the excited state.
INORGANIC CHEMISTRY FRONTIERS
(2022)
Article
Chemistry, Inorganic & Nuclear
Dion B. Nemez, Issiah B. Lozada, Jason D. Braun, J. A. Gareth Williams, David E. Herbert
Summary: This study presents the synthesis, characterization, and coordination chemistry of a doubly pi-extended bipyridine analogue, 6,6'-biphenanthridine (biphe), as well as the emission properties of its coordination complexes in the excited state.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Issiah B. Lozada, Jason D. Braun, J. A. Gareth Williams, David E. Herbert
Summary: This study presents a series of unique Zn(II) complexes with a pseudo-octahedral structure. By incorporating phenanthridine units into the ligands, these complexes exhibit extended luminescence lifetimes in the solid state. The research also indicates the role of aggregation in enhancing emission in solid state.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
David E. Herbert
Summary: The C-N bond is crucial for the properties and reactivity of coordination complexes. This paper presents an overview of our work investigating the impact of site-selective benzannulation on the chemistry and properties of phenanthridine as a molecule and ligand.
CANADIAN JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Dion B. Nemez, Baldeep K. Sidhu, Kevin Carlin, Albert Friesen, David E. Herbert
Summary: The synthesis of novel analogues of the antimalarial (hydroxy)chloroquine was achieved through the substitution of the chloro group at the 4-position of 4,7-dichloroquinolines with amino alcohols. Short-chain and long-chain coupling partners were used, with electron-donating amino and dimethylamino substituents being tolerated. The compounds were characterized using various techniques and crystal structures of selected products were obtained.
CANADIAN JOURNAL OF CHEMISTRY
(2023)
News Item
Chemistry, Multidisciplinary
Robert J. Ortiz, David E. Herbert
Summary: Charge-transfer emission, which is rare for iron coordination complexes, has been observed in an Fe(iii) complex. The emission arises from both metal-to-ligand and ligand-to-metal charge transfer.
Article
Chemistry, Inorganic & Nuclear
Robert J. Ortiz, Michael Shepit, Johan van Lierop, J. Krzystek, Joshua Telser, David E. Herbert
Summary: The ligand fields of Ni(II) complexes supported by diarylamido pincer-type amido ligands were investigated. The ligand field parameters were determined using HFEPR, SQUID magnetometry, and electronic absorption spectroscopy. The ability to electrochemically address ligand-based oxidations and the presence of electronic communication between N-amido moieties were also studied.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Issiah B. Lozada, Daniel Gussakovsky, Amarasooriya M. D. S. Jayawardhana, Sean A. Mckenna, Yao-Rong Zheng, David E. Herbert
Summary: This article reports the non-specific interactions between Pt(II) complexes supported by chelating, multidentate ligands and DNA. It is shown that CF3LPtCl exhibits turn-on luminescence through intercalation-mediated mechanism in O2-saturated aqueous buffer. Visible light irradiation significantly enhances its activity, leading to increased photocytotoxicity against a variety of human cancer cell lines. Mechanistic studies reveal improved cellular uptake of CF3LPtCl compared with cisplatin, with localization in the nucleus and mitochondria triggering effective apoptosis. Photosensitization experiments demonstrate that CF3LPtCl efficiently generates singlet dioxygen (1O2), suggesting its potential in photodynamic therapy.
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Mahnaz Aryaeifar, Hadi Amiri Rudbari, Olivier Blacque, Mohammad Khairul Islam, Rosario Scopelliti, Jason D. Braun, David E. Herbert, Giuseppe Bruno, Christoph Janiak, Mohammed Enamullah
Summary: The synthesis and characterization of a series of complexes were carried out to investigate the role of stereochemical rigidity in chirality induction, with X-ray and computational methods providing structural and property information for the compounds.