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Parenting Attitudes and Abusive Parenting among Incarcerated Mothers in Japan. 日本被监禁母亲的养育态度和虐待性养育。
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-03-01 Epub Date: 2022-10-12 DOI: 10.1177/0306624X221124853
Ayako Sasaki, Akemi Mochizuki, Daiki Yoshihara

The primary focus of this study was to explore the parenting attitudes that predict abusive parenting among incarcerated mothers in Japan. Data analyzed on 63 incarcerated mothers who had the legal custody of the youngest child revealed that belief in corporal punishment significantly predicted abusive parenting. The data further revealed that the impact of adverse childhood experiences and the parenting style of an intimate partner remained significant in predicting the risk of abusive parenting. These multiple risk factors affecting child abuse perpetration indicate the need to develop a multi-dimensional intervention in prison settings to address those multiple issues.

本研究的主要重点是探讨可预测日本被监禁母亲虐待子女行为的养育态度。对 63 名拥有最小子女法定监护权的被监禁母亲的数据进行分析后发现,相信体罚在很大程度上预示着虐待性养育。数据进一步显示,童年的不良经历和亲密伴侣的教养方式对预测虐待儿童的风险仍有显著影响。这些影响虐待儿童行为的多重风险因素表明,有必要在监狱环境中制定多维干预措施,以解决这些多重问题。
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引用次数: 0
Power and Intimacy Motives in Narratives About Closeness Presented by People Staying in a Penitentiary Institution. 监狱囚犯讲述亲密关系时的权力和亲密动机
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-03-01 Epub Date: 2022-11-03 DOI: 10.1177/0306624X221133014
Katarzyna Czubak-Paluch, Małgorzata Łysiak

The world of people imprisoned in penitentiary institutions may never be understood by those who enjoy their freedom. The present study investigated the narratives about close relations, produced by inmates, with the analyses focusing specifically on the motive of power and the motive of intimacy, as described by McAdams. It was hypothesized that, depending on the length of prison sentence, the inmates would differ significantly regarding these motives and secondly that the motive of intimacy and the subjects' age would be significant predictors for the duration of the prison sentence. The study involved 356 male inmates (M = 28.80; SD = 10.91) who were asked to write stories about close relations with their partners. The findings show that individuals with longer prison sentence present a higher level of the power motive focused on building a stronger self, compared to the inmates sentenced to prison for a shorter duration. A multivariate regression analysis showed that the duration of imprisonment is positively predicted by the subjects' age and negatively by the motive of intimacy.

享受自由的人可能永远无法理解监狱中被监禁者的世界。本研究调查了囚犯对亲密关系的叙述,分析的重点是麦克亚当斯所描述的权力动机和亲密动机。研究假设,根据服刑时间的长短,囚犯在这些动机方面会有显著差异;其次,亲密关系动机和受试者的年龄将成为服刑时间的重要预测因素。这项研究涉及 356 名男性囚犯(M = 28.80;SD = 10.91),要求他们撰写与伴侣亲密关系的故事。研究结果表明,与刑期较短的囚犯相比,刑期较长的囚犯表现出更高水平的权力动机,其重点是建立更强大的自我。多元回归分析表明,刑期长短与受试者的年龄呈正相关,与亲密关系动机呈负相关。
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引用次数: 0
Nonconventional Luminophores: Emission Mechanism, Regulation, and Applications.
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-07 DOI: 10.1021/acs.accounts.4c00794
Zihao Zhao, Anze Li, Wang Zhang Yuan
<p><p>ConspectusNonconventional luminophores, characterized by the absence of extended (hetero)aromatic building blocks and alternating single-double/triple bonds, are composed primarily of electron-rich moieties, such as heteroatoms, double bonds, aliphatic amines, carbonyls, hydroxyls, cyano groups, amides, and their grouped functionalities. These unique structural features, coupled with their intriguing luminescent properties, have garnered significant interest for both fundamental research and promising applications, thus enabling widespread exploration. They generally benefit from abundant resources, simple synthesis, outstanding biocompatibility, and excellent photostability, empowering their potential applications in bioimaging, data storage and encryption, anticounterfeiting, bio- and chemosensing, etc. However, their research is preliminary, and the luminescence mechanisms remain elusive. For diverse systems, proposed conjectures, including tertiary amine oxidation, proton transfer, impurities, hydrogen bonding, and peptide bond electron delocalization, lack consistent correlation and universality, with some being subsequently invalidated. This lack of a unifying framework has hampered the development of effective guidelines for molecular design and photoluminescence (PL) regulation. To address these issues, a clustering-triggered emission (CTE) mechanism, focusing on the electron-molecule-aggregate multilevel structure-activity relationships, has been proposed. Specifically, it identifies the "clustered chromophores" of electron-rich moieties as emissive species. The CTE mechanism not only elucidates the emission behaviors of diverse nonconventional luminophores but also guides the PL regulation and further development of novel multifunctional luminescent materials.This Account begins with a concise introduction to the proposed CTE mechanism, highlighting the significance of electron delocalization (through-space conjugation) within the "clustered chromophores" of electron-rich groups. It then delves into insights gained from various nonconventional luminescent systems, identifying three core components of the CTE mechanism: electron-rich moieties, their clustering, and the conformational rigidity of the resulting clusters. The CTE mechanism proves to be rational and universally applicable, encompassing natural products, (macro)biomolecules, and synthetic compounds and extending from singlet fluorescence to triplet phosphorescence. By strategically coordinating these elements, it is feasible to modulate intra/intermolecular interactions, through-space conjugation, and spin-orbit coupling within the clusters, thus enabling effective PL regulation and achieving red/near-infrared (NIR) room-temperature phosphorescence (RTP) in these systems through both internal/chemical (e.g., incorporating additional bridging units and heavy atoms) and external/physical (e.g., pressurization, conformation adjustments) methods. Furthermore, we investigate
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引用次数: 0
Electrochemical Sensing Mechanisms and Interfacial Design Strategies of Mesoporous Nanochannel Membranes in Biosensing Applications.
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-06 DOI: 10.1021/acs.accounts.4c00764
Hui Zeng, Kang Liang, Lei Jiang, Dongyuan Zhao, Biao Kong
<p><p>ConspectusPrecise and rapid detection of key biomolecules is crucial for early clinical diagnosis. These critical biomolecules and biomarkers are typically present at low concentrations within complex environments, presenting significant challenges for their accurate and reliable detection. Nowadays, electrochemical sensors based on nanochannel membranes have attracted significant attention due to their high sensitivity, simplicity, rapid response, and label-free point-of-care detection capabilities. The confined arena provided by the nanochannels for target recognition and interactions facilitates detection and signal amplification, leading to enhanced detection performance. The nanochannel membranes also can act as filters to repel the interferents and enable target detection in more complex environments. Thus, sensors based on nanochannel membranes are considered promising platforms for biosensing applications. However, challenges such as uncontrollable structures and unstable performance in some materials limit their applications and theoretical advancements. To investigate the relationship between architecture and sensing performance and to achieve reliable and efficient performance, it is essential to construct sensors with precise nanostructures possessing stable properties. With the development of nanomaterials technology, mesoporous nanochannel membranes with robust, controllable, and ordered mesostructures, along with tunable surface properties and tailored ion transport dynamics, have emerged as promising candidates for achieving reliable and efficient biosensing performance. Additionally, investigating the sensing mechanisms and key influencing factors will provide valuable insights into optimizing sensor architecture and enhancing the efficiency and reliability of biosensing technologies. In this Account, we highlight substantial advancements in mesoporous nanochannel membranes, which are mainly based on the research work published by our group. In the first section, we explore the underlying mechanisms of the sensing processes, including the solid-liquid interfacial interactions and nanoconfinement effects (i.e., electrostatic interactions, hydrophilic/hydrophobic interactions, and steric hindrance effects). We also delve into the key parameters including geometry, materials, recognition elements, and external factors related to mesoporous nanochannel membranes and their impacts on sensing mechanisms and performance. In particular, we point out that mesoporous nanochannel membranes with three-dimensional interconnected networks can facilitate ion penetration and lead to an increased number of binding sites, contributing to high sensitivity. Additionally, composite or multilevel mesoporous nanochannel membranes, particularly when integrated with external stimuli such as pH, light, and heat, can introduce unexpected properties, enhancing the sensing performance. These understandings provide valuable insights into the fundamental
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引用次数: 0
Catalytic Hydrogenolysis of Lignin into Serviceable Products.
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-05 DOI: 10.1021/acs.accounts.4c00644
Shuizhong Wang, Xiancheng Li, Rumin Ma, Guoyong Song
<p><p>ConspectusLignin, a major component of lignocellulosic biomass, accounts for nearly 30% of organic carbon on Earth, making it the most abundant renewable source of aromatic carbon. The valorization of lignin beyond low-value heat and power has been one of the foremost challenges for a long time. On the other hand, aromatic compounds, constituting a substantial segment of the chemical industry and projected to reach a market value of $382 billion by 2030, are predominantly derived from fossil resources, contributing to increased CO<sub>2</sub> emissions. Integrating lignin into the aromatic chemical supply chain will offer a promising strategy to reduce the carbon footprint and boost the economic viability of biorefineries. Thus, depolymerizing lignin biopolymers into aromatic chemicals suitable for downstream processing is an important starting point for its valorization. However, owing to lignin's complexity and heterogeneity, achieving efficient and selective depolymerization that yields desirable, isolable aromatic monomers remains a significant scientific challenge.The structure of lignins varies significantly in terms of subunits and linkages across plant species, leading to considerable differences in their reactivity, in the distribution of resulting monomers, and in their subsequent utilization. In this context, this Account highlights our recent studies on the catalytic hydrogenolysis of lignin into serviceable products for preparing valuable materials, fuels, and chemicals. First, we designed a series of catalytic systems for lignin hydrogenolysis specifically tailored to the structural features of lignin from wood, grass, and certain seed coats. To reduce reliance on expensive commercial catalysts like Pd/C, Ru/C, and Pt/C, we advanced heterogeneous metal catalysts by shifting from high-loaded nanostructured metals to low-loaded, atomically dispersed metals and replacing precious metals with nonprecious alternatives. This approach significantly reduces the cost of catalysts, enhances their atomic economy, and improves their catalytic activity and/or selectivity. Then, using the developed catalysts, phenolic monomers tethering a distinct side chain were selectively generated from the hydrogenolysis of lignin (from various plants), achieving yields close to the theoretical maximum. The high selectivity allowed the separation and purification of monomeric phenols from lignin reaction mixtures readily. To gain deeper insights into the cleavage of lignin C-O bonds, we designed deuterium-incorporated β-O-4 mimics (dimers and one polymer) for a mechanistic study, which excluded the pathways involving the loss of linkage protons and led to the proposal of a concerted hydrogenolysis process for β-O-4 cleavage. Finally, to enable the utilization of depolymerized lignin phenolic monomers, unconventional feedstocks in the current chemical industry, we developed a series of methods to transform them into valuable bioactive molecules, function
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引用次数: 0
Biological Polymers: Evolution, Function, and Significance.
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-05 DOI: 10.1021/acs.accounts.4c00546
Kavita Matange, Eliav Marland, Moran Frenkel-Pinter, Loren Dean Williams
<p><p>ConspectusA holistic description of biopolymers and their evolutionary origins will contribute to our understanding of biochemistry, biology, the origins of life, and signatures of life outside our planet. While biopolymer sequences evolve through known Darwinian processes, the origins of the backbones of polypeptides, polynucleotides, and polyglycans are less certain. We frame this topic through two questions: (i) Do the characteristics of biopolymer backbones indicate evolutionary origins? (ii) Are there reasonable mechanistic models of such pre-Darwinian evolutionary processes? To address these questions, we have established criteria to distinguish chemical species produced by evolutionary mechanisms from those formed by nonevolutionary physical, chemical, or geological processes. We compile and evaluate properties shared by all biopolymer backbones rather than isolating a single type. Polypeptide, polynucleotide, and polyglycan backbones are kinetically trapped and thermodynamically unstable in aqueous media. Each biopolymer forms a variety of elaborate assemblies with diverse functions, a phenomenon we call polyfunction. Each backbone changes structure and function upon subtle chemical changes such as the reduction of ribose or a change in the linkage site or stereochemistry of polymerized glucose, a phenomenon we call function-switching. Biopolymers display homo- and heterocomplementarity, enabling atomic-level control of structure and function. Biopolymer backbones access recalcitrant states, where assembly modulates kinetics and thermodynamics of hydrolysis. Biopolymers are emergent; the properties of biological building blocks change significantly upon polymerization. In cells, biopolymers compose mutualistic networks; a cell is an Amazon Jungle of molecules. We conclude that biopolymer backbones exhibit hallmarks of evolution. Neither chemical, physical, nor geological processes can produce molecules consistent with observations. We are faced with the paradox that Darwinian evolution relies on evolved backbones but cannot alter biopolymer backbones. This Darwinian constraint is underlined by the observation that across the tree of life, ribosomes are everywhere and always have been composed of RNA and protein. Our data suggest that chemical species on the Hadean Earth underwent non-Darwinian coevolution driven in part by hydrolytic stress, ultimately leading to biopolymer backbones. We argue that highly evolved biopolymer backbones facilitated a seamless transition from chemical to Darwinian evolution. This model challenges convention, where backbones are products of direct prebiotic synthesis. In conventional models, biopolymer backbones retain vestiges of prebiotic chemistry. Our findings, however, align with models where chemical species underwent iterative and recursive sculpting, selection, and exaptation. This model supports Orgel's "gloomy" prediction that modern biochemistry has discarded vestiges of prebiotic chemistry. B
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引用次数: 0
Near-Infrared-II Fluorescent Probes for Analytical Applications: From In Vitro Detection to In Vivo Imaging Monitoring.
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-05 DOI: 10.1021/acs.accounts.4c00671
Sha Liu, Wenhong Dong, Hui-Quan Gao, Zhaorui Song, Zhen Cheng
<p><p>ConspectusBiomarkers play a vital role in the regulation of life processes, especially in predicting the occurrence and development of diseases. For the early diagnosis and precise treatment of diseases, it has become necessary and significant to detect biomarkers with sensitivity, accuracy, simplicity, convenience, and even visualization. Fluorescent-probe-based techniques have been recognized as one of the most powerful tools for the sensitive detection and real time imaging of biomarkers in biological samples. However, traditional optical probes, mainly including the visible probes (400-700 nm) and the near-infrared I (NIR-I, 700-900 nm) probes, suffer from low sensitivity, poor resolution, strong absorption and scattering, and high background fluorescence, which hinder effective monitoring of biomarkers.Fortunately, the past decade has witnessed a remarkable evolution in the application fields of near-infrared II (NIR-II, 900-1700 nm) fluorescence, driven by its exceptional optical characteristics and the advancement of imaging technologies. Leveraging the superior penetration capabilities, negligible autofluorescence, and extended fluorescence emission wavelengths, NIR-II fluorescent probes significantly enhance the signal-to-noise ratio (SNR) of <i>in vitro</i> detection (IVD) and the temporal resolution of <i>in vivo</i> imaging. Our team has been committed to the design strategy, controlled synthesis, luminous mechanisms, and biomedical applications of NIR-II fluorescent probes. In this Account, we present the representative works in recent years from our group in the field of NIR-II fluorescent probes for analytical applications, ranging from <i>in vitro</i> detection of biomarkers to <i>in vivo</i> imaging monitoring of different biomarkers and various diseases, which also will further provide a general overview of analytical applications of NIR-II fluorescence probes. First, the <i>in vitro</i> analytical applications of NIR-II fluorescent probes are fully summarized, including tumor marker detection, virus and bacteria analysis, cell testing, and small-molecule sensing. Second, the <i>in vivo</i> imaging monitoring applications of NIR-II fluorescent probes are adequately discussed, including ROS detection, gas monitoring, pH sensing, small-molecule testing, receptor analysis, and the imaging diagnosis of some serious diseases. Finally, we further outline the application advantages of NIR-II fluorescent probes in analytical fields and also discuss in detail some challenges as well as their future development. There is a reasonable prospect that the <i>in vitro</i> detection technology and the <i>in vivo</i> imaging monitoring technology based on NIR-II fluorescent probes will exhibit great development potential in biomedical research and clinical disease diagnosis. We hope that this Account can expand their reach into an even broader spectrum of fields, further enhancing their impact on scientific discovery and medical practice.<
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引用次数: 0
Physical Phenomena in Porous Frameworks
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-04 DOI: 10.1021/acs.accounts.4c0083510.1021/acs.accounts.4c00835
Thomas Heine*, Mircea Dinca and Guangshan Zhou, 
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引用次数: 0
Computational Modeling of Electrocatalysts for CO2 Reduction: Probing the Role of Primary, Secondary, and Outer Coordination Spheres. 二氧化碳还原电催化剂的计算建模:探究主配位层、次配位层和外配位层的作用。
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-04 Epub Date: 2025-01-27 DOI: 10.1021/acs.accounts.4c00631
Christina M Zeng, Julien A Panetier
<p><p>ConspectusIn the search for efficient and selective electrocatalysts capable of converting greenhouse gases to value-added products, enzymes found in naturally existing bacteria provide the basis for most approaches toward electrocatalyst design. Ni,Fe-carbon monoxide dehydrogenase (Ni,Fe-CODH) is one such enzyme, with a nickel-iron-sulfur cluster named the C-cluster, where CO<sub>2</sub> binds and is converted to CO at high rates near the thermodynamic potential. In this Account, we divide the enzyme's catalytic contributions into three categories based on location and function. We also discuss how computational techniques provide crucial insight into implementing these findings in homogeneous CO<sub>2</sub> reduction electrocatalysis design principles. The CO<sub>2</sub> binding sites (e.g., Ni and "unique" Fe ion) along with the ligands that support it (e.g., iron-sulfur cluster) form the primary coordination sphere. This is replicated in molecular electrocatalysts via the metal center and ligand framework where the substrate binds. This coordination sphere has a direct impact on the electronic configuration of the catalyst. By computationally modeling a series of Ni and Co complexes with bipyridyl-<i>N</i>-heterocyclic carbene ligand frameworks of varying degrees of planarity, we were able to closely examine how the primary coordination sphere controls the product distribution between CO and H<sub>2</sub> for these catalysts. The secondary coordination sphere (SCS) of Ni,Fe-CODH contains residues proximal to the active site pocket that provide hydrogen-bonding stabilizations necessary for the reaction to proceed. Enhancing the SCS when synthesizing new catalysts involves substituting functional groups onto the ligand for direct interaction with the substrate. To analyze the endless possible substitutions, computational techniques are ideal for deciphering the intricacies of substituent effects, as we demonstrated with an array of imidazolium-functionalized Mn and Re bipyridyl tricarbonyl complexes. By examining how the electrostatic interactions between the ligand, substrate, and proton source lowered activation energy barriers, we determined how best to pinpoint the SCS additions. The outer coordination sphere comprises the remaining parts of Ni,Fe-CODH, such as the elaborate protein matrix, solvent interactions, and remote metalloclusters. The challenge in elucidating and replicating the role of the vast protein matrix has understandably led to a localized focus on the primary and secondary coordination spheres. However, certain portions of Ni,Fe-CODH's expansive protein scaffold are suggested to be catalytically relevant despite considerable distance from the active site. Closer studies of these relatively overlooked areas of nature's exceptionally proficient catalysts may be crucial to continually improve upon electrocatalysis protocols. Mechanistic analysis of cobalt phthalocyanines (CoPc) immobilized onto carbon nanotubes (CoPc/CN
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引用次数: 0
Using NMR Spectroscopy to Evaluate Metal-Ligand Bond Covalency for the f Elements. 用核磁共振光谱法评价金属-配体f元素的键共价。
IF 16.4 1区 化学 Q1 CHEMISTRY, MULTIDISCIPLINARY Pub Date : 2025-02-04 Epub Date: 2025-01-22 DOI: 10.1021/acs.accounts.4c00727
Trevor W Hayton, Jochen Autschbach
<p><p>ConspectusUnderstanding f element-ligand covalency is at the center of efforts to design new separations schemes for spent nuclear fuel, and is therefore of signficant fundamental and practical importance. Considerable effort has been invested into quantifying covalency in f element-ligand bonding. Over the past decade, numerous studies have employed a variety of techniques to study covalency, including XANES, EPR, and optical spectroscopies, as well as X-ray crystallography. NMR spectroscopy is another widely available spectroscopic technique that is complementary to these more established methods; however, its use for measuring 4f/5f covalency is still in its infancy. This Account describes efforts in the authors' laboratories to develop and validate multinuclear NMR spectroscopy as a tool for studying metal-ligand covalency in the actinides and selected lanthanide complexes. Thus far, we have quantified M-L covalency for a variety of ligand types, including chalcogenides, carbenes, alkyls, acetylides, amides, and nitrides, and for a variety of isotopes, including <sup>13</sup>C, <sup>15</sup>N, <sup>77</sup>Se, and <sup>125</sup>Te. Using NMR spectroscopy to probe M-C and M-N covalency is particularly attractive because of the ready availability of the<sup>13</sup>C and <sup>15</sup>N isotopes (both <i>I</i> = 1/2), and also because these elements are found in some of the most important f element ligand classes, including alkyls, carbenes, polypyridines, amides, imidos, and nitrides.The covalency analysis is based on the chemical shift (δ) and corresponding nuclear shielding constant (σ) of the metal-bound nucleus. The diamagnetic (σ<sub>dia</sub>), paramagnetic (σ<sub>para</sub>), and spin-orbit contributions (σ<sub>SO</sub>) to σ can be obtained and analyzed by relativistic density functional theory (DFT). Of particular importance is σ<sub>SO</sub>, which arises from the combination of spin-orbit coupling, the magnetic field, and chemical bonding. Its magnitude correlates with the amount of ligand s-character and metal <i>n</i>f (and (<i>n</i>+1)d) character in the M-L bond. In practice, Δ<sub>SO</sub>, the total difference between calculated chemical shift for the ligand nucleus including vs excluding SO effects, provides a more convenient metric for analysis. For the examples discussed herein, Δ<sub>SO</sub> accounts primarily for σ<sub>SO</sub> in an f-element complex, but also includes minor SO effects on the other shielding mechanisms and (usually) minor SO effects on the reference shielding. Δ<sub>SO</sub> can be very large, as in the case of [U(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>6</sub>] (348 ppm), which is not surprising as the An-C bonds in this example exhibits a high degree of covalency (e.g., 20% 5f character). However, even small values of Δ<sub>SO</sub> can indicate profound bonding effects, as shown by our analysis of [La(C<sub>6</sub>Cl<sub>5</sub>)<sub>4</sub>]<sup>-</sup>. In this case, Δ<sub>SO</sub> is only 9 ppm,
理解元素-配体共价是设计新的乏核燃料分离方案的核心,因此具有重要的基础和实际意义。大量的努力已经投入到定量共价在元素-配体键。在过去的十年中,许多研究采用了各种各样的技术来研究共价,包括XANES、EPR、光谱学以及x射线晶体学。核磁共振波谱是另一种广泛使用的光谱技术,是这些更成熟的方法的补充;然而,用它来测量4f/5f共价仍处于起步阶段。本报告描述了作者在实验室开发和验证多核核磁共振波谱作为研究锕系元素和选定镧系元素配合物中金属配体共价的工具所做的努力。到目前为止,我们已经量化了各种配体类型的M-L共价,包括硫属化合物、碳烯、烷基、乙酰基、酰胺和氮化物,以及各种同位素,包括13C、15N、77Se和125Te。利用核磁共振光谱来探测M-C和M-N共价是特别有吸引力的,因为13c和15N同位素(都是I = 1/2)的可用性,也因为这些元素存在于一些最重要的f元素配体类中,包括烷基、羰基、多吡啶、酰胺、酰亚胺和氮化物。共价分析是基于金属束缚核的化学位移(δ)和相应的核屏蔽常数(σ)。利用相对论密度泛函理论(DFT)可以得到并分析了抗磁(σdia)、顺磁(σpara)和自旋轨道对σ的贡献(σ so)。特别重要的是σSO,它是自旋轨道耦合、磁场和化学键共同作用的结果。它的大小与M-L键中配体s字符和金属nf(和(n+1)d)字符的数量有关。在实践中,ΔSO,计算的配体核化学位移的总差,包括vs,不包括SO效应,为分析提供了更方便的度量。对于本文讨论的例子,ΔSO主要解释了f元素络合物中的σSO,但也包括对其他屏蔽机制的轻微SO影响,以及(通常)对参考屏蔽的轻微SO影响。ΔSO可以非常大,例如[U(CH2SiMe3)6] (348 ppm),这并不奇怪,因为本例中的An-C键显示出高度的共价(例如,20%的5f字符)。然而,即使ΔSO的值很小,我们对[La(C6Cl5)4]-的分析也表明,它可以表明深刻的键合效应。在这种情况下,ΔSO仅为9ppm,与高离子化的La-C键(例如,
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引用次数: 0
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Accounts of Chemical Research
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