O. Farha, Xuan Zhang, Julia G. Knapp, Sylvia L. Hanna, Zhijie Chen, Peng Li
{"title":"Coordination Chemistry in the Structural and Functional Exploration of Actinide-Based Metal-Organic Frameworks","authors":"O. Farha, Xuan Zhang, Julia G. Knapp, Sylvia L. Hanna, Zhijie Chen, Peng Li","doi":"10.4019/bjscc.75.3","DOIUrl":"https://doi.org/10.4019/bjscc.75.3","url":null,"abstract":"bonds between ion/cluster-based nodes and organic linkers. As compared to transition The coordination chemistry between inorganic and organic species can be optimally exemplified by metal–organic frameworks (MOFs), whose structures and functionalities can be rationally designed from these highly tunable building blocks. The high porosity, stability, and versatile functionalities of MOFs have attracted wide-spread attention from energy-related research and pollution remediation to biomedical applications. A unique and underexplored subset of these materials are MOFs based on actinide nodes; these MOFs have distinguished themselves as a unique platform for investigating the versatile oxidation states, reactivity, and coordination chemistry of actinides. Herein, we will focus on the rational design and synthesis of actinide-based MOFs under the general guidelines of coordination chemistry for their structural and functional explorations. The dimensionality, topology, and structures of actinide-based MOFs can be controlled by selecting pre-designed building blocks of actinide-based nodes and organic linkers with certain desired coordination geometries and functionalities. These unique actinide-based MOFs have shown promise for applications in nuclear waste mitigation, pollution control, and catalysis.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70515089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Supraspace Chemistry: Molecular Array, Reactions, In-situ Observation","authors":"M. Shionoya","doi":"10.4019/bjscc.74.3","DOIUrl":"https://doi.org/10.4019/bjscc.74.3","url":null,"abstract":"","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"74 1","pages":"3-8"},"PeriodicalIF":0.0,"publicationDate":"2019-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47867216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Soft Porous Crystals: Extraordinary Responses to Stimulation","authors":"Franccois-Xavier Coudert","doi":"10.4019/bjscc.73.15","DOIUrl":"https://doi.org/10.4019/bjscc.73.15","url":null,"abstract":"Recent years have seen a large increase in the number of reported framework materials, including the nowadays-ubiquitous metal-organic frameworks (MOFs). Many of these materials show flexibility and stimuli-responsiveness, i.e. their structure can undergo changes of large amplitude in response to physical or chemical stimulation. We describe here a toolbox of theoretical approaches, developed in our group and others, to shed light into these materials' properties. We focus on their behavior under mechanical constraints, temperature changes, adsorption of guest molecules, and exposure to light. By means of molecular simulation at varying scale, we can now probe, rationalize and predict the behavior of stimuli-responsive materials, producing a coherent description of soft porous crystals from the unit cell scale all the way to the behavior of the whole crystal. In particular, we have studied the impact of defects in soft porous crystals, and developed a methodology for the study of their disordered phases (presence of correlated disorder, MOF glasses, and liquid MOFs).","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/bjscc.73.15","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42564011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Geometric and Electronic Structural Contributions to Fe/O<sub>2</sub> Reactivity.","authors":"Edward I Solomon, Shyam R Iyer","doi":"10.4019/bjscc.73.3","DOIUrl":"https://doi.org/10.4019/bjscc.73.3","url":null,"abstract":"<p><p>While two classes of non-heme iron enzymes use ferric centers to activate singlet organic substrates for the spin forbidden reaction with <sup>3</sup>O<sub>2</sub>, most classes use high spin ferrous sites to activate dioxygen. These Fe<sup>II</sup> active sites do not exhibit intense absorption bands and have an integer spin ground state thus are mostly EPR inactive. We have developed new spectroscopic methodologies that provide geometric and electronic structural insight into the ferrous centers and their interactions with cosubstrates for dioxygen activation and into the nature of the intermediates generated in these reactions. First, we present our variable-temperature variable-field magnetic circular dichroism (VTVH MCD) methodology to experimentally define the geometric and electronic structure of the high spin ferrous active site. Then, we focus on using Nuclear Resonance Vibrational Spectroscopy (NRVS, performed at SPring-8) to define geometric structure and VTVH MCD to define the electronic structure of the Fe<sup>III</sup>-OOH and Fe<sup>IV</sup>=O intermediates generated in O<sub>2</sub> activation and the spin state dependence of their frontier molecular orbitals (FMOs) in controlling reactivity. Experimentally validated reaction coordinates are derived for the anticancer drug bleomycin in its cleavage of DNA and for an alpha- ketoglutarate dependent dioxygenase in its selective halogenation over the thermodynamically favored hydroxylation of substrate.</p>","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"73 ","pages":"3-14"},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/bjscc.73.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37921700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamic Structure-Conversion Programming of Metal Complexes in Response to External Stimuli: Chiral Sensing and Achiral Sensing","authors":"H. Miyake","doi":"10.4019/BJSCC.72.38","DOIUrl":"https://doi.org/10.4019/BJSCC.72.38","url":null,"abstract":"生体内の金属タンパク質は、生体分子の構造固定や、 高選択的な分子認識、さらには高い酵素活性など多彩な 機能発現を担っている。多くの場合、金属イオンは置換活 性な配位子交換特性を持ち、外部刺激に応答した構造変 換と特異な機能発現を示す。ヘモグロビンがよく知られた 例である。酸素分子がヘム鉄中心に配位すると鉄中心の 酸化状態が変化し、この状態変化が引き金となって、鉄イ オンのポルフィリン環中心への移動、ヒスチジン側鎖の移 動、と次々に構造情報が伝達していき、最終的には酸素 分子の取り込みに対してアロステリック効果を示す 。 生体分子中での構造情報の伝達は不斉環境下でなさ れるので、不斉構造を含む情報伝達も極めて重要であ る。人工系においては、不斉情報の伝達を活用した不斉 分子の絶対配置の決定と光学純度の定量を行う『キラリ ティーセンシング』や、外部刺激に応答してらせん などキラルな三次元構造の制御や変換を行う『らせんス イッチング』は、バイオ、ナノ、エコ、マテリアル をキーワードとする多くの化学者にとって重要な研究課 題となっている。不斉な金属錯体では、有機配位子内の キラリティーとともに、配位立体化学が形成する錯体キ ラリティーの解析と活用が重要である。例えば、コバル ト (III)イオンなど置換不活性な金属中心をもつ錯体で は、エチレンジアミンなど不斉点をもたない配位子から も Λ–体と Δ–体といった対掌体 (エナンチオマー )が単 離される。それらは沸騰水溶液中でさえ安定で、ラセミ 化せず取り扱いやすいが、亜鉛粉末を加えると置換活性 なコバルト (II)錯体へ還元されるため、2時間以内にラ セミ化してしまう 。しかし、生体中でのイベントのよ うに必要なときに必要な機能を発現するには、その構造 を外部刺激により意図的に動かすことが重要である。金 属錯体は、特徴ある配位立体化学に加え、レドックス活 性やユニークな光学/磁気的特性、さらに小分子の活性 化など魅力的な性質をもつ。これらを生体系でみられる ようならせん構造中で外部刺激に応答して協同的に発揮 できれば、超分子レベルでの構造制御と機能発現が期待 される。本報では外部刺激に応答できる置換活性なキラ ル金属錯体に焦点を絞り、最近報告された簡便な合成法 と『キラリティーセンシング』や『らせんスイッチング』 を含む動的な構造スイッチングについて解説する。 置換活性な第一遷移金属イオンからなる金属錯体は通 常 4~ 6配位型構造を形成しやすい。特に、弱配位子場 Labile metal complexes have a dynamic coordination bond which is generally weaker than a common covalent bond found in organic molecules but more useful for incorporation of external donor molecules reversibly and dynamically. Since such labile metal complexes can rapidly construct and/or change specific chiral molecular structures, dynamic conversion of chiral molecular shapes can be applicable to sensing chiral and achiral external stimuli. This review provides recent examples of labile metal complexes for sensing of chiral and achiral molecules, some of which offer dynamic conversion of chiral structures by rapid ligand exchange phenomena in response to not only one specific external stimulus but also a unique combination of some external stimuli. This kind of dynamic responsiveness in labile metal complexes would be applicable to sophisticated nanoscience and related technology including dynamic structure and/or function switching of natural and/or artificial molecules.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.72.38","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41862551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fluorescence Properties of Dye Molecules Interacting with Nanoparticle Surface in Dye-Dispersing Titania Gels","authors":"Hiromasa Nishikiori, Mitsuya Shinzato","doi":"10.4019/BJSCC.72.30","DOIUrl":"https://doi.org/10.4019/BJSCC.72.30","url":null,"abstract":"光吸収、発光、センシングなど様々な機能をもつ有機 分子を無機固体表面上に固定化したり、固体内部に閉じ 込めたりして材料として利用することは、新規材料開発 において重要な技術である。機能性色素分子をゾル-ゲ ル法により固体マトリックス中に分散させる研究は、古 くから多くの研究者らによって行われている 。キサン テン色素は特定の波長領域 (400–500 nm)でのモル吸光 係数が高く、蛍光量子収率も高いことから、光エネルギ ーの収集や発光を利用するための材料として有用であ る。キサンテン色素は会合や凝集をおこしやすいが、シ リコンアルコキシドの溶液に混合しゲル化させることに よりシリカゲル中に単量体として分散させることができ る 。色素の会合状態はその分光特性を大きく変える ため、光機能を求める上ではよく注目される点である。 ゾル-ゲル反応の出発溶液中に均一に分散されていた色 素分子は、シロキサンネットワークが成長する過程にお いてその間隙やゲル細孔となる初期構造の中に取り込ま れていく 。酸触媒を添加して調製したシリカゾルでは、 ゾル-ゲル反応の進行に伴い色素分子はシリコンアルコ キシドの線状の重合体の網目構造の中に個々に取り込ま れていく傾向があるため、二量体などの会合体は形成さ れにくくなる。水溶液中での二量化平衡定数の大きいロ ーダミン色素を用いた場合には、調製条件により二量体 を形成することが予想される。しかし、ゾル-ゲル転 移において体積が 1/10以下に収縮する条件においても、 多量体や凝集体を形成することなく、シリカゲルのネッ トワーク中または狭い間隙に単量体もしくは二量体とし て取り込まれる傾向がある 。さらに界面活性剤や有 機修飾シリコンアルコキシドを用いることにより、単量 体の割合を増加させることができ、レーザー発光の効率 や光安定性を向上させることができる 。シリカゲル やアルミナゲル中のローダミン色素は、単量体または J 型二量体として安定に存在し強い蛍光性を示すことがわ かっている 。シリカゲル内の化学的環境を変えるこ とにより、色素の構造や機能を制御できるところがこの 系の特徴である。 色素増感太陽電池は色素の光エネルギー収集機能と金 The dye–titania interaction is very important for the electron injection process in dye-sensitized solar cells (DSSCs). For example, the steam treatment of a fluorescein-dispersing amorphous titania film remarkably improved the photoelectric conversion efficiency due not only to its crystallization but also to the dye–titanium surface complex formation. The titanium chelation of the carboxylate and carbonyl of the dye was promoted in the narrow spaces among the titania nanoparticles. Such interaction caused the ligand-to-metal charge transfer (LMCT) interaction. The complex formation enhanced the photocurrent due to improvement in the efficiency of the electron injection into the titania conduction band for the photoelectric conversion. A great degree of fluorescence quenching was observed in the steam-treated titania due to the electron injection from the dye into the titania. On the other hand, relative fluorescence quantum efficiency of fluorescein was enhanced in the titania gel films containing a small amount of silica due to the strong hydrogen bonding interaction between the TiOH groups on the titania surface and the carboxylate and carbonyl of the fluorescein species and a transformation from the anion to the highly fluorescent dianion species.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49553384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}