{"title":"Utilization of Polymeric Cyano-Bridged Metal Complexes as Heterogeneous Catalysts","authors":"Yamada Yusuke","doi":"10.4019/BJSCC.68.16","DOIUrl":"https://doi.org/10.4019/BJSCC.68.16","url":null,"abstract":"触媒は、種々の化学プロセスにおける化成品の合成や 排ガス処理などの環境浄化プロセスなど様々な用途で利 用されている重要な機能性材料であり、新しい化成品が 一つ生まれる度に、新しい触媒が一つ生みだされている と言われている。触媒はその使用時の形態により均一系 触媒と不均一系触媒に分類され、このうち不均一系触媒 は主に固体触媒である。固体触媒は、寿命が長い、反応 物や生成物からの分離や取扱いが容易である、といった 特徴を持つことから工業的に重要である。 これまで固体触媒材料としては、金属や金属酸化物が 多く用いられてきた。これらの材料の表面に生成する触 媒反応の活性点は、主に、吸着原子や、ステップやキン クと呼ばれる配位不飽和サイトである(Fig. 1)。これ らの活性点まわりの構造や電子状態を精密に制御するこ とで、より高活性かつ高選択的な触媒が得られる。しか し、これまで用いられてきた金属酸化物や金属の表面の 任意の場所に、配位不飽和サイトを意図的に作り出し、 原子レベルでその電子状態や配位環境を含めた立体構造 を精密に制御することは容易ではなく、分子性の新しい 固体触媒材料の利用が必要である。 配位高分子とは、架橋性配位子を用いることで複数の 金属イオンが連なった構造を持つ固体の金属錯体のポリ マーである 。近年、フタル酸やピラジンを始めとする 種々の架橋性多座配位子を利用して多くの配位高分子が 合成され、その合成や物性に関する研究が精力的に行わ れている 。これらの配位高分子の中で最も古くから 研究されているのは、プルシアンブルーに代表されるシ アノ配位子を用いたシアノ架橋金属錯体ポリマーであ る。シアノ架橋金属錯体ポリマーは、溶液中でアニオン 性の [M(CN)6] と適当な金属カチオン(M)を反応さ Recent reports on utilization of polymeric cyano-bridged metal complexes, which have reticular structures utilizing MC–CN–MN coordination networks, as heterogeneous catalysts have been reviewed. Among the complexes, the most widely investigated ones contain zinc ions at MN sites acting as Lewis acid, where polymerization of epoxide such as propylene oxide, esterification of fatty acids, and hydrolysis of glycerides are catalyzed. Another class of complexes containing redox active transition metals such as iron(II), cobalt(II) and copper(II) at MN sites, catalyze oxidation and reduction reactions. Some complexes thermally oxidize benzene and styrene to phenol and styrene oxide with hydrogen peroxide, respectively. Additionally, some complexes can also photocatalyze Fenton reaction to decompose organic dyes with hydrogen peroxide, benzene oxidation to phenol with molecular oxygen, and water oxidation to evolve dioxygen together with a photosensitizer. All the complexes allow the improvements to achieve highly active catalysts based on atomic insights with various manners.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"127 1","pages":"28"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.68.16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70514341","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":"Fluorescent Detection of Metal Ions and Pyrophosphate with TQEN-Based Quinoline Derivatives","authors":"Y. Mikata","doi":"10.4019/BJSCC.68.3","DOIUrl":"https://doi.org/10.4019/BJSCC.68.3","url":null,"abstract":"T P E N ( N , N , N ’ , N ’ t e t r a k i s ( 2 p y r i d y l m e t h y l ) ethylenediamine) は EDTA (ethylenediamine-N,N,N’,N’tetraacetic acid) の酢酸部位をピリジルメチル基に置き換 えた化合物であり(図 1)、様々な金属イオンと単核あ るいは複核錯体を形成する。TPEN の六つの窒素原子が 全て配位した六配位八面体構造を有する単核錯体の結晶 構造として、Fe, Hg, Zn, Cu, Co, Ni, Ru, Cr 錯体などが知 られている。TPEN は合成および精製が容易で、比較的 扱いやすい化合物である。解離するプロトンを持たず、 中性付近では電荷を持たない。EDTA と比較して脂溶性 が高く、細胞膜を通過して細胞の中に取り込まれる。 本研究では、TPEN のピリジルメチル基をキノリ ル メ チ ル 基 に 置 き 換 え た TQEN (N,N,N’,N’-tetrakis(2quinolylmethyl)ethylenediamine) に着目した(図 1)。金属 に対する配位部位として見た場合、キノリンはピリジン と比較して、塩基性の低さとペリ水素による立体障害の ため、金属に対する配位力が弱くなることが知られてい る。このように、弱い配位力のため錯体が不安定になる 点は一般的にあまり有利とは言えないが、金属配位の際 の立体障害により大きなイオン半径を有する金属との錯 形成が相対的に有利になると捉えるとこれは長所となり 得る。キノリンを含む化合物は剛直性があり、また分子 内および分子間でのスタッキング相互作用も期待できる ため、対応するピリジン化合物と比べて一般に結晶性が 良く、錯体の構造を結晶構造解析から議論できる点で非 常に有利である。さらに、キノリンは蛍光団としての機 能も持ち合わせている。筆者らはこれまで、蛍光団と金 属補足部位とが一体となったキノリン化合物の機能に関 する研究を行ってきた。本稿では、TQEN から始まるキ ノリン化合物の金属イオンセンサーとしての進化の過程 について筆者らの研究成果を中心に紹介する。","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"68 1","pages":"3-15"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.68.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70514490","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":"Photophysical Properties and Application of Transition Metal Complexes Having Arylborane Units","authors":"Eri Sakuda","doi":"10.4019/BJSCC.67.62","DOIUrl":"https://doi.org/10.4019/BJSCC.67.62","url":null,"abstract":"In this review, we overview the recent research trends on the photophysical properties and its application of metal complexes having arylborane charge transfer unit(s). The vacant p-orbital on the boron atom (p(B)) in a triarylborane derivative plays important roles in determining the electronic structure and the photophysical properties of the derivative. Recent studies on the spectroscopic and excited-state properties of arylborane compounds indicated that the characteristic absorption and emission bands were ascribed essentially to the charge transfer (CT) transition between the p -orbital of the aryl group ( p (aryl)) and p(B) : p (aryl)-p(B) CT. By utilizing such characteristics of triarylborane derivatives, new and novel approaches toward tuning of the redox, spectroscopic, and excited-state properties of metal complexes have been explored through combining the p (aryl)-p(B) CT interaction in a triarylborane derivative with the metal-to-ligand charge transfer (MLCT), intramolecular charge transfer (ILCT) state and electron or energy transfer of a metal complex.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"67 1","pages":"62-74"},"PeriodicalIF":0.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.67.62","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70514143","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":"Insertion of Molecular Oxygen into Palladium and Platinum-sp 3 Carbon Bonds","authors":"Y. Ura","doi":"10.4019/BJSCC.65.49","DOIUrl":"https://doi.org/10.4019/BJSCC.65.49","url":null,"abstract":"","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"65 1","pages":"49-52"},"PeriodicalIF":0.0,"publicationDate":"2015-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.65.49","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513271","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":"Metal-Organic Frameworks and Porous Coordination Polymers: Properties and Applications","authors":"M. P. Suh","doi":"10.4019/BJSCC.65.9","DOIUrl":"https://doi.org/10.4019/BJSCC.65.9","url":null,"abstract":"Metal-organic frameworks (MOFs) and porous coordination polymers (PCPs) generally have defined structures, permanent porosity, and high specific surface areas. They are synthesized from metal and organic building blocks by solvothermal reactions or self-assembly. MOFs and PCPs are considered to be a class of the most promising materials for hydrogen storage and for gas separation such as carbon dioxide capture from the flue gas or natural gas. However, gas adsorption on the pore surface of MOFs and PCPs is physisorption, and the interaction energy between the adsorbents and gas is too weak. Therefore, even though large amount of gases can be stored in the materials at a low temperature, the storage capacity falls down to very low values at ambient temperature. To enhance hydrogen gas storage in MOFs and PCPs, we have modified their pore spaces by various methods such as generating accessible metal sites, fabricating metal nanoparticles (NPs), including proper organic guests, and incorporating specific metal ion binding sites in the ligand. The generation of accessible metal sites is based on “Kubas” interactions of hydrogen molecules with the metal ions. The production of metal nanoparticles in PCPs, without using extra reducing agent and NP-stabilizing agents just at room temperature, is based on the redox chemistry between the redox-active components of the MOFs or PCPs and the metal ions. To capture CO2 selectively from the industry flue gas that contains not only CO2 but also other gases, we have developed smart 3-dimensional (3D) PCPs with very small pores, which are highly flexible. Since CO2 molecule has much higher polarizability and quadrupole moment than other gases, it would interact much more strongly with the flexible PCPs with very small pores and open up the windows while other gases cannot. We have also created various strategies such as post-synthetic modification of pore space with highly flexible carboxyl pendants, impregnation of metal ions in the pores of a MOF, and inclusion of branched polyethylenimine units in the pores of porous organic polymer. These induce stronger interactions with the CO2 molecules, and enhance the gas uptake capacities and the selectivity of CO2 adsorption In this review, properties and applications of metal-organic frameworks (MOFs) and porous coordination polymers (PCPs) are described. Many MOFs and PCPs are highly flexible and responsive to external stimuli. Sometimes they transform their structures to others by maintaining the single crystallinity. For decades, MOFs and PCPs have been regarded as a class of the promising materials for hydrogen storage and carbon dioxide capture applications since they adsorb large amounts of gases at low temperatures. However, their gas uptake capacities decrease dramatically at ambient temperature compared to those at low temperatures because they physic-sorb gases by weak interaction energies. Therefore, to enhance gas storage and separation abilities of MOFs a","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"65 1","pages":"9-22"},"PeriodicalIF":0.0,"publicationDate":"2015-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.65.9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513334","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":"Coordination Chemistry of Polyoxovanadates as Inorganic Ligands","authors":"Y. Hayashi","doi":"10.4019/BJSCC.66.12","DOIUrl":"https://doi.org/10.4019/BJSCC.66.12","url":null,"abstract":"ポリオキソメタレートは、酸素酸が縮合して形成され る分子性の多核金属酸素酸クラスターである。水溶液中 の酸素酸 [MOa]は、酸による脱水縮合反応によりポリ オキソメタレート [MmOb]を形成する。その結果、金 属イオン 1個当たりの酸素原子数は減少する (a > b/m)。 酸化物MxOyは、形式的にポリオキソメタレートがさら に脱水縮合した組成を持ち、O/M比がさらに小さくな る (b/m > y/x)。ポリオキソメタレートは、イソポリオ キソメタレート [McOd]およびヘテロポリオキソメタレ ート [XeMfOg]に分類され、ヘテロポリオキソメタレー トにはヘテロ原子と呼ばれる骨格を形成する金属イオ ンMとは異なる元素 Xが含まれる。最も 代表的なポリオキソ メタレートは、ケギ ン型 [XM12O40]やド ーソン型 [X2M18O62] などのヘテロポリオ キソメタレートであ る。これらの化合物は、可溶性の陰イオンとして存在し アルカリ金属イオンやアンモニウムイオンなどの塩とし て単離できる。リチウムやナトリウム塩はより大きな陽 イオンの塩よりも水に溶けやすい。アルキルアンモニウ ム類似の有機陽イオンを用いると、アセトン、アセトニ トリルやニトロメタンのような有機溶媒に可溶な塩を合 成できる 。現在ポリオキソメタレートは、アクチノイ ド元素を含む多様なヘテロ原子の導入や有機配位子との ハイブリッド化、それに伴う幅広い構造の多様性、そし て、最高酸化数の金属イオンから成る無機骨格の特徴か ら生じる耐酸化性や酸としての性質を応用して触媒やさ まざまな応用的視点からの研究が進められている 。 ポリオキソメタレートの末端酸素原子は金属との二重 結合M=Oと見なす。架橋酸素原子は、m2-架橋から m6架橋などの架橋形態が知られている。ポリオキソメタレ ートの構造は、100個以上の金属イオンからなるナノ分 子にまで拡張できるので、通常用いられる棒と球モデル で構造式を表すには複雑すぎる。そこで、図 1で示した ように多面体モデルで表すとMO6単位が単純に表され るので見やすくなる。MO4単位の場合は四面体で表現 する。多面体モデルでは、その中心に金属イオンが存在 し、頂点には酸素原子が存在する。 ポリオキソメタレートの末端酸素または架橋酸素原子 は、プロトン化に引き続く脱水縮合反応により反応する ので、水溶液中でポリオキソメタレートは異なる化学種 へと変化することができる。溶液中では、プロトン化し た化学種を含む、いくつかの関連する化学種と平衡状 態になる場合が多い。平衡化学種の分布は、pH、濃度、 Inorganic ligands, such as polyoxovanadates, may offer a new way to further expand the boundary of coordination chemistry for inorganic complexes featuring a part of metal oxide structures. Many industrially important applications require metal oxides that support modern electronics, magnets, sensors, and catalysts. However, because of the complexity of the oxides, it is difficult to elucidate the structure and property relationships. Investigating the reactivity and physical properties by modifying the oxide structures in a systematic manner is challenging to test the hypothesis of a postulated mechanism. For these reasons, designing a model complex to replicate those properties and reactivity is important by utilizing polyoxometalates as all-inorganic ligands. In this article, the fundamental chemistry of polyoxovanadates is described from the point of inorganic ligand system by the classification based on their structural building units.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"66 1","pages":"12-25"},"PeriodicalIF":0.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.66.12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513398","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}