Metal coordination has been used extensively as a template strategy in the field of supramolecular chemistry. Preorganization of molecular components into a desirable orientation by metal complexation has allowed for the designed synthesis of interlocking molecules in high yields. Synthetic chemists have since learned to intertwine discrete molecular entities into entangled architectures with increasing complexity limited only by imagination. This template strategy has recently been implemented in the making woven extended structures. By linking building units that contain a metal complex core, twoand three-dimensional (2D and 3D) frameworks can be constructed where long threads of covalently linked molecules that are interwoven at regular intervals and templated by the metal ions. Upon demetalation, the threads have high degrees of freedom for spatial deviation to take place between them while preserving the overall structure, endowing the material with exceptional mechanical properties and dynamics.
{"title":"Metal coordination as a template strategy to make resilient woven materials","authors":"Yuzhong Liu, O. Yaghi","doi":"10.4019/BJSCC.71.12","DOIUrl":"https://doi.org/10.4019/BJSCC.71.12","url":null,"abstract":"Metal coordination has been used extensively as a template strategy in the field of supramolecular chemistry. Preorganization of molecular components into a desirable orientation by metal complexation has allowed for the designed synthesis of interlocking molecules in high yields. Synthetic chemists have since learned to intertwine discrete molecular entities into entangled architectures with increasing complexity limited only by imagination. This template strategy has recently been implemented in the making woven extended structures. By linking building units that contain a metal complex core, twoand three-dimensional (2D and 3D) frameworks can be constructed where long threads of covalently linked molecules that are interwoven at regular intervals and templated by the metal ions. Upon demetalation, the threads have high degrees of freedom for spatial deviation to take place between them while preserving the overall structure, endowing the material with exceptional mechanical properties and dynamics.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.71.12","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43018360","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}
錯体化学を基盤とした応用研究における代表例の一つ として、Metal–Organic Framework (MOF) などの多孔性 配位高分子をはじめとした多孔性結晶材料の開発と機 能化が挙げられる 。これら多孔性結晶の主な用途は、 物質貯蔵や混合物分離、重合反応、触媒などであり、最 近では包接分子の構造解析手法としても活用されはじめ ているが、これらの機能の根幹は言うまでもなく結晶細 孔内への分子の包接である。すなわち、多孔性結晶の機 能設計や性能向上を図るためには、結晶細孔内での分子 包接・配列を精密に設計・制御することが極めて重要で ある。 そのためのアプローチの一つとして、分子認識能を有 するホスト化合物を構成要素として多孔性結晶を作成す ることができれば、細孔内での分子包接・配列をあらか じめプログラムすることが可能となり、その設計性およ び包接効率を格段に向上させることができる 。すな わち、環状ないしはケージ状ホスト化合物を構成要素と した多孔性結晶を合成できれば、それらの構成要素が本 来持つ高い分子認識能を結晶細孔内にそのまま組み込む ことが可能となる(Fig. 1)。例えば配位高分子では、柱 となる有機配位子にクラウンエーテル やピラーアレ ーン などの環状ホスト化合物を組み込んだ多孔性結 晶が合成されている。また、環状ホスト化合物自身を配 位高分子の柱そのものとして活用することもでき、その 代表例の一つは Stoddartらによって開発された CD-MOF であり、これはシクロデキストリン(CD)とアルカリ 金属イオンからなる多孔性配位高分子である。興味深い ことに、ある種の CD-MOFは食用原料のみから合成す ることも可能であり、Edible MOFとしても知られてい In this account, a new method for the creation of porous functional materials based on the self-organization of metallomacrocycles is described. For instance, the authors have developed a new series of porous molecular crystals, metal– macrocycle frameworks (MMFs), through crystallization of Pd3-macrocycles. It was also found that MMFs with multiple binding pockets on the pore surface served as excellent host frameworks for precise molecular arrangement, chiral recognition, sizespecific catalytic reaction, and in situ observation of a molecular adsorption process. In addition, the one-dimensional assembly of metallomacrocycles is also described as another approach for the construction of metal-modified pores and various metal arrays. This method is therefore one of the promising ways to develop unique porous materials such as highly efficient and selective catalysts based on the precise arrangement of guest compounds and metal ions in the pores.
作为以络合物化学为基础的应用研究的代表例之一，可以举出以Metal-Organic Framework（MOF）等多孔性配位高分子为首的多孔性结晶材料的开发和功能化。这些多孔性晶体的主要用途是物质贮藏、混合物分离、聚合反应、催化剂等，最近也开始作为包接分子的结构解析方法被活用，但这些功能的根本不言而喻是分子包接到晶体细孔内。即，为了实现多孔性晶体的功能设计和性能提高，精密地设计、控制晶体细孔内的分子包接、排列是极其重要的。作为为此的方法之一，如果能够以具有分子识别能力的主体化合物为构成要素制作多孔性晶体，则能够对细孔内的分子包接、排列进行粗加工程序，能够显著提高其设计性和包接效率。即，如果能够合成以环状或笼状主体化合物为构成要素的多孔性晶体，则能够将这些构成要素原本具有的高分子识别能力直接组装到晶体细孔内（Fig.1）。例如，在配位高分子中，合成了在作为柱的有机配位体中组装有冠醚或柱芳烃等环状主体化合物的多孔性结晶。另外，也可以将环状主体化合物自身作为配位高分子的柱本身来活用，其代表例之一是由Stoddart等人开发的CD-MOF，其是由环糊精（CD）和碱金属离子构成的多孔性配位高分子。有趣的是，某些CD-MOF也可以仅由食用原料合成，作为Edible MOF而广为人知的In this account，anew method for the creation of porous functional materials based on the self-organization of metallomacrocycles is described。For instance，the authors have developed anew series of porous molecular crystals，metal-macrocycle frameworks（MMFs），through crystallization of Pd3-macrocycles。It was also found that MMFs with multiple binding pockets on the pore surface served as excellent host frameworks for precise molecularrangement，chiral recognition，sizespecific alytic reaction，and in situ observation of a molecular adsorption process。In addition，the one-dimensional assembly of metallomacrocycles is also described as another approach for the construction of metal-modified pores and various metal arrays。This method is therefore one of the promising ways to develop unique porous materials such as highly efficient and selective catalys based on the precise arrangement of guest compounds and metalions in the pores。
{"title":"Creation of Porous Functional Materials based on Self-organization of Multinuclear Metallomacrocycles","authors":"S. Tashiro","doi":"10.4019/BJSCC.71.39","DOIUrl":"https://doi.org/10.4019/BJSCC.71.39","url":null,"abstract":"錯体化学を基盤とした応用研究における代表例の一つ として、Metal–Organic Framework (MOF) などの多孔性 配位高分子をはじめとした多孔性結晶材料の開発と機 能化が挙げられる 。これら多孔性結晶の主な用途は、 物質貯蔵や混合物分離、重合反応、触媒などであり、最 近では包接分子の構造解析手法としても活用されはじめ ているが、これらの機能の根幹は言うまでもなく結晶細 孔内への分子の包接である。すなわち、多孔性結晶の機 能設計や性能向上を図るためには、結晶細孔内での分子 包接・配列を精密に設計・制御することが極めて重要で ある。 そのためのアプローチの一つとして、分子認識能を有 するホスト化合物を構成要素として多孔性結晶を作成す ることができれば、細孔内での分子包接・配列をあらか じめプログラムすることが可能となり、その設計性およ び包接効率を格段に向上させることができる 。すな わち、環状ないしはケージ状ホスト化合物を構成要素と した多孔性結晶を合成できれば、それらの構成要素が本 来持つ高い分子認識能を結晶細孔内にそのまま組み込む ことが可能となる(Fig. 1)。例えば配位高分子では、柱 となる有機配位子にクラウンエーテル やピラーアレ ーン などの環状ホスト化合物を組み込んだ多孔性結 晶が合成されている。また、環状ホスト化合物自身を配 位高分子の柱そのものとして活用することもでき、その 代表例の一つは Stoddartらによって開発された CD-MOF であり、これはシクロデキストリン(CD)とアルカリ 金属イオンからなる多孔性配位高分子である。興味深い ことに、ある種の CD-MOFは食用原料のみから合成す ることも可能であり、Edible MOFとしても知られてい In this account, a new method for the creation of porous functional materials based on the self-organization of metallomacrocycles is described. For instance, the authors have developed a new series of porous molecular crystals, metal– macrocycle frameworks (MMFs), through crystallization of Pd3-macrocycles. It was also found that MMFs with multiple binding pockets on the pore surface served as excellent host frameworks for precise molecular arrangement, chiral recognition, sizespecific catalytic reaction, and in situ observation of a molecular adsorption process. In addition, the one-dimensional assembly of metallomacrocycles is also described as another approach for the construction of metal-modified pores and various metal arrays. This method is therefore one of the promising ways to develop unique porous materials such as highly efficient and selective catalysts based on the precise arrangement of guest compounds and metal ions in the pores.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.71.39","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48601991","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}
Transition metal complexes, having the coordination bonds with strong covalent-bond characters, undergo various bond-forming reactions, similar to the organo-transition metal complexes with a metal-carbon s -bond. This article reviews recent studies by the author and his co-workers on the multinuclear complexes of group 10 transition metal complexes having bridging Si- and Ge-ligands. Triangular triplatinum(0) complexes having three bridging diarylsilylene ligands are newly prepared, and undergo skeletal rearrangement on addition of alkynes. The complex with SiPh 2 ligands catalyzes hydrosilylation of aromatic aldehydes and ketones with H 2 SiPh 2 . Detailed studies on the dipalladium and diplatinum complexes with bridging Si- and Ge-ligands revealed unique chemical properties, such as activation of the Si–H bond of the ligand as well as bond forming reactions of the bridging germylene with germyl ligands. Tetra-, penta-, hexa-, and octa-nuclear Pd and Pt complexes with the bridging silylene and germylene ligands are obtained from heating a mixture of the metal-phosphine complexes, precursor of the Si- and Ge-ligands, and scavenger of the auxiliary ligands. Thus formed complexes react with metal halides and with the Si- and Ge-compounds to produce new multinuclear transition metal complexes. The reactions occur reversibly because of kinetic lability of the multinuclear complexes with the bridging Si- and Ge-ligands.
{"title":"Coordination Chemistry Pioneered by Bridging Si- and Ge-Ligands","authors":"K. Osakada","doi":"10.4019/BJSCC.71.3","DOIUrl":"https://doi.org/10.4019/BJSCC.71.3","url":null,"abstract":"Transition metal complexes, having the coordination bonds with strong covalent-bond characters, undergo various bond-forming reactions, similar to the organo-transition metal complexes with a metal-carbon s -bond. This article reviews recent studies by the author and his co-workers on the multinuclear complexes of group 10 transition metal complexes having bridging Si- and Ge-ligands. Triangular triplatinum(0) complexes having three bridging diarylsilylene ligands are newly prepared, and undergo skeletal rearrangement on addition of alkynes. The complex with SiPh 2 ligands catalyzes hydrosilylation of aromatic aldehydes and ketones with H 2 SiPh 2 . Detailed studies on the dipalladium and diplatinum complexes with bridging Si- and Ge-ligands revealed unique chemical properties, such as activation of the Si–H bond of the ligand as well as bond forming reactions of the bridging germylene with germyl ligands. Tetra-, penta-, hexa-, and octa-nuclear Pd and Pt complexes with the bridging silylene and germylene ligands are obtained from heating a mixture of the metal-phosphine complexes, precursor of the Si- and Ge-ligands, and scavenger of the auxiliary ligands. Thus formed complexes react with metal halides and with the Si- and Ge-compounds to produce new multinuclear transition metal complexes. The reactions occur reversibly because of kinetic lability of the multinuclear complexes with the bridging Si- and Ge-ligands.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.71.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48346262","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}
近年の量子化学理論および計算機の発達は、実在する 比較的大きな分子の第一原理計算を可能とした。また、 第一原理計算に関する商用ソフトウェアの普及は、広く 研究者に量子化学計算を実行する環境を提供したことも あり、様々な分子の電子状態、構造、そして特性が第一 原理的に求められるようになってきた。今や理論計算は 化学分野において、合成、測定に次ぐ第三のアプローチ としての地位を確立しつつある。実際、多くの化学雑誌 において、第一原理計算の結果を含んだ論文を目にする ようになった。錯体分野に関しても第一原理計算による 理論的解釈が行われるようになってきた。 錯体の電 子状態の特徴の一つには、主として d軌道による擬縮退 したフロンティア軌道と、そこに存在する金属イオンの 不対電子(=電子スピン)の存在があげられる。このよ うな、局在スピンサイトを有する系を一般的に開殻系と 呼ぶが、特に複核錯体では、錯体中の金属イオンが複数 の局在スピンサイトとなるため、多様なスピン状態を生 み出す。 この開殻性を有した物質群は、物性物理の分 野では強相関電子系とも呼ばれ、スピン・軌道・フォノ ンなどが絡み合い、例えば磁性、伝導性、光物性など 多様な物性を発現する。 また近年注目を集めている、 PSII光合成活性中心のMnクラスター やフェレドキ シンなどの電子伝達タンパク質に含まれる鉄-硫黄ク ラスター なども強相関電子系であり、生体は巧みに この性質を利用しながら反応を行なっていることも明ら かになりつつある。従って、第一原理計算を用い、これ らの分子構造・電子(スピン)状態そして物性発現機構 の関係性をミクロな視点から明らかにすることができれ ば、そこから機能性分子の設計原理を導出することも可 能となる。このように、第一原理計算による錯体の特性 解明、そして機能性分子の理論設計は今後ますます進展 することが予想される。しかしながら後述するように、 A broken-symmetry (BS) method is now widely used for systems that involve (quasi) degenerate frontier orbitals because of their lower cost of computations. The BS method splits up-spin and down-spin electrons into two different spatial orbitals. Within the BS method, therefore, a singlet spin state of the degenerate system is expressed as a spinpolarized state e.g. a singlet diradical. However the spin-polarized wavefunction suffers from a serious problem called a spin contamination error. An approximate spin projection (AP) method can eliminate the error from the BS solution by assuming the Heisenberg model, and one can obtain molecular energies and its derivatives without the error. In this accounts, we illustrate a theoretical background of the BS and AP methods, starting from a bond dissociation of the simplest H2 molecule. And we also show some examples of its application especially for Cr(II)2 complex that is a typical spin-polarized system with a multiple bond.
近年来，量子化学理论和计算机的发展使实际存在的较大分子的第一原理计算成为可能。此外，第一原理计算相关的商用软件的普及，为广大的研究人员提供了执行量子化学计算的环境，各种分子的电子状态、结构和特性也开始成为第一原理的要求。如今，理论计算在化学领域中逐渐成为继合成和测量之后的第三种方法。实际上，在很多化学杂志上都能看到包含第一原理计算结果的论文。关于配合物领域，也开始通过第一原理计算进行理论解释。配合物电子状态的特征之一，主要是由d轨道产生的拟缩的前沿轨道，以及存在于其中的金属离子的失对电子(即电子自旋)。具有这种局域自旋位点的系统一般被称为开壳系统，特别是在核络合物中，络合物中的金属离子会成为多个局域自旋位点，因此会产生多种自旋状态。具有开壳性的物质群在凝聚态物理的分支中也被称为强相关电子系统，自旋、轨道、声子等相互缠绕，表现出磁性、传导性、光物性等多种物性。另外，近年来引人注目的PSII光合作用活性中心的Mn集群和feredicin等电子传递蛋白质中含有的铁-硫簇等也是强相关电子系统，生物巧妙地利用这一性质进行反应的事情也逐渐被发现。因此，利用第一原理计算，如果能从微观角度明确这些分子结构、电子(自旋)状态以及物性表现机制之间的关系，就可以推导出功能性分子的设计原理。由此可见，基于第一原理计算的配合物特性阐明以及功能性分子的理论设计今后将会取得越来越大的进展。但是正如后面所述，A broken-symmetry (BS) method is now widely used for systems that involve (quasi)degenerate frontier orbitals because of their lower cost of computations. The BS method splitsup-spin and down-spin electrons into two different spatial orbitals. Within the BS method，therefore,a singlet spin state of the degenerate system is expressed as a spinpolarized state e.g.asingletdiradical. However the spin-polarized wavefunction suffers from a serious problem called a spincontamination error. An approximate spin projection (AP) method can eliminate the error from the BSlution by assuming the Heisenberg model，and one can obtain molecular energies and its derivatives without the error. In this accounts，we illustrate a theoretical background of the BS and AP methods，starting from a bond dissociation of the simplest H2 molecule. And we also show some examples of itsapplication especially for Cr(II)2 complex that is a typical spin-polarized system with a multiplebond。
{"title":"Development of approximate spin projection method and its application for elucidation of electronic structures, molecular structures and physical properties of polynuclear metal complexes","authors":"Y. Kitagawa, Toru Saito, K. Yamaguchi","doi":"10.4019/bjscc.71.57","DOIUrl":"https://doi.org/10.4019/bjscc.71.57","url":null,"abstract":"近年の量子化学理論および計算機の発達は、実在する 比較的大きな分子の第一原理計算を可能とした。また、 第一原理計算に関する商用ソフトウェアの普及は、広く 研究者に量子化学計算を実行する環境を提供したことも あり、様々な分子の電子状態、構造、そして特性が第一 原理的に求められるようになってきた。今や理論計算は 化学分野において、合成、測定に次ぐ第三のアプローチ としての地位を確立しつつある。実際、多くの化学雑誌 において、第一原理計算の結果を含んだ論文を目にする ようになった。錯体分野に関しても第一原理計算による 理論的解釈が行われるようになってきた。 錯体の電 子状態の特徴の一つには、主として d軌道による擬縮退 したフロンティア軌道と、そこに存在する金属イオンの 不対電子(=電子スピン)の存在があげられる。このよ うな、局在スピンサイトを有する系を一般的に開殻系と 呼ぶが、特に複核錯体では、錯体中の金属イオンが複数 の局在スピンサイトとなるため、多様なスピン状態を生 み出す。 この開殻性を有した物質群は、物性物理の分 野では強相関電子系とも呼ばれ、スピン・軌道・フォノ ンなどが絡み合い、例えば磁性、伝導性、光物性など 多様な物性を発現する。 また近年注目を集めている、 PSII光合成活性中心のMnクラスター やフェレドキ シンなどの電子伝達タンパク質に含まれる鉄-硫黄ク ラスター なども強相関電子系であり、生体は巧みに この性質を利用しながら反応を行なっていることも明ら かになりつつある。従って、第一原理計算を用い、これ らの分子構造・電子(スピン)状態そして物性発現機構 の関係性をミクロな視点から明らかにすることができれ ば、そこから機能性分子の設計原理を導出することも可 能となる。このように、第一原理計算による錯体の特性 解明、そして機能性分子の理論設計は今後ますます進展 することが予想される。しかしながら後述するように、 A broken-symmetry (BS) method is now widely used for systems that involve (quasi) degenerate frontier orbitals because of their lower cost of computations. The BS method splits up-spin and down-spin electrons into two different spatial orbitals. Within the BS method, therefore, a singlet spin state of the degenerate system is expressed as a spinpolarized state e.g. a singlet diradical. However the spin-polarized wavefunction suffers from a serious problem called a spin contamination error. An approximate spin projection (AP) method can eliminate the error from the BS solution by assuming the Heisenberg model, and one can obtain molecular energies and its derivatives without the error. In this accounts, we illustrate a theoretical background of the BS and AP methods, starting from a bond dissociation of the simplest H2 molecule. And we also show some examples of its application especially for Cr(II)2 complex that is a typical spin-polarized system with a multiple bond.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/bjscc.71.57","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70514979","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}
41 in of electro-and photocatalytic integrate materials devices for (light-driven) H 2 evolution. 42–47 the application cobalt oxime complexes as catalysts in such systems reviewed. Converting sunlight into storable chemical energy carriers, such as dihydrogen (H 2 ), through light-driven splitting of water is a widely studied approach to secure future energy supplies and sustainability. Molecular complexes based on inexpensive and earth-abundant 3d transition metals have been extensively explored as catalysts for the reduction of water to H 2 . Among these, cobalt complexes with an oxime functionality ( i.e., cobaloxime and cobalt diimine-dioxime) efficiently reduce protons in pure water with low to moderate overpotentials, and they have been shown to remain active under aerobic conditions. Based on their simple and straightforward synthesis in addition to their excellent electrochemical properties, they are often applied as the first-choice catalyst when testing new materials or introducing new concepts for H 2 evolution. In this review, their basic electrochemical and electrocatalytic properties as well as mechanistic investigations will be summarized, followed by an overview of their application in photocatalysis. Finally, their integration with (nano)materials for (photo)electrocatalytic H 2 evolution is presented and discussed.
{"title":"Photo- and electrocatalytic H2 evolution with cobalt oxime complexes","authors":"Janina Willkomm, E. Reisner","doi":"10.4019/BJSCC.71.18","DOIUrl":"https://doi.org/10.4019/BJSCC.71.18","url":null,"abstract":"41 in of electro-and photocatalytic integrate materials devices for (light-driven) H 2 evolution. 42–47 the application cobalt oxime complexes as catalysts in such systems reviewed. Converting sunlight into storable chemical energy carriers, such as dihydrogen (H 2 ), through light-driven splitting of water is a widely studied approach to secure future energy supplies and sustainability. Molecular complexes based on inexpensive and earth-abundant 3d transition metals have been extensively explored as catalysts for the reduction of water to H 2 . Among these, cobalt complexes with an oxime functionality ( i.e., cobaloxime and cobalt diimine-dioxime) efficiently reduce protons in pure water with low to moderate overpotentials, and they have been shown to remain active under aerobic conditions. Based on their simple and straightforward synthesis in addition to their excellent electrochemical properties, they are often applied as the first-choice catalyst when testing new materials or introducing new concepts for H 2 evolution. In this review, their basic electrochemical and electrocatalytic properties as well as mechanistic investigations will be summarized, followed by an overview of their application in photocatalysis. Finally, their integration with (nano)materials for (photo)electrocatalytic H 2 evolution is presented and discussed.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.71.18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47212191","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}
自然界におけるほとんどすべての生命活動は、恒常的 に得られる太陽光エネルギーを利用して大気中の二酸化 炭素から生物が利用可能な有機物を生産する光合成に依 存している。光合成を生命と地球の共進化の視点から眺 めて特筆すべき点は、藻類や緑色植物など多くの光合成 を行う生物が地球上に豊富に存在する水を電子の供給源 として用いる高度な仕組みを獲得したことである。副産 物として放出された大量の酸素は長い年月をかけて海中 や大気に蓄積され、生物に有害な紫外線を吸収するオゾ ン層が形成された。さらに、猛毒である酸素への耐性と 大きなエネルギー変化を伴う酸素循環を利用した呼吸機 能を生物が獲得することで、太陽光という無尽蔵のエネ ルギーを利用して有限な炭素を無機的環境と生物界の間 で無限に循環させることができる高効率で持続可能なエ ネルギー変換の仕組みが確立された。酸素の高い酸化力 は、膨大な数の有機化合物を代謝・生合成する酵素群の 分子進化と生理機能の多様化をもたらし、生物進化を推 進する原動力となった。光合成が生物界で水を分解して 酸素を発生させることができる唯一の反応系である事実 を考えれば、そのメカニズムを理解することは、学術的 意義に留まらず、地球温暖化や化石燃料枯渇に伴う環境・ エネルギー問題の解決を考える上で極めて重要な研究課 題になっていることは論を俟たない。 光合成の初期過程である光エネルギーから化学エネル ギーへの変換は、光の吸収と励起によって誘起される電 荷分離とそれに続く電子移動と ATP合成からなる膨大 な数の反応の連鎖である。一連の電子伝達反応の酸化側 末端で、光合成に必要な電子を供給する重要な役割を担 っているのが光化学系 II(Photosystem II、PSII)と呼ば れる膜タンパク質複合体である 。そのため、PSIIには 一定の位置と配向で固定された電子伝達コファクターと バルクの水分子をタンパク質内部に導く(あるいはプロ トンや酸素を排出する)輸送トンネル構造があり、周 囲には吸収した光エネルギーを PSII内部の特別な環境 に置かれたクロロフィル a二量体(反応中心 P680)に 集約するためのアンテナ系が高度に発達している 。輸 送トンネルの先には、酸素発生複合体(oxygen-evolving complex、OEC)と呼ばれる活性部位があり、水の分解・ 酸素発生反応(2H2O→ O2 + 4H + 4e)は OEC内のMn 酸化物クラスターの触媒作用によって起こる 。上で 述べたように、シアノバクテリアによる酸素発生を伴う This account describes a current summary of our computational studies intended to elucidate the mechanism underlying water oxidation by the tetranuclear Mn cluster in the oxygen-evolving complex of photosystem II, the most fundamental bioenergetic process required for the maintenance of life. We focus herein on several important findings about the relatively high oxidation (S2 and S3) states of the cluster that involve three or four Mn IV and one or no Mn ions. The presentation is designed to highlight how the cluster stores the oxidizing power, binds substrate water molecules, and activates them. We discuss the fundamental importance of the cooperative effects of multiple Jahn–Teller axes on Mn ions, which inevitably deform the cluster structure in such a direction as to promote substrate binding during S2 → S3 transition and O–O bond formation in the S3 state. Our interpretation is that the “distorted chair” topology of the cluster is the heart of efficient catalysis for oxygen evolution, and the presentation attempts to reflect this view.
自然界中几乎所有的生命活动都依赖于利用恒常获得的太阳能从大气中的二氧化碳生产生物可利用的有机物的光合作用。从生命和地球的共同进化的观点来看，光合作用值得一提的是，获得了藻类和绿色植物等进行很多光合作用的生物将地球上丰富存在的水作为电子的供给源的高度结构。作为副产物放出的大量氧气经过漫长的岁月积蓄在海中和大气中，形成了吸收对生物有害的紫外线的臭氧层。而且，通过生物获得对剧毒氧的耐受性和伴随大的能量变化的利用氧循环的呼吸功能利用太阳光这一无穷无尽的能源，建立了一种高效可持续的能源转换机制，可以使有限的碳在无机环境和生物界之间无限循环。氧的高氧化力导致了代谢、生物合成大量有机化合物的酶群分子进化和生理功能多样化，成为推动生物进化的原动力。考虑到光合作用是生物界唯一能够分解水产生氧的反应体系，理解其机理不仅具有学术意义在考虑解决伴随全球变暖和化石燃料枯竭的环境·能源问题上，这是极其重要的研究课题。从光合作用的初始过程光能到化学能量的转换是由光的吸收和激发引起的电荷分离以及随后的电子转移和ATP合成组成的大量反应的连锁。在一系列电子传递反应的氧化侧末端，负责供给光合作用所需电子的重要作用的是被称为光化学系II（Photosystem II，PSII）的膜蛋白复合体。因此，PSII具有以一定位置和取向固定的电子传递因子和将散装的水分子导入蛋白质内部（或排出质子或氧）的输送隧道结构在周围，用于将吸收的光能集中到放置在PSII内部的特别环境中的叶绿素a二聚体（反应中心P680）的天线系统高度发达。在输送通道的前方，有被称为氧发生复合体（oxygen-evolving complex，OEC）的活性部位，水的分解·氧发生反应（2H2O→O2+4H+4e）通过OEC内的Mn氧化物簇的催化作用而发生。如上所述，由于唾液细菌产生氧气，This account describes a current summary of our computational studies intended to elucidate the mechanism underlying water oxidation by the tetranuclear Mn cluster in the oxygen-evolving complex of photosystem II，the most fundamental bioenergetic process requireed for the mainanance of。We focus herein on several important findings about the relatively high oxidation（S2and S3）states of the cluster that involve three or four Mn IV and one or no Mn ions。The presentation is designed to highlight how the cluster stores the oxidizing power，binds substrate water molecules，and activates them。We discuss the fundamental importance of the cooperative effects of multiple Jahn–Teller axes on Mn ions，which inevitable deform the cluster structure in such a direction as to promote substrate binding during S2→S3transition and O-O bond formation in the S3state。Our interpretation is that the“distorted chair”topology of the cluster is the heart of efficient catalysis for oxygen evolution，and the presentation attempts to reflect this view。
{"title":"Functional significance of the “distorted chair” topology of the Mn cluster for oxygen evolution in photosynthesis","authors":"H. Isobe","doi":"10.4019/BJSCC.70.2","DOIUrl":"https://doi.org/10.4019/BJSCC.70.2","url":null,"abstract":"自然界におけるほとんどすべての生命活動は、恒常的 に得られる太陽光エネルギーを利用して大気中の二酸化 炭素から生物が利用可能な有機物を生産する光合成に依 存している。光合成を生命と地球の共進化の視点から眺 めて特筆すべき点は、藻類や緑色植物など多くの光合成 を行う生物が地球上に豊富に存在する水を電子の供給源 として用いる高度な仕組みを獲得したことである。副産 物として放出された大量の酸素は長い年月をかけて海中 や大気に蓄積され、生物に有害な紫外線を吸収するオゾ ン層が形成された。さらに、猛毒である酸素への耐性と 大きなエネルギー変化を伴う酸素循環を利用した呼吸機 能を生物が獲得することで、太陽光という無尽蔵のエネ ルギーを利用して有限な炭素を無機的環境と生物界の間 で無限に循環させることができる高効率で持続可能なエ ネルギー変換の仕組みが確立された。酸素の高い酸化力 は、膨大な数の有機化合物を代謝・生合成する酵素群の 分子進化と生理機能の多様化をもたらし、生物進化を推 進する原動力となった。光合成が生物界で水を分解して 酸素を発生させることができる唯一の反応系である事実 を考えれば、そのメカニズムを理解することは、学術的 意義に留まらず、地球温暖化や化石燃料枯渇に伴う環境・ エネルギー問題の解決を考える上で極めて重要な研究課 題になっていることは論を俟たない。 光合成の初期過程である光エネルギーから化学エネル ギーへの変換は、光の吸収と励起によって誘起される電 荷分離とそれに続く電子移動と ATP合成からなる膨大 な数の反応の連鎖である。一連の電子伝達反応の酸化側 末端で、光合成に必要な電子を供給する重要な役割を担 っているのが光化学系 II(Photosystem II、PSII)と呼ば れる膜タンパク質複合体である 。そのため、PSIIには 一定の位置と配向で固定された電子伝達コファクターと バルクの水分子をタンパク質内部に導く(あるいはプロ トンや酸素を排出する)輸送トンネル構造があり、周 囲には吸収した光エネルギーを PSII内部の特別な環境 に置かれたクロロフィル a二量体(反応中心 P680)に 集約するためのアンテナ系が高度に発達している 。輸 送トンネルの先には、酸素発生複合体(oxygen-evolving complex、OEC)と呼ばれる活性部位があり、水の分解・ 酸素発生反応(2H2O→ O2 + 4H + 4e)は OEC内のMn 酸化物クラスターの触媒作用によって起こる 。上で 述べたように、シアノバクテリアによる酸素発生を伴う This account describes a current summary of our computational studies intended to elucidate the mechanism underlying water oxidation by the tetranuclear Mn cluster in the oxygen-evolving complex of photosystem II, the most fundamental bioenergetic process required for the maintenance of life. We focus herein on several important findings about the relatively high oxidation (S2 and S3) states of the cluster that involve three or four Mn IV and one or no Mn ions. The presentation is designed to highlight how the cluster stores the oxidizing power, binds substrate water molecules, and activates them. We discuss the fundamental importance of the cooperative effects of multiple Jahn–Teller axes on Mn ions, which inevitably deform the cluster structure in such a direction as to promote substrate binding during S2 → S3 transition and O–O bond formation in the S3 state. Our interpretation is that the “distorted chair” topology of the cluster is the heart of efficient catalysis for oxygen evolution, and the presentation attempts to reflect this view.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"70 1","pages":"2-13"},"PeriodicalIF":0.0,"publicationDate":"2017-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.70.2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46158614","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}
The continuous search for smart and advanced materials with enhanced photofunctional features has attracted a world-wide interest and resulted in great efforts towards the investigations and developments of molecular-based functional materials. It has been known that the chemical and physical properties of various organic moieties can be influenced by and correlated to their molecular structures. As a result of this, the coordination chemistry of transition metal complexes, through the utilization of various transition metal centers and their incorporation into the organic moieties with diverse combinations, has been found to give rise to superior advantages of greater versatility of molecular design and thus leading to more in-depth understanding for the exploration of photofunctional materials with tunable photophysical and excited state properties. In the past few decades, the photophysics and photochemistry of transition metal complexes have drawn inter-disciplinary attention and resulted in significant impact towards materials and energy research, especially with the detailed investigations on the class of ruthenium(II) polypyridine complexes with the characteristic metal-to-ligand charge transfer (MLCT) excited state, arising from their rich photoredox and photoluminescence properties and good stability. These have provided insights into the exploration of molecular-based functional materials with concepts of supramolecular photochemistry. In addition to the ruthenium(II) polypyridine system, researchers also investigated the photophysics and photochemistry of iridium(III) system because of their synthetic versatility, high photoand thermal stabilities with tunable emission color and thus can be applied as triplet emitters and phosphorescent dopants in organic light emitting devices (OLEDs). In addition, lots of efforts have also been devoted into the exploration of new classes of luminescent transition metalligand chromophores and their application in materials chemistry and science by understanding and rationalization of their excited state properties. By the utilization of ligands with versatile structural and electronic properties, the excited state properties of transition metal complexes can be fine-tuned and controlled. For example, the incorporation of strong s-donating ligands has been found to cause drastic luminescence enhancement of some classes of transition metal complexes because of the destabilization of non-emissive d–d ligand field excited states. Compared to the d ruthenium(II) and iridium(III) complexes with octahedral geometry, the square-planar d transition metal complexes with coordinationunsaturated nature has been found to exhibit intriguing spectroscopic and luminescence properties due to their unique tendency to form non-covalent metal···metal interactions. Platinum(II) complexes have been extensively explored in previous years due to their intriguing chromphoric and aggregation properties. The introduction of sup
{"title":"Metal-Based Molecular Functional Materials - From Discrete Metal Complexes to Supramolecular Assembly, Nanostructures and Functions","authors":"V. Yam","doi":"10.4019/BJSCC.69.21","DOIUrl":"https://doi.org/10.4019/BJSCC.69.21","url":null,"abstract":"The continuous search for smart and advanced materials with enhanced photofunctional features has attracted a world-wide interest and resulted in great efforts towards the investigations and developments of molecular-based functional materials. It has been known that the chemical and physical properties of various organic moieties can be influenced by and correlated to their molecular structures. As a result of this, the coordination chemistry of transition metal complexes, through the utilization of various transition metal centers and their incorporation into the organic moieties with diverse combinations, has been found to give rise to superior advantages of greater versatility of molecular design and thus leading to more in-depth understanding for the exploration of photofunctional materials with tunable photophysical and excited state properties. In the past few decades, the photophysics and photochemistry of transition metal complexes have drawn inter-disciplinary attention and resulted in significant impact towards materials and energy research, especially with the detailed investigations on the class of ruthenium(II) polypyridine complexes with the characteristic metal-to-ligand charge transfer (MLCT) excited state, arising from their rich photoredox and photoluminescence properties and good stability. These have provided insights into the exploration of molecular-based functional materials with concepts of supramolecular photochemistry. In addition to the ruthenium(II) polypyridine system, researchers also investigated the photophysics and photochemistry of iridium(III) system because of their synthetic versatility, high photoand thermal stabilities with tunable emission color and thus can be applied as triplet emitters and phosphorescent dopants in organic light emitting devices (OLEDs). In addition, lots of efforts have also been devoted into the exploration of new classes of luminescent transition metalligand chromophores and their application in materials chemistry and science by understanding and rationalization of their excited state properties. By the utilization of ligands with versatile structural and electronic properties, the excited state properties of transition metal complexes can be fine-tuned and controlled. For example, the incorporation of strong s-donating ligands has been found to cause drastic luminescence enhancement of some classes of transition metal complexes because of the destabilization of non-emissive d–d ligand field excited states. Compared to the d ruthenium(II) and iridium(III) complexes with octahedral geometry, the square-planar d transition metal complexes with coordinationunsaturated nature has been found to exhibit intriguing spectroscopic and luminescence properties due to their unique tendency to form non-covalent metal···metal interactions. Platinum(II) complexes have been extensively explored in previous years due to their intriguing chromphoric and aggregation properties. The introduction of sup","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"69 1","pages":"21-28"},"PeriodicalIF":0.0,"publicationDate":"2017-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.69.21","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48024436","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}
In this account, recent advances in the design of bioorganometallic complexes by the conjugation of organometallic complexes with nucleobases are focused on to exhibit specific properties based on functional organization. A guanosine-based Au(I) bioorganometallic complex is demonstrated to serve as the reliable G-octamer scaffold via self-organization, showing a switchable emission based on aurophilic Au(I)-Au(I) interaction. The formation of the empty quartet, octamer, and polymeric columnar aggregate is able to be controlled by the amount of potassium ion. The tuning of the emission properties of the bioorganometallic platinum(II) complexes bearing a uracil moiety is also achieved by changing the direction of hydrogen bonding sites and the molecular scaffold having complementary hydrogen bonding sites for the uracil moiety. The semirigid bridging diphosphine ligand is performed to be a key factor in the arrangement of the phosphorus atoms on the same side to induce intramolecular Au(I)-Au(I) interaction, wherein R - and S -enantiomers based on Au(I)-Au(I) axis exist. It is noteworthy that the chirality of Au(I)-Au(I) axis is induced by the utilization of ( R )-BINAP as the axially chiral bridging diphosphine ligand. Another interesting feature of bioorganometallic complexes is their strong tendency to self-assemble through intermolecular hydrogen bonds between their nucleobase moieties.
{"title":"Functional Organization of Bioorganometallic Complexes Composed of Nucleobases","authors":"T. Moriuchi","doi":"10.4019/BJSCC.70.22","DOIUrl":"https://doi.org/10.4019/BJSCC.70.22","url":null,"abstract":"In this account, recent advances in the design of bioorganometallic complexes by the conjugation of organometallic complexes with nucleobases are focused on to exhibit specific properties based on functional organization. A guanosine-based Au(I) bioorganometallic complex is demonstrated to serve as the reliable G-octamer scaffold via self-organization, showing a switchable emission based on aurophilic Au(I)-Au(I) interaction. The formation of the empty quartet, octamer, and polymeric columnar aggregate is able to be controlled by the amount of potassium ion. The tuning of the emission properties of the bioorganometallic platinum(II) complexes bearing a uracil moiety is also achieved by changing the direction of hydrogen bonding sites and the molecular scaffold having complementary hydrogen bonding sites for the uracil moiety. The semirigid bridging diphosphine ligand is performed to be a key factor in the arrangement of the phosphorus atoms on the same side to induce intramolecular Au(I)-Au(I) interaction, wherein R - and S -enantiomers based on Au(I)-Au(I) axis exist. It is noteworthy that the chirality of Au(I)-Au(I) axis is induced by the utilization of ( R )-BINAP as the axially chiral bridging diphosphine ligand. Another interesting feature of bioorganometallic complexes is their strong tendency to self-assemble through intermolecular hydrogen bonds between their nucleobase moieties.","PeriodicalId":72479,"journal":{"name":"Bulletin of Japan Society of Coordination Chemistry","volume":"70 1","pages":"22-31"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4019/BJSCC.70.22","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70514830","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}
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