Organometallic Polymers of the Transition Metals

This article provides a comprehensive review of the synthesis, properties and applications of organometallic polymers of the transition metals. The different classes of organometallic polymers are described according to their structural make‐up, as well as by their methods of synthesis. A number of examples of each class are given to emphasize the richness and diversity in these areas of research. In addition to linear polymers, hyperbranched, crosslinked, star and dendritic polymers are also described. The properties that transition metal‐containing organometallic polymers possess, as well as the applications that these materials have found in various domains are highlighted.

     

Linear Conjugated Coordination Polymers Containing Eight-Coordinate Metal Centers

Two linear coordination polymers are reported in which conjugated organic ligands and nonrigid eight-coordinate metal centers are linked to form macromolecules with molecular weights of greater than 10⁴ Daltons. The tungsten(IV) chelate is an inert low-spin d² species with four oxygen and four nitrogen donors per metal with two bidentate blocking ligands and one bis-bidentate bridging ligand. The zirconium(IV) chelate is rendered inert through the use of a bis-quadridentate Schiff-base ligand. Future possibilities and potential uses are also discussed.     

Lattice Mismatch Induced Tunable Dimensionality of Transition Metal Di-chalcogenides

Low-dimensional materials have excellent properties which are closely related to their dimensionality. However, the growth mechanism underlying tunable dimensionality from 2D triangles to 1D ribbons of such materials is still unrevealed. Here, we establish a general kinetic Monte Carlo model for transition metal dichalcogenides (TMDs) growth to address such an issue. Our model is able to reproduce several key findings in experiments, and reveals that the dimensionality is determined by the lattice mismatch and the interaction strength between TMDs and the substrate. We predict that the dimensionality can be well tuned by the interaction strength and the geometry of the substrate. Our work deepens the understanding of tunable dimensionality of low-dimensional materials and may inspire new concepts for the design of such materials with expected dimensionality.     

Optically Active Organometallic Compounds of Transition Elements with Chiral Metal Atoms

Chiral transition metal atoms are not only present in tris-chelate complexes [M(LL)₃]ⁿ⁺, which were already resolved into the enantiomers by Alfred Werner, but also in organometallic half-sandwich complexes such as 1 with three- or four-legged piano-stool structure. These complexes have been tools in the elucidation of the spatial course of reactions and in organic syntheses. Applications in enantioselective catalysis are beginning to show up.     

Lanthanide and Transition Metal Coordination Polymers via Hydrothermal Reaction

Studies on the syntheses, structures and properties of lanthanide-transition metal complexes are of current great interest, because they can provide good models for investigation of the nature of magnetic exchange interaction between 3d and 41metal ions in the magnetic materials containing rare earth metals. Many of such studies were focused on discrete complexes which were synthesized from the conventional self-assembly reactions in solution. Although several infinite lanthanide-transition metal complexes containing organic ligands have been obtained by conventional solution synthetic method, the polymeric complexes have been poorly explored. Recently we try to use organic ligands for designing magnetic complexes comprising lanthanide and transition metal ions, especially Gd-Cu, Gd-Zn and Gd-Ag couple,with infinite structures, and hope to provide useful messages for the modeling of the magnetic exchange in magnetic materials. Herein reported are a series of lanthanide and transition metal polymeric complexes[{Gd₂M₃(pydc)₆(H₂O)₁₂}·4H₂O]_n and[{Gd₄M₂(pydc)₈(H₂O)₁₂}·4H₂O]_n (M=Cu, Ag,Zn) with 1D chain and 3D wave-like structure, which were prepared from the hydrothermal reactions of Gd₂O₃, pyridine-2,5-dicarboxylic acid (H₂pydc) and Zn(OAc)₂ or MO, respectively.     

含dppm桥的双核过渡金属配合物中金属─金属间的相互作用

应用ＥＨＭＯ法研究了一系列含ｄｐｐｍ双二苯基膦甲烷桥的双核过渡金属配合物［ＰｄＢｒ（ｄｐｐｍ）］_２，Ｍ_２Ｃｌ_２（μ－ＣＯ）（ｄｐｐｍ）_２（Ｍ＝Ｐｄ，Ｒｈ），［ＲｈＣｌ（ＣＯ）（ｄｐｐｍ）］_２，Ｍ_２－（μ－Ｃｌ）_２Ｃｌ_４（ｄｐｐｍ）_２（Ｍ＝Ｎｂ、Ｔａ、Ｒｅ、Ｒｕ）的电子结构。根据配合物的成键特征，对其金属－金属的相互作用进行了分析。计算结果可以作为解释这类配合物的某些物理化学性质的理论依据。     

含dppm桥的双核过渡金属配合物中金属─金属间的相互作用

应用ＥＨＭＯ法研究了一系列含ｄｐｐｍ双二苯基膦甲烷桥的双核过渡金属配合物［ＰｄＢｒ（ｄｐｐｍ）］_２，Ｍ_２Ｃｌ_２（μ－ＣＯ）（ｄｐｐｍ）_２（Ｍ＝Ｐｄ，Ｒｈ），［ＲｈＣｌ（ＣＯ）（ｄｐｐｍ）］_２，Ｍ_２－（μ－Ｃｌ）_２Ｃｌ_４（ｄｐｐｍ）_２（Ｍ＝Ｎｂ、Ｔａ、Ｒｅ、Ｒｕ）的电子结构。根据配合物的成键特征，对其金属－金属的相互作用进行了分析。计算结果可以作为解释这类配合物的某些物理化学性质的理论依据。     

主链含过渡金属和大π体系的金属有机聚合物研究进展

综述了主链含过渡金属物大π体系的金属有机聚合物的研究进展。这类聚合类中比较典型的是聚茂金属。主要介绍了主链含短时隔基、长间隔基、共轭间隔基的聚茂金属的合成方法和主要特性。在聚茂金属合成方法中，着重描述了开环聚合反应方法。     

Catalysis by Transition Metal Derivatives Bound to Structurally Ordered Polymers

It is well known that metalloenzymes are able to catalyze chemical reactions with a very high activity and selectivity|1–3|. Therefore the synthesis of complexes between transition metal derivatives and structurally ordered macromolecular ligands to give catalytic systems having high activity and stereoselectivity is of large interest from both applicative and speculative point of view. In this connection the main aim of this article is to emphasize the role of the constitutional and configurational order of the macromolecular ligand in determining the properties of the corresponding complexes with transition metal derivatives. This is of particular importance for designing catalytic systems displaying peculiar features as far as activity, selectivity and stereochemistry are concerned. Moreover a better insight into environment and coordination sphere of the polymer attached metal derivative can be of great help for mechanistic studies of the reactions involved.     

Hydrothermal Synthesis of Two New Transition Metal Coordination Polymers with Mixed Ligands

Hydrothermal reactions of 1, 2, 4‐benzenetricarboxylic acid, 1, 10‐phenanthroline and transition metal cations including Zn^II or Co^II, in basified aqueous solution gave rise to two complexes, [Zn₃(btrc)₂(1, 10‐phen)₂(H₂O)₂]_n ( 1 ), and [Co₃(btrc)₂(1, 10‐phen)₂(H₂O)₂]_n ( 2 ) (btrc = 1, 2, 4‐benzenetricarboxylate, and 1, 10‐phen = 1, 10‐phenanthroline). 1 2 crystalize isotypically in the triclinic space group P1¯. The btrc ligand acts as multi‐dentate bridging ligand in both compound 1 and 2 to link up transition metal atoms into lamella networks, which are further attached into three‐dimensional frameworks through complex hydrogen bonding and π‐π interactions. The photoluminescence spectrum for compound 1 has also been studied. The corresponding reaction with Cu²⁺ follows another pathway.     

Strongly Luminescent Cyclometalated Gold(III) Complexes Supported by Bidentate Ligands Displaying Intermolecular Interactions and Tunable Emission Energy

A series of charge‐neutral Au^III complexes, which comprise a dicarbanionic C‐deprotonated biphenyl ligand and bidentate ancillary ligands ([Au(C^C)(L^X)]; L^X=β‐diketonate and relatives (O^O), quinolinolate and relatives (N^O), and diphosphino (P^P) ligands), were prepared. All the complexes are emissive in degassed CH₂Cl₂ solutions and in thin‐film samples with Φ _em up to 18 and 35 %, respectively, except for 5 and 6 , which bear (N^O)‐type ancillary ligands. Variation of the electronic characteristics of the β‐diketonate ancillary ligand was demonstrated to be a viable route for tuning the emission color from blue‐green (peak λ _em at ca. 466 nm for 1 and 2 ; 501 nm for 4 a and 4 b ) to orange (peak λ _em at 585 nm for 3 ), in contrast to the common observations that the ancillary ligand has a negligible effect on the excited‐state energy of the Au^III complexes reported in the literature. DFT/time‐dependent (TD) DFT calculations revealed that the energies of the ³ππ*(C^C) and the ³ILCT(O^O) excited states (ILCT=intraligand charge transfer) switch in order on going from O^O=acetylacetonate (acac) to aryl‐substituted β‐diketonate ligands. Solution‐processed and vacuum‐deposited organic light‐emitting diode (OLED) devices of selected complexes were prepared. The vacuum‐deposited OLED fabricated with 2 displays a sky‐blue emission with a maximum external quantum efficiency (EQE) of 6.71 % and CIE coordinates of (0.22, 0.40). The crystal structures of 7 and 9 reveal short intermolecular Au^III⋅⋅⋅Au^III contacts, with intermetal distances of 3.408 and 3.453 Å, respectively. DFT/TDDFT calculations were performed on 7 and 9 to account for the noncovalent interactions. Solid samples of 1 , 3 , and 9 exhibit excimeric emission at room temperature, which is rarely reported in Au^III complexes.     

Ambient Temperature Synthesis and Structural Characterization of Six Transition Metal Acetylenedicarboxylate Coordination Polymers

This work reports the ambient temperature synthesis and structural characterization of six new first row transition metal acetylenedicarboxylate coordination polymers. The Co and two Ni compounds adopt structures in which the octahedral metals are connected into 1D chains via the acetylenedicarboxylate ligand. In contrast the Mn and two Zn compounds adopt 3D metal-organic frameworks; while the Mn compound is non-porous the two Zn structures contain dimeric or trimeric clusters connected into frameworks that are potentially porous. These two anionic metal-organic frameworks are, however, charged balanced by cations siting in their pores which greatly reduces the ability to access their porosity.     

A Series of Transition Metal Coordination Polymers Bearing 1,4‐Phenylenediacetate

The reactions of transition metal salts or hydroxide with 1,4‐phenylenediacetic acid (H₂PDA) in the presence of ancillary ligands 4,4′‐bipyridine (4,4′‐bpy) or imidazole (Im) produced five coordination polymers with the empirical formula [M(PDA)(4,4′‐bpy)(H₂O)₂]_n [M = Mn ( 1 ), Ni ( 2 )], [Cu(PDA)(4,4′‐bpy)]_n · 2nH₂O ( 3 ), [Ni(PDA)(Im)₂(H₂O)₂]_n · nH₂O ( 4 ), and [Cu(PDA)(Im)₂]_n · 2nH₂O ( 5 ). Their structures were determined by single‐crystal X‐ray diffraction analyses. The isomorphous 1 and 2 present a two‐dimensional sheet constructed by two kinds of one‐dimensional chains of –Ni^II–PDA^2––Ni^II– and –Ni^II–4,4′‐bpy–Ni^II–. Compound 3 features dinuclear subunits, which are further connected by two PDA^2– ligands and two 4,4′‐bpy ligands along (001) and (011) directions, respectively, to build a two‐dimensional sheet with the topology (4².6⁷.8)(4².6) different from those of 1 and 2 . Both 4 and 5 show one‐dimensional chain structure. The difference of compound 4 and 5 is that the two carboxylato groups of PDA^2– in 4 adopt monodentate coordination modes, whereas the two carboxylato groups of PDA^2– in 5 chelate to the metal ions. Magnetic susceptibility data of 1 were measured. Magnetically, 1 presents a one‐dimensional chain with a weak antiferromagnetic interaction (J =–0.064 cm^–1) between the intrachain Mn^II atoms mediated by 4,4′‐bpy.     

阳离子碳氢/碳氟表面活性剂与中性高聚物相互作用的研究

研究了阳离子碳氢表面活性剂十二烷基三烷基溴化铵[C12H25N(CnH2n＋1)3Br, n＝1, 2, 3, 4]和阳离子碳氟表面活性剂F[CF(CF3)CF2O]2CF(CF3)CONH(CH2)3N(C2H5)2CH3I (FCI-2)分别与中性高聚物聚氧乙烯(PEO, 分子量20000)和聚氧乙烯-聚氧丙烯三嵌段共聚物[(EO)76(PO)29(EO)76, F68]的相互作用. 结果表明, 所用的碳氢阳离子表面活性剂与PEO和F68均无相互作用, 但碳氟阳离子表面活性剂FCI-2与PEO和F68均具有明显的相互作用, 而且F68与FCI-2的相互作用强于PEO与FCI-2体系. 结果也初步表明碳氟表面活性剂与高聚物的相互作用强于碳氢表面活性剂-高聚物体系.     

反离子对全氟辛酸盐与高聚物的相互作用的影响

通过表面张力和电导率测定, 研究了全氟辛酸铵/四烷基铵(C7F15COON(CnH2n＋1)4, n＝0, 1, 2, 3, 4)与聚氧乙烯(PEO, 分子量20000)和聚氧乙烯聚氧丙烯三嵌段共聚物(Pluronic F68)的相互作用. 结果表明, 对PEO-C7F15COON(CnH2n＋1)4混合体系, 只有全氟辛酸铵、全氟辛酸四甲铵与PEO之间有明显的相互作用. 对F68-C7F15COON(CnH2n＋1)4混合体系, 只有全氟辛酸四丁铵未发现与F68有明显的相互作用. 说明全氟辛酸盐的反离子越大, 其与高聚物间的相互作用越弱. 增加高聚物的疏水性可以增强表面活性剂与高聚物的相互作用.     

Transitional Metal/Chalcogen Dependant Interactions of Hairpin DNA with Transition Metal Dichalcogenides,MX2

Owing to the attractive properties that transition metal dichalcogenides (TMDs) display, they have found recent application in the fabrication of biosensing devices. These devices involve the immobilization of a recognition element such as DNA onto the surface of TMDs. Therefore, it is imperative to examine the interactions between TMDs and DNA. Herein, we explore the effect of different transition metals (Mo and W) and chalcogens (S and Se) on the interactions between hairpin DNA and TMDs of both bulk and t‐BuLi exfoliated forms. We discovered that the interactions are strongly dependent on the metal/chalcogen composition in TMDs.     

Conducting and Photoactive Polymers on the Basis of Transition Metal Complexes: Electrochemical Synthesis

Mechanism of electrochemical oxidative polymerization and formation of polymers based on the transition metal complexes are considered. The complexes under study are assumed to have the resonance structures and a highly reactive imino group (–N=CH–) in the macrocyclic ring. IR spectra of the bis(salicylidene)ethylenediamine ligand (H₂Salen), [NiSalen] and [PdSalen] monomers, and the respective polymers are examined and used for the experimental substantiation of the proposed mechanism underlying the formation of conducting polymers.     

手性路易斯碱和过渡金属协同催化反应的进展

近年来过渡金属与以苯并四咪唑类化合物为代表的手性路易斯碱协同作用下的不对称催化反应取得了重要的进展,包括芳基醋酸酯α衍生化及乙内酰脲、二氢喹啉酮等结构的合成、双手性中心烯丙基化反应和α-氨基酸衍生物合成等.这些反应在有机合成中有广阔的应用前景.本文将对这类反应的研究进展做简要的介绍.