新型三甲基乙酸铑(Ⅱ)轴向配合物的合成、结构表征及催化性能

羧酸铑(II)配合物是一类结构独特的同核双金属化合物，通常表现出较高的催化活性和选择性，中心金属铑、配体类型和空间结构都影响其催化性能。本文以三甲基乙酸铑(II)为母体，吡啶-2-基(吡啶-3-基)甲酮(23ma)和二吡啶-2-基甲酮(22ma)为轴向配体，设计合成了2种新型的三甲基乙酸铑(II)轴向配合物。通过¹H NMR、¹³C NMR、 MS、 IR和X-单晶射线衍射对其结构进行表征，并测试了配合物对美罗培南类合成反应的催化性能。结果表明：与母体分子三甲基乙酸铑(II)相比，所合成的轴向配合物在美罗培南类合成体系中因存在溶解性较差等缺点，导致其催化性能均不佳。     

氮杂冠醚化单Schiff碱锰(III)配合物催化PNPP水解研究

将4种氮杂冠醚或吗啉取代的单Schiff碱锰(III)配合物作为仿水解酶模型催化α-吡啶甲酸对硝基苯酯(PNPP)水解。考察了单Schiff碱配体中取代基类型、氮杂冠醚取代的位置对其仿水解酶性能的影响;探讨了Schiff配合物催化PNPP水解的动力学和机理;提出了配合物催化PNPP水解的动力学模型。结果表明,在25℃条件下随着缓冲溶液pH值的增大,配合物催化PNPP水解速率提高,氮杂冠醚化单Schiff碱锰(III)配合物在催化PNPP水解反应中表现出良好的催化活性,Schiff碱配体结构显著影响配合物催化活性。     

氮杂冠醚取代非对称双Schiff碱配合物催化氧化对二甲苯研究

将一系列苯并-10-氮杂-15-冠-5或吗啉基取代的不对称双Schiff碱配合物作为催化剂,在常压和120℃条件下用于催化氧化对二甲苯研究。探讨了Schiff配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基等对催化氧化对二甲苯反应活性及其氧化产物选择性的影响。实验结果表明:配合物中氮杂冠醚的存在能显著缩短反应诱导期、提高催化活性和选择性;Schiff碱Mn(Ⅲ)配合物比Schiff碱Co(Ⅱ)和Schiff碱Cu(Ⅱ)具有更高的催化活性;氮杂冠醚Schiff碱Mn(Ⅲ)配合物催化氧化二甲苯的转化率和产物选择性分别达75%和90%。     

超临界条件下碳酸乙烯酯的均相催化合成

合成了几种四齿Schiff碱铝配合物，并用其在超临界条件下均相催化二氧化碳和环氧乙烷反应合成碳酸乙烯酯。其中，以轴向为乙氧基链的Schiff碱铝配合物的催化活性最高。在一定条件下，由于环氧乙烷与超临界二氧化碳具有混溶性，使得环加成反应在超临界条件下比非临界条件下进行得更快，反应温度对催化活性有很大影响。碱性配体对1－甲基咪唑的存在能有效地提高这些铝配合物的催化性能。同时，基于低温下的一些光谱数据，提出了可能的反应机理。     

金属离子在液相氧化中的催化作用——Ⅹ.过渡金属氯化物与简单配体原位形成的配合物在环己烯氧化反应中的催化作用

本文研究了由过渡金属氯化物(MnCl_2、FeCl_2、CoCl_2、CuCl)与2,2′-二吡啶原位形成的配合物,在环己烯氧化反应中的催化性能以及配体性质对所形成的配合物催化性能的影响.结果表明,多种过渡金属氯化物可与2,2′-二吡啶原位形成有催化活性的配合物,其催化活性与金属离子性质、形成配合物能力以及配体性质有关.     

铼联吡啶配合物的电喷雾质谱研究

利用电喷雾质谱（ESI-MS）对2，2'-联吡啶-4,4'-二羧酸乙酯与过渡金属铼的 系列配合物[（4,4'-(OOEt)_2-bpy)Re(CO)_3RPF_6] [其中bpy = 2,2'-联吡啶，R = 吡啶、4-甲基吡啶、4-羟基吡啶、4-氨基吡啶、10-（4-甲基吡啶基）吩噻嗪（ py-PTZ）进行分析，研究了配合物及其配体在不同源内CID(in-source collision induced dissociation, in-source CID)的相对稳定性。结果表明，随着源内 CID电压的升高，配合物中的配体R容易脱落并形成稳定的联吡啶三羰配位离子[(4, 4'(COOEt)_2-bpy)Re(CO)_3]~+。配体脱落从易到难的顺序为：吡啶 > 4-甲基吡啶 >-甲基吡啶>4-羟基吡啶>4-氨基吡啶>py-PTZ。     

吡咯甲酮基钴配合物:一种水氧化催化剂

具有催化水氧化性能钴配合物的研究,对于探索新型氧化反应、发展可持续清洁能源具有重要意义。本文制备了一种新型(3-((二(吡啶-2-亚甲基)氨基)甲基)(3,5-二甲基-1H-吡咯-2-基)甲酮(m-PDA)配体及其与CoCl2形成的Co(Ⅱ)配合物(Co1),运用IR、UV、NMR、ES-MS等方法表征了配体及配合物的结构。研究了Co1在均相溶液中化学驱动催化水氧化性能,结果表明Co1能催化纯水分解释放氧气,催化活性(TON)达到15.38。循环伏安法研究了配合物催化水氧化的过程,证实配合物Co1具有催化水分解释放氧气的特性,是一种新型非贵金属水氧化的分子催化剂。     

金属离子在液相氧化中的催化作用——Ⅹ.过渡金属氯化物与简单配体原位形成的配合物在环己烯氧化反应中的催化作用

本文研究了由过渡金属氯化物(MnCl₂、FeCl₂、CoCl₂、CuCl)与2,2′-二吡啶原位形成的配合物,在环己烯氧化反应中的催化性能以及配体性质对所形成的配合物催化性能的影响.结果表明,多种过渡金属氯化物可与2,2′-二吡啶原位形成有催化活性的配合物,其催化活性与金属离子性质、形成配合物能力以及配体性质有关.     

氮杂冠醚化双Schiff碱配合物催化羧酸酯水解的研究

将4种氮杂冠醚取代的双Schiff碱钴(H)、锰(m)配合物作为仿水解酶模型催化羧酸酯(PNPP)水解.考察了Schiff碱配合物中氮杂冠醚取代的位置、氮杂冠醚的数目对其仿水解酶性能的影响;探讨了Schiff配合物催化PNPP水解的动力学和机理;提出了配合物催化PNPP水解的动力学模型.结果表明,在25℃条件下随着缓冲溶液pH值的增大,配合物催化PNPP水解速率提高;四种氮杂冠醚取代的双Schiff碱配合物在催化PNPP水解反应中表现出良好的催化活性;氮杂冠醚3-取代的Schiff碱配合物CoL2的催化活性高于5-取代的Schiff碱配合物CoL1,含有2个氮杂冠醚的配合物CoL3的催化活性高于含有1个氮杂冠醚的配合物CoL2.     

Schiff碱N－氧化吡啶－2－甲醛缩氨基脲及其铜配合物的合成、晶体结构及谱学性质的研究

合成了Schiff碱N-氧化吡啶-2-甲醛缩氨基脲（PNOS）及其配合物[Cu(PNOS) (NO_3)_2],并用单晶X射线衍射法测定了配体和配合物结构。PNOS晶体中通过传统 氢键形成双层二维网状结构,再由非传统氢键自组装成三维网状结构。配合物[Cu (PNOS)(NO_3)_2]中的铜为六配位,畸变八面体结构,Schiff碱（PNOS）通过N-氧 化吡啶N-O的O原子,亚胺基C=N的N原子,及羰基C=O的O原子与铜配位;一个硝基以 单齿配体形式与铜配位,另一个则以双齿配体形式配位。配合物分子通过经典氢键 相互作用,形成单层二维网状结构,再通过非经典氢键作用,自组装成双层二维网 状结构。     

Carboxylate ligands drastically enhance the rates of oxo exchange and hydrogen peroxide disproportionation by oxo manganese compounds of potential biological significance

To mimic the carboxylate-rich active site of the manganese catalases more closely we introduced carboxylate groups into dimanganese complexes in place of nitrogen ligands. The series of dimanganese(III,IV) complexes of tripodal ligands [Mn(2)(L)(2)(O)(2)](3+/+/-/3-) was extended from those of tpa (1) and H(bpg) (2) to those of H(2)(pda) (3) and H(3)(nta) (4) (tpa=tris-picolylamine, H(bpg)=bis-picolylglycylamine, H(2)(pda)=picolyldiglycylamine, H(3)(nta)=nitrilotriacetic acid). While 3 [Mn(2)(pda)(2)(O)(2)][Na(H(2)O)(3)] could be synthesized at -20 degrees C and characterized in the solid state, 4 [Mn(2)(nta)(2)(O)(2)](3-) could be obtained and studied only in solution at -60 degrees C. A new synthetic procedure for the dimanganese(III,III) complexes was devised, using stoichiometric reduction of the dimanganese(III,IV) precursor by the benzil radical with EPR monitoring. This enabled the preparation of the parent dimanganese(III,III) complex 5 [Mn(2)(tpa)(2)(O)(2)](ClO(4))(2), which was structurally characterized. The UV/visible, IR, EPR, magnetic, and electrochemical properties of complexes 1-3 and 5 were analyzed to assess the electronic changes brought about by the carboxylate replacement of pyridine ligands. The kinetics of the oxo ligand exchanges with labeled water was examined in acetonitrile solution. A dramatic effect of the number of carboxylates was evidenced. Interestingly, the influence of the second carboxylate substitution differs from that of the first one probably because this substitution occurs on an out-of-plane coordination while the former occurs in the plane of the [Mn(2)O(2)] core. Indeed, on going from 1 to 3 the exchange rate was increased by a factor of 50. Addition of triethylamine caused a rate increase for 1, but not for 3. The abilities of 1-3 to disproportionate H(2)O(2) were assessed volumetrically. The disproportionation exhibited a sensitivity corresponding to the carboxylate substitution. These observations strongly suggest that the carboxylate ligands in 2 and 3 act as internal bases.     

Schiff碱配合物模拟酶催化性能的温度效应研究

研究了新型Schiff碱双锰配合物在模拟酶催化亚碘酰苯单加氧化环已烷反应及 被亚碘酰苯氧化破坏反应中的温度效应。结果表明，在模拟酶催化反应体系中同时 存在催化环已烷单加氧反应及催化剂的氧化破坏反应；催化反应速率及氧化破坏反 应速率均随反应温度升高有规律地增大，但氧化破坏反应比催化反应对反应温度更 敏感；催化反应总产率一般随反应温度升高而降低；最适宜的反应温度为25 ℃。     

General synthesis of di-mu-oxo dimanganese complexes as functional models for the oxygen evolving complex of photosystem II

A series of complexes with the formula [Mn(III/IV)2(mu-O)2(L)2(X)2]3+ have been prepared in situ from Mn(II)LCl2 precursors by a general preparative method (L = terpy, Cl-terpy, Br-terpy, Ph-terpy, tolyl-terpy, mesityl-terpy, t Bu3-terpy, EtO-terpy, py-phen, dpya, Me2N-terpy, or HO-terpy, and X = a labile ligand such as water, chloride, or sulfate). The parent complex, where L = terpy and X = water, is a functional model for the oxygen-evolving complex of photosystem II (Limburg, et al. J. Am. Chem. Soc. 2001, 123, 423-430). Crystals of Mn(II)(dpya)Cl2, Mn(II)(Ph-terpy)Cl2, Mn(II)(mesityl-terpy)Cl2, and an organic-soluble di-mu-oxo di-aqua dimanganese complex, [Mn(III/)(IV)2(mu-O)2(mesityl-terpy)2(OH2)2](NO3)3, were obtained and characterized by X-ray crystallography. Solutions of the in situ-formed di-mu-oxo dimanganese complexes were characterized by electrospray mass spectrometry, EPR spectroscopy, and UV-visible spectroscopy, and the rates of catalytic oxygen-evolving activity were assayed. The use of Mn(II)LCl2 precursors leads to higher product purity of the Mn dimers while achieving the 1:1 ligand to Mn stoichiometry appropriate for catalytic activity assay. These methods can be used to screen the catalytic activity of other di-mu-oxo dimanganese complexes generated by using a ligand library.     

The Stronger the Better: Donor Substituents Push Catalytic Activity of Molecular Chromium Olefin Polymerization Catalysts

The donor strength of bifunctional pyridine-cyclopentadienyl ligands was altered systematically by the introduction of donating groups in the para-position of the pyridine. In the resulting chromium complexes an almost linear correlation between donor strength and the nitrogen-chromium distance as well as the electronic absorption maximum is experimentally observed. The connection of electron-donating groups in the ligand backbone leads to an efficient transfer of the electronic influences to the catalytically active metal centre without restricting it through steric effects. Therefore, catalytic olefin polymerization activity, which is already very high for the previously studied catalysts, increase considerably by attaching para-amino groups to the chelating pyridine or quinoline, respectively. Combining electron-rich indenyl ligands with para-amino substituted pyridines lead to the highest catalytic activities observed so far for this class of organo chromium olefin polymerisation catalysts. The resulting polymers are of ultra-high molecular weight and the ability of the catalysts to incorporate co-monomers is also very high.     

A new coordination mode of 6‐methylnicotinic acid in trans‐tetraaquabis(6‐methylpyridine‐3‐carboxylato‐κO)cobalt(II) tetrahydrate

The title compound, [Co(C₇H₆NO₂)₂(H₂O)₄]·4H₂O, contains a Co^II ion lying on a crystallographic inversion centre. The Co^II ion is octahedrally coordinated by two 6‐methylpyridine‐3‐carboxylate ligands in axial positions [Co—O = 2.0621 (9) Å] and by four water molecules in the equatorial plane [Co—O = 2.1169 (9) and 2.1223 (11) Å]. There are also four uncoordinated water molecules. The 6‐methylpyridine‐3‐carboxylate ligands are bound to the Co^II ion in a monodentate manner through a carboxylate O atom. There is one strong intramolecular O—H...O hydrogen bond, and six strong intermolecular hydrogen bonds of type O—H...O and one of type O—H...N in the packing, resulting in a complex three‐dimensional supramolecular structure.     

Synthesis,crystal structure and activity for H2O2 disproportionation of a binuclear manganese(III) complex [(tol)Mn(bbml)2Mn(tol)](ClO4)2

The title binuclear Mn₂(III) complex was synthesized through the reaction of 2-[bis(2-benzimidazolylmethyl)amino]ethanol (Hbbml), Mn(DMSO)₆(ClO₄)₃ and o-toluic acid (Htol). X-ray structure analysis shows that the two Mn(III) atoms are bridged by the oxygen atoms of the two bbml ligands, forming a bis(μ-alkoxo)dimanganese core. Electrospray mass spectrometry (ES-MS) experiments shows that the complex cation may easily lose one or two tol⁻ ligands leaving an unoccupied coordination site, which would favor the coordination and activation of H₂O₂. Furthermore, its catalytic activity for the disproportionation of H₂O₂ and the effect of added heterocyclic base were also investigated. The complex has some similarities to manganese catalase in structure and activity.     

双[N,N'-亚烃基-2,2'-(芳亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]合双锰(Ⅱ)的合成、光谱特征及拟酶催化性能研究

首次报道了新型Schif碱类配体双[N,N-亚烃基-2,2-(苯亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]和双[N,N-(1,2-亚乙基)-2,2-(4-甲氧基苯亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]及其双锰配合物的合成方法、光谱特征及用配合物催化PhIO单加氧化环己烷反应的研究。     

Structural characterisation of the H-bonded [MnII(OH2)2...(OCH3)2MnIII] motif: a model for resting state hydroxylic solvent coordination in M(II)-M(III) enzymes

A mixed-valence dimanganese complex with two water ligands bound to the Mn(II) ion and two methoxide ligands bound to the Mn(III) ion in a H-bonded arrangement has been structurally characterised and models possible resting state water/hydroxide coordination in purple acid phosphatases.     

双[N, N'-亚烃基-2, 2'-(芳亚甲基)二(3, 4-二甲基吡咯-5-醛 缩亚胺)]合锰 (II)的合成及光谱特征

首次报道了七种新型Schiff碱配体双[N,N'-亚烃基-2,2'-(芳亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]及其双锰配合物的合成及光谱特征。     

Effects of axial coordination on the Ru-Ru single bond in diruthenium paddlewheel complexes

The 1,8-naphthyridine-based (NP-based) ligands with furyl, thiazolyl, pyridyl, and pyrrolyl attachments at the 2-position have been synthesized. Reactions of 3-MeNP (3-methyl-1,8-naphthyridine), fuNP (2-(2-furyl)-1,8-naphthyridine), tzNP (2-(2-thiazolyl)-1,8-naphthyridine), pyNP (2-(2-pyridyl)-1,8-naphthyridine), and prNP(-1) (2-(2-pyrrolyl)-1,8-naphthyridine) with [Ru2(CO)4(CH3CN)6]2+ lead to [Ru2(3-MeNP)2(CO)4(OTf)2] (1), [Ru2(fuNP)2(CO)4]2[BF4]2 (2), [Ru2(tzNP)2(CO)4][ClO4]2 (3), [Ru2(pyNP)2(CO)4][OTf]2 (4), and [Ru2(prNP)2(CO)4] (5). The molecular structures of complexes 1-5 have been established by X-ray crystallographic studies. The modulation of the Ru-Ru single-bond distances with axial donors triflates, furyls, thiazolyls, pyridyls, and pyrrolyls has been examined. A small and gradual increase in the Ru-Ru distance is measured with various donors of increasing strengths. The shortest Ru-Ru distance of 2.6071(9) angstroms is observed for the axially coordinated triflates in complex 1, and the longest Ru-Ru distance of 2.6969(10) angstroms is measured for axial pyrrolyls in complex 5. The Ru-Ru distances in complexes 3 (2.6734(7) angstroms) and 4 (2.6792(9) angstroms), having thiazolyls and pyridyls at axial sites respectively, are similar. The Ru-Ru distance for axial furyls in complex 2 (2.6261(9) angstroms) is significantly shorter than the corresponding distances in 3, 4, and 5. DFT calculations provide insight into the interaction of the Ru-Ru sigma orbital with axial donors. The Ru-Ru sigma orbital is elevated to a higher energy because of the interaction with axial lone pairs. The degree of destabilization depends on the nature of axial ligands: the stronger the ligand, higher the elevation of Ru-Ru orbital. The lengthening of Ru-Ru distances with respect to the axial donors in compounds 1-5 follows along the direction pyrrolyl > pyridyl approximately thiazolyl > furyl > triflate, and the trend correlates well with the computed destabilization of the Ru-Ru sigma orbitals.