Synthesis and Structural Characterization of {[Mn(phen)_2(OAc)(H_2O)]ClO_4}_2H_2O

1 INTRODUCTION Chemistry of manganese cluster has become an attractive research field because of the involvement of manganese in several biological redox-active sys- tems[1,2], especially in the oxygen-evolving complex (OEC) of photosystem Ⅱ (PSⅡ) in green plants[3]. It was thought that the coordination environment of Mn in OEC contains O and N donors, and the bind- ing of aqua to the Mn site may be important to the oxidation of aqua for the evolution of dioxygen[4, 5]. In recent …     

Synthesis and Structural Characterization of Mononuclear Mn~(II) Picolilato Complex Mn(2-C_5H_4NCOO)_2(H_2O)_2.1/2CH_3CN

1 INTRODUCTION Manganese has been implicated as an essential part of the active center in various manganese enzymes. Various nuclearities have been observed from mononuclear atom in superoxide dismutase [1] to the tetranuclear atom of oxygen evolution in photosystem II[2]. The manganese active centers in biological systems are surrounded by O and N coordination sphere[3, 4]. Synthetic efforts have produced a great variety of Mn clusters with varying nuclearity and oxidation states. Si…     

Synthesis and Crystal Structure of a Salicylaldehyde Ethylene Diamine Schiff Base Manganese (Ⅲ) Complex

1 INTRODUCTION Manganese is one of several first-row transition metal elements that have been found to play an important role in most biological systems. Perhaps the best known is in the process of photosynthesis during which water is oxidized to yield dioxygen, and it is generally believed that the process is related to a tetranuclear manganese cluster[1]. Other aspects of biological chemistry of manganese, such as three mononuclear manganese enzymes: manganese superoxide dismutase, per…     

Synthesis and Crystal Structure of a Spiral-chain Manganese(Ⅲ) Complex Containing Azide Bridge,[Mn(bzan)N_3]_n

1 INTRODUCTION It is now recognized that manganese plays an important role in numerous redox processes associating with the metabolism of dioxygen. This has prompted recent attempts to understand the coordination chemistry of Mn(Ⅲ) ions which are now believed to play a role in at least three enzymes: manganese superoxide dismutase (MnSOD)[1], manganese catalase[2] and photosynthetic oxygen- evolving complexes (OEC)[3]. New model complexes have appeared during the last ten years. Her…     

Synthesis and Crystal Structure of Mn（phen）（PhCOO）2（H2O）

1 INTRODUCTION During the last decade the manganese che- mistry has aroused great interest due to its diverse redox functions of enzymes in photosystem Ⅱ and its specially structural, magnetic and spectroscopic properties[1, 2]. A lot of manganese complexes involving carboxylate ligands have been reported, and their properties been fully explored[3, 4]. The coordination environment of the manganese site in biosystem often consists of oxygen and nitrogen atoms from the carboxylate groups…     

Synthesis and Crystal Structure of Mn(phen)(CF_3COO)(H_2O)_3·NO_3

1 INTRODUCTION The manganese(II) ion is a biologically essential element. Knowledge of its importance is increasing as more and more enzymes are found to contain manganese ions at the active center[1, 2]. The X-ray crystallographic structures of a consi…     

Synthesis and Structural Characterization of [Mn（sapn）（H2O）2]Br

1 INTRODUCTION Many of the recent advances in the coordination chemistry of manganese have been driven by the involvement of the manganese in several biological redox-active systems[1,2], of which the most important is the oxygen-evolving complex (EOC) of photosystem II (PS II) in green plants [3]. Since the preparations and structural characterizations of the complexes containing N,O-donor ligands have been studied extensively as simple active-site models for the photosystem II[4,5]…     

SYNTHESIS AND CATALYTIC PROPERTY OF POLYSTYRENE SUPPORTED PHENYLALANINE SCHIFF BASE COMPLEX OF Mn(Ⅱ) IN AEROBIC OXIDATION OF CYCLOHEXENE

1. INTRODUCTION The partial oxidation of alkenes (forming acids, aldehydes and alcohols) is of considerable interest to the chemical industry. In most cases, more than one oxygenated product is formed from a given starting material and all products are susceptible to complete oxidation to carbon dioxide and water [1]. As mimetic oxygen carrier or oxidation catalyst, metalloporphyrins have been widly studied [2~7]. Among the non-porphyrin systems, the manganese complexes of Schiff base are…     

Hydrothermal Synthesis and Crystal Structure of a Three-dimensional Compound {Mn（H2O）4（VO）2（PO4）2}n

1 INTRODUCTION Current research interest is focused on the designof structures built up from octahedral and tetrahedralbuilding blocks[1]. During the wide investigations intransition-metal phosphates for many years, a num-ber of new mixed transition-metal phosphates havebeen reported[2]. A great number of manganese phos-phates were largely discovered as minerals[1]. On theother hand, many vanadium phosphates have alsobeen prepared recently partly because of their poten-tial applications …     

Synthesis and Crystal Structure of a Novel Manganese Coordination Polymer Constructed by 3,5-Dimethylbenzoic Acid with 4,4'-Bipyridine

1 INTRODUCTION There has been extensive interest in manganese complexes containing carboxylate ligands due to the richness in structural chemistry and potential appli- cations in catalysis[1～6], for example, some highly efficient manganese catalysis mimics[7, 8]. Further- more, 4,4?-bipy is an excellent bridging ligand, and so far a number of one-, two- and three-dimensional infinite metal-4,4?-bipy frameworks have already been generated[9, 10]. However, of the above-mentio- ned framework…     

Inhibiting manganese(Ⅱ)from catalyzing electrolyte decomposition in lithium-ion batteries

A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)ion,1-aza-12-crown-4-ether(A12C4)with cavity size well matched manganese(Ⅱ)ion is used in this work as electrolyte additive.Theoretical and experimental results show that stable complex forms between A12C4 and manganese(II)ions in the electrolyte,which does not affect the solvation of Li ions.The strong binding effect of A12C4 additive reduces the charge density of manganese(II)ion and inhibits its destruction of the PF₆^-
structure in the electrolyte,leading to greatly improved thermal stability of manganese(II)ions-containing electrolyte.In addition to bulk electrolyte,A12C4 additive also shows capability in preventing Mn²⁺ from degrading SEI on graphite surface.Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.     

Synthesis and Crystal Structure of Tri-(2-mercaptopyridine N-oxide)bis(dimethyl sulfoxide) Dysprosium(III)

1 INTRODUCTION Transition-metal thiolato complexes have been of interest for the simulation of many metallo- enzymes where the thiolato group mimics the ligation of cysteinyl residues in proteins. Numerous complexes of transition elements with 1,2-bidentate oxothiolate ligands have been prepared[1~4]. Re- cently, we have studied a few transition metal complexes of 2-mercaptopyridine N-oxide (Hmpo) as bactericidal and antifungal reagents[5～7]. Although Hmpo exhibits unusual versatility…     

Synthesis and Structure of a New Dimanganese Complex [Mn2（μ-OAc）2（phen）4]（ClO4）2

1INTRODUCTION Manganese complexes have drawn considerable interests in recent years because they can serve as models for active sites of manganese-containing me-talloenzymes,such as photosystem II(PSII),man-ganese superoxide dismutase(MnSOD),manganese ribonucleotide reductase(MnRR)et al[1].The binu-clear manganese enzymes,including catalase,MnRR and arginase,were indicated to have carboxylato-,oxo-,hydroxo-or aquo-bridged cores[2~4].Structures with Mn substituted into the iron ribon…     

Synthesis and Crystal Structure of an Infinite 1D Zigzag Chain Compound (dimbH~+)(ClO_4~-) and Its Comparison with (dimb)2H_2O (dimb = 1,3-Di(imidazol-1-ylmethyl)-5-methylbenzene)

1 INTRODUCTION Recently the rational design and preparation of novel functional materials are one of the highlights in supramolecular chemistry and crystal engi- neering[1]. How to control the molecular structures and topology in the process of self-assembly has attracted extensively attention[2]. To date, a lot of complexes containing well-designed bidentate[3～6], tripodal[7, 8] and hexadentate[9] imidazole moiety ligands have been synthesized by chemists. Some of them have interestin…     

Hydrothermal Synthesis and Structure of a New Molybdenum Phosphate: (NH_3CH_2CH_2NH_3)_(2.5)[Mo_5O_(15)(PO_4) (HPO_4)]·7.5H_2O

1 INTRODUCTION A new class of materials of metal oxide clusters based on anionic molybdenum phosphate frameworks has received much attention as a consequence of their potential applications in catalysis and materials science [1]. As a result, some molybdenum phosphates have been studied [2,3]. Recently we have studied the structure of NaPMO material[4] and the spectrum of multicomponent compound with Keggin struc- ture [5]. Here we report the synthesis and crystal structure of a new…     

Synthesis and Structural Characterization of Bis(2,2''''-bpy)bis(azide)cobalt(III) nitrate dihydrate

1 INTRODUCTION The research on azide-bridged transition metal complexes has attracted great interest in the past decade due to their magnetic properties and potential applications[1~2]. A number of azide- bridged complexes with the end-to-end coordination mode affording antiferromagnetic exchange interactions and the end-on coordination mode showing ferromagnetic exchange interactions have been reported in recent years[3]. In the synthesis of azide bridged cobalt complexes, it was found …     

Synthesis and Crystal Structure of Trans-diaquabis(hexamethylenetetramine-N)bis(isothiocyanato)cobalt(Ⅱ) trans-tetraaquabis(isothiocyanato)cobalt(Ⅱ) dihydrate

1 INTRODUCTION Supramolecular compounds assembled by coordination covalent bonding or hydrogen bonding are of considerable interest due to their potential applications in developing new materials with magnetic, optical and catalytic properties[1]. One of the synthesis methods used to construct the functional compounds is that octahedral metal ion connects to polydentate ligand such as 4, 4?bipyridine, pyrazine and so on to form multi-dimensional supramolecular polymer[2]. Hmt (hexamethyl…     

Synthesis and Crystal Structure of N,N~′-Bis(p-nitrophenyl)-2,2~′-(p-phenylene-dioxy)diacetamide DMF Monohydrate

1 INTRODUCTION Many crown ethers have been synthesized[1, 2] and widely used[3～5]. The amide-type acyclic poly- ethers with versatile molecular structures offer many advantages over the traditional crown ethers, such as their potential activity for ion-selective electrodes[6] and the extraction of metal ions[7], so they have attracted much scientific attention[8～10]. In an effort to investigate the effect of skeleton of acyclic polyether on the extractability of metal ions, and to find …     

Synthesis and Structural Characterization of [Mn（phen）2（H2O）2]（OAc）2.6H2O

1 INTRODUCTION Water oxidation to oxygen gas by photo- synthetic apparatus of green plants and cyano- bacteria is the origin of this gas in the atmosphere. The water oxidation center is a tetranuclear, oxide- bridged manganese cluster with O,N-based peri- pheral ligation by amino acid side-chain group[1, 2]. The binding of aqua to the Mn site may be impor- tant to the oxidation of aqua for producing dioxygen. 1,10-Phenanthroline has been adopted to simulate coordination sphere of manga…     

SURFACE STRUCTURE AND BULK PROPERTIES OF FLUORINATED POLY(ETHER URETHANE)S AND POLY(ETHER URETHANE) BLENDS

INTRODUCTIONPolyurethanes (PU) have been widely used for manufacturing medical devices because of their excellentmechanical properties and moderate biocompatibility[1]. Although polyurethanes used in applications requiringall of the above properties have been successful for short-term use, the problems of long-term thromboresistanceand biostability in a biological environment still remain unsolved[2,3]. A legitimate approach to improving theproperties of polyurethanes is introduction of f…