Chloro and azido bonded manganese complexes: synthesis,structural, and magnetic studies

Two manganese complexes, [Mn₂(tptz)₂Cl₄] · CH₃CN (1) and [Mn(tptz(ac)(N₃)(H₂O)] · H₂O (2) (where tptz = 2,4,6-tri(2-pyridyl)-1,3,5-triazine, ac = acetate anion), were synthesized and characterized by elemental analyses, infrared spectra, and UV–Vis absorption spectral analyses. The structures of both the complexes were determined by single crystal X-ray diffraction analysis. Complex 1 is binuclear with chloro-bridged manganese ions at the Mn–Mn separation of 3.777(27) Å. Each manganese center in 1 is six coordinate with three nitrogens from a tridentate tptz, three chlorides (one terminal and two bridging), adopting a centrosymmetric distorted octahedral geometry. Various hydrogen bonds form 2-D spiral structures in 1 with Mn–Mn separation of 7.421(2) Å along a-axis and 9.121(2) Å along b-axis. Complex 2 is seven coordinate with pentagonal bipyramidal geometry. The metal center coordinates to three nitrogens from tptz, two oxygens from acetate, one nitrogen from azide, and one oxygen from water. It has a 1-D layered structure, where three independent molecules are linked by uncoordinated water present in the lattice. Magnetic susceptibility in the temperature range 5–300 K for 1 shows the presence of antiferromagnetic interaction between the local high-spin manganese(II) ions with J = ?0.17 cm^?1.     

Azido-Derivate des Pentamethylcyclopentadienyl-Vanadium(IV)-Fragments. Molekülstrukturen der Zweikernkomplexe [Cp*VCl(N3)(μ-N3)]2 und [Cp*V(N3)2(μ-N3)]2

Azido Derivatives of the Pentamethylcyclopentadienyl Vanadium(IV)-Fragment. Molecular Structures of the Binuclear Complexes [Cp*VCl(N₃)(μ-N₃)]₂ and [Cp*V(N₃)₂(μ-N₃)]₂ The stepwise reaction of Cp*VCl₃ with excess trimethylsilyl azide (Me₃Si–N₃) in solution leads to the paramagnetic, azido-bridged complexes [Cp*VCl₂(μ-N₃)]₂ ( 3 ), [Cp*VCl(N₃)(μ-N₃)]₂ ( 4 ) and [Cp*V(N₃)₂(μ-N₃)]₂ ( 5 ) which were characterized by their IR and mass spectra. The azide-rich binuclear complex 5 is also formed if a pentane solution of Cp*V(CO)₄ is stirred in the presence of excess Me₃Si–N₃ in an open vessel. According to the X-ray structure analyses both 4 and 5 are centrosymmetric molecules with a planar V(N)₂V four-membered ring. In the absence of free trimethylsilyl azide, solutions of 3 – 5 lose dinitrogen slowly; in the presence of traces of air, 5 is thereby converted to the diamagnetic, oxo-bridged complex [Cp*V(O)(N₃)]₂(μ-O) ( 6 ).     

O,O-二(β,β′-二叠氮异丙基)-α-对甲苯磺酰氨基-间硝基苄基磷酸酯的合成及晶体结构

首次合成了标题化合物C2 0 H2 3 N14 O7PS ,并通过元素分析、IR和1HNMR对化合物进行了表征 ,用X射线单晶衍射法测定了该化合物的晶体结构。晶体中一个不对称单元内有四个结晶学上独立的分子 ,这四个分子的构型基本相同。每两个分子之间以一对N—H…O氢键连接 ,生成一个非中心对称的二聚体 ,组成二聚体的两个分子侧链局部构象存在明显的差异。整个晶体则是由这些二聚体以vanderWaals作用力堆积而成。     

γ-Cyclodextrins possessing an azido group and a triisopropylbenzenesulfonyl group as useful synthetic and authentic intermediates for unsymmetrically functionalized derivatives

Seven isomers of cyclomaltooctaose (γ-cyclodextrin) whose C6s were unsymmetrically disubstituted with both an azido group and an arenesulfonyloxy group were prepared and each of them was isolated by reversed phase chromatography. The assignment of the modified positions in each regioisomers was unambiguously performed by chemical correlation with the authentic compounds and chemical conversion to the 3,6-anhydro derivatives followed by high-resolution 2D-¹H NMR (COSY, TOCSY, and HOHAHA) analyses. The compounds are versatile synthetic and authentic intermediates to prepare sophisticated derivatives with two different functionalities at desired positions on the molecule for supramolecular chemistry.     

From magnetic molecules to magnetic solids: An ab initio expertise

The efficiency of ab initio wavefunction based methods is demonstrated using various systems characterized by the presence of open shells. It is recalled that the low-energy spectroscopy of molecular architectures as well as extended materials is accessible and can be rationalized by including in a hierarchical way the valence (i.e. non-dynamical) and dynamical correlation effects. Such methodology not only allows one to investigate vertical transition energies but also gives access to a possible reading of the wavefunction in the ground and excited states.     

6-叠氮-6-脱氧凝聚多糖的选择性一步合成

由于含氨基或氨基衍生物的多糖对细胞表面及细胞之间的生理功能具有特殊的作用,在研究细胞之间有效作用的促进剂和抑制剂方面具有潜在的应用价值,因而叠氮化多糖作为制备氨基多糖及其衍生物的中间体受到人们的重视,含乙酰氨基的天然多糖（如Chitin）和氨基多糖（如Chitosan）,由于具有抗感染和医治创伤作用,广泛用于医疗领域,含氨基和硫酸酯的多糖肝素有很好的抗凝血作用和降血脂活性,已用于动脉硬化病的治疗,我们发现含乙酰氨基的硫酸化核聚糖具有很高的抗艾滋病毒活性,而且没有抗凝血的副作用。     

(R)‐2,3‐Cyclohexylideneglyceraldehyde,a Chiral Pool Synthon for the Synthesis of 2‐Azido‐1,3‐diols

A new approach was proposed for the synthesis of 2‐azido‐1,3‐diols from easily available and inexpensive chiral pool synthon (R)‐2,3‐O‐cyclohexylidene‐D ‐glyceraldehyde, through Mitsunobu azidation of 1,2‐diols. Both C(2) and C(1) azides in variable ratios were obtained in alkyl substituted diols with C(2) as the major one.     

Azide Chemistry – An Inorganic Perspective,Part II[‡] [3+2]‐Cycloaddition Reactions of Metal Azides and Related Systems

In whatever state of bonding – whether covalent to an organic residue or a heteroatom, or polar to ionic in contact with a metal – the azide moiety N₃ is characterized by its high potential of reactivity which essentially manifests itself in two basic processes: the elimination of dinitrogen and the entry into 1, 3‐dipolar cycloadditions with suitable dipolarophiles, the latter of which clearly predominates the chemistry of azide, also that of its metal compounds. In a preceding review entitled “Part I – Metal Azides: Overview, General Trends and Recent Developments” which was meant to lay the foundations for the present paper, these and other reactions have already been touched upon. The present review – Part II – now focusses in great detail on the formation of five‐membered heterocycles – tetrazol(at)es, triazol(at)es, triazolin(at)es, thiatriazol(at)es, etc. as well as various consecutive products – from azide and nitriles, isocyanides, alkynes, alkenes and heteroallenes (CS₂, RN=C=S) in the ligand sphere of the metal. Generally, these [3+2]‐cycloadditions are found to proceed under much milder conditions in comparison with the strictly organic case whose triumphant progress since the 1960s is intimately bound up with the name of Huisgen. Mechanistic considerations on the matter are presented. A secondary aspect still occupying quite a part of the discussion is concerned with the role of metals in [3+2]‐cycloadditions particularly of the highly topical “click”‐type, e.g. (CuAAC), (RuAAC). Likewise, a short chapter deals with the question of pentazol(at)e (N₅^–) which according to numerous theoretical studies could well be stabilized and isolated in combination with metals, e.g., in the form of azametallocenes. A last chapter is devoted to a cursory survey of related systems, in particular fulminato complexes, metallo nitrile ylides and metallo nitrile imines, in which the metal acts as a substituent on the 1, 3‐dipole (metallo‐1, 3‐dipole). Other systems with a metal substituent on the dipolarophile (metallo‐dipolarophile), or, with metal itself in the three‐ (two‐) atom arrangement constituting the dipole (dipolarophile) [metalla‐1, 3‐dipole, metalla‐dipolarophile] are only quoted by way of example.     

Michael addition of α-azido ketones on iminocoumarin derivatives: an efficient access to new functionalized azido chromenes

A facile one-pot synthesis of functionalized azido chromenes was achieved by Michael addition of α-azido ketones on iminocoumarin derivatives obtained from salicylaldehydes and malononitrile. Synthesized azido chromenes were successfully transformed into triazolyl chromenes by the [3+2] cycloaddition reaction.     

CYCLOADDITION REACTION OF THE AZIDO-BRIDGED CYCLOMETALLATED COMPLEX [Pd(dmba)N3]2 WITH CS2. CRYSTAL AND MOLECULAR STRUCTURE OF DI(μ, N,S-l,2,3,4-THIATRIAZOLE-5-THIOLATE)BIS[(N,N-DIMETHYLBENZYL-AMINE-C2,N)PALLADIUM(II)]

Abstract

The 1,3-dipolar cycloaddition of carbon disulfide to the coordinated azide in the cyclometal-lated compound [Pd(dmba)(N₃)]₂ (1), dmba = N,N-dimethylbenzylamine, was investigated. The compound obtained di(μ, N, S-l,2,3,4-thiatriazole-5-thiolate)-bis[(N,N-dimethylbenzylamine-C², N)palladium(II)] (2), was characterized by IR spectroscopy and X-ray diffraction. Complex (2) is dimeric with the two [Pd(N,N-dimethylbenzylamine)] moieties being connected by the two vicinal bridging N, S-l,2,3,4-thiatriazole-5-thiolate anions in a square-planar coordination for the palladium atoms.