Metallosupramolecular Complexes Derived from Bis(benzene‐o‐dithiol) Ligands

Meso complex versus helicate : A naphthalene‐bridged bis(benzene‐o‐dithiol) ligand reacts with Ti⁴⁺ to give both dinuclear triple‐stranded meso complexes and helicates, depending on the counterion employed during synthesis. DFT calculations performed with a simplified complex revealed that the interconversion of Λ to its Δ enantiomer proceeds via a C_3h‐symmetric transition state (see figure).

     

Neutral Penta‐ and Hexacoordinate Silicon(IV) Complexes Containing Two Bidentate Ligands Derived from the α‐Amino Acids (S)‐Alanine, (S)‐Phenylalanine,and (S)‐tert‐Leucine

The neutral hexacoordinate silicon(IV) complex 6 (SiO₂N₄ skeleton) and the neutral pentacoordinate silicon(IV) complexes 7 – 11 (SiO₂N₂C skeletons) were synthesized from Si(NCO)₄ and RSi(NCO)₃ (R=Me, Ph), respectively. The compounds were structurally characterized by solid‐state NMR spectroscopy ( 6 – 11 ), solution NMR spectroscopy ( 6 and 10 ), and single‐crystal X‐ray diffraction ( 8 and 11 were studied as the solvates 8? CH₃CN and 11? C₅H₁₂ ? 0.5 CH₃CN, respectively). The silicon(IV) complexes 6 (octahedral Si‐coordination polyhedron) and 7 – 11 (trigonal‐bipyramidal Si‐coordination polyhedra) each contain two bidentate ligands derived from an α‐amino acid: (S)‐alanine, (S)‐phenylalanine, or (S)‐tert‐leucine. The deprotonated amino acids act as monoanionic ( 6 ) or as mono‐ and dianionic ligands ( 7 – 11 ). The experimental investigations were complemented by computational studies of the stereoisomers of 6 and 7 .     

4,4’－二(磷酸二甲酯甲基)联苯连接的具有互穿结构的二维锰(II)配位聚合物的合成与结构研究

在常规条件下,合成了具有新颖结构的配位聚合物[Mn(bdpbp)2(NO3)2]n (1) [bdpbp =4,4’-二(磷酸二甲酯甲基)联苯]。配合物1由单晶x-射线衍射确定结构,并用元素分析、红外光谱、荧光光谱和热重进行了表征和性质研究。配合物1具有二维无限的网格状结构,形成双重互穿,并由弱的C-H···O氢键进一步连接成三维超分子网络。     

Novel Transition‐Metal (M=Cr,Mo, W,Fe) Carbonyl Complexes with Bis(guanidinato)silicon(II) Ligands

The donor‐stabilized silylene 2 (the first bis(guanidinato)silicon(II ) complex) reacts with the transition‐metal carbonyl complexes [M(CO)₆] (M=Cr, Mo, W) to form the respective silylene complexes 7 – 10 . In the reactions with [M(CO)₆] (M=Cr, Mo, W), the bis(guanidinato)silicon(II ) complex 2 behaves totally different compared with the analogous bis(amidinato)silicon(II ) complex 1 , which reacts with [M(CO)₆] as a nucleophile to replace only one of the six carbonyl groups. In contrast, the reaction of 2 leads to the novel spirocyclic compounds 7 – 9 that contain a four‐membered SiN₂C ring and a five‐membered MSiN₂C ring with a M?Si and M?N bond (nucleophilic substitution of two carbonyl groups). Compounds 7 – 10 were characterized by elemental analyses (C, H, N), crystal structure analyses, and NMR spectroscopic studies in the solid state and in solution.     

Structure and Magnetic Properties of Mononuclear Copper(II) Complexes with 2,2‐Bipyrimidine, 2,3‐Bis(2‐pyridyl)pyrazine,and 4‐Terpyridone Based Ligands

Four new complexes of [Cu(bpm)(ox)(H₂O)] ( 1 ), [Cu(tpd)(dca)(H₂O)] ( 2 ), [Cu(bppz)(N₃)₂] ( 3 ), and [Cu(bpm)₂(μ_1,3‐N₃)(N₃)] ( 4 ) (bpm = 2,2′‐bipyrimidine, bppz = 2,3‐bis(2‐pyridyl)pyrazine, tpd = 4‐terpyridone, dca = dicyanamide, ox = oxalate) have been prepared and characterized by X‐ray single‐crystal analysis and variable‐temperature magnetic measurements. Compounds 1–4 are essentially mononuclear Cu(II) complexes. However, in complex 1 , Cu(II) it was found that intermolecular hydrogen bonding through between H₂O and ox formed 1‐D chain structure. In complex 2 it was found that the hydrogen bonding between H₂O and tpd of the next molecule led to for a binuclear Cu(II) complex. In complex 3 , two nitrogen atoms, one of the pyridyl group of bppz and one of N₃^? ligands, are weakly coordinated to neighbor Cu(II) ion thus leading to formation of a 1‐D chain structure. In complex 4 , one nitrogen atom of terminated N₃^? is weakly coordinated to the neighbor Cu(II) site to form a 1‐D polymeric structure. The magnetic susceptibility measurements indicate that complex 1 and 4 exhibit a weak antiferromagnetic interaction whereas a ferromagnetic coupling has been established for complexes 2 and 3 .     

Homo‐ and Heterodinuclear Helicates of Lanthanide(III), Zinc(II) and Aluminium(III) Based on 8‐Hydroxyquinoline Ligands

Homonuclear helicates with rare‐earth‐metal(III) ions or heteronuclear derivatives with rare‐earth‐metal and aluminium or zinc centres are obtained in alkali‐metal‐templated self‐assembly processes from isobutenylidene‐bridged homoditopic bis(2‐carbamido‐8‐hydroxyquinoline)‐derived ligands 1 ? H₂ and 2 ? H₂ or heteroditopic (8‐hydroxyquinoline)(2‐carbamido‐8‐hydroxyquinoline)‐derived ligands 3 ? H₂ and 4 ? H₂. Diamagnetic coordination compounds possess a high stability in organic solvents such as CDCl₃, [D₄]MeOH or [D₆]DMSO and can be well characterised by ¹H NMR spectroscopy by using methylene protons and the protons of the vinylic units of the ligand as stereochemical or symmetry probes, respectively. Some of the homonuclear complexes could be crystallised and were characterised by using X‐ray diffraction studies. The complexes adopt a triple‐stranded helical structure with a central templating cation encapsulated in their interior. An unusual orientation of the double bond of one spacer towards this cation is observed. The homo‐ and heterodinuclear helicates with ytterbium(III), neodymium(III) or erbium(III) of ligands 2 and 4 were of special interest owing to their near‐infrared (NIR) emitting properties, which were investigated depending on the lanthanide and on the encapsulated alkali‐metal cation.     

The Stereochemical Course of the α‐Hydroxyphosphonate–Phosphate Rearrangement

The phosphonate–phosphate rearrangement is an isomerisation of α‐hydroxyphosphonates bearing electron‐withdrawing substituents at the α‐carbon atom. We studied the stereochemical course of this rearrangement with respect to phosphorus. A set of four diastereomeric α‐hydroxyphosphonates was prepared by a Pudovik reaction from two diastereomeric cyclic phosphites. The hydroxyphosphonates were separated and rearranged with Et₃N as base. In analogy to trichlorphon, which was the first reported compound undergoing this rearrangement. All four hydroxyphosphonates could be rearranged to 2,2‐dichlorovinyl phosphates. Single‐crystal X‐ray structure analyses of the α‐hydroxyphosphonates and the corresponding phosphates allowed us to show that the rearrangement proceeds with retention of configuration on the phosphorus atom.     

2‐(1 H‐1,2,3‐Triazol‐4‐yl)‐Pyridine Ligands as Alternatives to 2,2′‐Bipyridines in Ruthenium(II) Complexes

The synthesis of a variety of 2‐(1H‐1,2,3‐triazol‐4‐yl)‐pyridines by click chemistry is demonstrated to provide straightforward access to mono‐functionalized ligands. The ring‐opening polymerization of ε‐caprolactone initiated by such a mono‐functionalized ligand highlights the synthetic potential of this class of bidentate ligands with respect to polymer chemistry or the attachment onto surfaces and nanoparticles. The coordination to Ru^II ions results in homoleptic and heteroleptic complexes with the resultant photophysical and electrochemical properties strongly dependent on the number of these ligands attached to the Ru^II core.     

Formation of Self‐Templated 2,6‐Bis(1,2,3‐triazol‐4‐yl)pyridine [2]Catenanes by Triazolyl Hydrogen Bonding: Selective Anion Hosts for Phosphate

We report the remarkable ability of 2,6‐bis(1,2,3‐triazol‐4‐yl)pyridine ( btp ) compounds 2 with appended olefin amide arms to self‐template the formation of interlocked [2]catenane structures 3 in up to 50 % yield when subjected to olefin ring‐closing metathesis in CH₂Cl₂. X‐ray diffraction crystallography enabled the structural characterization of both the [2]catenane 3 a and the non‐interlocked macrocycle 4 a . These [2]catenanes showed selective triazolyl hydrogen‐bonding interactions with the tetrahedral phosphate anion when screened against a range of ions; 3 a , b are the first examples of selective [2]catenane hosts for phosphate.     

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and its Complexes with Copper(II) Chloride and Copper(II) Perchlorate

1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole (hnt), prepared by alkylation of 3‐nitro‐1, 2, 4‐triazole with 2‐chloroethanol, was found to react with copper(II) chloride and copper(II) perchlorate in acetonitrile/ethanol solutions giving complexes [Cu₂(hnt)₂Cl₄(H₂O)₂] and[Cu(hnt)₂(H₂O)₃](ClO₄)₂, respectively. They are the first examples of coordination compounds with a neutral N‐substituted 3‐nitro‐1, 2, 4‐triazole ligand. 1‐(2‐Hydroxyethyl)‐3‐nitro‐1, 2, 4‐triazole and the obtained complexes were characterized by NMR and IR spectroscopy, X‐ray, and thermal analyses. [Cu₂(hnt)₂Cl₄(H₂O)₂] presents a dinuclear chlorido‐bridged complex in which hnt acts as a chelating bidentate ligand, coordinated to the metal by a nitrogen atom of the triazole ring and an oxygen atom of the nitro group, and the copper atoms are inconsiderably distorted octahedral coordination. [Cu(hnt)₂(H₂O)₃](ClO₄)₂comprises a mononuclear complex cation, in which two nitrogen atoms of two hnt ligands in trans configuration and three water oxygen atoms form a square pyramidal environment around the copper atom, which is completed to an distorted octahedron with a bifurcated vertex due to two additional elongated Cu–O bonds with two nitro groups. In both complexes, Cu–O bonds with the nitro groups may be considered as semi‐coordinated.     

Synthesis and Platinum Complexes of an Alane‐Appended 1,1′‐Bis(phosphino)ferrocene Ligand

An aryldimethylalane‐appended analogue of 1,1′‐bis(diphenylphosphino)ferrocene, FcPPAl, was prepared, and reaction with [Pt(nb)₃] (nb=norbornene) afforded [Pt(η²‐nb)(FcPPAl)] ( 1 ). Heating a solution of 1 to 80 °C resulted in crystallization of [{Pt(FcPPAl)}₂] ( 2 ), whereas treatment of 1 with C₂H₄, C₂Ph₂, H₂, or CO provided [PtL(FcPPAl)] [L=C₂H₄ ( 3 ), C₂Ph₂ ( 4 )], [PtH₂(FcPPAl)] ( 5 ), and [Pt(CO)(FcPPAl)] ( 6 ). In all complexes, the FcPPAl ligand is coordinated through both phosphines and the alane. Whereas 2 adopts a T‐shaped geometry at platinum, 3 – 5 are square‐pyramidal, and 6 is distorted square‐planar. The hydride and carbonyl complexes feature unusual multicenter bonding involving platinum, aluminum, and a hydride or carbonyl ligand.     

Chromium Bis(anthracene‐η6) Complexes – A DFT Study

Chromium bisanthracene‐η⁶ complexes are considered within the framework of density functional theory using LANL2DZ and 6‐31+G(d) basis sets and B3LYP functional. The complexation with both the same types of rings of anthracene decks (AA‐ and BB‐type complexes) and with different rings (AB‐type complex) are considered. The optimized geometries and the associated quantum chemical properties are comparatively discussed for the both types of basis sets used. LANL2DZ basis set yielded some unreasonable results. B3LYP/6‐31+G(d) level of calculations yielded the stability order as AA > BB > AB. IR spectra of AA and BB‐type complexes resemble each other. The C–H frequencies are almost the same for both of the anthracene decks, whereas they differ in the case of AB‐type complex. UV/Vis spectra of the complexes all absorb above 500 nm. AA and AB‐type complexes in contrast to BB‐type display rather complex pattern. The NICS(0) values of various rings in the complexes considered are obtained and discussed.     

The Preparation of (8‐Hydroxyquinolinato)Bis(2‐Phenylpyridyl)Iridium Complexes and Their Photophysical Properties

Four derivatives of the titled compounds, (8‐hydroxyquinoline)bis(2‐phenylpyridyl)iridium ( IrQ(ppy)₂ ), were prepared. Two of them were confirmed by single crystal X‐ray diffraction analyses, in which solvent molecules were found to be incorporated in the crystal lattices. Their emission spectra display separated dual bands in de‐aerated solutions at about 515 and 645 nm upon excitation. These green and red emissions are attributed to the triplet metal‐to‐ligand charge transfer (³MLCT) and triplet ligand centered (³LC) transitions in Ir(ppy)₂ and IrQ, respectively. It is suggested that such a multiple emission is feasible by nearly orthogonal orientation between the ppy and quinoline ligands in the mixed‐ligand Ir‐compounds which prohibits energy transfer between the two different ligands. The electroluminescence (EL) of these compounds was examined by the fabrication of light‐emitting diodes (LEDs). Unlike the spectra in solutions, their EL spectra displayed only the red emission band. Devices displaying white light can be obtained by mixing the red emission of IrQ(ppy)₂ with a compatible blue emitter (NPB) in separated layers.     

对苯二甲酸、2-(3-吡啶基)苯并咪唑配位聚合物的合成、晶体结构和发光

在水热条件下,对苯二甲酸(H2Bdc)和2-(3-吡啶基)苯并咪唑(3-PyHBIm)与Cd(NO3)2、Zn(NO3)2反应,得到配合物{[Cd(3-PyHBIm)(Bdc)(H2O)2](H2Bdc)1/2}n (1)、[Zn(3-PyHBIm)2(Bdc)(H2O)2]n (2)。单晶X-射线衍射结构分析表明,两个化合物均呈一维聚合结构,3-PyHBIm配体采用吡啶氮原子单齿配位。在配合物1中,对苯二甲酸根作为四齿配体,桥联Cd(II)离子,形成一维锯齿链状配位聚合物,两个水分子呈顺式配位。该化合物含有对苯二甲酸客体分子,通过强的氢键,构成三维超分子框架。在配合物2中,对苯二甲酸根作为双齿配体,结合Zn(II)离子,形成直线链状配位聚合物,两个水分子呈反式配位。两个配位聚合物都对热稳定,在固体状态下,呈蓝色发光。     

Electropolymerizable IrIII Complexes with β‐Ketoiminate Ancillary Ligands

A series of electropolymerizable cyclometallated Ir^III complexes were synthesized and their electrochemical and photophysical properties studied. The triphenylamine electropolymerizable fragment was introduced by using triphenylamine‐2‐phenylpyridine and, respectively, triphenylamine‐benzothiazole as cyclometalated ligands. The coordination sphere was completed by two differently substituted β‐ketoiminate ligands deriving from the condensation of acetylacetone or hexafluoroacetylacetone with para‐bromoaniline. The influence of the ‐CH₃/‐CF₃ substitution to the electrochemical and photophysical properties was investigated. Both complexes with CH₃ substituted β‐ketoiminate were emissive in solution and in solid state. Highly stable films were electrodeposited onto ITO coated glass substrates. Their emission was quenched by electron trapping within the polymeric network as proven by electrochemical studies. The ‐CF₃ substitution of the β‐ketoiminate leads instead to the quenching of the emission and inhibits electropolymerization.     

A New Chair‐shaped Conformation Containing HgHgOHgHgO: Synthesis and Structure of Hg4(L2)2(NO3)4 (L2 = morpholin‐4‐ylpyridin‐2‐ylmethyleneamine)

. The complex Hg₄(L²)₂(NO₃)₄ ( 1 ) (L² = morpholin‐4‐ylpyridin‐2‐ylmethyleneamine) has been synthesized and characterized by CHN analysis, IR, and UV/Vis spectroscopy. The crystal structure of 1 was determined using single‐crystal X‐ray diffraction. The crystal structure of 1 contains four mercury atoms, four nitrate anions (two terminal and two bridge ones) and two L² ligand molecules. A chair shape, six‐membered ring is formed with the sequence OHgHgOHgHg built from Hg–Hg dumbbells and oxygen atoms from the nitrate co‐ligands. In the crystal structure, the asymmetric unit of the compound is built up by one‐half of the molecule. It contains the Hg₂²⁺ moiety with a mercury–mercury bonded core, in which one diimine ligand is coordinated to one of the mercury atoms. The nitrate anions act as anisobidentate and bidentate ligands.