Syntheses,Structures, and Properties of Two Coordination Compounds of Pb(II) and Cd(II) with Quinoline‐8‐oxy‐acetate Acid

Quinoline‐8‐oxy‐acetate acid (8‐qoacH) reacts with M(II) (M=Pb and Cd) to give rise to two coordination complexes [Pb(8‐qoac)₂] ( 1 ) and [Cd(8‐qoac)(bdc)_0.5(H₂O)₂] ( 2 ) under hydrothermal conditions. They are characterized by single‐crystal X‐ray diffraction, IR, elemental, thermal analyses and luminescent analysis. The Pb metal centers connect the 8‐qoac anions to form a 1D linear chain in 1 . In 2 , two symmetrical [Cd(8‐qoac)(H₂O)₂] are bridged by a 1,4‐bdc^2? to generate a coordination unit [Cd(8‐qoac)(bdc)_0.5(H₂O)₂], and all the units are further connected to a 2D supramolecular layer‐like structure via hydrogen bonds. TG analyses indicate that 1 exhibits higher thermostability than 2 . Fluorescence spectrum of compound 2 in solid state shows strong fluorescence property.     

Geometry and Spin Change at the Heart of a Cobalt(II) Complex: A Special Case of Solvatomorphism

Structural analysis and spectroscopic methods revealed a special case of solvatomorphism: hydrogen‐bonding‐induced geometry and spin change within a same N,O‐(bis)chelate of cobalt(II). Solid‐state structures are presented for both the tetrahedral and the solvated square‐planar forms of the complex. Magnetic‐moment measurements and ESR spectroscopy confirmed the high‐spin state of the tetrahedral form (μ_eff=4.7 μ_B) and the low‐spin state of the square‐planar solvatomorph. Specific hydrogen‐bonding interactions between the solvent molecules and the complex chelate ring (O1 ??? H?CHCl₂ (d=2.26 Å, D=3.24 Å, θ=173°); O2 ??? H?CHCl₂ (d=2.22 Å, D=3.19 Å, θ=165°)) play a pivotal role in biasing the system toward the low‐spin ground state.     

M-Carboxylic Acid Induced Formation of New Coordination Polymers for Efficient Photocatalytic Degradation of Ciprofloxacin

Four new 2–3D materials were designed and synthesized by hydrothermal methods, namely, {[(L1·Cu·2H₂O) (4,4-bipy)_0.5] (β-Mo₈O₂₆)_0.5·H₂O} (1), {[(L1·Cu)₂·(4,4-bipy)] (Mo₅O₁₆)} (2), {Co(L1)₂}_n (3), and {[(L1)₂][β-Mo₈O₂₆]_0.5·5H₂O} (4). [L1=5-(4-aminopyridine) isophthalic acid]. The degradation of ciprofloxacin (CIP) in water by compounds 1–4 was studied under visible light. The experimental results show that compounds 1–4 have obvious photocatalytic degradation effect on CIP. In addition, for compound 1, the effects of temperature, pH, and adsorbent dosage on photocatalytic performance were also investigated. The stability of compound 1 was observed by a cycle experiment, indicating that there was no significant change after three cycles of CIP degradation.     

The silica-like extended polymorphism of cobalt(II) imidazolate three-dimensional frameworks: X-ray single-crystal structures and magnetic properties

Five polymorphous frameworks of cobalt(II) imidazolates (1-5) have been prepared by solvatothermal syntheses. Of these, compound 3 has already been synthesized in a gas-phase reaction by Seel et al. in 1969 and structurally characterized by Sturm et al. in 1975. The new synthetic strategy affords four polymorphous frameworks of cobalt(II) imidazolates (1, 2, 4, 5) of crystalline substances, of which the compound 4 (a = b = 23.450(3), c = 12.460(3) A, tetragonal, I4(1)cd, Z = 16) is an isomorphous compound of [Zn(im)(2)]( infinity ), which was also synthesized in a gas-phase reaction in 1980. The frameworks of compounds 1 and 2 are porous and isostructural; they have the same framework topology that represents a novel uninodal (6,4)-net: 1: a = 18.513(4), b = 24.368(5), c = 9.2940(19) A, orthorhombic, Fdd2, Z = 16; 2: a = 17.635(4), b = 27.706(6), c = 9.0810(18) A, orthorhombic, Fdd2, Z = 16. The framework of compound 5 exhibits a topology of zeolitic structure with the unit-cell parameters: a = 24.3406(8), b = 9.4526(3), c = 24.8470(8) A, beta = 91.977(1) degrees, monoclinic, P2(1)/n, Z = 4. All polymorphous frameworks of cobalt(II) imidazolates reflect the structural features of silica (SiO(2)) and also exhibit different magnetic behaviors, although the imidazolates transmit the antiferromagnetic coupling between the cobalt(II) ions in all cases. However, the uncompensated antiferromagnetic couplings arise from spin-canting are sensitive to the structures: compound 1 is an antiferromagnet with T(N) = 13.11 K; compounds 2-4 are weak ferromagnets (canted antiferromagnets): 2 shows a very weak ferromagnetism below 15 K, 3 exhibits a relatively strong ferromagnetism below 11.5 K and a coercive field (H(C)) of 1800 Oe at 1.8 K, and 4 displays the strongest ferromagnetism of the three cobalt imidazolates and demonstrates a T(C) of 15.5 K with a coercive field, H(C), of 7300 Oe at 1.8 K. However, compound 5 seems to be a hidden canted antiferromagnet with a magnetic ordering temperature of 10.6 K.     

两种铜配位聚合物的晶体结构和量子化学计算

在水热条件下以4-硝基邻苯二甲酸（4-H₂nph）/2,2''-联吡啶-4,4''-二甲酸（H₂bda）为主要配体,3-（2-吡啶基）吡唑（HL）/1,4-双（咪唑基-1-基）丁烷（bib）为辅助配体制备了2种新的金属有机配位聚合物[Cu₄（4-nph）（L）₆]_n （1）和{[Cu₂（bda）₂（bib）₂（H₂O）₄]·4H₂O}_n （2）。通过元素分析、红外光谱、热重X射线单晶衍射和X射线粉末衍射对它们进行了表征。结果表明,配合物1属于单斜晶系,C2/c空间群。晶胞参数：a=1.956 16（8） nm,b=1.290 68（8） nm,c=2.160 34（12） nm,β=97.073（2）°,V=5.412 9（5） nm³,Z=4。配合物2属于三斜晶系,P1空间群。晶胞参数：a=0.962 22（15） nm,b=1.102 90（17） nm,c=1.404 3（2） nm,α=72.752（4）°,β=79.271（4）°,γ=67.065 （3）°,V=1.306 6（4） nm³,Z=1。在配合物1中,羧基配体4-nph^2-通过单齿模式桥联金属中心,形成一维结构。在配合物2中,柔性bib配体连接金属中心形成具有26元环的双核结构。此外,还用Gaussian16程序PBE0/LANL2DZ方法从配合物1的晶体结构中提取“分子片段”进行了量子化学计算。计算结果表明配位原子与铜（Ⅱ）离子之间存在着共价作用。     

The anhydride route to Group 15/16 ligands in oligomeric and polymeric environments: from metal complexes to supraionic chemistry

The aim of this paper is to introduce a synthetic concept suitable for the preparation of a broad variety of compounds. The so-called anhydride route (in this article the term anhydride is used for compounds derived from corresponding acids by formal loss of H2O, H2S and H2Se) has so far led to a range of unusual Group 15/16 ligands in oligomeric and polymeric environments. Commonly, reactions of neutral precursor molecules, for example, [{RP(S)(mu-S)}2] (R=4-anisyl) Lawesson's reagent or [{PhP(Se)(mu-Se)}2] Woollins's reagent and metal salts are performed to result in novel coordination compounds in which ligands and metal atoms form coordination oligomers and polymers. An attempt is made to relate the outcome of the investigations to the type of metal used. By relating the strength of ionic interactions, which correspond to metal-donor distances, to phenomena observed in the solid-state structures, an aspect of supraionic chemistry is described. Chemistry of and beyond novel Group 15/16 anions is further discussed using a novel approach in coordination chemistry where the chemical nature of ligands is unknown prior to the experiment despite the use of a range of similar starting materials.     

对苯二甲酸及双酚A衍生物构筑的二维镉配位聚合物的合成、结构及性质

以4,4-二（4-羟乙基苯并咪唑基苯基）丙烷（L₁）,4,4-二（4-羟乙基咪唑基苯基）丙烷（L₂）为原料,通过水热法得到2个二维结构的配位聚合物{[Cd（L₁）（bdc）H₂O]·2DMA}_n（1）,[Cd（L₂）（bdc）H₂O]_n（2）（H₂bdc=对苯二甲酸,DMA=N,N-二甲基乙酰胺）,通过X-射线单晶洐射、热重以及红外光谱对其进行了表征。结果显示晶体1为单斜晶系,P2/c空间群。晶体2为单斜晶系,C2/c空间群。配合物2为2D→2D穿插结构。热重分析表明配合物1和2分别在343和325℃时分解。     

Heavy alkaline earth metal pyrazolates: synthetic pathways, structural trends, and comparison with divalent lanthanoids

Two series of heavy alkaline earth metal pyrazolates, [M(Ph(2)pz)(2)(thf)(4)] 1 a-c (Ph(2)pz=3,5-diphenylpyrazolate, M=Ca, Sr, Ba; THF=tetrahydrofuran) and [M(Ph(2)pz)(2)(dme)(n)] (M=Ca, 2 a, Sr, 2 b, n=2; M=Ba, 2 c, n=3; DME=1,2-dimethoxyethane) have been prepared by redox transmetallation/ligand exchange utilizing Hg(C(6)F(5))(2). Compounds 1 a and 2 b were also obtained by redox transmetallation with Tl(Ph(2)pz). Alternatively, direct reaction of the alkaline earth metals with 3,5-diphenylpyrazole at elevated temperatures under solventless conditions yielded compounds 1 a-c and 2 a-c upon extraction with THF or DME. By contrast, [M(Me(2)pz)(2)(Me(2)pzH)(4)] 3 a-c (M=Ca, Sr, Ba; Me(2)pzH=3,5-dimethylpyrazole) were prepared by protolysis of [M[N(SiMe(3))(2)](2)(thf)(2)] (M=Ca, Sr, Ba) with Me(2)pzH in THF and by direct metallation with Me(2)pzH in liquid NH(3)/THF. Compounds 1 a-c and 2 a-c display eta(2)-bonded pyrazolate ligands, while 3 a,b exhibit eta(1)-coordination. Complexes 1 a-c have transoid Ph(2)pz ligands and an overall coordination number of eight with a switch from mutually coplanar Ph(2)pz ligands in 1 a,b to perpendicular in 1 c. In eight coordinate 2 a,b the pyrazolate ligands are cisoid, whilst 2 c has an additional DME ligand and a metal coordination number of ten. By contrast, 3 a,b have octahedral geometry with four eta(1)-Me(2)pzH donors, which are hydrogen-bonded to the uncoordinated nitrogen atoms of the two trans Me(2)pz ligands. The application of synthetic routes initially developed for the preparation of lanthanoid pyrazolates provides detailed insight into the similarities and differences between the two groups of metals and structures of their complexes.     

对苯二甲酸及双酚A衍生物构筑的二维镉配位聚合物的合成、结构及性质(英文)

以4,4-二(4-羟乙基苯并咪唑基苯基)丙烷(L1),4,4-二(4-羟乙基咪唑基苯基)丙烷(L2)为原料,通过水热法得到2个二维结构的配位聚合物{[Cd(L1)(bdc)H2O]·2DMA}n(1),[Cd(L2)(bdc)H2O]n(2)(H2bdc=对苯二甲酸,DMA=N,N-二甲基乙酰胺),通过X-射线单晶洐射、热重以及红外光谱对其进行了表征。结果显示晶体1为单斜晶系,P2/c空间群。晶体2为单斜晶系,C2/c空间群。配合物2为2D→2D穿插结构。热重分析表明配合物1和2分别在343和325℃时分解。     

A Two‐Coordinate Cobalt(II) Imido Complex with NHC Ligation: Synthesis,Structure, and Reactivity

The synthesis, structural characterization, and reactivity of the first two‐coordinate cobalt complex featuring a metal–element multiple bond [(IPr)Co(NDmp)] ( 4 ; IPr=1,3‐bis(2′,6′‐diisopropylphenyl)imidazole‐2‐ylidene; Dmp=2,6‐dimesitylphenyl) is reported. Complex 4 was prepared from the reaction of [(IPr)Co(η²‐vtms)₂] (vtms=vinyltrimethylsilane) with DmpN₃. An X‐ray diffraction study revealed its linear C? Co? N core and a short Co? N distance (1.691(6) Å). Spectroscopic characterization and calculation studies indicated the high‐spin nature of 4 and the multiple‐bond character of the Co? N bond. Complex 4 effected group‐transfer reactions to CO and ethylene to form isocyanide and imine, respectively. It also facilitated E? H (E=C, Si) σ‐bond activation of terminal alkyne and hydrosilanes to produce the corresponding cobalt(II) alkynyl and cobalt(II) hydride complexes as 1,2‐addition products.     

Reaction chemistry of complexes containing Pt--H, Pt--SH, or Pt--S fragments: from their apparent simplicity to the maze of reactions underlying their interconversion

The relevance of platinum in the reaction of thiophene and derivatives with homogeneous transition-metal complexes as models for hydrodesulfurization has led us to the study of the reaction chemistry of complexes containing Pt--H, Pt--SH, and Pt--S fragments. Exploration of the reactions triggered by addition of controlled amounts of Na2S or NaSH to [Pt2(H)2(mu-H)(dppp)2]ClO4 (1) has provided evidence of the formation of complexes [Pt2(mu-H)(mu-S)(dppp)2]ClO4 (2), [Pt(H)(SH)(dppp)] (3), [Pt2(mu-S)2(dppp)2] (4), [Pt2(mu-S)(dppp)2] (5) and [Pt(SH)2(dppp)], in which dppp denotes 1,3-bis(diphenylphosphanyl)propane. Consequently, complexes 1, 2, and 5 as well as the already reported 3, 4, and [Pt(SH)2(dppp)] have been obtained and fully characterized spectroscopically. Also the crystal structures of 1 and 2 have been solved. Complexes 1-5 constitute the main framework of the network of reactions that account for the evolution of 1 under various experimental conditions as shown in Scheme 1. Apparently, this network has complexes 2 and 4 as dead-ends. However, their reciprocal interconversion by means of the replacement of one bridging hydride or sulfide ligand in the respective {Pt(mu-H)(mu-S)Pt} and {Pt(mu-S)2Pt} cores enables the closure of the reaction cycle involving complexes 1-5. Theoretical calculations support the existence of the undetected intermediates proposed for conversion from 1 to 2 and from 3 to 2 and also account for the fluxional behavior of 1 in solution. The intermediates proposed are consistent with the experimental results obtained in comparable reactions carried out with labeled reagents, which have provided evidence that complex 1 is the source of the hydride ligands in complexes 2 and 3. Overall, our results show the strong dependence on the experimental conditions for the formation of complexes 1-5 as well as for their further conversion in solution.     

2D LnIII(Nd/La)‐AgI Heterometallic and TmIII Homometallic Coordination Polymers Based on Pyridine Dicarboxylate ­Ligands

Two 2D 4d‐4f heterometallic coordination polymers, [LnAg(Py26DC)₂(H₂O)₃] · 3H₂O [Ln = Nd ( 1 ), La ( 2 ); H₂Py26DC = pyridine‐2,6‐dicarboxylic acid], and one 2D lanthanide homometallic coordination polymer, [Ln(Py25DC)(ox)_0.5(H₂O)₂] [Ln = Tm ( 3 ); H₂Py25DC = pyridine‐2,5‐dicarboxylic acid; ox = oxalate], were synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction analysis. Both complexes 1 and 2 are isostructural and exhibit 3‐connected 2D heterometallic layer structures with the Schläfli symbol of (8² · 10), whereas complex 3 represents an extended 2D homometallic network structure with (4,4) topology.