Design and structural extension of a supramolecular inclusion-compound host made by the formation of dimers of isonicotinic acid and thiocyanato coordinating bridges

A new host design for an inclusion compound with a preference for large planar aromatic guest molecules has been proposed. Our host design includes a rectangular cavity made using a long and a short building block based on the concept of supramolecular chemistry. The long building block facilitates the inclusion of large guests, and the short building block prevents the formation of an interpenetrated structure, which is often observed in frameworks with large void spaces. The long building block is made when dimers of 4-pyridinecarboxylic acid (isoH) form through hydrogen bonding between the two carboxylic acid moieties. This isoH dimer can link two transition metal centers using the N atoms at both ends to act as a long building block. For the short building block, the thiocyanato ion was used. This makes a bent bridge between two metal centers to form a 1D double-chain [M(SCN)2]infinity complex. From the self-assembly of isoH, SCN- and Ni2+, a 2D network of [Ni(SCN)2(isoH)2]infinity, in which the 1D [Ni(SCN)2]infinity complexes are linked by the isoH dimers, is built up. The rectangular cavity is formed as a mesh within the 2D network. The crystal of our inclusion compound has a layered structure of 2D networks, and a 1D channel-like cavity penetrating the layered 2D networks is formed where guests may be included. Moreover, our host design has the advantage of easy extension of the host structure. Replacement of isoH with another component and use of three components is possible for making the long building block. In the latter case, a linear spacer having two carboxy groups is inserted into the isoH dimer to form a long building block with a trimer structure. Based on our host design, a series of new inclusion compounds were synthesized. The crystal structures of three compounds were determined by single crystal X-ray diffraction. These were a biphenyl inclusion compound [Ni(SCN)2(isoH)2].1/2C12H10 (the basic case), a 9,10-dichloroanthracene inclusion compound [Ni(SCN)2(acrylH)2].1/2C14H8Cl2, where isoH is replaced with 3-(4-pyridinyl)-2-propenoic acid (acrylH), and a perylene inclusion compound [Ni(SCN)2(isoH)2(fumaricH2)].1/2C20H12, whose long building block is a trimer inserted with fumaric acid (fumaricH2) as a linear spacer.     

New bis-, tris- and tetrakis(pyrazolyl)borate ligands with 3-pyridyl and 4-pyridyl substituents: synthesis and coordination chemistry

The new ligands dihydrobis[3-(4-pyridyl)pyrazol-1-yl]borate [Bp(4py)]-, hydrotris[3-(4-pyridyl)pyrazol-1-yl]borate [Tp(4py)]-, tetrakis[3-(4-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]-, dihydrobis[3-(3-pyridyl)pyrazol-1-yl]borate [Bp(3py)]-, hydrotris[3-(3-pyridyl)pyrazol-1-yl]borate [Tp(3py)]- and tetrakis[3-(3-pyridyl)pyrazol-1-yl]borate [Tkp(4py)]- are derivatives of the well known bis-, tris- and tetrakis-(pyrazolyl)borate cores, bearing 4-pyridyl or 3-pyridyl substituents attached to the pyrazolyl C3 positions. These pyridyl groups cannot chelate to the metal ions in the poly(pyrazolyl) cavity but are externally directed. Structural studies on a range of metal complexes show how, in many cases, coordination of these pendant pyridyl groups to the M(pyrazolyl)n core of an adjacent metal complex fragment results in formation of coordination oligomers or polymeric networks. [Tl(Bp(3py))], [Tl(Bp(4py))] and [Tl(Tp(4py))] form one-dimensional polymeric chains via coordination of one of their pendant pyridyl units to the Tl(I) centre of an adjacent complex fragment; in contrast, in [Tl(Tp(3py))] coordination of all three pendant pyridyl units to separate Tl(I) neighbours results in formation of a two-dimensional polymeric sheet. In [Tl(Tkp(3py))] and [Tl(Tkp(4py))] the Tl(I) is coordinated by two or three of the four pyrazolyl arms, respectively; bridging interactions of pendant 4-pyridyl groups with adjacent Tl(I) centres result in a two-dimensional sheet forming in each case. In Ag(Tkp(4py)) each Ag(I) ion is coordinated by two pyrazolyl rings, and two bridging pyridyl ligands from other complex units, resulting in a one-dimensional chain consisting of pairs of cross-linked zigzag chains. In contrast to these polymeric coordination networks, the structures of [Cu(Tp(4py))] and [(Tp(3py))Cd(CH3CO2)] are dimers, with a pendant pyridyl residue from the first metal centre attaching to a vacant coordination site on the second, and vice versa; these dimers are stabilised by pi-stacking interactions between sections of the two ligands. [Ni(Tp(3py))2] is monomeric, with an octahedral coordination geometry arising from two tris(pyrazolyl)borate chelates; the array of pendant 3-pyridyl groups is involved only in intramolecular hydrogen-bonding. [(Tp(4py))Re(CO)3] is also monomeric, with a facial arrangement of three pyrazolyl ligands and three carbonyls, with the pendant 4-pyridyl groups not further coordinated. [(Tp(2py))Re(CO)3], based on the related ligand hydrotris[3-(2-pyridyl)pyrazol-1-yl]borate, has a similar fac-(CO)3(pyrazolyl)3 coordination geometry.     

Nonlinear optically active polymeric coordination networks based on metal m-pyridylphosphonates

A family of polymeric coordination networks based on meta-pyridylphosphonate bridging ligands has been synthesized and characterized by single-crystal X-ray crystallography. Compounds [M(2)(L-Et)(4)(mu-H(2)O)] (M = Mn, 1; Co, 2; Ni, 3; L-Et = ethyl-4-[2-(3-pyridyl)ethenyl]phenylphosphonate) were obtained by hydro(solvo)thermal reactions between diethyl-4-[2-(3-pyridyl)ethenyl]phenylphosphonate (L-Et(2)) and corresponding metal salts, while [Cd(L-H)(2)], 4 (L-H is monoprotonated 4-[2-(3-pyridyl)ethenyl]phenylphosphonate), was obtained by a hydro(solvo)thermal reaction between (L-H(2)).HBr and Cd(CF(3)SO(3))(2).6H(2)O. Compounds 1-3 are isostructural and crystallize in noncentrosymmetric space group Fdd2, and they adopt a complicated 3D framework structure composed of [M(2)(L-Et)(4)(mu-H(2)O)] building units, while compound 4 adopts a centrosymmetric 3D network structure resulted from linking 1D sinusoidal cadmium phosphate chains with L-H bridging ligands. Consistent with their polar structures, compounds 1-3 exhibit powder second harmonic generation signals larger than that of potassium dihydrogen phosphate.     

Structural diversity of silver(I) 4,6-dipyridyl-2-aminopyrimidine complexes: effect of counteranions and ligand isomerism

Using two ligands, 4,6-bis(2-pyridyl)-2-aminopyrimidine (L1) with two N,N'-chelating sites and 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (L2) (as the isomer of L1) containing one chelating site and one bridging unit, a series of novel Ag(I) complexes varying from zero- to two-dimensions have been prepared and their crystal structures determined via single-crystal X-ray diffraction. The two ligands are employed for the first time in coordination chemistry. The structures of compounds 1-3 are directed by the counteranions adopted in the reaction system: The reaction of L1 with AgNO3 yielded a dimer [Ag2L12](NO3)2 (1). The reaction of L1 with AgCF3SO3 led to a one-dimension "V-shaped" chain {[AgL1](CF3SO3)}n (2). When AgSCN was used, a one-dimension ladder {[Ag2L1(SCN)2].H2O}n (3) was obtained. While ligand L2 reacted with AgNO3, a two-dimension {[Ag2(L2)2](NO3)2.H2O}n (4) was prepared with the help of an argentophilic interaction. Compounds 1-4 display room-temperature photoluminescence.     

New metallomesogenic polymers built by self-assembly of non-mesomorphic stilbazole dimers and CF3SO3Ag through coordination bonds

Supramolecular liquid-crystalline main-chain polymers have been obtained by self-assembly of non-mesomorphic bifunctional ligands and a transition metal ion. Stibazole dimers, bis[2-(2-{4-[2-(4-pyridyl)vinyl]phenoxy}ethoxy)ethyl] ether (1) and 1,2-bis[2-(2-{4-[2-(4-pyridyl)vinyl]phenoxy}ethoxy)ethoxy]benzene (2) have been synthesized and complexed with silver trifluoromethanesulfonate (CF₃SO₃Ag). The metallomesogenic polymeric complexes formed by coordination bonds between the pyridyl groups of the stilbazole dimers and the silver ion exhibit smectic phases.     

Hydrothermal Syntheses and Structural Characterizations of Two ML-Containing Polyoxomolybdates:[Cu~Ⅱ_2(HL)_3]_2[Mo_8O_(26)]·(H_2O)_4 and [Ni~Ⅱ(HL)_3]_2(Mo_8O_(26))·(H_2O)_3(HL=3-(2-Pyridyl)pyrazole)

Two new polyoxomolybdate compounds,namely CuII2(HL)3]2[Mo8O26]·(H2O)4(1) and [NiII(HL)3]2(Mo8O26)·(H2O)3(2)(HL = 3-(2-pyridyl)pyrazole),were designed and synthesized under hydrothermal conditions.X-ray diffraction analyses reveal that compound 1 consists of one β-Mo8O264-cluster and a Cu2 dimer which is built from two Cu(II) ions linked by three 3-(2-pyridyl)pyrazole ligands.Compound 2 is generated by two kinds of polyoxomolybdate clusters of α-[Mo8O26]4-and β-[Mo8O26]4-.In complexes 1 and 2,the multi-dimensional frameworks are con-structed with the help of hydrogen-bonding links between the terminaloxygen atoms of [Mo8O26]4-,water molecules,and 3-(2-pyridyl)pyrazole ligands.Crystal data of 1:C24H25Cu2Mo4N9O15,Mr = 1190.37,monoclinic,space group P21/c,a = 10.850(2),b = 18.510(4),c = 17.230(3) ,β = 100.57(3)°,V = 3401.6(12) 3,Z = 4,Dc = 2.324 g/cm3,F(000) = 2312,μ = 2.742 mm-1,R = 0.0302 and wR = 0.0775(Ⅰ 2σ(Ⅰ));Crystal data for 2:C48H48Mo8N18Ni2O29,Mr = 2225.98,monoclinic,space group P21/n,a = 20.799(2),b = 14.7970(13),c = 23.141(2) ,β = 91.6180(10)°,V = 7119.0(11) 3,Z = 4,Dc = 2.077 g/cm3,F(000) = 4344,μ = 1.968 mm-1,R = 0.0309 and wR = 0.0696(Ⅰ 2σ(Ⅰ)).     

苯并[a]蒽在TiO2颗粒表面的多相光化学反应

利用原位漫反射红外光谱(DRIFTS)并结合气相色谱-质谱(GC-MS)分析研究了苯并[a]蒽(B[a]A)在TiO₂颗粒气固界面的光化学反应过程. 结果表明, 在氙灯照射下, 苯并[a]蒽在TiO₂颗粒气固界面发生光催化反应, 表面羟基和表面氧参与了光催化反应, 主要产物为苯并[a]蒽-7,12-二醌, 根据分析结果给出了苯并[a]蒽在TiO₂颗粒表面的光化学反应机理模型. 在模拟太阳光(22 mW·cm^-2)照射下, 苯并[a]蒽在TiO₂颗粒表面的光降解过程符合指数衰减方程, 半衰期为6.8 min.     

Crystalline inclusion compounds constructed through self-assembly of isonicotinic acid and thiocyanato coordination bridges

The synthesis, crystal structures, inclusion ability, and structural robustness of novel crystalline inclusion compounds of [Ni(SCN)2(isoH)2].xG (isoH = isonicotinic acid; G = aromatic guest) are described. The inclusion compounds are constructed by stacking identical 2D host layers that consist of SCN-, isoH, and Ni2+ with van der Waals contact separation. In the layer, two types of rectangular cavities (A-type and B-type) are formed, and the guests are included in the former cavity. The inclusion compounds were categorized into four stacking modes according to the difference in the stacking mode of the layers. A systematic investigation of the crystal structures of the 21 inclusion compounds clarified the close relationship between the molecular structure of the guest and the resultant stacking mode of the layers.     

Ligand-bridged dinuclear cyclometalated Ir(III) complexes: from metallamacrocycles to discrete dimers

Metallamacrocycles 1, 2, and 3 of the general formula [{Ir(ppy)(2)}(2)(μ-BL)(2)](OTf)(2) (ppyH = 2-phenyl pyridine; BL = 1,2-bis(4-pyridyl)ethane (bpa) (1), 1,3-bis(4-pyridyl)propane (bpp) (2), and trans-1,2-bis(4-pyridyl)ethylene (bpe) (3)) have been synthesized by the reaction of [{(ppy)(2)Ir}(2)(μ-Cl)(2)], first with AgOTf to effect dechlorination and later with various bridging ligands. Open-frame dimers [{Ir(ppy)(2)}(2)(μ-BL)](OTf)(2) were obtained in a similar manner by utilizing N,N'-bis(2-pyridyl)methylene-hydrazine (abp) and N,N'-(bis(2-pyridyl)formylidene)ethane-1,2-diamine (bpfd) (for compounds 4 and 5, respectively) as bridging ligands. Molecular structures of 1, 3, 4, and 5 were established by X-ray crystallography. Cyclic voltammetry experiments reveal weakly interacting "Ir(ppy)(2)" units bridged by ethylene-linked bpe ligand in 3; on the contrary the metal centers are electronically isolated in 1 and 2 where the bridging ligands are based on ethane and propane linkers. The dimer 4 exhibits two accessible reversible reduction couples separated by 570 mV indicating the stability of the one-electron reduced species located on the diimine-based bridge abp. The "Ir(ppy)(2)" units in compound 5 are noninteracting as the electronic conduit is truncated by the ethane spacer in the bpfd bridge. The dinuclear compounds 1-5 show ligand centered (LC) transitions involving ppy ligands and mixed metal to ligand/ligand to ligand charge transfer (MLCT/LLCT) transitions involving both the cyclometalating ppy and bridging ligands (BL) in the UV-vis spectra. For the conjugated bridge bpe in compound 3 and abp in compound 4, the lowest-energy charge-transfer absorptions are red-shifted with enhanced intensity. In accordance with their similar electronic structures, compounds 1 and 2 exhibit identical emissions. The presence of vibronic structures in these compounds indicates a predominantly (3)LC excited states. On the contrary, broad and unstructured phosphorescence bands in compounds 3-5 strongly suggest emissive states of mixed (3)MLCT/(3)LLCT character. Density functional theory (DFT) calculations have been carried out to gain insight on the frontier orbitals, and to rationalize the electrochemical and photophysical properties of the compounds based on their electronic structures.     

Synthesis and characterization of novel grid coordination polymer networks generated from unsymmetrically bridging ligands

Self-assembly between simple unsymmetrical ligands, such as 1-(3-pyridyl)-2-(4-pyridyl)ethene (L(1)) and 1-methyl-1'-(3-pyridyl)-2-(4-pyrimidyl)ethene (L(2)), and Co(NCS)(2) affords the unprecedented two-dimensional grid coordination polymers [Co(L(1))(2)(NCS)(2)](infinity) (1) and [Co(L(2))(2)(NCS)(2)](infinity) (2), respectively, with novel topological features which cannot be achieved using symmetrically bridging ligands.     

Anion influence on the structure and magnetic properties of a series of multidimensional pyrimidine-2-carboxylato-bridged copper(II) complexes

Seven new polynuclear copper(II) complexes of formula [Cu(mu-pymca)2] (1) (pymca(-) = pyrimidine-2-carboxylato), [Cu(mu-pymca)Br] (2), [Cu(mu-pymca)Cl] (3), [Cu(mu-pymca)(SCN)(H2O)] x 4 H2O (4), [Cu(mu-pymca)N3] (5), [Cu2(mu1,5-dca)2(pymca)2] (6) (dca = dicyanamide), and K{[mu-Au(CN)2]2[(Cu(NH3)2)2(mu-pymca)]}[Au(CN)2]2 (7) have been synthesized by reactions of K-pymca with copper(II) ions in the presence of different counteranions. Compound 1 is a linear neutral chain with a carboxylato bridging ligand in a syn-anti coordination mode, whereas complexes 2 and 3 consist of cationic linear chains with cis and trans bis(chelating) pymca bridging ligands. Complex 4 adopts a helical pymca-bridged chain structure. In complex 5, zigzag pymca-bridged chains are connected by double end-on azide bridging ligands to afford a unique honeycomb layer structure. Complex 6 is a centrosymmetric dinuclear system with double mu 1,5-dicyanamide bridging ligands and pymca end-cap ligands. Complex 7 is made of pymca-bridged dinuclear [Cu(NH3)2(mu-pymca)Cu(NH3)2](3+) units connected by [Au(CN)2](-) anions to four other dinuclear units, giving rise to cationic (4,4) rectangular nets, which are linked by aurophilic interactions to afford a singular 3D network. Variable-temperature magnetic susceptibility measurements show that complex 1 exhibits a very weak antiferromagnetic coupling through the syn-anti (equatorial-axial) carboxylate bridge (J = -0.57 cm(-1)), whereas complexes 2-4 and 7 exhibit weak to strong antiferromagnetic couplings through the bis(chelating) pymca bridging ligand J = -17.5-276.1 cm(-1)). Quantum Monte Carlo methods have been used to analyze the experimental magnetic data for 5, leading to an antiferromagnetic coupling (J = -34 cm(-1)) through the pymca ligand and to a ferromagnetic coupling (J = 71 cm(-1)) through the azide bridging ligands. Complex 6 exhibits a very weak antiferromagnetic coupling through the dicyanamide bridging ligands (J = -5.1 cm(-1)). The magnitudes of the magnetic couplings in complexes 2-5 have been explained on the basis of the overlapping between magnetic orbitals and DFT theoretical calculations.     

New metal-organic frameworks with large cavities: selective sorption and desorption of solvent molecules

Five novel transition metal complexes [Cd(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (1), [Cu(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (2), [Ni(II) (3)(tpba-2)(2)(SCN)(6)].6 THF.3 H(2)O (3), [Cd(II) (2)(tpba-2)(SCN)(3)]ClO(4) (4), [Cu(I) (3)(SCN)(6)(H(3)tpba-2)] (5) [TPBA-2 = N',N',N'-tris(pyrid-2-ylmethyl)-1,3,5-benzenetricarboxamide, THF=tetrahydrofuran] were obtained by reactions of the corresponding transition metal salts with TPBA-2 ligand in the presence of NH(4)SCN using layering or solvothermal method, respectively. The results of X-ray crystallographic analysis showed that complexes 1, 2 and 3 are isostructural and have the same 2D honeycomb network structure with Kagomé lattice, in which all the M(II) (M = Cd, Cu, Ni) atoms are six-coordinated, and the TPBA-2 ligands adopt cis,cis,cis conformation while the thiocyanate anions act as terminal ligands. Capsule-like motifs are found in 1, 2 and 3, in which six THF molecules are hosted, and the results of XPRD and solid-state (13)C NMR spectral measurements showed that the compound 1 can selectively desorb and adsorb THF molecules occurring along with the re-establishment of its crystallinity. In contrast to 1, 2 and 3, complex 4 has different 2D network structure, resulting from TPBA-2 ligands with cis,trans,trans conformation, thiocyanate anions serving as end-to-end bridging ligands, and the incomplete replacement of perchlorate anions, which further link the 2D layers into 3D framework by the hydrogen bonds. In complex 5, the Cu(II) atoms are reduced to Cu(I) during the process of solvothermal reaction, and the Cu(I) atoms are connected by thiocyanate anions to form a 3D porous framework, in which the protonated TPBA-2 ligands are hosted in the cavities as templates.     

Nickel(II)-phenoxyl radical complexes: structure-radical stability relationship

Nickel(II) complexes of N3O-donor tripodal ligands, 2,4-di-tert-butyl-6-[([bis(2-pyridyl)methyl]amino)methyl]phenol (HtbuL), 2,4-di-tert-butyl-6-[([(6-methyl-2-pyridyl)methyl](2-pyridylmethyl)amino)methyl]phenol (HtbuLMepy), and 2,4-di-tert-butyl-6-[([bis(6-methyl-2-pyridyl)methyl]amino)methyl]phenol (HtbuL(Mepy)2), were prepared, and [Ni(tbuL)Cl(H2O)] (1), [Ni(tbuLMepy)Cl] (2), and [Ni(tbuL(Mepy)2)Cl] (3) were structurally characterized by the X-ray diffraction method. Complexes 1 and 3 have a mononuclear structure with a coordinated phenolate moiety, while 2 has a dinuclear structure bridged by two chloride ions. The geometry of the Ni(II) center was found to be octahedral for 1 and 2 and 5-coordinate trigonal bipyramidal for 3. Complexes 1-3 exhibited similar absorption spectra in CH3CN, indicating that they all have a mononuclear structure in solution. They were converted to the phenoxyl radicals upon oxidation with Ce(IV), giving a phenoxyl radical pi-pi transition band at 394-407 nm. ESR spectra at low temperature and resonance Raman spectra established that the radical species has a Ni(II)-phenoxyl radical bond. The cyclic voltammograms showed a quasi-reversible redox wave at E1/2=0.46-0.56 V (vs Ag/AgCl) corresponding to the formation of the phenoxyl radical, which displayed a first-order decay with a half-life of 45 min at room temperature for 1 and 26 and 5.9 min at -20 degrees C for 2 and 3, respectively. The radical stability increased with the donor ability of the N ligands.     

Highly efficient separation of a solid mixture of naphthalene and anthracene by a reusable porous metal-organic framework through a single-crystal-to-single-crystal transformation

The three-dimensional crystalline porous metal-organic framework [Ni(2)(μ(2)-OH(2))(1,3-BDC)(2)(tpcb)](n) (1) [1,3-H(2)BDC = 1,3-benzenedicarboxylic acid; tpcb = tetrakis(4-pyridyl)cyclobutane] was used to separate a solid mixture of naphthalene and anthracene at room temperature via selective adsorption of naphthalene. The process involved a single-crystal-to-single-crystal transformation. The guest naphthalene molecules could be exchanged with ethanol, and the host, 1, could be regenerated by removal of the guest ethanol molecules.     

Total synthesis of (-)-8-O-methyltetrangomycin (MM 47755)

A stereoselective total synthesis of the natural antibiotic (-)-8-O-methyltetrangomycin 1 is reported. The essential steps for this convergent synthesis are the transformation of a geraniol epoxide into a chiral octadiyne derivative, which was converted into a triyne. The cobalt-mediated [2+2+2] cycloaddition of the triyne led to a benz[a]anthracene system, which was oxidized with Ag(Py)(2)MnO(4) to a benz[a]anthraquinone. Deprotection with aqueous HF in acetonitrile and photooxidation afforded the desired product (-)-1. [reaction: see text]     

Synthesis,Spectral Characterization of Polymeric Nickel(II) Tetrathiocyanato Diargentate(I) Complexes with Some Acylhydrazones and Their Bio-activity

Polymeric heterobimetallic complexes of the type Ni[Ag(SCN)₂]₂.L (where L = acetophenone benzoylhydrazone (abh), acetophenone isonicotinoyl hydrazone (ainh), acetophenone salicyloyl hydrazone (ash), acetophenone anthraniloyl hydrazone (aah), p-hydroxy acetophenone benzoylhydrazone (phabh), p-hydroxy acetophenone isonicotinoyl hydrazone (phainh), p-hydroxy acetophenone salicyloyl hydrazone (phash) and p-hydroxy acetophenone anthraniloyl hydrazone (phaah) were synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic moment, electronic and IR spectra, thermal and X-ray diffraction studies. Nickel(II) in the complexes has spin-free octahedral geometry. The hydrazone ligands are bi-coordinate bonding through > C═O and > C═N-groups. The complexes form a polymeric structure by bridging SCN groups between two metal centers. Thermal studies (TGA and DTA) on Ni[Ag(SCN)₂]₂.ash indicate multi-steps decomposition pattern which are both exothermic and endothermic. X-ray powder diffraction parameters for Ni[Ag(SCN)₂]₂.ash and Ni[Ag(SCN)₂]₂.phainh correspond to tetragonal and orthorhombic crystal lattices respectively. The ligands, as well as their complexes, show significant antifungal and antibacterial activity. The metal complexes are more active than the parent ligands.     

From simple to complex: topological evolution and luminescence variation in a copper(I) pyridylpyrazolate system tuned via second ligating spacers

By systematically varying the geometric length and electronic properties of the second ligating ligands of halogen (Cl(-), Br(-), and I(-)) and pseudohalogen (CN(-), SCN(-), and N(3)(-)) anions, we synthesized 11 isomeric/isostructural copper(I) complexes: [Cu(2)(L3-3)I](n) (1), [Cu(2)(L4-4)Br](n) (2-Br), [Cu(2)(L4-4)Cl](n) (2-Cl), [Cu(2)(L3-4)(CN)](n) (3), [Cu(2)(L3-3)(CN)](n) (4), [Cu(3)(L4-4)(CN)(2)](n) (5), {[Cu(2)(L4-4)Br](2)·CuBr}(n) (6-Br), {[Cu(2)(L4-4)Cl](2)·CuCl}(n) (6-Cl), [Cu(2)(L4-4)(SCN)](n) (7α-SCN), [Cu(2)(L4-4)(SCN)](n) (7β-SCN), and [Cu(2)(L4-4)(N(3))](n) (7α-N(3)). These structures are based on a series of isomeric pyridylpyrazole ligands, namely, 3,5-bis(3-pyridyl)-1H-pyrazole (HL3-3), 3-(3-pyridyl)-5-(4-pyridyl)-1H-pyrazole (HL3-4), and 3,5-bis(4-pyridyl)-1H-pyrazole (HL4-4), and their structural features range from 1-D (1), 2-D (2), and 3-D noninterpenetration (3), to 3-D 2-fold interpenetration (4 and 5), to 3-D self-catenation (6 and 7), exhibiting a trend from simple to complex with dimension expansion and an interpenetrating degree increase. The five most complex structures (6 and 7) with self-catenated networks are based on 2-fold interpenetrated networks linked via appropriate second ligating spacers (Cl(-), Br(-), SCN(-), and N(3)(-)), representing a strategy to construct self-catenated coordination polymers through cross-linking interpenetrated frameworks. Moreover, these complexes exhibit strong photoluminescence, which is mainly ascribed to Cu(I)-related charge transfers (MLCT, MC, and MMLCT) regulated by the electronic properties of halogen or pseudohalogen. The topological evolution and luminescence variation presented in this work open an avenue to understanding the luminescence origin and the structure-property relationship of luminescent coordination polymers.     

Structures and physical properties of oligomeric and polymeric metal complexes based on bis(pyridyl)-substituted TTF ligands and an inorganic analogue

The bis(pyridyl)-substituted TTF derivative, 2,6(7)-bis(4-pyridyl)-1,4,5,8-tetrathiafulvalene (TTF(py)(2)), and an inorganic analogue, [Ni(4-pedt)(2)] (4-pedt = 1-(pyridin-4-yl)ethylene-1,2-dithiolate), were used as bridging ligands to construct two multinuclear complexes {Co(II)(2)(Tp(Ph2))(2)(OAc)(2)[TTF(py)(2)]} (1, Tp(Ph2) = hydridotri(3,5-diphenylpyrazol-1-yl)borate) and {Co(II)(2)(Tp(Ph2))(2)(OAc)(2)[Ni(4-pedt)(2)]} (2), and two 1D zigzag chain complexes, {[M(II)(tta)(2)][TTF(py)(2)]}(n) (M = Cu for 3, and Mn for 4; tta = thenoyltrifluoroacetonate). X-Ray structural studies indicate that complexes 1 and 2 are very similar as a result of the isolobal analogy between TTF(py)(2) and [Ni(4-pedt)(2)], whereas complexes 3 and 4 are isostructural. The absorption spectra, electrochemical and magnetic properties for these new complexes have been studied. The results show that the interactions between the paramagnetic ions are weak owing to the large separation of the bridging ligands of TTFs and the inorganic analogue.     

双(二吡啶胺)配体的二维和三维超分子配位聚合物的合成与晶体结构

从含4,4'-二吡啶胺结构单元的双(二吡啶胺) 桥联配体出发,采用溶剂热法合成了两个结构新颖的配位聚合物：[CdL1Br2]n?7.5nH2O (L1 = N,N,N′,N′-四(4-吡啶)-1,4-苯二胺) (1)和[Cu2L2(μ1,1,3-SCN)2]n?nMeOH (L2 = N,N-二(2-吡啶)-N',N'-二(4-吡啶)-1,4-苯二胺) (2),对它们进行了元素分析、红外光谱等表征,并用X-射线单晶衍射测定了其晶体结构。单晶测试结果显示,配合物1中配体L1的四个吡啶N原子均参与配位,桥联了4个Cd原子,每个Cd原子与四个吡啶 N 原子和两个溴配位,形成六配位的八面体构型。通过这些配位作用,最终形成包含 Kagome 结构的三维超分子网络。配合物2 是由一维柱状 {Cu(SCN)}n 链通过 L2 桥联生成的二维结构。有趣的是,L2中具有螯合能力的2,2'-二吡啶胺单元并未参与配位,只有4,4'-二吡啶胺单元中的两个吡啶N原子分别与一个 Cu(I) 配位,连接了相邻两条平行的{Cu(SCN)}n 链,生成二维结构。     

Temperature dependence of the crystal lattice organization of coordination compounds involving nitronyl nitroxide radicals: a magnetic and structural investigation

Four new mononuclear complexes of formula Cd(PN)(4)(NCS)(2) (A), Cd(PNN)(4)(N(3))(2) (B), Zn(PNN)(4)(N(3))(2) (C), and Zn(PNN)(2)(NCS)(2) (D), where PNN stands for 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and PN for 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl, were synthesized and structurally and magnetically characterized. The X-ray structures of compounds B and C were also determined at 90 K. Compounds A[bond]C crystallize in the triclinic space group P 1 macro (No. 2), and D crystallizes in the monoclinic space group P2(1)/m (No. 11). A[bond]C adopt a centrosymmetric distorted octahedral geometry in which the metal ions are bonded to four radical ligands through the nitrogen atom of the pyridyl rings and the azido or thiocyanato ligands occupy the apical positions. Compound D adopts a distorted tetrahedral geometry in which the zinc ion is bonded to two radicals and two thiocyanato ligands. As suggested by their magnetic behavior, the low-temperature X-ray structures of B and C show that these compounds undergo a clear structural change with respect to the room-temperature structures. The experimental magnetic behaviors were perfectly reproduced by a dimer model for A[bond]C and an alternating chain model for D while the sudden breaks observed in the chi(M)T versus T curves for B and C were well accounted for by the high- and low-temperature X-ray structures. For all these complexes the crystal structures favor significant overlap between molecular magnetic orbitals leading to rather strong intermolecular antiferromagnetic interactions.