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1.
The structures of new compounds containing Zn(II) ions and bpp (1,3-bis(4-pyridyl)propane) ligands have been determined. The coordinating halides (Br or Cl) produce one-dimensional compounds 6 and 7, and intra- and inter-chain CH?X (X = Br or I) interactions play roles for building crystal structures with the flexible bpp ligands. The non-coordinating anions do not produce hydroxyl bridged zinc cations or polymeric compounds, and produce only a monomeric complex 4 containing four bpp ligands and two water ligands. Previously reported polymeric compounds 1 and 2 containing hydroxyl-bridged zinc cations [Zn2OH] were found to carry out the catalytic transesterification of a range of esters with methanol at room temperature under the mild conditions, whereas the rest of compounds did not catalyze the transesterification reactions at all. In addition, the catalysts 1 and 2 have shown even better catalytic activity than zinc salts Zn(NO3)2 and Zn(OTf)2.  相似文献   

2.
The complexes of Cu(I), Cu(II), Ni(II), Zn(II) and Co(II) with a new polypyridyl ligand, 2,3-bis(2-pyridyl)-5,8-dimethoxyquinoxaline (L), have been synthesized and characterized. The crystal structures of these complexes have been elucidated by X-ray diffraction analyses and three types of coordination modes for L were found to exist in them. In the dinuclear complex [Cu(I)L(CH3CN)]2·(ClO4)2 (1), L acts as a tridentate ligand with two Cu(I) centers bridged by two L ligands to form a box-like dimeric structure, in which each Cu(I) ion is penta-coordinated with three nitrogen atoms and a methoxyl oxygen atom of two L ligands, and an acetonitrile. In [Cu(II)L(NO3)2]·CH3CN 2, the Cu(II) center is coordinated to the two nitrogen atoms of the two pyridine rings of L which acts as a bidentate ligand. The structures of [Ni(II)L(NO3)(H2O)2]·2CH3CN·NO3 (3), [Zn(II)L(NO3)2 (H2O)]·2CH3CN (4) and [Co(II)LCl2(H2O)] (5) are similar to each other in which L acts as a tridentate ligand by using its half side, and the metal centers are coordinated to a methoxyl oxygen atom and two bipyridine nitrogen atoms of L in the same side. The formation of infinite quasi-one-dimensional chains (1, 4 and 5) or a quasi-two-dimensional sheet (2) assisted by the intra- or intermolecular face-to-face aryl stacking interactions and hydrogen bonds may have stabilized the crystals of these complexes. Luminescence studies showed that 1 exhibits broad, structureless emissions at 420 nm in the solid state and at 450 nm in frozen alcohol frozen glasses at 77 K. Cyclic voltammetric studies of 1 show the presence of an irreversible metal-centered reduction wave at approximately −0.973 V versus Fc+/0 and a quasi-reversible ligand-centered reduction couple at approximately −1.996 V versus Fc+/0. The solution behaviors of these complexes have been further studied by UV-Vis and ESR techniques.  相似文献   

3.
Three ZnII complexes containing bispicam ligands (bispicam = bis(2-pyridylmethyl)amine), [Zn(bispicam)2](NO3)2·2CH3OH 4A, [Zn(bispicam)(NO3)2] 4B, and [Zn(bispicam)2](OTf)26, were obtained, and their structures were determined by X-ray crystallography. Complexes of the general formulation [Zn(bispicam)2]X2 (X = Cl (1), Br (2), I (3), NO3 (4A), ClO4 (5), and OTf (6)) show fac geometric isomers (a) or enantiomers (c) and (d) according to anions. Moreover, complexes 4-6 could carry out the catalytic transesterification of a range of esters with methanol under the mild conditions. Importantly, the catalyst 4B with an unsaturated structure has shown better efficiency than the catalysts, 4A, 5, and 6, having saturated structures. To explain this reactivity difference, two different reaction mechanisms have been proposed (metal-based vs. amide N-H-based).  相似文献   

4.
To investigate the effect of organic anions on the coordination frameworks, we synthesized three new complexes, namely, Zn(DPA)(bpimb)0.5(H2O) (1), Zn(BDC)(bpimb)0.5 (2) and Zn2(SDBA)2(bpimb)·H2O (3) (H2DPA = diphenic acid; H2BDC = isophthalic acid; H2SDBA = 4,4′-dicarboxybiphenylsulfone), which were obtained by the reactions of 1,4-bis((2-(pyridin-2-yl)-1H-imidazol-1-yl)methyl)benzene (bpimb) as main ligand, and several aromatic polycarboxylate as organic anions with Zn(NO3)2·6H2O. Single-crystal structure analysis shows that complex 1 is a one-dimensional chain structure, which is further interlinked into a higher-dimensional supramolecular framework by hydrogen-bonding interactions. In 2, BDC bridge Zn(II) atoms to give dimeric units, which are further linked by bpimb ligands to form sql nets. In 3, SDBA ligands and bpimb ligands connect Zn(II) ions into catenane-like two-dimensional layers. These catenane-like two-dimensional layers stack in an ABAB fashion to form a 3D supramolecular network. The distinct structures indicate three kinds of carboxylic ligands with different lengths and angles play fundamental roles in the formation of the final products. In addition, the luminescence measurements reveal that three complexes exhibit strong fluorescent emissions in the solid state at room temperature.  相似文献   

5.
Self-assembly of flexible 1,3-bis(1,2,4-triazol-1-yl)propane (btp), inorganic Cu(II) salt and rigid benzene-based carboxylate coligand generates four complexes, {[Cu(btp)2(CH3OH)(H2O)]·H2O·2ClO4}n (1), {[Cu(btp)(Hbtc)2]·0.5H2O}n (2), [Cu(btp)2(H3btea)2]n (3), and [Cu(btp)(nb)2] (4) (H3btc = 1,3,5-benzenetricarboxylic acid, H4btea = 1,2,4,5-benzenetetracarboxylic acid, Hnb = p-nitrobenzoic acid), which are fully structural characterized by single-crystal X-ray crystallography, elemental analysis, IR, and TG-DTA techniques. Structural determinations reveal that the polymeric two-dimensional (2D) Cu-btp grid-like layer for 1, 1D linear single- and double-stranded chains for 2 and 3, as well as the discrete binuclear structure for 4, are jointly directed by the coordination polyhedrons of the Cu(II) ion and the exo-bidentate bridging btp core ligand with various conformations. The theoretical calculations suggest that the trans-trans btp is the most stable conformation, and the metal binding site is collectively determined by the electron density of N donors and the spatial orientation of the btp ligand. Unexpectedly, the polycarboxylate anions in 1-4 can only act as terminal coligands not popular bridging connectors. The thermal stability of the resulting complexes is also compared.  相似文献   

6.
Non-centrosymmetric 1D and 3D coordination networks [Zn(L)2(H2O)]2 · CH3CN · 3H2O (1), and [Cd2.5(L)5] · EtOH · 5H2O (2), have been synthesized hydro(solvo)thermally between Zn(II) or Cd(II) ions and methyl 4-[2-(4-pyridyl)ethenyl]cinnamate (L-Me), respectively. X-ray single-crystal diffractions studies show that 1 adopts a caterpillar-shaped 1D chain structure, while 2 has a complicated 3D structure formed by linking cadmium-carboxylate chains with the L ligands. Both face-to-face and edge-to-face π-π interactions between the L ligands are key to the polar arrangement of the L ligands in 1. The dipole moments of all the L ligands have on the other hand essentially cancelled out in 2, and the polar axis is defined by the cadmium-carboxylate chains. Consistent with their polar structures, powder second harmonic generation measurements indicate that 1 and 2 exhibit powder SHG intensities of 75 and 20 versus α-quartz, respectively.  相似文献   

7.
Reaction of the salt KCpCo(CN)3 (1) with zinc iodide leads to the formation of a highly insoluble Co(III)/Zn(II) polymeric chain. However, pyridine was found to disrupt the aggregate that is formed to yield a crystalline trimetallic complex consisting of two CpCo(CN)3 anions bridging a Zn(py)4 dication through the cyanide ligands, [CpCo(CN)2(μ-CN)]2Zn(py)4 (2). Along these same lines, reaction of CpCo(CN)2PPh3 (3) with AlCl3 or CoCl2 leads to the formation of a highly crystalline Co(II)/Co(III) diamond, [CpCo(PPh3)(μ-CN)2CoCl2]2 (4). Molecular structures of 1, 2, 3 and 4 were determined by single-crystal X-ray crystallography.  相似文献   

8.
9.
The supramolecular structural diversities in mixed ligand systems derived from a series of dicarboxylate anions with varying chain lengths and N-donor exo-bidentate ligand equipped with hydrogen bonding capable amide backbone with Co(II)/Zn(II) metal centers are analyzed. In this context, two complexes namely (Co(L1)2(malonate)(H2O)2} (1a), {Zn(L1)2(malonate)(H2O)2} (1b) and one coordination polymer namely {[Co(μ-L1)(μ-glutarate)(H2O)] · H2O}n (4) (where L1 = N-(4-pyridyl)nicotinamide) have been synthesized and crystallographically characterized. The main aim of this work is to explore the effects of chain lengths of the anionic carboxylate ligands such as malonate, succinate, maleate, and glutarate, in determining the final architecture of coordination compounds based on the mixed ligands. Analyses of the structures revealed that the length of the bridging ligands have prominent effect in the formation of hierarchical structures.  相似文献   

10.
A new family of one-dimensional oxalato-bridged metal(II) complexes with formula {[M(ox)(abpt)]·4H2O}n [MII = Mn (1), Fe (2), Co (3), Zn (4); ox = oxalate dianion; abpt = 4-amino-3,5-bis(2-pyridyl)-1,2,4-triazole] has been synthesized and chemically, structurally and magnetically characterized. The crystal structures of compounds 2-4 have been solved by single crystal X-ray diffraction, whereas complex 1 has been studied by means of X-ray powder diffraction methods. All of them are isomorphous and crystallize in the triclinic space group P. The metal atoms are bridged by bis-bidentate oxalate anions forming zig-zag chains in which bidentate chelating abpt ligands complete the octahedral O4N2 donor set. The crystal structures show an open-framework that contains rectangular channels in which easily removable hydrogen bonded ribbons of water molecules are located. The occurrence of antiferromagnetic intrachain interactions for compounds 1-3 was determined by cryomagnetic susceptibility measurements.  相似文献   

11.
We have prepared and characterized two cationic ligands and their Ag(I) coordination compounds. For the bidentate ligand 2, 2,2-bis-pyridin-2-ylmethyl-2,3-dihydro-1H-isoindolium bromide, we obtained the organometallic polymer [AgL]x[CF3SO3]2x (4), and the unimolecular complex [AgL2][PF6]3 (5). Compound 4 exists as an organometallic linear polymer with triflate anions either bonded to Ag(I) or non-bonded and sandwiched between the polymer chains. Complex 5 is the only unimolecular example in this series due to the non-interaction of anions with Ag(I) or with the cationic portion of the ligand. In the case of the tridentate cationic ligand 3-(3-pyridin-2-yl-2-pyridin-2-ylmethy-propyl)-benzyl-triethylammonium bromide (3), two dimeric Ag(I) complexes are formed, [Ag2L2][CF3SO3]4 (6), and [Ag2(CH3CN2)2L2][PF6]4 (7). Both of these dimers have essentially similar structures, with a closed-shell Ag(I)?Ag(I) interaction of approximately 3.00 Å in both cases; the pyridyl moieties of the ligands are forced into an electronically unfavourable face-to-face arrangement. The coordination spheres of the Ag(I) cations are completed by in the case of 6, and by CH3CN solvent in the case of 7. In the extended packing diagrams, the arrangements of 6 and 7 are driven by intermolecular π-stacking and cation-anion interactions.  相似文献   

12.
Four Cd(II) metal-organic complexes, namely, [Cd(Cl)2(bbdmbm)] (1), [Cd(NO3)(N3)(bbdmbm)1.5] (2), [Cd(BBA)2(bbdmbm)(H2O)] (3), [Cd(DNBA)2(bbdmbm)] (4), (bbdmbm = 1,1-(1,4-butanediyl)bis(5,6-dimethylbenzimidazole), HBBA = 4-bromobenzoic acid, and HDNBA = 3,5-dinitrobenzoic acid) have been obtained from hydrothermal reactions of different Cd(II) salts with the mixed ligands of bbdmbm and five anions (Cl, NO3, N3, BBA and DNBA). Single crystal X-ray diffraction analyses reveal that the four complexes exhibit different structures. Complex 1 possesses a one-dimensional (1D) helical chain, which is finally extended into a two-dimensional (2D) supramolecular structure through π-π stacking interactions. Complex 2 shows a 1D ladderlike chain bridged by bbdmbm ligands with two kinds of coordination conformations. Complex 3 is a 1D coordination polymer and is ultimately extended into a 2D supramolecular network through H-bonding interactions. Complex 4 displays a dinuclear cluster, which is finally packed into a three-dimensional (3D) supramolecular framework through three kinds of π-π stacking interactions. The Cd(II) exhibits four different coordination modes in complexes 1-4, respectively. The results indicate that the anion ligands with different steric hindrance and size play important roles in the coordination modes of Cd(II) and construction of the title complexes, leading to the structural diversity. In addition, the conformations of bbdmbm ligand also show some effect on the final structures. Fluorescence properties of complexes 1-4 are reported in this paper.  相似文献   

13.
Four new zinc(II) complexes [Zn(dien)(μ-nic)]2(BPh4)2·2CH3OH (1), {[Zn(dien)(isonic)]BPh4}n (2), [Zn(tren)(nic)]BPh4 (3) and [Zn(tren)(isonic)]BPh4 (4) (dien/tren = diethylenetriamine/triethylenetriamine, nic/isonic = nicotinate/isonicotinate anion) were synthesized and structurally characterized by IR, 1H NMR and single crystal X-ray diffraction. In the zinc(II) complexes of dien, both nicotinate and isonicotinate connect the zinc(II) ions via N,O-bis-monodentate mode. Complex 1 contains a centrosymmetric dinuclear unit bridged by two nicotinate anions in anti-parallel way. Complex 2 is characterized by an infinite one-dimensional zigzag chain bridged by isonicotinate anion in an end-to-end mode. The Zn···Zn distance is 6.782 for 1 and 8.805 Å for 2. While in the complexes of tren, both 3 and 4 are mononuclear complexes with nicotinate and isonicotinate coordinated to zinc(II) ion through only one oxygen atom of their carboxylate groups. The zinc(II) ions in all of the four complexes are in a distorted trigonal bipyramidal geometry. Complex 3 forms a dinuclear unit and complex 4 forms an infinite 2D sheet structure through intermolecular H-bonds. In all of the crystal lattices, the counterions act to balance the electronic charge at the same time to construct different 3D structures through noncovalent interactions such as C-H···π, N-H···π and van der Waals interactions.  相似文献   

14.
Treatment of 3-(4-carboxyphenylhydrazono)pentane-2,4-dione (HL) with transition metal ions afforded four novel complexes, [Zn(L)(μ2-OOCCH3)(H2O)]n (1), [Zn(L)2(MeOH)4] (2), {[Cd4(η2-L)4(μ2-η2-L)4(H2O)4(MeOH)2]·MeOH} (3) and [Cd(η2-L)(μ2-η2-OOCCH3)(H2O)2]n (4). Their crystal structures have been characterized by single-crystal X-ray crystallography. In polymer 1, the acetate anions bridge the Zn(II) ions forming an infinite one-dimensional (1-D) chain with L units acting as monodentate ligands in the side chain. In mononuclear complex 2, two L ligands act as monodentate fashion to coordinate to the Zn(II) ion. In its solid-state structure, [Zn(L)2(MeOH)4] groups are joined together by hydrogen bonds forming a three-dimensional (3-D) supramolecular network. In tetranuclear complex 3, four Cd(II) ions are linked by four μ2-η2-L ligands, and chelated by another four L ligands, respectively. In polymer 4, the acetate anions bridge the Cd(II) ions leading to a 1-D chain containing chelating L units in the side chain.  相似文献   

15.
The synthesis and characterization of four new complexes with the bioactive ligand 3-aminoflavone (3-af) are reported. The complexes of general formula [M(3-af)2(H2O)2](NO3)2 · nH2O], where M = Co(II), Ni(II), and Zn(II), and n = 0, 2, 0, respectively, and [Cu(3-af)2(NO3)2] compound were prepared and studied. In particular, to investigate the binding in detail, the crystal structures of the free ligand (3-af) and [Cu(3-af)2(NO3)2] (1) were determined. The new coordination compounds were identified and characterized by elemental analysis, magnetic measurements, and infrared and ligand-field spectra. The crystal structure of the Cu(II) complex reveals that the ligand acts as a N,O-bidentate chelate ligand forming a five-membered ring with the copper(II) ion. The copper(II) ion is octahedrally surrounded by the two amino nitrogens and two carbonyl oxygens from two chelating organic ligands in trans arrangement. Two molecules of coordinated nitrate anions occupy axial positions. The spectral and magnetic properties are in accordance with the structural data of the copper(II) compound. From X-ray powder-diffraction patterns and IR spectra, the complexes of nickel(II) (2) and cobalt(II) (3) were found to be mutually isomorphous. The results of the spectroscopic studies suggest a mononuclear structure of 2 and 3 complexes. The variable-temperature (1.8-300 K) magnetic susceptibility data of 2 indicate a weak ferromagnetic interaction. The magnetic behavior of complex 3 is characteristic of cobalt(II) systems with an important orbital contribution via spin-orbit-coupling and also suggests a weak ferromagnetic interaction.  相似文献   

16.
Four cadmium(II) complexes of the semirigid tridentate ligand 8-[(pyridin-4-yl)methylthio] quinoline (TQMP4, L), namely, [CdL2](ClO4)2 (1), [Cd(L)Br2] (2), [Cd2(L)2(NO3)4] (3), and [Cd2(L)2I4] (4), have been prepared by the methods of layering and the diffusing of diethyl ether. The structures of the complexes have been identified by elemental analysis (EA), infrared spectra (IR) and single-crystal diffraction. The different coordination modes of the ligands and counter anions result in a 2D (4, 4) net structure in complex 1, a 1D polymer chain in complex 2, and 0D binuclear rings in complexes 3 and 4. Their antibacterial and antifungal activities were also tested.  相似文献   

17.
Six novel Cd(II) coordination polymers based on 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl (btmb), namely, [Cd(btmb)2I2]n (1), [Cd(btmb)I2]n (2), {[Cd(btmb)2(NO3)2]·H2O}n (3), {[Cd(btmb)2(SCN)2]·3H2O}n (4), {[Cd(btmb)(CH3COO)2(H2O)]·CH3CN}n (5) and [Cd(btmb)Cl2(H2O)]n (6) have been synthesized by the reactions of btmb with Cd(II) salts in the presence of different anions (I, , NCS, CH3COO or Cl) under appropriate reaction conditions. The assemblies of btmb with CdI2 afford two different structures: two-dimensional (2D) rhombohedral grid layer network structure 1 and 2D layer structure 2 involved with one-dimensional (1D) linear cadmium chains. Treatment of btmb with Cd(NO3)2·4H2O gives rise to a 2D grid network structure 3 which is similar to 1. When the I or NO3 anions were replaced by NCS, CH3COO or Cl, different 1D coordination polymers 4-6 were obtained, respectively. Polymer 4 displays a 1D double-chain structure, while both polymers 5 and 6 show 1D zigzag chain structures. In addition, the luminescence measurements reveal that polymers 1-6 exhibit different fluorescent emissions in the solid-state at room temperature, which can be attributed to the various coordination environments of Cd(II), solvent molecules and different packing interactions in these polymers.  相似文献   

18.
Herein, we report the synthesis and characterization of a third polymorph of trans-[Co(2,3,2-tet)(NO2)2]NO3, III, crystallizing in space group (No. 2) obtained during an attempt to reproduce the synthesis of a previously reported polymorph, I (for more details of polymorphs I and II, see Introduction and references cited therein). The cations of polymorphs I and II differ primarily by the angles that the planes of the two -NO2 ligands make with one another; the former being considerably larger than that in II. Polymorph III resembles II in that the torsional angular differences between the trans-nitro ligands are also small, but differ notably from that in I.The structure of the compound [(5-Me-(dpt)Co(NO2)3], was determined also. The space group is P21/n, with two molecules in the asymmetric unit, whose occupancies are 65% and 35% for molecules IVa and IVb, respectively. Again, the two differ by the torsional angles of the nitro ligands, specially two of them whose angular orientations are vastly different. Molecules IVa and IVb are compared with a previously obtained polymorph V of this same compound reported earlier. Once more, V is closely related in stereochemistry to IVb, but differs markedly from IVa in nitro torsional angles.In all cases, the Co(amine) fragments are closely super-imposable and the differences in nitro torsional angles are the result of the availability of several amine hydrogens of the basal plane with which to make intra-molecular hydrogen bonds. Clearly, these hydrogen bonds must be of very similar strength and the barriers to rotation of the -NO2 ligands must have energies similar to the energetics of the hydrogen bonds causing the torsional motions.  相似文献   

19.
The ligands bis-(imidazolium) hexafluorophosphate (Himy = -C3N2H3-, imidazolium; R = 1-naphthylmethylene, 1a; 9-anthracenylmethylene, 1b) with an oxoether chain were easily prepared by the reaction of substituted imidazole with the diglycol diiodide, followed by exchange of anions with . 1a and 1b reacted with Ag2O in DMSO or CH3CN to yield [2 + 2] dinuclear Ag(I) NHCs macrocyclic complexes 2a and 2b, which showed much different conformation in solid corresponding to the R- substituent. Carbene transmetalation reactions of 2a-b with Au(SMe2)Cl give dinuclear Au(I) analogs 3a and 3b. The new NHCs complexes were characterized by elemental analyses, 1H NMR, 13C NMR and the structures of 2a-b and 3a were confirmed by X-ray diffraction determination.  相似文献   

20.
Reaction of 2-(diphenylphosphinomethyl)pyridine (PMP-21) with the silver(I) salts of tetrafluoroborate , triflate (Otf), and trifluoroacetate (tfa) affords dinuclear complexes (2-4), where the ligand bridges the two silver centers, and the anions interact with the metal centers to varying degrees. Further reaction of AgBF4 and AgOtf with reaction solutions containing PMP-21 and either the bidentate 5,5′-dimethyl-2,2′-bipyridine or 4,4′-bipyridine ligands produce dimeric and bridged structural motifs. The ability of 5,5′-dimethyl-2,2′-bipyridine to chelate and the 4,4′-bipyridine to serve as a connector between metal centers, allows the construction of coordinative structures where the effect of ligand ratio and either interacting or non interacting anions influence the silver coordination environment, allowing it to take on several geometries including trigonal bipyramidal, 5, both T-shaped and tetrahedral in a single structure, 6 and 8, trigonal pyramidal, 7, and trigonal planar, 9. Structures 2, 3, and 4 display comparable Ag-Ag contacts ranging from 2.7979(10) to 3.0538(4) Å, with a corresponding weakening of the metallophilic interaction when a bipyridine ligand is coordinated. Low-temperature luminescence spectra were collected for all compounds and are compared.  相似文献   

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