Coordination polymers. IX

Poly-(butanediol-1,4-adipate) and poly-(diethyleneglycol-succinate) polyesters and their ionized derivatives, containing Mg²⁺ and Zn²⁺ ions with different stoichiometric ratios to the chain-end COOH groups of the polyesters have been investigated by derivatograph.The thermal decompositions of the metal-containing polyesters differ significantly from those of the unionized polyesters. These differences are connected with the chemical repeating unit of the polyesters and the chemical nature of the metal ions, and proportional to the amount of the latter.An explanation is given of the catalytic effect of metal ions on the process of decomposition of the polyesters.

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Zusammenfassung Poly-(butandiol-1,4-adipat) und Poly-(diethylenglycolsuccinat) polyester und ihre «ionisierten» Derivate — mit Mg²⁺ — und Zn²⁺-Ionengehalt in verschiedenen stöchiometrischen Verhältnissen zu den endständigen COOH-Gruppen der Polyester — wurden im Derivatographen untersucht.Die thermische Zersetzung der metallhaltigen Polyester unterscheidet sich wesentlich von nicht-ionisierten Polyestern. Diese Unterschiede sind mit den sich wiederholenden chemischen Einheiten der Polyester und der chemischen Beschaffenheit der Metallionen verbunden, und proportional dem Anteil derselben.Es wird eine Erklärung des katalytischen Effekts der Metallionen auf den Zersetzungsvorgang der Polyester gegeben.

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-1,4 «» , Mg²⁺ Zn²⁺ . , «» . . .

     

Coordination polymers containing rotaxane linkers

A class of coordination polymers in which the linking ligands are mechanically interlocked rotaxane molecules is reviewed. To date, four different, axle - wheel templating motifs have been used to create the [2]pseudorotaxane linkers for these unique solid-state materials; (1) protonated diaminoalkane axles with cucurbit[6]uril wheels, (2) 1,2-bis(4,4'-bipyridinio)ethane axles with dibenzo[24]crown-8 wheels, (3) 2,6-naphthalene dicarboxylate axles with tetra-imidazolium macrocycle wheels and (4) a Cu(i) complex of a 1,10-phenanthroline containing dicarboxylate axle with a 1,10-phenanthroline containing crown ether wheel. The synthesis and solid state structure of each coordination polymer is described. The future directions of this area of research and some designs for the next generation of these compounds are discussed.     

Coordination polymers of copper(I) halides

A total of 21 complexes of CuX (X = Cl, Br, I) with bridging ligand (B = 4,4'-dipyridyl (Bpy), pyrazine (Pyz), quinoxaline (Quin), phenazine (Phz), 1,4-diazabicyclo[2.2.2]octane (DABCO), and hexamethylenetetramine (HMTA)) have been synthesized. The products show two stoichiometries: [CuXB] (type 1) and [(CuX)2B] (type 2). Both types can be obtained for B = Bpy, depending on the conditions of preparation. In these cases, the type 2 stoichiometry is the kinetic product. Type 2 complexes only are found for B = Pyz (X = I), Quin, Phz, DABCO, and HMTA. Type 1 complexes form for Pyz (X = Cl, Br). Thermogravimetic analyses of the complexes reveal the general decomposition trend: 1 --> 2 --> [(CuX)2B(1/2)] --> CuX. The X-ray crystal structure of [CuBr(Pyz)] (type 1) features copper atoms bridged by Br and Pyz, forming 2D sheets of fused rectangular Cu4Br2(Pyz)2 units. The X-ray structure of [(CuI)2(Quin)] (type 2) shows 2D layers composed of [Cu2I2]infinity "stair step" chains which are cross-linked by Quin ligands. A total of 16 complexes of CuXL (L = P(OPh)3) with bridging ligand (B = those above and 1,4-dimethylpiperazine (DMP)) have also been prepared. All of these products, except those of HMTA, are of type 3 formulation, [(CuXL)2B]. The HMTA products have the formula [CuX(HMTA)], type 4. Thermal decomposition of the type 3 and 4 complexes occurs with initial loss of B, L, or both. The X-ray structures of [(CuBrL)2(Bpy)] and [(CuBrL)2(Pyz)] (type 3) reveal 1D chains formed from rhomboidal (LCu)2Br2 units linked by the B ligand. The type 4 structure of [CuBrL(HMTA)] is shown by X-ray to be a simple halide-bridged dimer.     

Studies on coordination polymers : Part II. Coordination polymers of 1,6-dihydroxyphenazine

Coordination polymers of 1, 6-dihydroxyphenazine (I) with Cu(II), Zn(II), Ni (II), Co(II) and Hg(II) were prepared and studied. All the polymers formed were dark blue to black powders, very insoluble in the common solvents, apparently of low molecular weight, and decomposed at temperatures ranging from 200 to 280°. The zinc polymer was the most stable, mercury the least. Infrared studies confirmed the proposed chelation reaction between the metal ion and (I). The polymers of Co and Hg were amorphous, whereas those of Cu, Zn, and Ni were crystalline. When used as a spot test reagent, (I) gave instant color reactions with 15 common ions but neither the sensitivity nor selectivity of the reagent is impressive.     

Coordination polymers with carborane anions: silver dinitrile complexes

Crystalline materials have been isolated and characterized from mixing the silver carborane salts Ag(CB(11)H(12)) or Ag[Co(C(2)B(9)H(11))(2)] with nitrile ligands, either terminal acetonitrile or potentially bridging alkanedinitriles. Most of the complexes showed B-H...Ag interactions between the silver center and carborane anion. [Ag(acetonitrile)(2)(CB(11)H(12))] has a hexagonal network structure. [Ag(malonitrile)(2)(CB(11)H(12))] is a discrete dimeric complex, while [Ag(4)(succinonitrile)(5)(CB(11)H(12))(4)], [Ag(glutaronitrile)(2)][Co(C(2)B(9)H(12))(2)], and [Ag(glutaronitrile)[Co(C(2)B(9)H(11))(2)]] all show coordination chain structures. The carborane anions in [Ag(adiponitrile)[Co(C(2)B(9)H(11))(2)]] bridge between Ag centers to give a 3D CdSO(4)-related coordination polymer. The structure of [Ag(malonitrile)(2)](BF(4)) was also determined to have an unusual chiral diamondoid structure with a skewed 2-fold interpenetration.     

Coordination polymers of rare-earth elements with 2-aminoterephthalic acid

Coordination polymers of REEs with 2-aminoterephthalic acid [Ln₂(C₈H₅NO₄)₃(H₂O)₅] _n · 2nH₂O (Ln = Eu, Gd, or Tb) and [Y₂(C₈H₅NO₄)₃(H₂O)₄] _n · 4nH₂O were prepared by hydrothermal synthesis. Studies of the thermal behavior of these coordination polymers have shown that the removal of the solvate and the coordinated water molecules occurs at heating to 250°C and dehydratation products are stable up to 400°C. Detailed studies of the magnetic behavior of Eu, Gd, and Tb polymers were performed.     

Coordination polymers based on aluminum(III) porphyrins

Aluminum(III) porphyrin carboxylate complexes have shown an affinity for a sixth nitrogenous ligand. The use of isonicotinic or nicotinic acid, which offers both a carboxylate and a nitrogen donor in the same molecule, resulted in the formation of one-dimensional (1-D) coordination polymers. The complexes and their linear oligomers have been characterized by (1)H NMR spectroscopy and nanoelectrospray ionization spectrometry. X-ray analyses confirmed the formation of the 1-D polymers in the solid state.     

Coordination polymers of indium, scandium, and yttrium

Data on inorganic and metal-organic indium, scandium, and yttrium coordination polymers mainly with halide (pseudohalide) and N,O-donor ligands have been generalized and systematized. The effect of the metal cation nature and coordination number, stereochemistry, and ligand environment on the formation of polymers of different dimensionality is considered. 129 references.     

Coordination polymers with macrocyclic cages and pockets within their backbones

The reaction between the flexible ligand (1,4-bis(pyridine-2-yl-methanethio)benzene) and Ag+ produces two novel coordination polymers with macrocyclic cages or pockets contained within their backbones, depending upon the ratio of starting materials.     

Coordination/organometallic polymers based on diphosphine and diisocyanide ligands

This paper reviews various coordination/ organometallic polymers in which the metal atoms are incorporated in the backbone using diphosphine and diisocyanide ligands. Such ligands includes diphosphines of the type bis(diphenylphosphino)alkane where alkane is (CH₂)_m with m = 1, 3-6, bis(diphenylphosphino)acetylene (dpa), and bis(dimethylphosphino)methane (dmpm), and diisocyanides such as 1,8-diiso-cyano-p-menthane (dmb) and p-diisocyanotetra-methylbenzene (ditmb). The metal fragments are monocations such as Cu⁺, Ag⁺, and Au⁺, dinuclear species such as Pd₂(dmb)₂²⁺, Pd₂(dppm)₂²⁺, M₂(dmpm)₃²⁺ (M = Cu, Ag), and clusters such as M₄(dmb)₄²⁺ (M = Pd, Pt).     

Coordination polymers containing 1D channels as selective luminescent probes

Two 3d-4f heterometallic coordination polymers {[Ln(PDA)3Mn1.5(H2O)3].3.25H2O}infinity with 1D channels were synthesized under hydrothermal conditions (PDA = pyridine-2,6-dicarboxylic acid; Ln = Eu (1); Ln = Tb (2)). The emission intensities of 1 and 2 increased significantly upon addition of Zn2+, while the introduction of other metal ions caused the intensity to be either unchanged or weakened. The case implies that 1 and 2 may be used as luminescent probes of Zn2+.     

Coordination power adjustment of surface-regulating polymers for shaping gold polyhedral nanocrystals

PVP (poly(vinyl pyrrolidone)) is a common polymer that behaves as a surface-regulating agent that shapes metal nanocrystals in the polyol process. We have used different polymers containing tertiary amide groups, namely PVCL (poly(vinyl caprolactam)) and PDMAm (poly(N,N-dimethyl acrylamide)), for the synthesis of gold polyhedrons, including octahedrons, cuboctahedrons, cubes, and higher polygons, under the present polyol reaction conditions. The basicity and surface coordination power of the polymers are in the order of PVCL, PVP, and PDMAm. A correlation is observed between the coordination power of the polymers and the resulting gold nanocrystal size. Strong coordination and electron donation from the polymer functional groups to the gold surface restrict particle growth rates, which leads to small nanocrystals. The use of PVCL can yield gold polyhedral structures with small sizes, which cannot be achieved in the reactions with PVP. Simultaneous hydrolysis of the amide group in PDMAm leads to carboxylate functionality, which is very useful for generating chemical and bioconjugates through the formation of ester and amide bonds.     

Coordination polymers of copper(II) with some dicarboxysiloxane ligands

Several new coordination polymers of copper(II) with different carboxylate ligands containing siloxane units were synthesized by equilibrium polycoordination reactions of copper(II) acetate with the proper dicarboxylic acid (i.e. 1,3‐bis(3‐carboxypropyl)tetramethyldisiloxane, α,ω‐bis(3‐carboxypropyl)oligodimethylsiloxane, and 1,3‐bis(sebacomethyl)tetramethyldisiloxane) in solution (methanol), at room temperature. Some variations in the feed molar ratios were made. The resulting polymers having a polycoordination degree between 5 and 71 are soluble in a wide range of common organic solvents. The formation of polymers was proved by IR and UV–VIS absorption spectroscopy. The thermal behaviour of the coordination polymers was analysed by thermogravimetry in air. The silicon and copper contents and inherent viscosities were also determined. Copyright © 2002 John Wiley & Sons, Ltd.     

Coordination polymers from silver(I) and bifunctional pyridyl ligands

Coordination polymers and a macrocycle formed from the reactions between flexible bis(2-pyridyl) ligands and AgCF(3)SO(3) are reported. The type of structure formed depends on the choice of ligand and the stoichiometry of the reaction. When 1 equiv of 1,4-bis(pyridin-2-ylmethoxy)benzene (L2), 4,4'-bis(pyridin-2-ylmethoxy)biphenyl (L4), or bis((4-pyridin-2-ylmethoxy)phenyl)methane (L5) is used, 1D chain coordination polymers held together via Ag-N bonds are generated. When a 2:1 ratio of L2 and silver ion is used, a 2D porous network is formed. The reaction between silver ions with a mixture of ligands (L1 and L2 in 1:1 ratio, L1 = 1,4-bis((pyridin-2-yl-methyl)thio)benzene) results in a novel 1D ABAB type coordination copolymer where L1 and L2 act as a bis-bidentate and a bis-monodentate ligand, respectively. The reaction of 1-(pyridin-2-ylmethoxy)-4-((pyridin-2-yl-methyl)thio)benzene (L3) with silver ions in a 1:1 ratio gives a bimetallic macrocycle rather than a polymeric species. Structural analyses of the polymeric compounds suggest that interactions between the aromatic rings play a significant role in stabilizing the polymeric structures.     

Coordination polymers derived from magnesium and barium complexes of redox-active ligands

The reactions of monomeric complexes [(dpp-bian)M(THF)_n](M = Mg, n = 3; M = Ba, n = 5; dpp-bian = 1,2-bis[(2,6-di-isopropylphenyl)imino]acenaphthene) with 4,4'-bipyridine (4,4'-bipy) in THF proceed with electron transfer from dpp- bian2– to 4,4'-bipy0 to afford 1D coordination polymers [(dpp-bian)M(4,4'-bipy)(THF)_n]_m (M = Mg, n = 1; M = Ba, n = 2) that contain simultaneously radical anion ligands dpp-bian– and 4,4'-bipy . Addition of DME to coordination polymer [(dpp-bian)Mg(4,4'-bipy)(THF)_n]_m results in fragmentation of polymeric chains to give dinuclear magnesium species [{(dpp-bian)Mg(DME)}₂(4,4'-bipy)]. Barium analogue [{(dpp-bian)Ba(DME)₂}₂(4,4'-bipy)] has been prepared by reacting of complex [(dpp-bian)Ba(DME)2.5] with 4,4'-bipy in DME.     

Coordination polymers of silver(I) with ditopic cross-conjugated dienone

The reaction of the silver salts AgX (a: X = BF₄^-, b: X = ClO₄^-, c: X = OTf^–) with α,α'-di(3/4-pyridylmethylene)cycloalkanones (L¹–L³) and piperidones (L⁴–L⁷) results in the formation of coordination products of general composition [AgX(L ⁿ )(solvent)] and [AgX(L ⁿ )] (L ⁿ = L¹–L⁷). All complexes were characterized by elemental analysis and IR-spectroscopy. The structures of [Ag(ClO₄)(L¹)(MeC≡N)]_∞ (1b · MeC≡N) and [Ag(ClO₄)(L¹)]_∞ (1b) in the solid state are reported. In both structures {Ag(L¹)}⁺ building units are linked to each other via Ag–N_pyridine primary bonds resulting in the formation of infinite chains. In both structures the ligands L¹ are fixed in transoid conformations, thus forming zig-zag polar chains. The structure of 1b · MeC≡N consists of pairs of tightly and loosely stacked chains. The tightly packed chains are weakly coupled by perchlorate anions acting as μ-bridges in between Ag(I) centers as well as by π–π-stacking interactions of unsaturated fragments of the respective ligands. In contrast, polar 2D layers composed of {Ag(L¹)} _m ^m+ chains, which interdigitate via multiple weak interactions by Ag–O contacts, are found in the solid structure of 1b. The dissolution of coordination products in coordinating solvents like MeCN or DMSO leads to the decomposition of complexes due to formation of silver-solvent coordination compounds. The coordination products 1–5 are stable in solid state against exposure to the ambient light, whereas solutions of the compounds, especially in DMSO-d₆, appeared to be photochemically labile. As revealed by NMR spectroscopic studies, the organic components undergo trans-cis isomerization.     

Coordination polymers and hybrid networks of different dimensionalities formed by metal sulfites

In our effort to explore the use of the sulfite ion to design hybrid and open-framework materials, we have been able to prepare, under hydrothermal conditions, zero-dimensional [Zn(C12H8N2)(SO3)].2H2O, I (a = 7.5737(5) A, b = 10.3969(6) A, c = 10.3986(6) A, alpha = 64.172(1) degrees , beta = 69.395(1) degrees , gamma = 79.333(1) degrees , Z = 2, and space group P), one-dimensional [Zn2(C12H8N2)(SO3)2(H2O)], II (a = 8.0247(3) A, b = 9.4962(3) A, c = 10.2740(2) A, alpha = 81.070(1) degrees , beta = 80.438(1) degrees , gamma = 75.66(5) degrees , Z = 2, and space group P), two-dimensional [Zn2(C10H8N2)(SO3)2].H2O, III (a = 16.6062(1) A, b = 4.7935(1) A, c = 19.2721(5) A, beta = 100.674(2) degrees , Z = 4, and space group C2/c), and three-dimensional [Zn4(C6H12N2)(SO3)4(H2O)4], IV (a = 11.0793(3) A, c = 8.8246(3) A, Z = 2, and space group P42nm), of which the last three are coordination polymers. A hybrid open-framework sulfite-sulfate of the composition [C2H10N2][Nd(SO3)(SO4)(H2O)]2, V (a = 9.0880(3) A, b = 6.9429(2) A, c = 13.0805(5) A, beta = 91.551(2) degrees , Z = 2, and space group P21/c), with a layered structure containing metal-oxygen-metal bonds has also been described.     

Coordination polymers with adjustable dimensionality based on CuII and bis-imidazolyl bridging ligand

1,4-Bis(imidazol-1-yl)butane was synthesized from imidazole and 1,4-dibromobutane in an alkaline medium. A variation of the molar ratio of reagents in the system copper(II) chloride dihydrate and 1,4-bis(imidazol-1-yl)butane (bImB) upon heating in N,N-dimethylformamide resulted in the synthesis of two new coordination polymers [Cu(bImB)Cl₂] (1) and [Cu(bImB)₂Cl₂] (2), which were structurally characterized. Product 1 was found to possess a chain structure, while structure 2 is built of neutral layers, with the dimensionality of the extended coordination structures being determined by the reaction conditions. The new compounds were characterized by IR spectroscopy, elemental analysis, and powder X-ray diffraction data.

     

Coordination polymers undergoing spin crossover and reversible ligand exchange in the solid

Here we report the synthesis and characterisation of a polymer made up of a system of parallel 2-D grids of Fe(II) ions linked by [Au(CN)2]- bridges and its transformation into a new system of three interpenetrated 3-D coordination open frameworks with the NbO topology. Reversibility of this crystal-to-crystal transformation is evidenced by X-ray crystallographic data and from their spin crossover properties.