Cationic Coordination Polymer Research Articles

A Molecular Antenna Coordination Polymer from Cadmium(II) and 4,4’-Bipyridine Featuring Three Distinct Polymer Strands in the Crystal

Reaction of cadmium perchlorate and the prototypical linear bridging ligand 4,4’-bipyridine (4,4’-bipy) in an ethanol/water mixture affords the one-dimensional coordination polymer, [{Cd(m-4,4’-bipy)(4,4’-bipy)2(H2O)2}(ClO4)2 × 2 4,4’-bipy × 4.5 H2O]n (1). The Cd2+ ions adopt an octahedral coordination sphere and are joined into linear chains by 4,4’-bipy via two trans coordination sites. The remaining two trans sites in the equatorial plane carry terminally monodentate-bound 4,4’-bipy ligands, resulting in a molecular antenna arrangement. The two axial sites of each Cd2+ ion are occupied by aqua ligands. Compound 1 crystallizes in the non-centrosymmetric, monoclinic space group C2 with three similar, crystallographically independent, cationic coordination polymer strands in the unit cell, which essentially differ only in the conformations of the 4,4’-bipyridyl ligands. Consistent with the similarity of the local coordination environments of the three independent Cd atoms in the structure, 113Cd MAS NMR spectroscopy reveals a single resonance line at 89 ppm.

Topological diversity in zinc coordination polymers with 5-substituted isophthalate and bis(4-pyridylmethyl)piperazine ligands

The structures of luminescent divalent zinc coordination polymers containing a 5-substituted isophthalate ligand and the long-spanning hydrogen-bonding capable tethering ligand bis(4-pyridylmethyl)piperazine (bpmp) show a wide variety of two- and three-dimensional topologies. {[Zn(NO2ip)(Hbpmp)][ZnCl(H2O)(NO2ip)]}n (1, NO2ip = 5-nitroisophthalate) possesses parallel two-fold interpenetrated cationic (4,4) coordination polymer grids along with embedded anionic one-dimensional (1-D) chain motifs. The chloride-free derivative {[Zn5(NO2ip)6(Hbpmp)2(bpmp)]·2H2O}n (2) manifests trinuclear units linked into a complex doubly interpenetrated 4,8-connected binodal 3-D lattice with (456)2(414614) topology. {[Zn(OHip)(bpmp)]·H2O}n (3, OHip = 5-hydroxyisophthalate) has a five-fold interpenetrated diamondoid topology, while [Zn2(tBuip)2(bpmp)]n (4, tBuip = 5-tert-butylisophthalate) shows a two-fold interpenetrated primitive cubic net based on dimeric units. {[Zn(OMeip)(bpmp)]·8H2O}n (5, OMeip = 5-methoxyisophthalate) adopts an undulating (4,4) single-grid 2-D topology. {[Zn(sip)(Hbpmp)]·4H2O}n (6, sip = 5-sulfoisophthalate) displays a novel three-fold interpenetrated 3,5-connected binodal lattice with (426)(426583) topology.

Substituent Dependent Dimensionality in Luminescent Zinc Isophthalate Coordination Polymers Containing Bis(3‐pyridylmethyl)piperazine

AbstractDivalent zinc coordination polymers containing bis(3‐pyridylmethyl)piperazine (3‐bpmp) and isophthalate ligands have been hydrothermally synthesized and structurally characterized by single‐crystal X‐ray diffraction. {[Zn(ip)(H3‐bpmp)]ClO4·4H2O}n (1, ip = isophthalate) has twofold parallel interpenetrated (4,4) grid cationic coordination polymer nets, with unligated perchlorate ions and intriguing infinite water molecule chains. {[Zn2(NO2ip)3(H23‐bpmp)(H2O)5]·3H2O}n (2, NO2ip = 5‐nitroisophthalate) exhibits a supramolecular lattice built from 1D chain motifs, revealing a significant dependence of topology on the steric bulk of the dicarboxylate ligand. Luminescent properties for 1 and 2 are also reported.

Silver(I) and Mercury(II) Complexes with 1‐Methyl‐1,2,4‐triazole as Models for Metal‐Mediated Base Pairs – Formation of Discrete Complexes in Solution vs. One‐ and Two‐Dimensional Coordination Polymers in the Solid State

AbstractThe coordination chemistry of 1‐methyl‐1H‐1,2,4‐triazole(1‐mtri) with respect to the linearly coordinating metal ions silver(I) and mercury(II) has been established. The ligand serves as a model nucleobase for the artificial 1,2,4‐triazole nucleoside. Solution studies show that 2:1 complexes are formed with both metal ions in water. Mercury(II) forms more stable complexes than silver(I), with a stability constant of log β2 of 10.5 ± 2.5 vs. 4.3 ± 0.4 for the silver(I) complex. In the solid state, different types of cationic coordination polymers are formed. The silver complex [Ag(1‐mtri)](ClO4) (1) comprises a one‐dimensional coordination polymer [Ag2(1‐mtri)2]n2n+, showing a 1:1 ratio of ligand to metal. By contrast, the mercury complex [Hg(1‐mtri)2](ClO4)2 (2) retains a 2:1 stoichiometry while forming a two‐dimensional coordination polymer. In compound 2, mercury(II) is coordinated in a distorted octahedral fashion, with two normal and four long bonds, resulting in a compressed octahedron.

A >22 Å long metal-complex anion and a 1D cationic coordination polymer, both based on 4,4′-bipyridine- N, N′-dioxide, yielding a 3D and 2-fold interpenetrated fsc net of the hydrogen-bonded metal-organic 1D polymer

The cationic one-dimensional (1D) coordination polymer chain 1 ∞ {[Co(μ-bpdo)(H 2O) 4] 2+} and the metal-complex anion trans-[Co(SO 4) 2(bpdo) 2(H 2O) 2] 2−, both based on the 4,4′-bipyridine- N, N′-dioxide (bpdo) ligand, form a complementary supramolecular pair 1 ∞ {[Co(μ-bpdo)(H 2O) 4] 2+} n n[Co(SO 4) 2(bpdo) 2(H 2O) 2] 2− ( 1) with respect to charge balance and hydrogen bonding. With a length of >22.14 Ǻ along the bpdo–Co–bpdo axis the metal-complex trans-[Co(SO 4) 2(bpdo) 2(H 2O) 2] 2− is one of the longest and anisotropic counter anions (aspect ratio 22.14:8.11:4.17) observed so far in coordination polymers. Hydrogen-bonding of the anion links the cationic metal-organic 1D polymer into a 2-fold interpenetrated three-dimensional (3D) fsc (or sqc11) 4,6-c 2-nodal net of stoichiometry (4-c)(6-c) with square-planar, 4-connected (Co in anion) and octahedral, 6-connected (Co in cation) nodes in a 1:1 ratio. The 4-c point symbol is (4 4.6 2), the 6-c one (4 4.6 10.8) yielding a point symbol for the fsc net of (4 4.6 2)(4 4.6 10.8). The synthesis of 1 requires the presence of a Schiff base. Synthesis under the same conditions in the absence of the Schiff base yields the molecular complex and cocrystal [Co(bpdo)(H 2O) 5]SO 4·1/2bpdo ( 2) which is related (as pseudo-polymorph) to the known solvate [Co(bpdo)(H 2O) 5]SO 4·2H 2O ( 3) (CSD Refcodes RAXMUZ and RAXMUZ01).

Formation of a Chiral Host with Axially Chiral Cationic 1D Coordination Polymers Composed of Achiral Building Blocks and Inclusion of Anionic Tris-Chelate Complexes in an Unbalanced Δ/Λ Ratio

Abstract Two crystals, [{Co(hfac)2}{Ni(pyterpy)2}][Co(hfac)3]2 (1) and [Co(CNacac)2][Ni(pyterpy)2]SO4·xG (2), composed of 1D cationic coordination polymers were prepared by self-assembly of achiral component metal complexes in solution (hfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dionato, CNacac = 3-cyanopentane-2,4-dionato, pyterpy = 4′-(4-pyridyl)-2,2′:6′,2′′-terpyridine, G = methanol and water). 1 is chiral and spontaneously optically resolved, whereas 2 is achiral. In 1, an alternate linkage of [Co(hfac)2] and [Ni(pyterpy)2]2+ forms a 1D coordination polymer and twisting of the two complexes about the principal axis of the 1D polymer makes the polymer axially chiral. The 1D polymers stack to create two-types of 1D channels, where anionic complexes [Co(hfac)3]− are included. One channel contains only Δ-[Co(hfac)3]−, whereas the other contains an equal amount of Δ- and Λ-[Co(hfac)3]−. Therefore, the Δ/Λ ratio of [Co(hfac)3]− is 3/1. In the case of 2, 1D coordination polymers are formed by an alternate linkage of [Co(CNacac)2] and [Ni(pyterpy)2]2+. They are chiral due to twisting of one pyridine ring in [Ni(pyterpy)2]2+, however, there are inversion centers in 2. These results demonstrated that axial chirality can be introduced into 1D coordination polymers by twisting the two component metal complexes alternately linked. This method is useful and prospective for preparing chiral coordination polymers from achiral building blocks.

Catena-Poly[[[(dimethylmalonato-κ2O:O′)(perchlorato-κO)copper(II)]-μ-bis(3-pyridylmethyl)piperazinediium-κ2N1′:N4′] perchlorate dihydrate

In the title compound, {[Cu(C5H6O4)(ClO4)(C16H22N4)]ClO4·2H2O}n, square-pyramidally coordinated Cu atoms with perchlorate and dimethyl­malonate ligands are connected into cationic sinusoidal coordination polymer chains by doubly protonated bis­(3-pyridylmeth­yl)piperazine (3-bpmp) ligands. The chains aggregate into pseudo-layers parallel to the (101) crystal planes by N—H⋯O hydrogen bonding. Unligated perchlorate anions and water mol­ecules of crystallization provide additional hydrogen bonding between pseudo-layers.

Synthesis, Crystal Structures and Thermal Analysis of Two New Silver(I)–Dithioether Lamellar Coordination Polymers

Two new silver(I)–dithioether coordination polymers based on the self-assembly of the dithioether ligands L n −R = CH3–S(CH2) n S–CH3 (n = 1, 3) and AgX silver salts, where X = ClO4 − (1) and PF6 − (2), have been synthesized and characterized by single crystal X-ray diffraction and TGA. The crystallographic data of those complexes are: (1) Monoclinic P21/c; a = 16.5861(3) A; b = 10.1048(2) A; c = 15.7843(3) A; β = 112.570(1)°; V = 2442.83(8) A3; Z = 4. (2) Monoclinic P21/n; a = 8.6500(2) A; b = 9.4053(2) A; c = 24.0357(6) A; β = 92.750(2)°; V = 1953.19(8) A3; Z = 4. In both complexes, the dithioether building blocks propagated the silver(I) centers to build cationic lamellar coordination polymers, while ClO4 − and PF6 −, which were sandwiched between silver-ligand sheets, counterbalance only the charge of the networks. The thermogravimetric investigation reveals that those complexes decompose in a single step respectively to metallic silver and silver salt. Two new silver(I)–dithioether coordination polymers, obtained from the self-assembly of dithioether ligands and AgX salts with noncoordinating counteranions (X = ClO4 − and PF6 −), were characterized by X-ray crystallography and thermogravimetric analysis (TGA).

Syntheses and characterization of three hybrid materials based on polymeric copper complexes and saturated Keggin polyoxoanions

Three novel heteropolytungstates, [Cu(phen)2]4[α-SiW12O40] (1), [Cu4(4,4′-bpy)3(2,2′-bpy)4][α-SiW12O40] · H2O (2) and [Cu(4,4′-bpy)(4,4′-Hbpy)0.5]2[PW12O40] (3) (phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR, TG analyses and single-crystal X-ray diffraction. Compound (1) exhibits interesting chiral layer constructed from interperpendicular helical chains running along a crystallographic 21 axis in the c and a directions. Furthermore, the chiral layers are connected by the [α-SiW12O40]4− anions via hydrogen bonding interactions to form a 3D superamolecular structure. The [Cu4(4,4′-bpy)3(2,2′-bpy)4]4+ coordinated complexes in compound (2) are packed together via the aromatic π–π stacking interactions and exhibit an interesting 3D sandglasslike “host” network with 1D channels, in which [α-SiW12O40]4− anions “guests” reside. Compound (3) has a unique 2D superamolecular network, which is composed of cationic CuI coordination polymer chains and discrete [PW12O40]3− polyoxoanions as linkers. It is noteworthy that the monprotonated 4,4′-bpy ligands of (3) act as arms and connect the adjacent 2D network, generating a 3D interpenetrating superamolecular structure.

Catena-Poly[[[bis(2-pyridone-κO)sodium]-di-μ-2-pyridone-κ4O:O] tetrafluoroborate

In the title compound, [Na(C5H5NO)4]BF4, each Na+ ion, lying on an inversion centre, is octa­hedrally coordinated by four bridging and two terminal pyridone ligands, creating a cationic coordination polymer chain with tetra­fluoro­borate anions occupying the spaces between the chains.

Silver(I) Complexes of Fixed, Polytopic Bis(pyrazolyl)methane Ligands: Influence of Ligand Geometry on the Formation of Discrete Metallacycles and Coordination Polymers

Reactions of the arene-linked bis(pyrazolyl)methane ligands m-bis[bis(1-pyrazolyl)methyl]benzene, (m-[CH(pz)2]2C6H4, Lm), p-bis[bis(1-pyrazolyl)methyl]benzene, (p-[CH(pz)2]2C6H4, Lp), and 1,3,5-tris[bis(1-pyrazolyl)methyl]benzene (1,3,5-[CH(pz)2]3C6H3, L3) with AgX salts (pz = 1-pyrazolyl; X = BF4- or PF6-) yield two types of molecular motifs depending on the arrangement of the ligating sites about the central arene ring. Reactions of the m-phenylene-linked Lm with AgBF4 and AgPF6 afford complexes consisting of discrete, metallacyclic dications: [Ag2(mu-Lm)2](BF4)2 (1) and [Ag2(mu-Lm)2](PF6)2 (2). When the p-phenylene-linked Lp is treated with AgBF4 and AgPF6, acyclic, cationic coordination polymers are obtained: {[Ag(mu-Lp)]BF4}infinity (3) and {[Ag(mu-Lp)]PF6}infinity (4). Reaction of the ligand L3, containing three bis(pyrazolyl)methane units in a meta arrangement, with an equimolar amount of AgBF4 again yields discrete metallacyclic dications in which one bis(pyrazolyl)methane unit on each ligand remains unbound: [Ag2(mu-L3)2](BF4)2 (5). Treatment of L3 with an excess of AgBF4 affords a polymer of metallacycles, {[Ag3(mu-L3)2](BF4)3}infinity (6), with one of the bis(pyrazolyl)methane units on each ligand bound to a silver cation bridging two metallacycles. The supramolecular structures of the silver(I) complexes 1-6 are organized by noncovalent interactions, including weak hydrogen bonding, pi-pi, and anion-pi interactions.

Influence of anions on the dimensionality of extended networks based on CuI cations and 1,4,5,8,9,12-hexaazatriphenylene (HAT) ligands

Reactions of Cu I salts with 1,4,5,8,9,12-hexaazatriphenylene (HAT) afford three types of cationic coordination polymers depending on the anion present in the reaction solution. In the crystal structure of {[Cu(HAT)][BF4]x1/3(C6H6)}infinity, (1), Cu ions and HAT molecules form extended layers that are best described as strongly distorted honeycomb nets. The space between the layers is occupied by [BF4]- anions and solvent molecules. {[Cu(HAT)][PF6]}infinity, (2), crystallizes as a chiral (10,3)-a net with [PF6]- anions residing in the cavities of the three-dimensional metal-organic framework. The crystal structure of {[Cu4(HAT)3][SbF6]4x3C6H6}infinity, (3), is based on unique extended [Cu4(HAT)3]infinity "nanotubules" filled with solvent molecules and [SbF6]- anions.

Tetranuclear [Rh4(mu-PyS2)2(diolefin)4] complexes as building blocks for new inorganic architectures: synthesis of coordination polymers and heteropolynuclear complexes with electrophilic d8 and d10 metal fragments.

The reaction of [Rh4(mu-PyS2)2(cod)4] (PyS2 = 2,6-pyridinedithiolate, cod = 1,5-cyclooctadiene) with CF3SO3Me gave the cationic complex [Rh(4)(mu-PyS(2)Me)(2)(cod)4][CF3SO3]2 (1) with two 6-(thiomethyl)pyridine-2-thiolate bridging ligands from the attack of Me+ at the terminal sulfur atoms of the starting material. Under identical conditions [Rh4(mu-PyS2)2(tfbb)4] (tfbb = tetrafluorobenzobarrelene) reacted with CF3SO3Me to give the mixed-ligand complex [Rh(4)(mu-PyS2)(mu-PyS2Me)(tfbb)4][CF3SO3] 2. The nucleophilicity of the bridging ligands in the complexes [Rh4(mu-PyS2)2(diolefin)4] was exploited to prepare heteropolynuclear species. Reactions with [Au(PPh3)(Me2CO)][ClO4] gave the hexanuclear complexes [(PPh3)2Au2Rh4(mu-PyS2)2(diolefin)4][ClO4]2 (diolefin = cod (3), tfbb (4)). The structure of 4, solved by X-ray diffraction methods, showed the coordination of the [Au(PPh3)]+ fragments to the peripheral sulfur atoms in [Rh4(mu-PyS2)2(diolefin)4] along with their interaction with the neighbor rhodium atoms. Neutral coordination polymers of formula [ClMRh4(mu-PyS2)2(diolefin)4]n (M = Cu (5, 6), Au (7)) result from the self-assembly of alternating [Rh4(mu-PyS2)2(diolefin)4] ([Rh4]) blocks and MCl linkers. The formation of the infinite polymetallic chains was found to be chiroselective for M = Cu; one particular chain contains exclusively homochiral [Rh4] complexes. Cationic heterometallic coordination polymers of formula [MRh4(mu-PyS2)2(diolefin)4]n[BF4]n (M = Ag (8, 9), Cu (10, 11)) and [Rh5(mu-PyS2)2(diolefin)5]n[BF4]n (12, 13) result from the reactions of [Rh4] with [Cu(CH2CN)4]BF4, AgBF4, and [Rh(diolefin)(Me2CO)2]BF4, respectively. The heterometallic coordination polymers exhibit a weak electric conductivity in the solid state in the range (1.2-2.8) x 10(-7) S cm(-1).

First use of the succinamate(−1) ligand in 3d-metal chemistry: dinuclear copper(II) complexes with the rare [Cu 2(η 1:μ 2-O 2CR) 2(η 1:η 1:μ 2-O 2CR)] +, [Cu 2(η 1:η 1:μ 2-O 2CR) 2] 2+ and [Cu 2(μ-OH)(μ-OH 2)(η 1:η 1:μ 2-O 2CR)] 2+ cores, and a novel one-dimensional polymerization of two different dimers (R=CH 2CH 2CONH 2)

A systematic investigation of the reactions of 3d-metal ions with succinamate(−1) (LH −) in the presence of aromatic N, N ′-donors has been initiated and initial results are described. Several reaction schemes involving various copper(II) sources, LH − and 4,4 ′-dimethyl-2,2 ′-bipyridine (dmbpy) or 2,2 ′-bipyridine (bpy) afforded the new complexes [Cu 2(LH) 3(dmbpy) 2](OH) · H 2O · MeOH ( 1a), [Cu 2(LH) 2(dmbpy) 2(H 2O) 2](ClO 4) 2 · 2H 2O ( 2), [Cu 4(LH) 5(dmbpy) 4] n (ClO 4) 3 n · nH 2O · 0.53 nMeOH ( 3) and [Cu 2(OH)(H 2O)(LH)(bpy) 2](ClO 4) 2 ( 4), which have been characterized by single-crystal X-ray crystallography and IR spectroscopy. The dinuclear complexes contain extremely rare cores, while the novel cationic coordination polymer 3 consists of alternating dinuclear units.

Crystal engineering of an inclusion coordination polymer with cationic pocket-like structure and its property to form metal–organic nanofibers

The reaction of cobalt nitrate hexahydrate with 4,4 ′-bipyridine (BPY) under hydrothermal conditions produced a new cationic pocket-like coordination polymer built by mixed double-hydrogen-bonded and coordinated 4,4 ′-bipyridine rectangular-grid with inclusion species, and this material has been fabricated into metal–organic nanofibers by electrospinning.

Silver(I)–3,6-bis(pyridin-3-yl)-1,2,4,5-tetrazine coordination polymers: a diversity of chain motifs

The influence of solvent and anion on the formation of coordination polymers between silver(I) and 3,6-bis(pyridin-3-yl)-1,2,4,5-tetrazine (3,3′-pytz), a bridging ligand that can adopt both cisoid and transoidconformations, is reported. Reaction of AgPF 6 in MeCN with 3,3′-pytz in CH 2Cl 2 gives ([{Ag(NCMe) 2}(μ-3,3′-pytz)][PF 6]·MeCN) ∞, 1, of AgPF 6 in MeNO 2 and 3,3′-pytz in CH 2Cl 2 gives ([{Ag 2(μ-3,3′-pytz) 2}(μ-3,3′-pytz)][PF 6] 2·4MeNO 2) ∞, 2, and of AgCF 3SO 3 in MeCN and 3,3′-pytz in CH 2Cl 2 gives {[Ag(μ-3,3′-pytz)]CF 3SO 3} ∞, 3. These cationic coordination polymers exclusively form chain structural motifs. That in 1, ([{Ag(NCMe) 2}(μ-3,3′-pytz)] +) ∞, has a castellated construction with each tetrahedral silver(I) center coordinated by two solvent molecules as well as two linking transoid-oriented 3,3′-pytz bridges (Ag⋯Ag 13.210 Å) in a 1:1 polymeric chain. That in 2, ([{Ag 2(μ-3,3′-pytz) 2}(μ-3,3′-pytz)] 2+) ∞, is novel. It is the first coordination polymer to exhibit both cisoid and transoid conformations of a bridging ligand coordinated to the same metal center. Pairs of silver(I) centers are linked by pairs of cisoid-oriented 3,3′-pytz molecules (Ag⋯Ag = 11.695 Å) to form [Ag 2(μ-3,3′-pytz) 2] motifs, which are bridged, in turn, by transoid-oriented 3,3′-pytz molecules (Ag⋯Ag = 13.318 Å) to form a 3:2 ligand:metal infinite polymeric zigzag chain. That in 3, {[Ag(μ-3,3′-pytz)] +} ∞, has a zigzag architecture despite being based on linear silver(I) centers. Transoid-oriented 3,3′-pytz molecules link silver(I) centers (Ag⋯Ag 13.225 Å) to give a 1:1 ligand:metal infinite polymeric zigzag chain. The chains aggregate in parallel pairs linked by weak Ag⋯Ag contacts (Ag⋯Ag = 3.220 Å), which are supported by (μ 2-κO,κO′) bridging CF 3SO 3 − anions.