One-dimensional Coordination Chains Research Articles

Phase Transition and Luminescent Property Change Induced by Different Organic Cations in One-Dimensional Double Perovskites.

Double perovskites (DPs) have attracted attention in the field of luminescence due to their inherent broadband emission of self-trapping excitons. In this work, we choose [(CH3)3NCH2CHCH2]+ and [CH3CHOHCH2NH2]+ as organic cations to synthesize two new organic-inorganic hybrid DPs, [(CH3)3NCH2CHCH2]2KInCl6 (1) and [CH3CHOHCH2NH2]2KInCl6 (2). The [KCl6]3- and [InCl6]3- octahedra are interchangeably connected by sharing two opposite faces, forming a one-dimensional coordination chain. Each K atom coordinates with six chlorine atoms in 1, while it coordinates with two oxygen atoms in addition to the six chlorine atoms in 2. The coordination between ions K and O in compound 2 may have significantly reduced its luminescence. As a result, compound 1 shows bright-yellow light with a quantum yield of more than 90%, while 2 shows weak blue light with a quantum yield of only 0.98%. In addition, different from no phase transition found in 2, 1 undergoes a reversible phase transition at 324/307 K in the heating-cooling cycle. Through structural and spectral analysis and density functional theory calculation, we conclude that the larger degree of [InCl6]3- octahedral distortion and the larger anion distance (In···In) also cause the PLQY of compound 1 to be higher than that of compound 2.

Novel CuI coordination polymer self-assembled from 2,5-bis(pyridin-4-yl)-1,3,4-oxadiazole and thiocyanate ions: Synthesis, structural characterization, Hirshfeld surface analysis, thermal and magnetic studies

The synthesis and crystal structure of one-dimensional (1-D) coordination polymer from an angular dipyridyl ligand 2,5-bis(pyridine-4-yl)-1,3,4-oxadiazole (4-pox) and CuCl2⋅2H2O, [CuI(4-poxH)(SCN)(μ1,3-SCN)]n (named complex 1), are reported. The investigated copper(I) complex crystallizes in the monoclinic crystal system with space group P21/n. UV–vis and FTIR suggest the co-presence of the 4-pox ligand and the pseudohalide, in the isolated complex. This was confirmed by a crystallographic study which shows that the copper is in a tetrahedral environment, linked to two thiocyanate groups and to two nitrogen atoms, one belonging to the pyridine ring and the others to thiocyanate group. The crystallographic study also reveals the protonation of the unbound organic ligand pyridine. The crystal cohesion is assured by different intermolecular hydrogen bonds, π–π stacking, and coordination bonds (N–Cu and S–Cu). Therefore, the one-dimensional coordination chains are further interconnected by hydrogen bonds and π–π stacking to from a three-dimensional supramolecular framework. This behaviour was confirmed by Hirshfeld surface analysis. The thermal analysis reveals that complex 1 is thermally stable up to 160 °C. The magnetic measurements indicated the diamagnetic nature of this CuI coordination polymer.

In situ thermal-induced generation of {Ag0AgI} dimer within Co-Ag phosphonates

The thermal decomposition of AgNO3 is known to produce metallic Ag, but single-atomic dispersion is hard to achieve instead of the aggregation state of nanoparticles. Herein, we develop an efficient approach to thermally generate and stabilize single Ag atoms via the coordination effect. Two desired Co-Ag phosphonates [AgI2CoIII2(notpH3)2(NO3)]X [X = NO3− (1) or ClO4− (2)] were synthesized by solid-phase grinding method or solution crystallization. Both crystal structures reveal slightly different packing arrangements of various lattice anions and identical one-dimensional (1-D) coordination chains, formed in each case by the coordination of Ag(I) to the metalloligand Co(notpH3) and NO3− anion. The number of Ag(I) ions connected to each NO3− anion reduces from 5 in bulk AgNO3 to 2 in compounds 1 and 2, leading to the AgNO3 component stepwise decomposition at a lower temperature (<300 °C). During the thermal decomposition, the changes of supermolecular structures and Ag oxidation states were monitored by PXRD, IR and XAFS measurements. The most interesting finding is that 1 and 2 can retain chain structures and harvest Ag(0) atoms in the chain by controlling decomposition temperatures (220 °C for 1 and 254 °C for 2).

Structural diversity, magnetic properties and luminescence of NiII, CoII and ZnII coordination polymers derived from 3,3'-[(5-carboxy-1,3-phenylene)bis(oxy)]dibenzoic acid and 1,10-phenanthroline.

Three novel coordination polymers (CPs), namely poly[[di-μ-aqua-bis{μ4-3,3'-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoato-κ5O1:O1',O3:O5:O5'}bis(1,10-phenanthroline-κ2N,N')trinickel(II)] dimethylformamide 1.5-solvate trihydrate], {[Ni3(C21H11O8)2(C12H8N2)2(H2O)2]·1.5C3H7NO·3H2O}n, (I), poly[[di-μ-aqua-bis{μ4-3,3'-[(5-carboxylato-1,3-phenylene)bis(oxy)]dibenzoato-κ5O1:O1',O3:O5:O5'}bis(1,10-phenanthroline-κ2N,N')tricobalt(II)] diethylamine disolvate tetrahydrate], {[Co3(C21H11O8)2(C12H8N2)2(H2O)2]·2C2H7N·4H2O}n, (II), and catena-poly[[aqua(1,10-phenanthroline-κ2N,N')zinc(II)]-μ-5-(3-carboxyphenoxy)-3,3'-oxydibenzoato-κ2O1:O3], [Zn(C21H12O8)(C12H8N2)(H2O)]n, (III), have been synthesized by the reaction of different metal ions (Ni2+, Co2+ and Zn2+), 3,3'-[(5-carboxy-1,3-phenylbis(oxy)]dibenzoic acid (H3cpboda) and 1,10-phenanthroline (phen) under solvothermal conditions. All the CPs were characterized by elemental analysis, single-crystal and powder X-ray diffraction, FT-IR spectroscopy and thermogravimetric analysis. Complexes (I) and (II) have isomorphous structures, featuring similar linear trinuclear structural units, in which the central NiII/CoII atom is located on an inversion centre with a slightly distorted octahedral [NiO6]/[CoO6] geometry. This comprises four carboxylate O-atom donors from two cpboda3- ligands and two O-atom donors from bridging water molecules. The terminal NiII/CoII groups are each connected to the central NiII/CoII cation through two μ1,3-carboxylate groups from two cpboda3- ligands and one water bridge, giving rise to linear trinuclear [M3(μ2-H2O)2(RCOO)4] (M = Ni2+/Co2+) secondary building units (SBUs) and the SBUs develop two-dimensional-networks parallel to the (100) plane via cpboda3- ligands with new (32·4)2(32·83·9)2(34·42.82·94·103) topological structures. Zinc complex (III) displays one-dimensional coordination chains and the five-coordinated Zn atom forms a distorted square-pyramidal [ZnO3N2] geometry, which is completed by two carboxylate O-atom donors from two distinct Hcpboda2- ligands, one O atom from H2O and two N atoms from a chelating phen ligand. Magnetically, CP (I) shows weak ferromagnetic interactions involving the carboxylate groups, and bridging water molecules between the nickel(II) ions, and CP (II) shows antiferromagnetic interactions between the Co2+ ions. The solid-state luminescence properties of CP (III) were examined at ambient temperature and the luminescence sensing of Cr2O72-/CrO42- anions in aqueous solution for (III) has also been investigated.

Formation of One-Dimensional Coordination Chains for High-Performance Anode Materials of Lithium-Ion Batteries via a Bottom-Up Approach.

Understanding the chemistry of coordination compounds as lithium storage materials is significant for advancing lithium-ion batteries' technology. Coordination compounds have become a new family of versatile anode materials because the metal center, the ligand, and the nonrigid crystal structure can simultaneously contribute to the lithium storage capacity. However, the capacities and cycling abilities of coordination compounds are relatively low in comparison to inorganic nanomaterials, and the mechanism for lithium storage is unclear. This work reports that linking the mononuclear complex [Ni(PBIM)2(HIPA)] (1), where PBIM = 2-(2-pyridyl)benzimidazole, and HIPA = 5-hydroxyisophthalic acid, to a one-dimensional coordination polymer [Ni(PBIM)(HIPA)]n (2) via coordination bonds by a facile bottom-up assembly route can significantly enhance the lithium storage capacity from 554 mA h g-1 of 1 to 1025 mA h g-1 of 2 at 100 mA g-1. A combined experimental and theoretical study shows that the favorable lithium-ion diffusion pathways afforded by the coordination-chain-based structure of 2 are responsible for its superior electrochemical property.

Synthesis and Characterization of a Cobalt Coordination Polymer with Bis(4-(1H-Imidazol-1-Yl)Phenyl)Methanone and 1,1′-Biphenyl-2,2′-Dicarboxylate

A cobalt coordination polymer with the formula {[Co(bipmo)(bpa)]n · H2O}n(1) (bipmo = = bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2bpa = 1,1′-biphenyl-2,2′-dicarboxylic acid) is synthesized and structurally characterized. The single crystal X-ray diffraction analysis shows that the coordination geometry of the Co(II) ion is a quite distorted octahedron. The Co1 atom is octahedrally coordinated by four O atoms from two bpa2− ligands, and two N atoms from two bipmo ligands. Interestingly, adjacent Co ions are linked by bpa2− bridges to generate an infinite one-dimensional coordination chain along the b axis, which are further connected by bipmo to generate two-dimension layers parallel to the (1 0 1) plane. The thermal stability of the complex are also investigated.

Synthesis and characterization of a cobalt coordination polymer with bis(4-(1H-imidazol-1-yl)phenyl)methanone and 1,1'-biphenyl-2,2'-dicarboxylate

A cobalt coordination polymer with the formula {[Co(bipmo)(bpa)]n·H2O}n (1) (bipmo = bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2bpa = 1,1'-biphenyl-2,2'-dicarboxylic acid) is synthesized and structurally characterized. The single crystal X-ray diffraction analysis shows that the coordination geometry of the Co(II) ion is a quite distorted octahedron. The Co1 atom is octahedrally coordinated by four O atoms from two bpa2– ligands, and two N atoms from two bipmo ligands. Interestingly, adjacent Co ions are linked by bpa2– bridges to generate an infinite one-dimensional coordination chain along the b axis, which are further connected by bipmo to generate two-dimension layers parallel to the (1 0 1) plane. The thermal stability of the complex are also investigated.

Two 1-D Coordination Polymers Containing Zinc(II) Hexaborates: [Zn(en){B6O7(OH)6}]·2H2O (en = 1,2-diaminoethane) and [Zn(pn){B6O7(OH)6}]·1.5H2O (pn = 1,2-diaminopropane)

The synthesis and characterization by single-crystal X-ray diffraction (XRD) studies of two new zinc(II) hexaborate(2−) complexes, [Zn(en){B6O7(OH)6}]·2H2O (en = 1,2-diaminoethane) (1) and [Zn(pn){B6O7(OH)6}]·1.5H2O (pn = 1,2-diaminopropane) (2), are reported. These complexes crystallize from aqueous solutions containing 10:1 ratios of B(OH)3 and the appropriate Zn(II) amine complexes ([Zn(en)3][OH]2 or [Zn(pn)3][OH]2) through self-assembly processes. The hexaborate(2−) anions in 1 and 2 are coordinated to two Zn(II) centers and form one-dimensional (1-D) polymeric coordination chains. R22(8) and R22(6) inter-chain H-bond interactions play an important role in these self-assembly processes and are discussed.

Mechanochromic Switching between Delayed Fluorescence and Phosphorescence of Luminescent Coordination Polymers Composed of Dinuclear Copper(I) Iodide Rhombic Cores.

The synthesis and photophysical properties of two luminescent CuI coordination polymers, [Cu2 I2 (PPh3 )2 (3-tpyb)]n and [Cu2 I2 (PPh3 )2 (4-tpyb)]n (Cu-3-tpyb and Cu-4-tpyb; PPh3 =triphenylphosphine, m-tpyb=1,3,5-tris(m-pyridyl)benzene (m=3, 4)), are described. X-ray structural analysis indicated that one-dimensional coordination chains comprising rhombic {Cu2 I2 (PPh3 )2 } cores and m-tpyb bridging ligands were formed. Both Cu-3-tpyb and Cu-4-tpyb exhibited blue-to-yellow thermally activated delayed fluorescence (TADF) that originated from mixing of the metal-to-ligand and halide-to-ligand charge-transfer excited states and moderate emission quantum yields of 0.29 and 0.27, respectively, at 298 K. Further, mechanochromic luminescence was observed for both complexes. The emission lifetimes indicated that the origin of emission switched from TADF to phosphorescence, which was derived from the triplet cluster-centered (3 CC) emissive state generated by grinding-induced amorphization.

Making an order: the concerted alignment of [MOF5]2- (M = Nb and Ta) dipolar anions in one-dimensional coordination chains sustained by tris(3,4,5-trimethyl-1H-pyrazole)copper(II).

Electronic distortions, which are inherent in the oxide fluoride anions [MOF5]2- (M = Nb and Ta), provide an origin of polar molecular arrangements for the development of new polar second-harmonic-generating, piezo-, pyro- and ferroelectric materials. It is still a challenge to expand this approach to the realm of metal-organic polymers, while insufficient control over the environment of the [MOF5]2- units results in their orientational disorder and loss of polarity. The structures of catena-poly[[tris(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II)]-μ-oxido-[tetrafluoridoniobium(V)]-μ-fluorido], [CuNbF5O(C6H10N2)3]n, (I), and its isostructural pentafluoridooxidotantalate(V) analogue, catena-poly[[tris(3,4,5-trimethyl-1H-pyrazole-κN2)copper(II)]-μ-oxido-[tetrafluoridotantalum(V)]-μ-fluorido], [CuTaF5O(C6H10N2)3]n, (II), are the first examples of the strict orientational order of [MOF5]2- (M = Nb and Ta) in one-dimensional coordination chains. A primary factor for the exact discrimination of one orientation of the anion over the other is strong and shape-selective multiple interactions of [MOF5]2- with the inherently acentric CuL32+ platform, with a set of two coordination and three N-H...F hydrogen bonds. In (I) and (II), the Cu2+ ions exhibit distorted square-pyramidal fivefold coordination formed by three pyrazole N atoms and the oxide O atom, defining the equatorial plane, and the anionic bridging F atom (which is trans with respect to the M-O bond) residing in the apical position. The inorganic bridges connect CuL32+ moieties into polar zigzag chains; the bulk polarity of the structure is eliminated by an antiparallel alignment of the individual chains. These chains are further connected through C-H...F hydrogen bonding and very weak C-H...π interactions of the organic ligands.

Construction and photocatalytic properties of two metal-mediated coordination polymers based on benzene-1,3,5-tricarboxylic acid and trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene.

With the rapid development of modern industry, water pollution has become an intractable environmental issue facing humans worldwide. In particular, the organic dyes discharged into natural water from dyestuffs, dyeing and the textile industry are the main sources of pollution in wastewater. To eliminate these types of pollutants, degradation of organic contaminants through a photocatalytic technique is an effective methodology. To exploit more crystalline photocatalysts for the degradation of organic dyes, two coordination polymers, namely catena-poly[[(3,5-dicarboxybenzene-1-carboxylato-κO1)silver(I)]-μ-trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene-κ2N:N'], [Ag(C9H5O6)(C12H10N2)]n or [Ag(H2BTC)(3,4'-bpe)]n, (I), and poly[[(μ3-5-carboxybenzene-1,3-dicarboxylato-κ4O1,O1':O3:O3)[μ-trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene-κ2N:N']cadmium(II)] monohydrate], {[Cd(C9H4O6)(C12H10N2)]·H2O}n or {[Cd(HBTC)(3,4'-bpe)]·H2O}n, (II), have been prepared by the hydrothermal reactions of benzene-1,3,5-tricarboxylic acid (H3BTC) and trans-1-(pyridin-3-yl)-2-(pyridin-4-yl)ethene (3,4'-bpe) in the presence of AgNO3 or Cd(NO3)2·4H2O, respectively. These two title compounds have been structurally characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction. In (I), the AgI ions and organic ligands form a one-dimensional coordination chain, and adjacent coordination chains are connected by Ag...O interactions to give rise to a two-dimensional supramolecular network. Each two-dimensional network is entangled with other equivalent networks to generate an infrequent interlocked 2D→3D (2D and 3D are two- and three-dimensional, respectively) supramolecular framework. In (II), the CdII ions are bridged by the HBTC2- and 3,4'-bpe ligands, which lie across centres of inversion, to give a two-dimensional coordination network. The thermal stabilities and photocatalytic properties of the title compounds have also been studied.

Supramolecular Spangling, Crocheting, and Knitting of Functionalized Pyrene Molecules on a Silver Surface.

Pyrenes, as photoactive polycyclic aromatic hydrocarbons (PAHs), represent promising modules for the bottom-up assembly of functional nanostructures. Here, we introduce the synthesis of a family of pyrene derivatives peripherally functionalized with pyridin-4-ylethynyl termini and comprehensively characterize their self-assembly abilities on a smooth Ag(111) support by scanning tunneling microscopy. By deliberate selection of number and geometric positioning of the pyridyl-terminated substituents, two-dimensional arrays, one-dimensional coordination chains, and chiral, porous kagomé-type networks can be tailored. A comparison to phenyl-functionalized reference pyrenes, not supporting the self-assembly of ordered structures at low coverage, highlights the role of the pyridyl moieties for supramolecular crocheting and knitting. Furthermore, we demonstrate the selective spangling of pores in the two-dimensional pyrene assemblies by a distinct number of iodine atoms as guests by atomically resolved imaging and complementary X-ray photoelectron spectroscopy.

A new cobalt(II)-containing coordination polymer composed of dinuclear metal units: synthesis, crystal structure, and magnetic properties with DFT calculations

A new Co(II)-based compound with a 3-phenyl-5-(pyridin-4-yl)-1,2,4-triazole (4-Hppt) and isophthalic acid (H2ip) mixed ligand, [Co(4-Hppt)2(ip)] (1), has been synthesized and structurally and magnetically characterized. The structure of compound 1 consists of one-dimensional coordination chains based on the Co2 units bridged by dual carboxylate groups, where the pyridyl nitrogen atoms in 4-Hppt ligands are located in the axial coordination sites of the octahedral Co(II) nodes. Magnetic investigation suggests that the magnetic coupling derived from the dinuclear Co(II) ions is a moderately antiferromagnetic exchange in the title compound. Moreover, DFT calculations have been performed on the compound to offer a qualitatively theoretical explanation of the magnetic behavior.

Two three-dimensional supramolecular networks built from metallophenols through hydrogen bonds and coordinate bonds

Crystallization of Co(NO3)2 with 4-(imidazol-1-yl)phenol (L) gave a complex formulated as [Co(L)6](NO3)2, whose X-ray crystal structure revealed a twofold inclined interpenetrated network supported by extensive hydrogen bonding and π–π stacking interactions. Crystallization of Co(ClO4)2, L and dicyanamide (dca) in ethanol gave a complex formulated as [Co(L)4(μ-dca)] n (ClO4) n ·4n(EtOH)·nH2O. The X-ray crystal structure of this complex consisted of a three-dimensional open framework, constructed by one-dimensional coordination chains through extensive interchain quadruplicate hydrogen bonding interactions between the phenols and uncoordinated amides. The magnetic properties of [Co(L)4(μ-dca)] n (ClO4) n ·4n(EtOH)·nH2O have been studied, revealing weak antiferromagnetic exchange between cobalt atoms. Crystallization of Co(NO3)2 with 4-(imidazol-1-yl)phenol (L) gave a complex formulated as [Co(L)6](NO3)2, whose X-ray crystal structure revealed a twofold inclined interpenetrated network constructed by extensive hydrogen bonding and π–π interaction. Crystallization of Co(ClO4)2, L and sodium dicyanamide (Na(dca)) in ethanol gave a complex formulated as [Co(L)4(μ-dca)] n (ClO4) n ·4n(EtOH)·nH2O, which is a three-dimensional open framework, constructed by one-dimensional coordination chains through extensive interchain quadruplicate hydrogen bonding interactions between the phenols and uncoordinated amides.

Syntheses, structures, and properties of nine d10or p-block coordination polymers based on a ligand containing both terpyridyl and sulfo groups

Nine new coordination compounds, namely, {[Zn(HDSPTP)2(H2O)4]·6H2O}n (H2DSPTP = 4′-(2,4-disulfophenyl)-4,2′:6′,4′′-terpyridine, (1), [Cd(DSPTP)(H2O)2]n (2), {[Ag(HDSPTP)]·30H2O}n (3), {[Ag(HDSPTP)(H2O)]·3H2O}n (4), [Ag2(DSPTP)]n (5), {[Ag4(DSPTP)2(H2O)3]·2H2O}n (6), [Pb(DSPTP)(H2O)2]n (7), {[Pb(DSPTP)(H2O)3]·3H2O}n (8), and [PbK(DSPTP)(NO3)(H2O)2]·H2O}n (9), were synthesized by introducing a ligand with both terpyridyl and sulfo groups as organic linkers. The reaction of H2DSPTP with Zn(II) salts only resulted in a mononuclear complex (compound 1), in which most donor groups appear uncoordinated, whereas the reaction with Cd(II) salts under similar conditions resulted in a three-dimensional (3D) twofold interpenetrated dia framework (compound 2). The reactions of H2DSPTP with AgCF3CO2 or AgNO3 resulted in compounds 3–6 with different structures: a porous supramolecular framework via interlaced packing of one-dimensional (1D) coordination chains (compound 3), a two-dimensional (6,3) network based on coordination bonds and Ag⋯O interactions (compound 4), a 3D framework based on 1D [Ag2(2-SO3−)2]n secondary building blocks (compound 5), and a twofold interpenetrated framework with a binodal (4,6)-connected fsh topology based on planar tetranuclear SBUs as nodes (compound 6). The reactions of H2DSPTP with Pb(NO3)2 resulted in the following three compounds: a 3D twofold interpenetrated dia framework (complex 7), a twofold interpenetrated (6,3) network (compound 8), and a 3D complicated framework based on tetranuclear SBUs, double-bridge DSPTP2− ligands, and [K(H2O)]+ species (compound 9). The structural diversity is mainly attributed to the rich coordination behaviors of the HDSPTP−/DSPTP2− ligands and the metal center and can be controllably synthesized by altering the metal to ligand ratio, added alkali, and the pH value for the Ag(I) and Pb(II) compounds. Compound 2 exhibits a high thermal stability above 500 °C, undergoes a crystalline–amorphous–crystalline phase transition as temperature is increased from 25 °C to 500 °C, and shows an amorphous–crystalline phase transition when rehydrated. Moreover, the luminescence properties of all the compounds were also investigated.

Three-Dimensional Silver-dabco Coordination Polymers with Zeolitic or Three-Connected Topology

The simple linear linking ligand diazabicyclo[2.2.2]octane (dabco) combines with silver(I) to form three-dimensional (3D) coordination polymers which have either a zeolitic mtn topology structure or a (10,3)-b ths network according to the counteranion used. The tetrahedral anions BF4– or ReO4– promote formation of [Ag(dabco)2]·X, which has a 3D four-connected mtn framework of fused 512 and 64512 cages, and the material shows modest absorption of iodine. The bulky anion [Co(C2B9H11)2]− and an excess of dabco promote formation of complex [Ag2(dabco)3(CH3CN)2]·2[Co(C2B9H11)2] with a three-connected (10,3)-b network, while use of 1 equiv of dabco gives a previously reported [Ag(dabco)]·[Co(C2B9H11)2], which has a one-dimensional coordination chain structure.

Crystal structures and magnetic properties of three new azide-bridged dinuclear metal(II) compounds with zwitterionic dicarboxylate ligand

Three coordination polymers of different transition metal ions with azide and the zwitterionic dicarboxylate ligand 1-carboxymethylpyridinio-3-benzoate (L) were synthesized, and structurally and magnetically characterized. They are formulated as [M(L)(N3)·2H2O] (M=Co, 1; Mn, 2) and [Cu(L)(N3)·H2O] (3). In the isomorphous compounds 1 and 2, octahedrally coordinated metal ions are linked by the (μ-EO-N3)2 (EO=end-on) double bridges to give dinuclear motifs, which are linked by the zwitterionic dicarboxylate ligands to produce one-dimensional (1D) coordination chains. Compounds 3 and 1 (and 2) are pseudo-isomorphous, since they crystallize in the same space group, exhibit similar crystal structures, but have different numbers of coordinated water molecules. The chains are further stabilized and packed into 3D architectures through intra- and interchain hydrogen bonding and/or π–π stacking interactions. Magnetic studies on 1 and 3 reveal that the (μ-EO-N3)2 double bridges mediate ferromagnetic coupling between metal(II) ions.

Transformation of a Mother Crystal to a Daughter Crystal through Amorphous Phase: De-assembly of Coordination Helices upon Heating and Re-assembly through Aquation

The nonlinear optical active chiral complex 1 [{Co(2,5-pdc)(H2O)2}H2O]n (2,5-pdc = 2,5-pyridine dicarboxylate) has been synthesized via a solvothermal technique using the achiral 2,5-pdc ligand. Complex 1 (phase 1), a two-dimensional coordination polymer, undergoes crystalline to amorphous (phase 2) transformation upon deaquation, which under reaquation generates a new microcrystalline phase (phase 3). The crystal structure of phase 3 has been determined by powder X-ray diffraction analysis (PXRD), which reveals that the resultant microcrystalline phase 3 is an achiral complex consisting of one-dimensional coordination chains. Phase 3 undergoes reversible structural transformation via amorphous phase (phase 2) upon dehydration and subsequent rehydration. This amorphous phase shows selective adsorption of water from a water–DMF mixture and water–CCl4 mixture. Phase 1 to phase 3 structural transformation proceeds through selective bond breaking. The magnetic studies of the two crystalline and the amorphous ...

Metal-directed syntheses of coordination polymers via in situ ligand reactions from the same precursor, 2-(1H-benzeimidazol-2-yl)-acetonitrile

Abstract Three new coordination polymers, [Co(HBit) 2 ] n ( 1 ), [Mn(HBit) 2 ] n ( 2 ) (H 2 Bit = 2-((1H-tetrazol-5-yl)methyl)-1H-benzo[d]imidazole), and [CdCl(MBi)(HMBi)] n ( 3 ), (HMBi = 2-methyl-1H-benzo-[d]imidazole), have been hydrothermally synthesized via in situ ligand reaction. Compounds 1 and 2 are isomorphous and display interesting 3D chiral supramolecular frameworks constructed from one-dimensional 4 1 helical chains. Complex 3 possesses a one-dimensional coordination chain, which is further connected to a 2D layer by intermolecular hydrogen bonds. More interestingly, both H 2 Bit and HMBi ligands are in situ generated from the same precursor, 2-(1H-benzo[d]imidazol-2-yl)-acetonitrile, and the formation may depend on the kind of metal ion. Furthermore, the solid-state luminescence of complex 3 was investigated at room temperature.

Structural Diversity and Magnetic Properties of Five Cu(II) Complexes with Mixed Naphthalene-Based Dicarboxyl Tecton and Different N-Donor Co-Ligands

Five new Cu(ii) complexes have been prepared by employing 2,3-naphthalenedicarboxylic acid (H2ndc) and different N-donor co-ligands, namely, [Cu(ndc)(H2O)]n (1), [Cu(ndc)(H2O)2]n (2), {[Cu1.5(ndc)(OH)(H2O)2]·2.5H2O}n (3), {[Cu(ndc)(phen)(H2O)]·CH3OH}n (4) (phen = 1,10-phenanthroline), and {[Cu2(H0.5ndc)2(4bpy)3](ClO4)·2H2O}n (5) (4bpy = 4,4′-bipyridine). Complex 1 displays a two-dimensional (2D) (4,6)-connected (32.44)2(34.42.64.75)(34.43.64.74) coordination network. Complex 2 shows a 2D 3-connected hcb network which is further interlinked via the interlayered C–H⋯π interactions to result in a three-dimensional (3D) supramolecular network. Complex 3 is a one-dimensional (1D) coordination chain which is further interlinked by the C–H⋯π and π⋯π interactions to lead to the formation of the final 3D supramolecular network. When the N-donor co-ligands phen and 4,4′-bipyridine (4bpy) were introduced, the 1D complex 4 and the 4-connected sql layered complex 5 were constructed, respectively. The final supramolecular frameworks of 4 (2D) and 5 (3D) are extended by hydrogen-bonding and C–H⋯π interactions. The structural diversity of the complexes was triggered by different reaction conditions and N-donor co-ligands. Moreover, the magnetic properties of the complexes have also been investigated and discussed.