Ligand-directed molecular architectures: self-assembly of two-dimensional rectangular metallacycles and three-dimensional trigonal or tetragonal prisms

Rh-coordinated histidyl bolaamphiphile assembly: a catalyst for the isomerization of cis-stilbene and cis-alkene

In this study, we present a colloidal assembly of histidyl bolaamphiphiles whose imidazoles coordinate with rhodium ions (HisC7[Rh]) to exhibit catalytic isomerization activity for cis-stilbene and cis-alkene molecules. The histidyl bolaamphiphiles self-assemble to form a soft scaffold that functions analogously to an apoenzyme. This scaffold exposes multiple histidyl imidazoles and carboxylates on its surface, to which rhodium ions bind, generating catalytically active sites. The Rh coordination with the biochemical functional groups was verified through comprehensive vibrational spectroscopy and calorimetry. The colloidal HisC7[Rh] demonstrated a significant catalytic effect on the isomerization of cis- to trans-stilbene under mild H2 conditions, resulting in 69% yield of trans-stilbene. In contrast, when Rh(cod)2BF4 was employed as a control catalyst, only the hydrogenated products of bibenzyl were obtained. These findings underscore the crucial role of histidyl motifs in exhibiting unique catalytic isomerization activity through the coordination with Rh. The catalytic activity of HisC7[Rh] is governed by several factors, such as rhodium content, solvent composition, temperature, and H2 pressure. Moreover, HisC7[Rh] displayed moderate isomerization activity towards not only stilbene but also unsaturated fatty acid isomers, highlighting its expansive potential as an isomerization catalyst.

Self-Assembly of Rhenium(I) Double-Stranded Helicate and Mesocate from Flexible Ditopic Benzimidazolyl/Naphthanoimidazolyl N-Donor and Rigid Bis-Chelating Hydroxyphenylbenzimidazolyl N∩OH-Donor Ligands: Synthesis, Characterization, and Photophysical and B-DNA Docking Studies

The self-assembly of three rheniumtricarbonyl core-based supramolecular coordination complexes (SCCs), fac-[Re(CO)3(μ-L)(μ-L')Re(CO)3] (1-3) was carried out using Re2(CO)10, rigid bis-chelating ligand (HO∩N-Ph-N∩OH (L1) (where HO∩N = 2-hydroxyphenylbenzimidazolyl), and flexible ditopic N-donor ligands (L2 = bis(3-((1H-benzoimidazol-1-yl)methyl)-2,4,6-trimethylphenyl)methane, L3 = bis(3-((1H-naphtho[2,3-d]imidazol-1-yl)methyl)-2,4,6-trimethylphenyl)methane, L4 = bis(4-(naphtho[2,3-d]imidazol-1-yl-methyl)phenyl)methane) via a one-pot solvothermal approach. In the solid state, the dinuclear SCCs adopt heteroleptic double-stranded helicate and meso-helicate architectures. The supramolecular structures of the complexes are retained in the solution based on the 1H NMR and electrospray ionization (ESI)-mass analysis. The spectral and photophysical properties of the complexes were studied both experimentally and using time-dependent density functional theory (TDDFT) calculations. All of the supramolecules exhibited emission in both solution and solid states. Theoretical studies were conducted to determine the chemical reactivity parameters, molecular electrostatic potential surface plots, natural population, and Hirshfeld analysis for complexes 1-3. Additionally, molecular docking studies were carried out for complexes 1-3 with B-DNA.

Selective Supramolecular Recognition of Nitroaromatics by a Fluorescent Metal-Organic Cage Based on a Pyridine-Decorated Dibenzodiaza-Crown Macrocyclic Co(II) Complex

Two isomorphous fluorescent (FL) lantern-shaped metal-organic cages 1 and 2 were prepared by coordination-directed self-assembly of Co(II) centers with a new aza-crown macrocyclic ligand bearing pyridine pendant arms (L_py). The cage structures were determined using single-crystal X-ray diffraction analysis, thermogravimetric, elemental microanalysis, FT-IR spectroscopy, and powder X-ray diffraction. The crystal structures of 1 and 2 show that anions (Cl^- in 1 and Br^- in 2) are encapsulated within the cage cavity. 1 and 2 bear two coordinated water molecules that are directed inside the cages, surrounded by the eight pyridine rings at the "bottom" and the "roof" of the cage. These hydrogen bond donors, π systems, and the cationic nature of the cages enable 1 and 2 to encapsulate the anions. FL experiments revealed that 1 could detect nitroaromatic compounds by exhibiting selective and sensitive fluorescence quenching toward p-nitroaniline (PNA), recommending a limit of detection of 4.24 ppm. Moreover, the addition of 50 μL of PNA and o-nitrophenol to the ethanolic suspension of 1 led to a significant large FL red shift, namely, 87 and 24 nm, respectively, which were significantly higher than the corresponding values observed in the presence of other nitroaromatic compounds. The titration of the ethanolic suspension of 1, with various concentrations of PNA (>12 μM) demonstrated a concentration-dependent emission red shift. Hence, the efficient FL quenching of 1 was capable of distinguishing the dinitrobenzene isomers. Meanwhile, the observed red shift (10 nm) and quenching of this emission band under the influence of a trace amount of o- and p-nitrophenol isomers also showed that 1 could discriminate between o- and p-nitrophenol. Replacement of the chlorido with a bromido ligand in 1 generated cage 2 which was a more electron-donating cage than 1. The FL experiments showed that 2 was partially more sensitive and less selective toward NACs than 1.

Reactions of noble-metal oxides in ionic liquids near room temperature

The reaction of Ag₂O, Au₂O₃, and HgO with CuCl, CuI, AgCl, AgI, AuCl, and AuI in ionic liquids ([EMIm]Cl, [BMIm]Cl) near room temperature (20-80 °C) is evaluated and results in the new compounds (C₈H₁₄N₂)CuCl, (C₈H₁₄N₂)AgI, (C₆H₁₀N₂)AuCl, [(C₈H₁₄N₂)₂Hg][CuCl₃], [(C₈H₁₄N₂)₂Hg][AgCl₃], and [EMIm][Ag₂I₂Cl]. Thereof, (C₈H₁₄N₂)CuCl, (C₈H₁₄N₂)AgI, (C₆H₁₀N₂)AuCl, [(C₈H₁₄N₂)₂Hg][CuCl₃], and [(C₈H₁₄N₂)₂Hg][AgCl₃] are NHC complexes (NHC: N-heterocyclic carbene) with M-C bonds (M: Cu, Ag, Au, Hg). Whereas (C₈H₁₄N₂)CuCl and (C₈H₁₄N₂)AgI crystallize as single molecules, (C₆H₁₀N₂)AuCl is dimerized via aurophilic interactions. [(C₈H₁₄N₂)₂Hg][CuCl₃] and [(C₈H₁₄N₂)₂Hg][AgCl₃] exhibit Hg atoms with two Hg-C bonds. Moreover, (C₈H₁₄N₂)AgI shows intense green fluorescence at room temperature with a quantum yield of 44%, whereas all other compounds do not show any emission at room temperature. Finally, [EMIm][Ag₂I₂Cl] is not an NHC compound but contains _∞ ¹[AgI_1/2I_2/4Cl_1/2]^- chains with infinite d¹⁰-d¹⁰ interaction of the silver atoms. The title compounds are characterized by single-crystal structure analysis, infrared spectroscopy, thermogravimetry, and fluorescence spectroscopy.

Visible-light excited luminescent trigonal prismatic metallocages from a template-directed assembly

Trigonal prismatic metallocages based on Cu₃Pz₃ and Cu₂I₂/Cu₂Br₂ with 24-component were assembled via a template-directed strategy. They showed rare visible-light responsive red emissions based on Cu₂I₂/Cu₂Br₂ coordination chromophores.

A chiral self-sorting photoresponsive coordination cage based on overcrowded alkenes

In recent years, increasing efforts have been devoted to designing new functional stimuli-responsive supramolecular assemblies. Here, we present three isomeric supramolecular coordination complexes consisting of a Pd2L4 stoichiometry. As shown by NMR, CD and X-ray studies, as well as DFT calculations, these complexes form cage-like structures by chiral self-sorting. Photochromic ligands derived from first generation molecular motors enable light-driven interconversion between the three isomers. Two of the isomers were able to form host-guest complexes opening up new prospects toward stimuli-controlled substrate binding and release.

fac-Re(CO)3-based neutral heteroleptic tetrahedrons

Four new flexible ditopic nitrogen donors possessing a xylene spacer and 2-phenylbenzimidazolyl or its derivatives as a coordinating unit and one rigid bis-chelating ligand consisting of two 2-hydroxyphenylbenzimidazolyl motifs and a central phenylene spacer were synthesized and further used with Re₂(CO)₁₀ for making a new family of neutral, heteroleptic tetrahedral-shaped supramolecular coordination complexes via a one-pot approach. The new ligands and the complexes were characterized using various analytical and spectroscopic methods. The molecular structures of the complexes were determined using single crystal X-ray diffraction analysis, which reveal that four rhenium cores are arranged in the vertices, and four ligands are at the edges of the tetrahedron.

[Ag-Ag]2+ Unit-Encapsulated Trimetallic Cages: One-Pot Syntheses and Modulation of Argentophilic Interactions by the Uncoordinated Substituents

Four [Ag-Ag]²⁺ unit-encapsulated trimetallic cages 1-4 were synthesized from one new tripodal ligand L and silver salts in different solvent systems by a one-pot method. The formation of coordination cages occurred simultaneously with the condensation of amino groups and ketone. The remarkable structural feature of cages 1-4 is their spontaneous incorporation of [Ag-Ag]²⁺ cationic units. Moreover, the argentophilic interactions are modulated by the uncoordinated amino substituents. The study herein shows that modification and subtle changes of the cage structures could be realized by a one-pot synthetic method.

Sulfate Donor Based Dinuclear Heteroleptic Triple-Stranded Helicates from Sulfite and Ditopic Nitrogen Donor Ligands and Their Transformation to Dinuclear Homoleptic Double-Stranded Mesocates

Sulfate donor based supramolecular coordination complexes [{ fac-Re(CO)₃}(μ-SO₄)(L ⁿ)₂{ fac-Re(CO)₃}] (1-3) were obtained using ditopic N donors (L ⁿ; n = 1-3), NaHSO₃, and Re₂(CO)₁₀ in a one-pot, multicomponent, coordination-driven self-assembly approach, in which SO₃^2- becomes oxidized to SO₄^2- during the reaction and acts as a building framework. Complexes 1-3 were characterized using IR, ESI-TOF-MS, and ¹H NMR spectroscopy. The structures of complexes 1-3 were confirmed using single-crystal X-ray diffraction analysis. The transformation of the dinuclear heteroleptic triple-stranded helicate to the dinuclear homoleptic double-stranded mesocate [{Re(CO)₃Cl}₂(L ⁿ)₂] (L ⁿ = L¹, L², L³; 4a-6a) was achieved by the addition of BaCl₂. The direct treatment of Re(CO)₅X (X = Cl, Br) with L¹/L²/L³ yielded the dinuclear homoleptic double-stranded helicates [{Re(CO)₃X}₂ (L ⁿ)₂] (4b-6b and 7-9).

Marigold Flower-Like Assemblies of Phosphorescent Iridium-Silver Coordination Polymers

Racemic and enantiopure phosphorescent iridium(III)-silver(I) coordination polymers are reported. The polymers rac-, Λ-, and Δ-IrAg were formed, respectively, by the assembly of the chiral iridium metalloligands rac-, Λ-, and Δ-[Ir(mesppy)₂ (qpy)]PF₆ (rac-, Λ- and Δ-Ir) where mesppy is 2-phenyl-4-mesitylpyridinato and qpy is 4,4':2',2'':4'',4'''-quaterpyridine, and Ag⁺ ions through N_py -Ag linear coordination. The polymers have been characterized in MeNO₂ solution by ¹ H and ¹ H DOSY NMR and CD spectroscopies and in the solid-state by scanning electron microscopy (SEM). The crystal structures of the racemic polymer rac-IrAg has been obtained by X-ray diffraction. The polymers rac-, Λ-, and Δ-IrAg exhibited orange/red emission in solution, in films and as crystals, with intensities comparable to those of the corresponding iridium metalloligands rac-, Λ-, and Δ-Ir. The morphology of the enantiopure polymers in the solid-state resembles marigold flower-like nano-porous assemblies while the racemic polymer possesses an irregular morphology formation.

Ring-to-Cage Structural Conversion via Template Effect in a Gold(I) Metallosupramolecular System

A unique example of a ring-to-cage structural conversion in a multinuclear gold(I) coordination system with d-penicillamine (d-H2 pen) is reported. The reaction of [Au2 Cl2 (dppe)] (dppe=1,2-bis(diphenylphosphino)ethane) with d-H2 pen in a 1:1 ratio gave [Au4 (dppe)2 (d-pen)2 ] ([1]), in which two [Au2 (dppe)]2+ units are linked by two d-pen S atoms in a cyclic form so as to have two bidentate-N,O coordination arms. The subsequent reaction of [1] with Cu(OTf)2 afforded [Au4 Cu(dppe)2 (d-pen)2 ]2+ ([2]2+ ), in which a CuII ion is chelated by the two coordination arms in [1] to form an AuI4 CuII bicyclic metallocage. A similar reaction using Cu(NO3 )2 was accompanied by the ring expansion of [1] to [Au8 (dppe)4 (d-pen)4 ], leading to the production of [Au8 Cu2 (dppe)4 (d-pen)4 ]4+ ([3]4+ ). In [3]4+ , two CuII ions are each chelated by the two coordination arms to form an AuI8 CuII2 tricyclic metallocage, accommodating a nitrate ion. The use of Ni(NO3 )2 or Ni(OAc)2 instead of Cu(NO3 )2 commonly gave a tricyclic metallocage of [Au8 Ni2 (dppe)4 (d-pen)4 ]4+ ([4]4+ ), but a water molecule was accommodated inside the AuI8 NiII2 metallocage.

Self-Assembled PdII6 Molecular Spheroids and Their Proton Conduction Property

A series of molecular spheroids (SP1-SP4) was synthesized using pseudolinear bisimidazole and bisbenzimidazole donors in combination with Pd(NO₃)₂ acceptor via coordination-driven self-assembly. They were characterized by NMR and mass spectrometry, and the solid-state structures of SP1 and SP3 were confirmed by X-ray diffraction. Crystal packing revealed the presence of molecular channels with water molecules in the channels as proton source. All the systems showed proton conductivity across a wide range of temperature and relative humidity. Furthermore, the mode of proton conduction in these molecular spheroids was explored by performing a control experiment using 2,4-dinitrophenol molecule, which indicates that the proton conductivity in the present case increases with increasing surface area of these molecular spheroids.

NHC Pd(II) and Ag(I) Complexes: Synthesis, Structure, and Catalytic Activity in Three Types of C-C Coupling Reactions

Four bis-benzimidazolium salts, 1,4-bis[1'-(N-R-benzimidazoliumyl)methyl]-2,3,5,6-tetramethylbenzene 2X- (L 1 H 2 ·(PF 6 ) 2 : R = ethyl, X = PF6; L 2 H 2 ·Br 2 : R = picolyl, X = Br; L 3 H 2 ·Br 2 : R = benzyl, X = Br; and L 4 H 2 ·Br 2 : R = allyl, X = Br), and their three N-heterocyclic carbene (NHC) Pd(II) and Ag(I) complexes, L 1 Pd 2 Cl 4 (1), L 2 Ag 2 Br 2 (2), and L 4 (AgBr) 2 (3), as well as one anionic complex L 3 H 2 ·(Ag 4 Br 8 ) 0.5 (4), have been synthesized and characterized. Complex 1 adopts a funnel-like type of structure, complex 2 adopts a cyclic structure, and complex 3 is an open structure. In the crystal packing of 1-4, one-dimensional polymeric chains and two-dimensional supramolecular layers are formed via intermolecular weak interactions, including hydrogen bonds, π-π interactions, and C-H···π contacts. The catalytic activities of NHC Pd(II) complex 1 in three types of C-C coupling reactions (Suzuki-Miyaura, Heck-Mizoroki, and Sonogashira reactions) were studied. The results show that this catalytic system is efficient for these C-C coupling reactions.

Reaction Chemistry of Silver(I) Trifluoromethanesulfonate Complexes of Nitrogen-Confused C-Scorpionates

Two new C-scorpionate ligands with a bis(3,5-dimethylpyrazol-1-yl)methyl group bound to the 3 position of either an N-tosyl (^TsL*) or an N-H pyrazole (^HL*) ring have been prepared. The silver(I) complexes of these new ligands and the two previously reported analogous ligands with unsubstituted bis(pyrazol-1-yl)methyl groups (^TsL and ^HL) in both 1:1 and 2:1 ligand/metal ratios were investigated to explore the effects of ligand sterics on their physical and chemical properties. The structurally characterized derivatives of the type [Ag(L)₂](OTf) are four-coordinate, where the confused pyrazolyl is not bound to the metal. On the other hand, three 1:1 complexes [Ag(L)](OTf) had all pyrazolyls bound, while the μ-κ¹,κ¹-^TsL derivative had an unbound confused pyrazolyl. The molecularity of the latter four ranged from polymeric to dimeric to monomeric in the solid with increasing steric bulk of the ligand. The utility of these complexes in stoichiometric ligand-transfer reactions and in styrene aziridination was demonstrated. Thus, tricarbonylmanganese(I) complexes were prepared as kinetically inert models for comparative solution diffusion NMR studies. Also, [Fe(^HL)₂](OTf)₂ was prepared for similar reasons and to compare the effects of anion on spin-crossover properties.

Cu3L2 metal–organic cages for A3-coupling reactions: reversible coordination interaction triggered homogeneous catalysis and heterogeneous recovery

A novel Cu₃L₂ metal–organic cage, which features coordination interaction triggered solubility, can be a highly active and reusable catalyst to homogeneously catalyse the one-pot aldehyde–alkyne–amine A³-coupling reaction.

Coordination supramolecules with oxazoline-containing ligands

This highlight focuses on the recent development of oxazoline-based discrete coordination complexes and coordination polymers.

A novel N-methylimidazolium-based poly(ionic liquid) to recover trace tetrachloroaurate from aqueous solution based on multiple supramolecular interactions

Two novel ionic liquids, [Bzmim]Cl and [Bzmim][AuCl₄], were synthesized to recover Au(iii) in aqueous solution.

Anion-coordination-directed self-assemblies

This review introduces the interplay of anion coordination and supramolecular self-assembly, presenting recent progress in anion-induced and anion-coordination-based self-assemblies.

Structures and single crystal to single crystal transformations of cadmium frameworks using a flexible tripodal ligand

Various cadmium coordination polymers were constructed using a flexible tris-imidazole ligand and they showed single crystal to single crystal transformations during anion exchange.

Anion-Directed Metallocages: A Study on the Tendency of Anion Templation

Self-assembly of Cu(NO₃ )₂ ⋅3 H₂ O and di(3-pyridylmethyl)amine (dpma) with addition of different acids (HNO₃ , HOAc, HCl, HClO₄ , HOTf, HPF₆ , HBF₄ , and H₂ SO₄ ) afforded a family of anion-templated tetragonal metallocages with a cationic prismatic structure of [(G^n- )⊂{Cu₂ (Hdpma)₄ }]^(8-n)+ (G^n- =NO₃^- , PF₆^- , SiF₆^2- ) with different ligating anions/solvents (NO₃^- , Cl^- , ClO₄^- , OTf^- , H₂ O) outside the cage. Systematic competitive experiments have rationalized the tendency of anion templation towards the formation of metallocages [(G^n- )⊂{Cu₂ (Hdpma)₄ }]^(8-n)+ as occurring in the order SiF₆^2- ≈PF₆^- >NO₃^- >SO₄^2- ≈ClO₄^- ≈BF₄^- . This sequence is mostly elucidated by shape control over size selectivity and electrostatic attraction between the cationic {Cu₂ (Hdpma)₄ }⁸⁺ host and the anionic guests. In addition, these results have also roughly ranked the anion coordination ability in the order Cl^- , ClO₄^- , OTf^- >NO₃^- >BF₄^- , CH₃ SO₄^- . Magnetic studies of metallocages 1 t and 2-4 suggest that the fitted magnetic interaction, being weakly magnetically coupled overall, is interpreted as a result of the combination of intracage ferromagnetic coupling integrals and intercage antiferromagnetic exchange; both contributions are very weak and comparable in strength.

Crystal structure of poly[aqua-bis(nitrato-κ2 O,O′)-(μ3-1,3-benzimidazol-3-ium-1,3-diacetato-κ4 O,O′:O′′:O′′′)dysprosium(III)], C11H11DyN4O11

C11H11DyN4O11, monoclinic, P21/c (no. 14), a = 12.073(4) Å, b = 14.704(4) Å, c = 8.763(3) Å, β = 94.233(5)°, V = 1551.3(8) Å3, Z = 4, R gt(F) = 0.0201, wR ref(F 2) = 0.0555, T = 293 K.

Crystal structure of tetraaqua-bis(1,3-benzimidazol-3-ium-1,3-diacetato-κO)copper(II) hemihydrate, C22H27CuN4O12.50

C22H27CuN4O12.50, triclinic, P1̅ (no. 2), a = 7.3950(11) Å, b = 9.4574(15) Å, c = 9.6619(15) Å, α = 81.139(2)°, β = 75.457(3)°, γ = 77.974(3)°, V = 636.02(17) Å3, Z = 1, R gt(F) = 0.0371, wR ref(F 2) = 0.1020, T = 293 K.

Perfect symmetrical cyclic aromatic trimer motif in tripodal molecule

A family of substituted benzimidazolyl-based tripodal molecules with alkyl substituted spacers was synthesized, showing perfect symmetric cyclic aromatic trimer motifs which remained intact in the solid as well as solution state.

Rhenium(I)-Based Monocyclic and Bicyclic Phosphine Oxide-Coordinated Supramolecular Complexes

Neutral, flexible ditopic phosphine (P-P) or phosphine oxide (O=P-P=O) donors, rigid anionic bis-chelating oxygen donors, and Re₂(CO)₁₀ were used to assemble ten phosphine oxide (P=O)-donor-based neutral monocyclic M₂LL'-, bicyclic M₄L₂L″-, and bicyclic M₄LL'₂-type supramolecular coordination complexes (SCCs). A soft ditopic phosphine donor was transformed into a hard ditopic phosphine oxide donor, during the formation of the cyclic complexes 1-3, 5-6, and 9-10. Complexes 4, 7, and 8 were obtained using a hard P=O donor ligand. These SCCs were characterized using elemental analysis, FTIR, NMR, and single-crystal X-ray diffraction analysis. The absorption properties of 1-8 were studied using absorption UV-vis spectroscopic methods, and the results were analyzed using theoretical calculations. The results revealed that the neutral P=O donor significantly influenced the photophysical properties by enhancing the absorption coefficient in the visible region.

Spheroid Metallacycles and Metallocavitands with Calixarene- and/or Cleft-Shaped Receptors on the Surface

Flexible hexatopic ligands, 1,2,3,4,5,6-hexakis(1H-naphtho[2,3-d]imidazol-1-ylmethyl)benzene (L(2)) and 1,2,3,4,5,6-hexakis(4,5-diphenylimidazol-1-ylmethyl)benzene (L(3)), containing six neutral naphthanoimidazolyl and 4,5-diphenylimidazolyl N donors were synthesized and used to assemble M6L6L'-type [M = Re(CO)3, L = anionic angular rigid NN donors, and L' = flexible hexatopic N donors] spheroid metallacycles. These molecules with a diameter of ∼17 Å were obtained from Re2(CO)10, H-L (imidazole, benzimidazole, and naphthanoimidazole), and L' [1,2,3,4,5,6-hexakis(benzimidazol-1-ylmethyl)benzene (L(1)), L(2), and L(3)] in a one-step process. Ligands L(2) and L(3) were characterized by elemental analysis, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and (1)H NMR spectroscopy. Metallacycles 1-5 were characterized by elemental analysis, ESI-TOF-MS, Fourier transform infrared spectroscopy, and single-crystal X-ray diffraction analysis. Molecules 1, 2, and 4 can be considered as metallocavitands and contain multiple solvent-accessible receptors, i.e., two metallocalix[3]arene units and six/four calix[4]arene-/cleft-shaped receptors, on the surface. Guests such as acetone molecules could be accommodated in the calix[4]arene/cleft-shaped receptor of the metallocavitands.

Four coordination polymers derived from a one-pot reaction and their controlled synthesis

Four different Co(ii) coordination polymers have been built by two flexible ligands 4,4'-dicarboxydiphenyl sulfone (4,4'-sdb) and 1,4-bis((1H-imidazol-1-yl)methyl) benzene (BMB) in a one-pot solvothermal reaction. The structures of and are new, and and have been reported. The crystal structures of were obtained, namely [Co(4,4'-sdb)(BMB)]n (), {[Co2(4,4'-sdb)2(BMB)]·2H2O}n (), and [Co3(4,4'-sdb)2(DMF)(H2O)3]n (), but was confirmed by PXRD. Both and are 2D layered structures with sql topology and their point symbol is {4(4)·6(2)}. These complexes have been characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry, elemental analysis, and powder X-ray diffraction measurements. By changing the synthesis conditions, four different Co(ii) coordination polymers can be obtained respectively.