MOFs as Versatile Catalysts: Synthesis Strategies and Applications in Value-Added Compound Production

Catalysts played a crucial role in advancing modern human civilization, from ancient times to the industrial revolution. Due to high cost and limited availability of traditional catalysts, there is a need to develop cost-effective, high-activity, and nonprecious metal-based electrocatalysts. Metal-organic frameworks (MOFs) have emerged as an ideal candidate for heterogeneous catalysis due to their physicochemical properties, hybrid inorganic/organic structures, uncoordinated metal sites, and accessible organic sections. MOFs are high nanoporous crystalline materials that can be used as catalysts to facilitate polymerization reactions. Their chemical and structural diversity make them effective for various reactions compared to traditional catalysts. MOFs have been applied in gas storage and separation, ion-exchange, drug delivery, luminescence, sensing, nanofilters, water purification, and catalysis. The review focuses on MOF-enabled heterogeneous catalysis for value-added compound production, including alcohol oxidation, olefin oligomerization, and polymerization reactions. MOFs offer tunable porosity, high spatial density, and single-crystal XRD control over catalyst properties. In this review, MOFs were focused on reactions of CO2 fixation, CO2 reduction, and photoelectrochemical water splitting. Overall, MOFs have great potential as versatile catalysts for diverse applications in the future.

Extracting of Trace Quantities of Copper Using Novel Modified Magnetite Nanoparticles for Atomic Absorption Spectrometry Analysis

Background:

Copper is one of several heavy metals. A low concentration of copper is vital for animals and plants, whereas it is highly toxic to aquatic plants and bacteria in a high concentration. Therefore, copper ions in water and food must be controlled, and as a result, the development of novel methods for the determination of copper in water samples is of interest.

Objective:

Different techniques have been proposed for copper ions extraction and determination. The magnetic solid -phase extraction method is considered superior to the other method for simplicity, its higher enrichment, and the need for lower quantities of solvents. The novel modified magnetite nanoparticles as the sorbent, along with the atomic absorption spectrometry analysis, can be a low‐cost, simple and rapid method for this propose.

Methods:

Traces of Cu(II) in environmental samples were preconcentrated using a novel magnetic adsorbent developed based on 2,2´-((1E,1´E)-hydrazine-1,2-diylidenebis(methanylylidene)) diphenol coated magnetite nanoparticles. The influence of ligand concentration, amount of adsorbent, pH, type of eluent, sample volume, and effects of interfering ions was optimized. The adsorbed species were eluted for analysis through atomic absorption spectrometry.

Results:

A linear calibration curve was recorded from 2 to 40 µg ml-1 (r2= 0.999) under optimal conditions, and the detection limit of the method was as low as 1.6 µg ml-1. Also, good recoveries were obtained for the real sample analysis.

Conclusion:

The developed procedure constituted a rapid extraction, a low-cost and efficient method, and was used for the analysis of copper ions in the tap, river, and lake water.

Ultrasonic-assisted synthesis and the structural characterization of novel the zig-zag Cd(II) metal-organic polymer and their nanostructures

A sonochemical method was used to synthesize nano-rods of a novel cadmium(II) metal-organic coordination polymer, [Cd(p-2yeinh)(NO₂)]_n (1) (p-2yeinh = pyridin-2-yl ethylidene-isonicotinohydrazide). The effect of the synthesis parameters such as time, concentrations and irradiation power has been studied and optimized. It was shown that the thickness of rods has changed from 27 nm to 45 nm. The compounds were characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, X-ray powder diffraction (XPRD), and single crystal X-ray analysis. The X-ray structure analysis revealed that the Cd(II) atom is coordinated by one oxygen and three nitrogen atoms from two p-2yeinh ligands and two oxygen atoms of single nitrite anion with a CuN₃O₃ donor set with distorted octahedral geometry. The crystal taking the form of a one-dimensional zig-zag polymer. The adjacent chains connected by π-π of adjacent aromatic rings of p-2yeinh and other weak interactions. Consequently, the weak interactions also allow the 1D zig-zag structure to form a 3D metal-organic coordination polymer. CdO nanoparticles were prepared by thermolysis of compound 1 at 180 °C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XPRD to be 23 nm. The morphology and size of the prepared CdO nanoparticles were further studied using SEM.

Ultrasonic-assisted synthesis of nano lead(II) coordination polymer as precursors for preparation of lead(II) oxide nano-structures: Thermal, optical properties and XRD studies

Nano structure of a lead (II) coordination polymer [Pb₂(C₂Cl₃O₂)₂(NO₃)₂(C_l2H₈N₂)₂]_n (1), has been synthesized by a sonochemical method in different concentrations. The nano particles were characterized by scanning electron microscopy (SEM) X-ray powder diffraction (XRD), FT-IR spectroscopy and elemental analyses. The thermal stability of nano structure is closely investigated via thermal gravimetric (TGA), and compared with crystalline structure. The compounds are then heated to 600 °C to produce PbO nano particles. The resulting PbO is characterized through XRD and SEM analyses. Concentration of initial reagents effects on size and morphology of nano-structured compound 1 have been studied and show that low concentrations of initial reagents decreased particles size and leaded to uniform nano particles morphology. The photoluminescence properties of the prepared compound, as crystalline and as nanoparticles, have been investigated. The result showed a good correlation between the size and emission wavelength.

Thermolysis synthesis of pure phase NiO from novel sonochemical synthesized Ni(II) nano metal-organic supramolecular architecture

Nano-structures of a new supramolecular coordination compound of divalent nickel with the pyrazol (pzH) containing the terminal azide anions, [Ni(pzH)₂(N₃)₂] (1), with discrete molecular architecture (DMA) in solid state was synthesized via sonochemical method. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction, IR, and elemental analysis. Compound 1 was structurally characterized by single crystal X-ray diffraction and the single-crystal X-ray data shows that the coordination number of Ni (II) ions is six, (NiN₆), with four N-donor atoms from neutral "pzH" ligands and two N-donors from two terminal azide anions. The supramolecular features in these complexes are guided and controlled by weak directional intermolecular interactions. The structure of the title complex was optimized by density functional theory calculations. Calculated structural parameters and IR spectra for the title complex are consistent with the crystal structure. The NiO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant.

Sonochemical synthesis and structural determination of novel the nano-card house Cu(II) metal-organic coordination system

A sonochemical method by using various time and concentrations of initial reagents and power of irradiation, was used to synthesize nano-card house of a new copper(II) metal-organic coordination system, {[Cu₂(p-2yeinh)₂Cl₂]·(H₂O)}_n (1), where p-2yeinh=pyridin-2-yl ethylidene-isonicotinohydrazide. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, X-ray powder diffraction (XPRD), and single crystal X-ray analysis. The X-ray structure revealed that the Cu(II) atom is coordinated by one oxygen and three nitrogen atoms from two p-2yeinh ligands and one chloride anion with a CuN₃OCl donor set with square pyramid geometry. This arrangement produces a large quadric nuclear square ring composed of four square pyramid Cu(II) moieties linked together by two p-2yeinh units (M4L4). The adjacent frameworks connected by strong hydrogen bonding interactions of methanol molecules that interact together and with the rings and π-π interactions of adjacent aromatic rings of p-2yeinh and other weak interactions. Consequently, the labile interactions also allow the discrete structure to form a 3D metal-organic coordination network. CuO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XPRD to be 38nm. The morphology and size of the prepared CuO nanoparticles were further studied using SEM.

Sonochemical synthesis of nano lead(II) metal-organic coordination polymer; New precursor for the preparation of nano-materials

Nano-sheets of a novel Pb(II)-based 3D metal-organic coordination polymer [Pb₂(nih)₂(NO₃)₄(CH₃OH)]_n (1) were synthesized by a branched-tube method and sonochemical reaction. The synthesis was done using various times, concentrations of initial reagents, and irradiation power. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray powder diffraction (XRD), and single-crystal X-ray analysis. The X-ray analysis of the structures revealed the composition and stereochemistry of the basic building block, which had with a formula of {Pb₂(nih)₂(NO₃)₄(CH₃OH)}. These blocks are connected by covalent bonds originating from the nih and nitrate ligands and form infinite 3D metal-organic polymeric chains. The effect of triethylamine on the speed of nucleation was also investigated. Lead oxide nanoparticles were obtained by thermolysis of 1 at 180°C using oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XRD to be 36nm. The morphology and size of the PbO nanoparticles were also studied using SEM.

Synthesis and characterization of nano-peanuts of lead(II) coordination polymer [Pb(qcnh)(NO3)2]n with ultrasonic assistance: A new precursor for the preparation of pure-phase nano-sized PbO

A sonochemical method was used to synthesize nano-peanuts of a new lead(II) coordination 1D polymer, [Pb(qcnh)(NO₃)₂]_n (1), where qcnh=2-quinolincarbaldehyde nicotinohydrazide. The compound was characterized by scanning electron microscopy (SEM), elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), and single crystal X-ray analysis. The X-ray structure revealed that the Pb(II) atom is coordinated by one oxygen and three nitrogen atoms from two qcnh ligands and five oxygen atoms from three nitrate ligands in an 8+1 fashion with a PbN₃O₆ donor set. One of the PdN distances in the vicinity of the central atom is a bit longer (Pb1N1=2.939(4) Å), which shows the effect of the 6s² lone electron pair localized within the valence shell of the lead(II) atom. PbO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant. The average diameter of the nanoparticles was estimated by XRD to be 28nm. The morphology and size of the prepared PbO nanoparticles were further studied using SEM.

Ultrasound-assisted fabrication of a novel nickel(II)-bis-pyrazolyl borate two-nuclear discrete nano-structured coordination compound

Ultrasound was used to synthesize nano-structures of [Ni(bpzB)₂]₂(1), a new two-nuclear discrete-coordination compound of divalent nickel with bis-pyrazolyl borate(bpzB). The nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction, infrared, and elemental analysis. The single-crystal X-ray data show that the coordination number of Ni(II) ions is four (Ni1N₄ and Ni2N₄) with square planar geometry. The supramolecular features in these complexes are guided and controlled by weak directional intermolecular interactions. The discrete molecules interact with each other through labile interactions, creating a 3D supramolecular framework.

Ultrasound-assisted fabrication of a new nano-rods 3D copper(II)-organic coordination supramolecular compound

High-energy ultrasound irradiation has been used for the synthesis of a new copper(II) coordination supramolecular compound, [Cu2(μ-O2CCH3)2(μ-OOCCH3)(phen)2](BF4) (1), ("phen" is 1,10-phenanthroline) with nano-rods morphology. The new nano-structure was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses. Compound 1 was structurally characterized by single crystal X-ray diffraction. The utilization of high intensity ultrasound has found as a facile, environmentally friendly, and versatile synthetic tool for the supramolecular coordination compounds.

Magnetic property, DFT calculation, and biological activity of bis[(μ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] complex

The dinuclear complex bis[(μ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] (1) was synthesized, and characterized by X-ray, FTIR and thermal analysis. The fitting of magnetic susceptibility and magnetization curve of (1) indicates the occurrence of weak antiferromagnetic exchange interaction between copper(II) ions. The electronic structure has been also determined by density functional theory (DFT) method. Complex (1) displayed potent anticancer activity against B16 (Melanoma), MDA-MB-32 (Breast Adenocarcinoma), A549 (Lung Adenocarcinoma), HT-29 (Colon Adenocarcinoma) and SF (Astrocytoma) cell lines with an average IC50 value of 0.726 μg/ml compared to 4.88 μg/ml for cisplatin. Complex (1) has a better therapeutic index and toxicological profile than cisplatin, and has demonstrated a potential chemotherapeutic property.

A novel polyvinyl chloride-membrane optical sensor for the determination of Cu(2+) ion based on synthesized (N'(1)E,N'(2)E)-N'(1),N'(2)-bis(pyridine-2-ylmethylene)oxalohydrazide: experimental design and optimization

A copper (Cu(2+)) ion-selective bulk optode was constructed by using (N'(1)E,N'(2)E)-N'(1),N'(2)-bis(pyridine-2-ylmethylene)oxalohydrazide as ionophore and NaTPB in DBP matrices. Central composite design under response surface methodology was applied for the optimization of variables including pH, amount of ligand, amount of additive and response time which significantly affect the response of proposed sensor. At optimum specified conditions, the high stability, reproducibility and relatively long lifetime of the optical sensor suggest its ability for accurate and precise monitoring of Cu(2+) ion content in various real samples over a concentration range of 1.6×10(-6) to 3.17×10(-5)molL(-1) with a limit of detection of 8.1×10(-7)molL(-1) during response time 6.9min. The proposed optical sensor was successfully applied for the determination of Cu(2+) ion in tap water and different samples.

Comparative studies on removal of Erythrosine using ZnS and AgOH nanoparticles loaded on activated carbon as adsorbents: Kinetic and isotherm studies of adsorption

Erythrosine adsorption (Er) onto ZnS and AgOH nanoparticle-loaded activated carbon (ZnS-NP-AC and AgOH-NP-AC) was studied and results were compared. Subsequent preparation were fully analyzed by different approach such as BET to obtain knowledge about surface area, pore volume, while FT-IR analysis give comprehensive information about functional group the dependency of removal percentage to adsorbent mass, initial Er concentration and contact time were investigated and optimum conditions for pH, adsorbent dosage, Er concentration and contact time was set as be 3.2, 0.016g, 20mg/L and 16min and 3.2, 0.015g, 19mg/L and 2min for ZnS-NP-AC and AgOH-NP-AC, respectively. The equilibrium data correspond to adsorption strongly follow Langmuir model by ZnS-NP-AC and Freundlich model for AgOH-NP-AC. High adsorption capacity for of 55.86-57.80mgg(-1) and 67.11-89.69mgg(-1) for ZnS-NP-AC and AgOH-NP-AC, respectively. The result of present study confirm the applicability of small amount of these adsorbent (<0.02g) for efficient removal of Er (>95%) in short reasonable time (20min).

Sonochemical syntheses of binuclear lead(II)-azido supramolecule with ligand 3,4,7,8-tetramethyl-1,10-phenanthroline as precursor for preparation of lead(II) oxide nanoparticles

The new neutral binuclear lead(II) azido coordination compound, [Pb ₂(tmph) ₂(μ-N₃)₂(CH₃COO) ₂] (1) [tmph = 3,4,7,8-tetramethyl-1,10-phenanthroline], has been synthesized by a sonochemical method. Single crystal X-ray structure shows that the overall structure of 1 is binuclear unit. Complex 1 has a bridging azido pathway, end-to-end bridging azides between a pair of lead(II) centers. This is further extended into a one-dimensional (1D) and three-dimensional (3D) supramolecular structure by Pb⋯C and π–π weak directional intermolecular interactions. The coordination number of lead(II) ions is seven, PbN₄O₃, with two N-donor atoms from tmph ligands and three O-donors from acetate anions and two N-donors from two azide anions. It has a "stereo-chemically active" electron lone pair, and the coordination sphere is hemidirected. The PbO nanoparticles were obtained by thermolysis of 1 at 180 °C with oleic acid as a surfactant. The morphology and size of the prepared PbO samples were further observed using scanning electron microscopy (SEM).

Sonochemical syntheses of two new flower-like nano-scale high coordinated lead(II) supramolecular coordination polymers

Two new neutral nano flower polymeric lead(II) coordination compounds, [Pb(tmph)(μ-SCN)₂]n (1) and [Pb(tmph)(μ-NO₃)₂]n (2), [tmph=3,4,7,8-tetramethyl-1,10-phenanthroline], have been synthesized by a sonochemical process and characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), FT-IR spectroscopy and elemental analyses. SEM image shows the nano flower morphology for the products. Single-crystal X-ray studies show that the overall structure of the both 1 and 2 are 1D double chain net-like coordination polymers. Compound 1 has a very rare bridging cyanato pathway; a tetra dentate bridging between four Pb(II) centers. 1D double chains of compounds 1 and 2 further extended into two-dimensional (2D) and three dimensional (3D) supramolecular structures by strong π-π directional intermolecular interactions, respectively.

Efficient adsorption of Europhtal onto activated carbon modified with ligands (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine (M) and (1E,2E)-1,2-bis(pyridin-3-ylmethylene)hydrazine (SCH-4); response surface methodology

Porous activated carbon was modified with (1E,2E)-1,2-bis(pyridin-4-ylmethylene)hydrazine (M) and (1E,2E)-1,2-bis(pyridin-3-ylmethylene)hydrazine (SCH-4).

Bis{4-bromo-2-[(naphthalen-1-ylimino)methyl]phenolato-κ2N,O}copper(II)

The title complex, [Cu(C₁₇H₁₁BrNO)₂], lies on a centre of inversion. The chelating Schiff base anions define a square-planar N₂O₂ donor set. The nearly perpendicular orientation of the naphthyl residues of the chelate ring [dihedral angle = 82.12 (12)°] precludes the Cu^II centre from additional coordination. In the refinement, the naphthyl rings were found to be disordered over two positions.; the major component has a site occupancy of 0.667 (4).

Dichlorido{1-[N-(5-chloro-2-oxidophenyl)carboximidoyl]naphthalen-2-olato-κ3O,N,O′}(methanol-κO)tin(IV)

In the title complex, [Sn(C₁₇H₁₀ClNO₂)Cl₂(CH₃OH)], the Sn^IV atom features a distorted octa­hedral geometry defined by the O,N,O′-donors of the dianion, two Cl atoms and the methanol O atom. The six-membered chelate ring has a half-chair conformation with the Sn atom lying 0.449 (4) Å out of the plane defined by the remaining atoms (r.m.s. deviation = 0.0238 Å). Supra­molecular helical chains along [100], mediated by O—H⋯O hydrogen bonds, feature in the crystal packing. Chains are linked by C—H⋯O, C—H⋯Cl and π–π [centroid–centroid distance = 3.598 (2) Å] inter­actions.

catena-Poly[[(1,10-phenanthroline-κN,N')lead(II)]-di-μ-nitrato-κO,O':O'';κO:O',O''-[(1,10-phenanthroline-κN,N')lead(II)]-bis-(μ-2,2,2-trichloro-acetato-κO:O')]

In the title Pb^II complex, [Pb₂(C₂Cl₃O₂)₂(NO₃)₂(C₁₂H₈N₂)₂]_n, the 1,10-phenanthroline ligand is chelating, the nitrate anion chelates one Pb^II ion and simultaneously bridges a neighbouring Pb^II ion via the third O atom, and the trichloro­acetate anion is bidentate, bridging two Pb^II ions. The coordination geometry is based on a penta­gonal–bipramidal geometry defined by an N₂O₅ donor set with no obvious stereochemical role for the lead-bound lone pair of electrons. The coordination polymer has a zigzag topology along [010] and comprises alternating eight-membered {PbONO}₂ and {PbOCO}₂ rings.

Di-μ-chlorido-bis-[(1,10-phenanthroline-κN,N')(trichloro-acetato-κO)copper(II)]

The title compound, [Cu₂(C₂Cl₃O₂)₂Cl₂(C₁₂H₈N₂)₂], features a centrosymmetric binuclear complex. The coordination geometry around the Cu^II atom is square-pyramidal, comprising two N atoms from a symmetrically chelating 1,10-phenanthroline ligand, one O atom from a trichloro­acetate ligand and two Cl⁻ anions. In addition, there is a weak intra­molecular Cu⋯O inter­action of 2.9403 (14) Å involving the carbonyl O atom of the trichloro­acetate ligand. The central Cu₂Cl₂ core takes the form of a rhombus, owing to the disparate Cu—Cl bond lengths. Mol­ecules are connected in the crystal structure by C—H⋯Cl and C—H⋯O inter­actions.

cis-Dioxido[N'-(2-oxidobenzyl-idene)pyridinium-4-carbohydrazidato-κO,N',O']vanadium(V)

The title Schiff base complex, [V(C(13)H(10)N(3)O(2))O(2)], features a square-pyramidal coordination geometry defined by the O,N',O'-donors of the tridentate Schiff base ligand and two oxide O atoms; one oxide O atom occupies the apical position. In the crystal, pyridinium-oxide N-H⋯O hydrogen bonds lead to zigzag supra-molecular chains with a flattened topology along [101]. The investigated crystal was twinned by nonmerohedry; the minor component refined to 18.5 (5)%.

{4-Bromo-2-[(5-chloro-2-oxidophen-yl)imino-methyl]-phenolato-κO,N,O'}(methanol-κO)(methano-lato-κO)-oxidovanadium(V)

The title Schiff base complex, [V(C₁₃H₇BrClNO₂)(CH₃O)O(CH₃OH)], features a vanadyl group, a tridentate Schiff base ligand, and coordinated methanol and methano­late ligands. The NO₅ donor set is based on a distorted octa­hedron. Helical supra­molecular chains along [010] are found in the crystal structure mediated by O—H⋯O hydrogen bonds formed between the coordinating methanol mol­ecule and the phenolate O atom of the chloro­benzene residue.

catena-Poly[[lead(II)-μ-(2-oxidobenz-aldehyde isonicotinoylhydrazonato)] methanol monosolvate]

The Pb atom in the polymeric title compound, {[Pb(C₁₃H₉N₃O₂)]·CH₃OH}_n, is five-coordinated within an N₂O₂ donor set and a lone pair of electrons, as the N-isonicotinamido­salicylaldiminate ligand coordinates the Pb^II atom via the O,N,O′-donors and simultaneously bridges a neighbouring Pb atom via the pyridine N atom; the coordination geometry is based on a trigonal bipyramid with the O atoms in axial positions. The resulting supra­molecular chain is a 3₁ helix along the c axis. These chains are linked via inter­molecular Pb⋯O,N inter­actions, as well as O—H⋯O hydrogen bonds.

catena-Poly[[lead(II)-μ-N'-[1-(pyridin-2-yl-κN)ethyl-idene]isonicotino-hydrazidato-κN',O:N] perchlorate]

The Pb(II) atom in the polymeric title compound, {[Pb(C(13)H(11)N(4)O)]ClO(4)}(n), is coordinated by the N'-[1-(pyridin-2-yl-κN)ethyl-idene]isonicotinohydrazidate ligand via its O,N,N'-donors and simultaneously bridged by a neighbouring ligand via the pyridin-2-yl N atom. The resultant supra-molecular chain is a zigzag along the a axis. The stereochemistry of the Pb(II) atom is defined by an N(3)OE donor set (E = lone pair of electrons), which results in a Ψ-trigonal-bipyramidal coordination with the O and pyridin-2-yl N atoms in axial positions. The dihedral angle between the pyridine rings of the ligand is 6.3 (3)°. The supra-molecular cationic chains are linked into a three-dimensional array via secondary Pb⋯O [3.133 (6) and 3.28 (7) Å] and Pb⋯N [3.028 (4) Å] inter-actions. Weak C-H⋯O inter-actions and aromatic π-π stacking [centroid-centroid separation = 3.693 (2) Å] also occur in the crystal.

catena-Poly[[[bis-(methanol-κO)lead(II)]-μ-N'-[1-(pyridin-2-yl-κN)ethyl-idene]isonicotinohydrazidato-κN',O:N] perchlorate]

The Pb(II) atom in the polymeric title compound, {[Pb(C(13)H(11)N(4)O)(CH(3)OH)(2)]ClO(4)}(n), is coordinated by an N'-[1-(pyridin-2-yl-κN)ethyl-idene]isonicotinohydrazidate ligand via O,N,N'-donors and simultaneously bridged by a neighbouring ligand via the isonicotinoyl N atom; two additional sites are occupied by methanol O atoms. The resultant supra-molecular chain is a zigzag along the c axis. The Pb(II) atom is seven-coordinated within an N(3)O(3) donor set and a lone pair of electrons, which defines a Ψ-pentagonal-bipyramidal coordination geometry with the pyridine N and lone pair in axial positions. The supra-molecular chains are linked into the two-dimensional array via inter-molecular Pb⋯N [3.020 (4) Å] inter-actions. Layers stack along the a axis, being connected by O-H⋯O hydrogen bonds formed between the coordinated methanol mol-ecules and perchlorate anions.