New inorganic/organic coordination polymers generated from bidentate Schiff-base ligands

Ultrasound-Assisted Synthesis and Crystal Structure of Novel 2D Cd (II) Metal–Organic Coordination Polymer with Nitrite End Stop Ligand as a Precursor for Preparation of CdO Nanoparticles

In the present research, a sonochemical approach was applied to prepare new cadmium(II) coordination 2D polymer, [Cd(L)(NO2)2]n (L = 1,2-bis(1-(pyridin-3-yl)ethylidene)hydrazine) and structurally characterized with various spectroscopic techniques including XRD, elemental analysis, SEM, and IR spectroscopy. The coordination number of cadmium (II) ions is seven (CdN2O5) by two nitrogen atoms from two organic Schiff base ligand and five oxygen of nitrite anions. The 2D sheet structures ended by nitrite anions and the nitrite anion displayed the end-stop role. The comprehensive system showed a three-dimensional structure with several weak interactions. The high-intensity ultrasound is regarded as an easy, environmentally-friendly, and flexible synthetic instrument for the compounds of coordination. CdO NPs was obtained by thermolysing 1 at 180 °C with oleic acid (as a surfactant). Further, the size and morphology of the produced CdO nanoparticles were investigated through SEM.

1D Copper(II)-Aroylhydrazone Coordination Polymers: Magnetic Properties and Microwave Assisted Oxidation of a Secondary Alcohol

The 1D Cu(II) coordination polymers [Cu₃(L¹)(NO₃)₄(H₂O)₂]_n (1) and [Cu₂(H₂L²)(NO₃)(H₂O)₂]_n(NO₃)_n (2) have been synthesized using the aroylhyrazone Schiff bases N'¹,N'²-bis(pyridin-2-ylmethylene)oxalohydrazide (H₂L¹) and N'¹,N'³-bis(2-hydroxybenzylidene)malonohydrazide (H₄L²), respectively. They have been characterized by elemental analysis, infrared (IR) spectroscopy, UV-Vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), single crystal X-ray diffraction and variable temperature magnetic susceptibility measurements (for 2). The ligand (L¹)²⁻ coordinates in the iminol form in 1, whereas the amide coordination is observed for (H₂L²)²⁻ in 2. Either the ligand bridge or the nitrate bridge in 2 mediates weak antiferromagnetic coupling. The catalytic performance of 1 and 2 has been investigated toward the solvent-free microwave-assisted oxidation of a secondary alcohol (1-phenylethanol used as model substrate). At 120°C and in the presence of the nitroxyl radical 2,2,6,6-tetramethylpiperydil-1-oxyl (TEMPO), the complete conversion of 1-phenylethanol into acetophenone occurs with TOFs up to 1,200 h⁻¹.

Four Mixed-Ligand Zn(II) Three-Dimensional Metal-Organic Frameworks: Synthesis, Structural Diversity, and Photoluminescent Property

Assemblies of four three-dimensional (3D) mixed-ligand coordination polymers (CPs) having formulas, {[Zn₂(bdc)₂(4-bpdh)]·C₂H₅OH·2H₂O}_n (1), [Zn(bdc)(4-bpdh)]_n (2), {[Zn₂(bdc)₂(4-bpdh)₂]·(4-bpdh)}_n (3), and {[Zn(bdc)(4-bpdh)]·C₂H₅OH}_n (4) (bdc²⁻ = dianion of 1,4-benzenedicarboxylic acid, 4-bpdh = 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene) have been synthesized and structurally characterized by single-crystal X-ray diffraction method. Structural determination reveals that the coordination numbers (geometry) of Zn(II) ions in 1, 2, 3, and 4 are five (distorted square-pyramidal (SP)), six (distorted octahedral (O_h)), five (trigonal-bipyramidal (TBP)), and four (tetrahedral (T_d)), respectively, and are bridged by 4-bpdh with bis-monodentate coordination mode and bdc²⁻ ligands with bis-bidentate in 1, chelating/bidentate in 2, bis-monodentate and bis-bidentate in 3, and bis-monodentate in 4, to generate two-fold interpenetrating 3D cube-like metal-organic framework (MOF) with pcu topology, non-interpenetrating 3D MOF, two-fold interpenetrating 3D rectangular-box-like MOF with pcu topology and five-fold interpenetrating diamondoid-like MOF with dia topology, respectively. These different intriguing architectures indicate that the coordination numbers and geometries of Zn(II) ions, coordination modes of bdc²⁻ ligand, and guest molecules play important roles in the construction of MOFs and the formation of the structural topologies and interpenetrations. Thermal stabilities, and photoluminescence study of 1–4 were also studied in detail. The complexes exhibit ligands based photoluminescence properties at room temperature.

A microporous MOF with a polar pore surface exhibiting excellent selective adsorption of CO2 from CO2–N2 and CO2–CH4 gas mixtures with high CO2 loading

A microporous MOF (IITKGP-5) with polar pore surface exhibits highly selective sorption of CO₂ from flue gas as well as landfill gas mixture with IAST selectivity for 435.5 and 151.6 at 273 K/100 kPa respectively.

A Cd(ii) based metal organic framework: a photosensitive current conductor

A novel cadmium(ii) based metal organic framework, [Cd(3-bpd)(SCN)2]n () where 3-bpd = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene has been synthesized and characterized by elemental analysis, various spectroscopic techniques, TGA and single crystal X-ray diffraction analysis. X-ray analysis shows the formation of an undulated polymeric two-dimensional network parallel to the (0 -1 1) plane. Current conduction properties of have been explored in the dark and in the presence of light. The study shows that current conduction of the complex increases with the increase of the incident light intensity. On progression of intensity of glancing radiation the photosensitivity of has been increased. The time dependent light response on charge carrier conduction reveals that complex may uncover new ground to explore in optoelectronic switching applications.

Effect of π–π stacking interactions on the emission properties of cadmium metal–organic frameworks based on 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene

Experimental and theoretical luminescence properties have been studied for multidimensional cadmium metal–organic frameworks based on the luminescent 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene linker.

Organic–inorganic hybrid catalysts containing new Schiff base for environment friendly cyclohexane oxidation

Organic and inorganic entities have been hybridized using 3-aminopropyltriethoxysilane (APTES) linker for the synthesis of three novel organic–inorganic hybrid catalysts [Cu(ii), Co(ii) and Ni(ii)].

Photoluminescent 3D lanthanide MOFs with a rare (10,3)-d net based on a new tripodal organic linker

Isomorphous Ln-MOFs with a rare (10,3)-d network were assembled from a dual functional ligand which sensitizes Ln-based luminescence, achieving high quantum yield for Tb-MOF.

A one-dimensional coordination polymer based on a di-Schiff base supported trinuclear CuII subunit

A novel one-dimensional Cu(II) coordination polymer, catena-poly[bis(μ(4)-3-{[2-(3-hydroxy-2-oxidobenzylidene)hydrazinylidene]methyl}benzene-1,2-diolato)dimethanoltricopper(II)], [Cu(3)(C(14)H(10)N(2)O(4))(2)(CH(3)OH)(2)](n), (I), was constructed with a di-Schiff base supported centrosymmetric trinuclear Cu(II) subunit. In the subunit, two peripheral symmetry-related Cu(II) cations have square-pyramidal CuNO(4) geometry and the central third Cu(II) cation lies on an inversion centre with octahedral CuN(2)O(4) geometry. In (I), each partially deprotonated di-Schiff base 3-{[2-(3-hydroxy-2-oxidobenzylidene)hydrazinylidene]methyl}benzene-1,2-diolate ligand (Hbcaz(3-)) acts as a heptadentate ligand to bind the Cu(II) centres into chains along the a axis. A centrosymmetric Cu(2)O(2) unit containing an asymmetrically bridging O atom, being axial at one Cu atom and equatorial at the other Cu atom, links the trinuclear Cu(II) subunit into a one-dimensional chain, which is reinforced by intramolecular phenol-methanol O-H...O and methanol-phenolate O-H...O hydrogen bonds. Interchain π-π stacking interactions between pyrocatechol units, with a distance of 3.5251 (18) Å, contribute to the stability of the crystal packing.

Two one-dimension copper(II) coordination polymers based on imine-based bidentate Schiff-base ligand: synthesis, crystal structure and luminescent properties

Two new one-dimension copper(II) coordination polymers [CuL(2)(NCS)(2)](n) (1) and [CuL(2)(NO(3))(2)](n) (2) (L=(C(5)H(4)N)C(CH(3))=N-N=(CH(3))C(C(5)H(4)N)) have been synthesized and characterized by IR, elemental analysis, TG technique and X-ray crystallography. Each Cu(II) atom has a distorted octahedral N(6) (1) or N(4)O(2) (2) environment with four pyridyl N atoms from four ligands and two N atoms from two NCS(-) anions for polymer 1 or two O atoms from two NO(3)(-) anions for polymer 2, respectively. A pair of bis-monodentate bridging ligands links two Cu(II) centers to form one dimension chain structure containing bimetallic 22-membered macrometallacyclic rings. 1D chain is held together with its neighboring ones via C-H⋯S hydrogen bonds for 1 and C-H⋯O hydrogen bonds, C-H⋯π interactions for 2 to form a 3D supramolecular structure, respectively. The luminescent properties of the polymers 1 and 2 were investigated in the solid state at room temperature.