Syntheses and crystal structures of a series of new divalent metal phosphonates with imino-bis(methylphosphonic acid)

Hydrothermal reactions of divalent transition metal salts with imino-bis(methylphosphonic acid), NH(CH₂PO₃H₂)₂ (H₄L) afforded three new metal phosphonates, namely, Cu[NH(CH₂PO₃H)₂] 1, {Co[NH₂(CH₂PO₃H)(CH₂PO₃)](H₂O)₂}·H₂O 2 and Mn[NH₂(CH₂PO₃H)(CH₂PO₃)](H₂O) 3. When HO₂C(CH₂)₃N(CH₂PO₃H₂)₂ was used as the phosphonate ligand and 4,4′-bipy as the second metal linker, {Cu₄[NH(CH₂PO₃)₂]₂(4,4′-bipy)(H₂O)₄}·9H₂O 4 with a pillared layered architecture was obtained. The NH(CH₂PO₃)₂ anion resulted from the cleavage of the HO₂C(CH₂)₃-group during the reaction. Although compounds 1-3 have a same M/L ratio (1:1), they exhibit totally different structures.Compound 1 has a linear chain structure, in which each pair of square-pyramidal coordinated copper(II) ions are bridged by two phosphonate oxygen atoms to form a Cu₂O₂ dimeric unit, and such dimeric units are further interconnected via phosphonate groups to form a [010] chain. Compound 2 has a layered architecture built from CoO₆ octahedra bridged by phosphonate ligands. In compound 3, the interconnection of the manganese(II) ions by bridging imino-diphosphonate ligands leads to a 3D network. Compound 4 has a pillar-layered structure, the layers composed of Cu(II) ions bridged by aminodiphosphonate ligands are interconnected by 4,4′-bipy ligands to form channels along c-axis. Several factors that affect the structures of the metal phosphonates formed have also been discussed. Compounds 2 and 3 show predominant antiferromagnetic interactions between magnetic centers.     

Hydrothermal syntheses, characterizations and crystal structures of a new lead(II) carboxylate-phosphonate with a double layer structure and a new nickel(II) carboxylate-phosphonate containing a hydrogen-bonded 2D layer with intercalation of ethylenediamines

Hydrothermal reactions of N,N-bis(phosphonomethyl)aminoacetic acid (HO₂CCH₂N(CH₂PO₃H₂)₂) with metal(II) salts afforded two new metal carboxylate-phosphonates, namely, Pb₂[O₂CCH₂N(CH₂PO₃)(CH₂PO₃H)]·H₂O (1) and {NH₃CH₂CH₂NH₃}{Ni[O₂CCH₂N(CH₂PO₃H)₂](H₂O)₂}₂ (2). Among two unique lead(II) ions in the asymmetric unit of complex 1, one is five coordinated by five phosphonate oxygen atoms from 5 ligands, whereas the other one is five-coordinated by a tridentate chelating ligand (1 N and 2 phosphonate O atoms) and two phosphonate oxygen atoms from two other ligands. The carboxylate group of the ligand remains non-coordinated. The bridging of above two types of lead(II) ions through phosphonate groups resulted in a 〈002〉 double layer with the carboxylate group of the ligand as a pendant group. These double layers are further interlinked via hydrogen bonds between the carboxylate groups into a 3D network. The nickel(II) ion in complex 2 is octahedrally coordinated by a tetradentate chelating ligand (two phosphonate oxygen atoms, one nitrogen and one carboxylate oxygen atoms) and two aqua ligands. These {Ni[O₂CCH₂N(CH₂PO₃H)₂][H₂O]₂}⁻ anions are further interlinked via hydrogen bonds between non-coordinated phosphonate oxygen atoms to form a 〈800〉 hydrogen bonded 2D layer. The 2H-protonated ethylenediamine cations are intercalated between two layers, forming hydrogen bonds with the non-coordinated carboxylate oxygen atoms. Results of magnetic measurements for complex 2 indicate that there is weak Curie-Weiss behavior with θ=−4.4 K indicating predominant antiferromagnetic interaction between the Ni(II) ions. Indication for magnetic low-dimension magnetism could not be detected.     

New metal phosphonates containing coordination piperazine or pyridyl groups

Reactions of transition metal(II) salts with three aminophosphonic acids, 1-[(H₂O₃PCH₂)₂NCH₂CH₂−]-piperazine-4-CH₂PO₃H₂ (H₆L¹), 3-pyridyl-CH₂N(CH₂PO₃H₂)₂ (H₄L²) and 4-pyridyl-CH₂N(CH₂PO₃H₂)₂ (H₄L³) afforded three new metal phosphonates, namely, Cu(H₄L¹)·2H₂O (1), Co(H₃L²)₂·H₂O (2) and [Co(H₂L³)(H₂O)]·H₂O (3). The structure of compound 1 features a 1D chain in which the CuN₂O₃ and CPO₃ polyhedra are interconnected by bridging phosphonate ligands to form 1D chains. Compound 2 has a layered structure. The cobalt(II) ions in the octahedral coordination geometries and {CPO₃} tetrahedra are interconnected into an inorganic chain via -N(CH₂PO₃H)₂ moieties, and adjacent chains are further bridged by the coordination pyridyl groups of H₃L² into a 2D layer. The structure of compound 3 features a 2D double layered structure, in which the Co(II) ions are interconnected by bridging phosphonate groups into a 1D chain along b-axis. Neighboring chains are interconnected by coordination pyridyl groups into a double layer perpendicular to the c-axis.     

Synthesis, crystal structures, and luminescent properties of two types of lanthanide phosphonates

Hydrothermal reactions of different lanthanide(III) salts with an amino-diphosphonate ligand (H₄L=C₆H₅CH₂N(CH₂PO₃H₂)₂) led to two series of lanthanide phosphonates, namely, Ln(H₂L)(H₃L) (Ln=La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; Tb, 7). Compounds 1-5 feature a one-dimensional (1D) chain structure in which dimers of two edge-sharing LnO₈ polyhedra are interconnected by bridging phosphonate groups, such 1D arrays are further interlinked via strong hydrogen bonds between non-coordinated phosphonate oxygen atoms into a two-dimensional (2D) layer with the phenyl groups of the ligands orientated toward the interlayer space. Compounds 6 and 7 also show a different 1D array in which the LnO₆ octahedra are bridged by phosphonate groups via corner-sharing, such chains are also further interlinked by hydrogen bonds into a 2D supramolecular layer. Compounds 5 and 7 emit red and green light with a lifetime of 2.1 and 3.7 ms, respectively.     

New N-pyrazole, P-phosphinite hybrid ligands and corresponding Rh(I) complexes: X-ray crystal structures of complexes with [Rh, N, P-phosphinite, Cl, (CO)] core

Two new N-pyrazole, P-phosphinite hybrid ligands 3-(3,5-dimethyl-1H-pyrazol-1-yl)propyldiphenylphosphinite (L³) and 2-(3,5-diphenyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L⁴) are presented. The reactivity of these ligands and two other ligands reported in the literature (3,5-dimethyl-1H-pyrazol-1-yl)methyldiphenylphosphinite (L¹) and 2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyldiphenylphosphinite (L²) towards [RhCl(CO)₂]₂ (1) have been studied and complexes [RhCl(CO)L] (L = L² (2), L³ (3) and L⁴ (4)) have been obtained. For L¹ only decomposition products have been achieved. All complexes were fully characterised by analytical and spectroscopic methods and the resolution of the crystalline structure of complexes 2 and 3 by single-crystal X-ray diffraction are also presented. In these complexes, the ligands are coordinated via κ²(N,P) to Rh(I), forming metallocycles of seven (2 and 4) or eight (3) members and finish its coordination with a carbonyl monoxide and a trans-chlorine to phosphorus atom. In both complexes, weak intermolecular interactions are present. NMR studies of complexes 2-4 show the chain N-(CH₂)_x-O becomes rigid and the protons diastereotopic.     

X-ray crystal structures of novel platinum(II) and palladium(II) complexes of dialkyl phosphonated phosphines

Two diethyl phosphonated phosphine ligands of formula Ph₂P(CH₂)₃PO₃Et₂ (ligand L) and Ph₂P(4-C₆H₄PO₃Et₂) (ligand L′) were used to prepare different complexes of platinum(II) (1, cis-PtCl₂L₂; 2, trans-PtCl₂L₂·H₂O; 3A and 3B, cis- and trans-PtCl₂L′₂) and palladium(II) (4, [PdCl₂L]₂; 5, trans-PdCl₂L₂·H₂O; 6, trans-PdCl₂L′₂·CH₂Cl₂). The single-crystal X-ray structure analyses of complexes 1, 2, 4-6 indicate that complexation involved only the phosphine end, whereas the strong polarization of the PO bond was highlighted by the formation of hydrogen bonds with a water molecule in 2 and 5, and with a dichloromethane molecule in 6, with an exceptionally short CH?O hydrogen bond length (C?O separation 3.094(3) Å).     

Hydrothermal syntheses, crystal structures and properties of three coordination frameworks based on a new semirigid ligand and benzenedicarboxylate

Three novel polymers, {[Cd(m-bdc)(L)]·H₂O}_n (1), [Co(m-bdc)(L)_0.5(H₂O)]_n (2) and [Zn₅(L)₂(p-bdc)₅(H₂O)]_n (3) based on 1,1′-bis(pyridin-3-ylmethyl)-2,2′-biimidazole (L) ligand and benzenedicarboxylate isomers, have been prepared and structurally characterized. Compound 1 exhibits a 2D architecture with (4²·6)(4²·6⁷·8) topology, which is synthesized by L and 1,3-benzenedicarboxylate (m-bdc) ligands. Compound 2 is constructed from 1D chains that are linked by L ligands extending a 2D (4,4) grid. Compound 3 is a 3D framework with (4³)(4⁶·6¹⁸·8⁴) topology, which is composed of trinuclear clusters and five-coordinated metal centers joined through 1,4-benzenedicarboxylate (p-bdc) and L ligands. Moreover, the fluorescent properties of L ligand, compounds 1 and 3 are also determined.     

Syntheses, structures and properties of silver(I) complexes with flexible 1,3,5-tris(pyridylmethoxyl)benzene ligands

Five new silver(I) complexes [Ag₂(L₂)₂](BF₄)₂·CH₃CN·CH₃OH (1), [Ag(L₂)(CF₃SO₃)] (2), [Ag(L₃)]ClO₄·CH₃OH (3), [Ag₂(L₃)₂](CF₃SO₃)₂·CH₃CN·CH₃OH·H₂O (4) and [Ag(L₃)]PF₆·2CH₃CN (5) [L₂=1,3,5-tris(2-pyridylmethoxyl)benzene, L₃=1,3,5-tris(3-pyridylmethoxyl)benzene] were synthesized and characterized by single crystal X-ray diffraction analyses. In complexes 1-5, ligands L₂ and L₃ show different conformations and act as three-connectors, while the Ag(I) atom serves as three-connecting node to result in the formation of 2D and 3D frameworks. Complexes 1 and 2 with different counteranions have similar 2D network structure with the same (4,8²) topology. Complex 3 has a 3D structure with (10,3)-a topology while complexes 4 and 5 have the same 2D (6,3) topological structure. The results showed that the structure of organic ligands and counteranions play subtle but important role in determining the structure of the complexes. In addition, the photoluminescence and anion-exchange properties of the complexes were investigated in the solid state at room temperature.     

Synthesis,characterisation and crystal structures of three trinuclear cadmium(II) complexes with multidentate Schiff base ligands

Three novel Schiff base Cd(II) trimeric complexes, [Cd₃(L¹)₂(SCN)₂(CF₃COO)₂] (1), [Cd₃(L¹)₂(SCN)₂(HCONMe₂)] (2) and [Cd₃(L²)₂{N(CN)₂}₂] (3) have been prepared from two different symmetrical Schiff bases H₂L¹ and H₂L² (where H₂L¹ = N¹,N³-bis(salicylideneimino)diethylenetriamine, a potentially pentadentate Schiff base with a N₃O₂ donor set, and H₂L² = N¹,N³-bis(3-methoxysalicylideneimino)diethylenetriamine, a potentially heptadentate Schiff base with a N₃O₄ donor set). All the complexes have been synthesised under similar synthetic procedures and their crystal structures have been established by single crystal X-ray diffraction methods. The ligands and their metal complexes have been characterised by analytical and spectroscopic techniques. Among the three complexes, 1 and 3 are linear whereas 2 is a cyclic trimer. In 1 and 3, all the doubly phenoxo bridged Cd(II) metal centres are in a distorted octahedral environment. In complex 2, two of the three Cd(II) centres reside in a distorted octahedral environment and the remaining one enjoys a monocapped octahedral geometry. Altogether the variety in the bridging mode of two new salen-type ligands has been established through these complexes.     

Syntheses and structures of Ag(I) complexes containing 1,4-bis(4,5-dihydro-2-oxazolyl)benzene

The reactions of the polydentate ligand 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (L) with AgX (X = CH₃COO⁻, ClO₄⁻ and CF₃SO₃⁻) afforded the complexes [Ag₂(L)(CH₃COO)₂]_∞ (1), [Ag₂(L)₃(ClO₄)₂]_∞ (2), and [Ag(L)(CF₃SO₃)]_∞ (3), whereas the reaction of L with Ag₂SO₄ in MeOH/H₂O system afforded {[Ag₂(L)₃(H₂O)₃][SO₄] · 9H₂O}_∞ (4). The EA and IR have been recorded and all the complexes have been structurally characterized by X-ray crystallography, confirming that complexes 1–4 are two-dimensional coordination polymeric frameworks. The bidentate L ligands in complexes 3 and 4 adopt both the syn and anti conformation and those in 1 and 2 adopt the anti conformation only. The anions CH₃CO₂⁻ in complex 1 bridge the Ag(I) atoms in η¹, η², μ₃-coordination mode forming a 1-D zig-zag –[Ag(CH₃COO)]_n– chains, while the anions ClO₄⁻, CF₃SO₃⁻ and SO₄²⁻ in complexes 2–4 are not coordinated to the Ag(I) atoms, but all of them play an important roles in linking cationic 2-D frameworks into 3-D supramolecular structures.     

Syntheses, characterizations and crystal structures of two new lead(II) amino and carboxylate-sulfonates with a layered and a pillared layered structure

Reactions of lead(II) acetate with m-aminobenzenesulfonic acid (HL¹) and 5-sulfoisophthalic acid (H₃L²) afforded two new lead(II) sulfonates, Pb(L¹)₂1 and Pb₂(L²)(μ₃-OH)(H₂O) 2. In compound 1, the lead(II) ion is eight-coordinated by two sulfonate groups bidentately, two sulfonate groups unidentately and two amino groups from six ligands. Each L¹ ligand is tetradentate and bridges with three Pb(II) ions. The interconnection of the Pb(II) ions via bridging sulfonate ligands resulted in 〈100〉 and 〈200〉 layers. In compound 2, one Pb(II) ion is six-coordinated by a carboxylate group bidentately, by two carboxylate groups unidentately, by a sulfonate oxygen atom and by an OH anion, whereas the other one is six-coordinated by a bidentate chelating carboxylate group, two μ₃-OH anions, a sulfonate oxygen atom and an aqua ligand. The interconnection of irregular PbO₆ polyhedra via carboxylate-sulfonate ligands resulted in the formation of a pillared layered structure with the 2D layer being formed; the lead(II) ions, hydroxyl groups, carboxylate and sulfonate groups and the benzene ring as the pillar agent.     

Coordination and extraction studies of an unexplored bi-functional ligand,carbamoyl methyl pyrazole (CMPz) with uranium(VI), lanthanum(III) and cerium(III) nitrates

The bi-functional carbamoyl methyl pyrazole ligands, C₅H₇N₂CH₂CONBu₂ (L₁), C₅H₇N₂CH₂CONⁱBu₂ (L₂), C₃H₃N₂CH₂CONBu₂ (L₃), C₃H₃N₂CH₂CONⁱBu₂ (L₄) and C₅H₇N₂CH₂CON(C₈H₁₇)₂ (L₅) were synthesized and characterized by spectroscopic and elemental analysis methods. The selected coordination chemistry of L₁ to L₄ with [UO₂(NO₃)₂ · 6H₂O], [La(NO₃)₃ · 6H₂O] and [Ce(NO₃)₃ · 6H₂O] has been evaluated. Structures for the compounds [UO₂(NO₃)₂ C₅H₇N₂CH₂CONBu₂] (6) [UO₂(NO₃)₂ C₅H₇N₂CH₂CONⁱBu₂] (7) and [Ce(NO₃)₃{C₃H₃N₂CH₂CONⁱBu₂}₂] (11) have been determined by single crystal X-ray diffraction methods. Preliminary extraction studies of the ligand L₅ with U(VI) and Pu(IV) in tracer level showed an appreciable extraction for U(VI) and Pu(IV) up to 10 M HNO₃ but not for Am(III). Thermal studies of the compounds 6 and 7 in air revealed that the ligands can be destroyed completely on incineration.     

Two isomeric lead(II) carboxylate-phosphonates: syntheses, crystal structures and characterizations

Two isomeric layered lead(II) carboxylate-phosphonates of N-(phosphonomethyl)-N-methyl glycine ([MeN(CH₂CO₂H)(CH₂PO₃H₂)]=H₃L), namely, monoclinic Pb₃L₂·H₂O 1 and triclinic Pb₃L₂·H₂O 2, have been synthesized and structurally determined. Compound 1 synthesized by hydrothermal reaction at 150°C is monoclinic, space group C2/c with a=19.9872(6), b=11.9333(1) and c=15.8399(4) Å, β=110.432(3)°, V=3540.3(1) Å³, and Z=8. The structure of compound 1 features a 〈400〉 layer in which the lead(II) ions are bridged by both phosphonate and carboxylate groups. The lattice water molecules are located between the layers, forming hydrogen bonds with the non-coordinated carboxylate oxygen atoms. Compound 2 with a same empirical formula as compound 1 was synthesized by hydrothermal reaction at 170°C. It has a different layer structure from that of compound 1 due to the adoption of a different coordination mode for the ligand. It crystallizes in the triclinic system, space group with cell parameters of a=7.1370(6), b=11.522(1), c=11.950(1) Å, α=110.280(2), β=91.625(2), γ=95.614(2)°, V=915.3(1) Å³ and Z=2. The structure of compound 2 features a 〈020〉 metal carboxylate-phosphonate double layer built from 1D lead(II) carboxylate chains interconnected with 1D lead(II) phosphonate double chains. XRD powder patterns of compounds 1 and 2 indicate that each compound exists as a single phase.     

Synthesis, characterization and crystal structures of palladium(II) complexes containing neutral, one and twofold deprotonated 1,2,4-triazine species

The synthesis and characterization of three new palladium(II) complexes of 4-amino-6-ethyl-1,2,4-triazine-3-thion-5-one (AETTO, H₃L), [PdCl₂(H₃L)]·H₂O (1), [Pd₂Cl₂(H₂L)(PPh₃)₃]NO₃·2CH₃CN (2) and [Pd(HL)(PPh₃)₂] (3), are reported. All the synthesized compounds are air-stable and were characterized by elemental analyses, IR, NMR spectroscopy and mass spectrometry. In addition, the molecular structures of the complexes have been determined by X-ray single crystal diffraction. On the basis of the crystallographic data, the neutral ligand in 1 and the deprotonated ligands in 2 and 3 act as bidentate NS donors. The singly deprotonated ligand in 2 acts as a bridging agent between two metal centers in the binuclear Pd^II-complex.     

New organotin(IV) complexes of nicotinamide, isonicotinamide and some of their novel phosphoric triamide derivatives: Syntheses, spectroscopic study and crystal structures

Three novel phosphoramidate ligands with formula , R = Nicotinamide(nia), R′ = NHC(CH₃)₃(L₁), NH(C₆H₁₁) (L₂); R = isonicotinamide(iso), NH(C₆H₁₁) (L₃) and their new organotin(IV) complexes with formula SnCl₂(CH₃)₂(X)₂, X = L₁ (C₁), L₂ (C₂), L₃ (C₃) plus SnCl₂(CH₃)₂(L₄)₂(C₄), L₄ = isoP(O)[NHC(CH₃)₃]₂, were synthesized and characterized by ¹H, ¹³C, ³¹P,¹¹⁹Sn NMR, IR, UV-Vis spectroscopy and elemental analysis. Two novel complexes of nia and iso with formula SnCl₂(CH₃)₂(X)₂, X = nia (C₅), iso (C₆) were also prepared and all the complexes were spectroscopically studied in comparison to their related ligands and to each other. The crystal structure of complexes C₁, C₃, C₄, and C₅ were determined by X-ray crystallography. -Sn-Cl···H-N- major hydrogen bonds beside other electrostatic interactions produced a three dimensional polymeric cluster in the crystalline lattice of C₁, C₃, C₅ and a two dimensional polymeric chain in C₄. Results showed that coordination of the phosphoramidate ligand (L₄) to Sn in C₄ has been occurred from the nitrogen site of the pyridine ring similar to C_5,C₆ in which there is no PO donor site; however, in C₁ and C₃ the active donor site of corresponding ligands is PO. It seems that in these complexes there is a competition between PO and N_pyridine donor sites and the influential factor which determines the winner site is the type of substituents on phosphorus atom.     

Different crystal structures and luminescent properties of zinc and cadmium coordination polymers constructed from two flexible thioether ligands with different alkyl chains

Treatments of nitrogen-containing heterocyclic dithioether ligands, 1,2-bis(4-(pyridin-3-yl) pyrimidin-2-ylthio) ethane (L¹) and 1,3-bis (4-(pyridin-3-yl) pyrimidin-2-ylthio) propane (L²), with zinc or cadmium salts have resulted in the interesting frameworks with structural motifs from a mononuclear macrocycle or a dinuclear macrocycle to an one-dimensional structure. A small difference of the alkyl length between L¹ and L² led to conspicuous changes of the fluorescent properties of both ligands and their complexes. Mainly due to the size of metal atoms, structures of [ZnL²I₂] (1) and [CdL²I₂] (2) are varied from a mononuclear macrocycle to a 1D framework, while {[ZnL²(H₂O)₄](ClO₄)₂}₂ (3) and {[CdL²(H₂O)₄](ClO₄)₂}₂ (4) are dinuclear macrocycles in which perchlorate anions may play an important template role. As for complexes 5–8 ([ZnL¹I₂]_n (5), [CdL¹I₂]_n (6), {{[ZnL¹₂(H₂O)₄](ClO₄)₂}_0.5 · L¹_0.5 · CH₃OH} (7), {{[Cd_0.5L¹(H₂O)₂](ClO₄)}₂ · CH₃OH · L¹} (8)), the self-assemble processes were mainly directed by the organic ligand in the reactions of L¹ with metal salts. Complexes 1–4 exhibit blue fluorescence emissions, among which 1 and 2 may be suitable as candidates for blue fluorescent materials.     

Syntheses, characterizations and crystal structures of two lead(II) phosphonate-sulfonate hybrid materials

Hydrothermal reactions of lead(II) acetate with 5-sulfoisophthalic acid monosodium salt (NaH₂BTS) and N-(phosphonomethyl)-N-methylglycine, MeN(CH₂CO₂H)(CH₂PO₃H₂) (H₃L¹), or a new aminodiphosphonic acid, 3-Pyridyl-CH₂N(CH₂PO₃H₂)₂ (H₄L²), afforded two novel lead(II) phosphonate-sulfonate hybrids, namely, Pb₃[L¹][BTS][H₂O]·H₂O 1 and Pb₂[HL³][BTS]·H₂O 2 (H₂L³=3-Pyridyl-CH₂(Me)N(CH₂PO₃H₂)). H₂L³ was formed as a result of the decomposition of one phosphonate group in H₄L² during the reaction. Compound 1 crystallizes in the triclinic space group with a=9.9148(4) Å, b=10.4382(4) Å, c=10.6926(2) Å, α=96.495(2)°, β=110.599(2)°, γ=98.433(2)°, V=1008.31(6) Å³, and Z=2. The structure of compound 1 features a 3D network built from the interconnection of hexanuclear Pb₆(L¹)₂ units and 1D double chains of lead(II) carboxylate-sulfonate. Compound 2 crystallizes in the monoclinic space group P2₁/c with a=9.5403(7) Å, b=11.6170(8) Å, c=19.7351(15) Å, β=97.918(2)°, V=2166.4(3) Å³, and Z=4. Compound 2 has a 3D network structure built by the cross-linkage of 1D double chains of lead(II) phosphonates and 2D layers of lead(II) carboxylate-sulfonate.     

Nickel(II)-triphenylphosphine complexes of ONS and ONN chelating 2-hydroxyacetophenone thiosemicarbazones

The complexes [Ni(L¹)(PPh₃)] (1) and [Ni(L²)(PPh₃)]·HCl (2) were synthesized by the reaction of [Ni(PPh₃)Cl₂] and dibasic 2-hydroxyacetophenone-S-R-4-R¹-thiosemicarbazones (R/R¹: H/CH₃, L¹H₂; CH₃/H, L²H₂). The ligands and the complexes were characterized using elemental analysis, IR and ¹H NMR spectra. In both complexes, the thiosemicarbazone ligands coordinate to nickel(II) by giving two protons. Complex 1 is formed through the phenolate oxygen, azomethine nitrogen and sulfur atoms of L¹ and the P atom of a triphenylphosphine ligand. In complex 2, L² is functional through an ONN donor set, containing a thioamide nitrogen instead of a sulfur atom. X-ray analysis indicated distorted square planar structures for the complexes, and the nickel atoms lie slightly above the planes structured by the donor atoms. In the crystal forms of 1 and 2, some phenyl ring protons of the phosphine ligand give intramolecular hydrogen bonds with the donor atoms of the thiosemicarbazone moiety, namely the phenolate oxygen (in complexes 1 and 2) and N⁴ nitrogen (in complex 2).     

Syntheses, structures, thermal stabilities and luminescence of two new 3D zinc phosphonates

A 1,4-Butanediamine has been introduced as a structure-directing agent to synthesize two 3D zinc phosphonates under hydrothermal conditions, [(H₃N(CH₂)₄NH₃) Zn₂((O₃PCH₂)₂NCH₂PO₃H)(Cl)] (1) and [(H₃N(CH₂)₄NH₃)Zn₃(O₃P(CH₂)₂PO₃)₂] (2). Compounds 1∼2 were characterized by single-crystal X-ray diffraction along with powder XRD, EA, IR and TGA. Compound 1 is a 3D open-framework consisting of tetranuclear units and 16-membered-ring channel. In compound 2, each trinuclear unit contacts with surrounding six trinuclear units through O-P-O groups into a single hybrid layer, which is further pillared by O₃P(CH₂)₂PO₃ groups to form a 3D open-framework with 1D channel. In both compounds, 1,4-butanediamines are protonated and encapsulated into the channel through hydrogen bondings. Solids 1 and 2 are thermally stable up to 300 and 350 °C under air atmosphere, respectively. The luminescent properties of solids 1 and 2 are also studied in detail.