Synthesis,crystal structures,and characterization of copper(II) carboxylate complexes incorporating 1,10-phenanthroline and bipyridine

A series of Cu(II) carboxylate complexes (carboxylate?=?2-fluorobenzoic acid (2-HFBA) or 4-fluorobenzoic acid (4-HFBA)) containing either one chelating 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, and thermal analyses. In [Cu(bipy)(H₂O)(2-FBA)₂] (1), [Cu(bipy)(H₂O)(4-FBA)₂] (3), and [Cu(phen)(H₂O)(2-FBA)₂] (4), Cu is five-coordinate in a square pyramidal geometry and four-coordinate in [Cu(phen)(2-FBA)₂] (2). The four complexes are extended into 1-D chains through hydrogen-bonding and π?···?π interactions in 1 and 4, only hydrogen-bonding in 2, and π?···?π interactions in 3. These contacts lead to aggregation and supramolecular self-assembly.     

Haloalkane adsorption into 1-D ensembles’ channels: Zn(II) coordination polymers

Abstract

Self-assembly of ZnX₂ (X^–?=?Cl^–, Br^–, and I^–) with 2,7-bis(isonicotinoyloxy)naphthalene (L) in a mixture of ethanol and dichloromethane yields 1-D zigzag chains of [ZnX₂L·2CH₂Cl₂]_n composition. The 1-D chains form an ensemble constituting hydrophobic suprachannels of 4.0–4.4?×?4.4–5.0 Ų with repeat units of ZnL for [ZnCl₂L] and [ZnBr₂L], and those of 5.2?×?12.0 Ų with repeat units of Zn₂L₂ for [ZnI₂L] in the appropriate arrays via C–H···π and π···π interactions. The most interesting feature is that alcohol molecules are not incorporated into the haloalkane-philic channels. That is, the channels discriminate haloalkanes from alcohols. Furthermore, the exchange of solvate molecules in a crystalline state indicates that the unique channels show different absorptions of haloalkanes such as CH₂Cl₂, CH₂Br₂, CH₂I₂, CHCl₃, 1,2-dichloroethane, and 1,2-dibromoethane.     

Lone pair···π interactions on the stabilization of intra and intermolecular arrangements of coordination compounds with 2-methyl imidazole and benzimidazole derivatives

Abstract

Spectroscopic and single crystal X-ray diffraction studies of coordination compounds of Co^II, Ni^II, Zn^II, and Pd^II with phenylsulfonyl imidazole and benzimidazole derivatives (2-mfsiz, 2-mfsbz) were performed. The relevance of non-covalent interactions on the stabilization of intra and intermolecular arrangements in the ligands and their coordination compounds was investigated. The imidazole 2-mfsiz ligand presents two enantiomeric conformers, where the ethylphenylsulfone moiety stabilizes intermolecular lone pair···π (S–O···π_(phe)) and H···π contacts, while its tetrahedral coordination compounds, [M(2-mfsiz)₂X₂] (M²⁺?=?Co, Ni, Zn; X?=?Cl, Br) showed intramolecular lone pair···π interactions (S–O···π_(iz)). On the other hand, compounds [Cu₂(2-mfsiz)₂(µ₂-AcO)₄] and trans-[Pd(2-mfsiz)₂Cl₂] do not present lone pair···π interactions due to the metal ion geometry (square base pyramidal or square planar), which leads to formation of π_(iz)···π_(phe) interactions. For the benzimidazole ligand 2-mfsbz, an intramolecular, H_(phe)···π_(bz) contact was observed, remaining in its tetrahedral and octahedral coordination compounds, [M(2-mfsbz)₂X₂] (M²⁺?=?Co, Zn; X?=?Cl, Br, NO₃). This interaction limits the free rotation of the ethylphenylsulfone moiety for stabilization of an intermolecular lone pair···π interaction (S–O···π_(iz)). The dimeric [Zn₂(2-mfsiz)₂(µ²-AcO)₄] compound has a π_(bz)···π_(phe) contact. Theoretical calculations confirmed the non-covalent interactions in the ligands and their coordination compounds.     

Syntheses and structures of Cd(II) and Co(II) compounds of 4-[(3-pyridyl)methylamino]benzoate anion

Three coordination polymers containing Cd(II) and Co(II), connected via 4-[(3-pyridyl)methylamino]benzoate (L^?), have been synthesized in hydrothermal conditions. In [Cd(L)Cl] _n (1), adjacent Cd(II) cations are linked by carboxylates to give a dinuclear cluster. Pairs of L^? bridge the dinuclear cluster to form double helical chains, and these chains are further linked by Cl^? to produce a 4-connected net with (4²?·?6³?·?8) topology. [CdL₂] _n (2) contains 1-D ladder-like chains. The packing structure displays a 3-D supramolecular structure, with π?···?π interactions stabilizing the framework. [CoL₂] _n (3) has a 2-D extended supramolecular structure via π?···?π interactions of 1-D coordination polymers of 3. The crystal structures of 1–3 have been determined by single-crystal X-ray diffraction. Luminescent properties for 1 and 2 are discussed.     

Two novel trinuclear cluster-based coordination polymers with 2,6-Di-imidazol-1-yl-pyridine: solvothermal syntheses,crystal structures,properties and Hirshfeld surface analysis

Two novel trinuclear cluster-based coordination polymers {[M₃(dip)(AcO)₆]·(X)}_n (1, M = Cu, X = CH₃OH; 2, M = Co, X = 2H₂O) (dip is 2,6-Di-imidazol-1-yl-pyridine), have been synthesised and structurally determined by single crystal X-ray diffraction, element analysis. Crystallographic unit of 1 consists of three Cu(II), six acetic ions, one dip ligand and one methanol molecule, which formed 1D chain through acetic bridges. The 1D chain further constructed 2-D network through dip ligand bridge which formed 3-D network through π···π interaction. Crystallographic unit of 2 consists of three Co(II), six acetic ions, one dip ligand and two water molecules. The trinuclear unit further formed a dimmer through dip ligand bridge which constructed 1-D through dip ligand bridge. The 1D chain further constructed 2-D network through π···π interaction. IR and UV–vis spectrum properties of 1 and 2 were studied. In addition, Hirshfeld surface analysis was also studied for 1.     

Syntheses,structures of Mn(II), Ni(II), Cu(II) and Zn(II) coordination complexes based on 3,4,5-trifluorobenzeneseleninic acid and N-donor ligands

Abstract

Five new coordination complexes [Mn^II (L₁)₂(4,4′-bpy)]_n (1), [Ni^II (L₁)₂(4,4′-bpy)]_n (2), [Zn^II (L₁)₂(4,4′-bpy)]_n (3), [Cu^II (L₁)₂(phen)₂]Cl₂ (4) and [Cu^II ₂(L₁)₂(2,2′-bpy)₂]Cl₂ (5) (HL₁?=?3,4,5-trifluorobenzeneseleninic acid, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine and phen = 1,10-phenanthroline), have been synthesized and characterized by single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), elemental analysis and IR spectroscopy. Complexes 1–3 display similar layers structures. In 1–3, the adjacent layers are further connected through π···π interactions to form three-dimensional supramolecular structures. Complexes 4 and 5 show a dimer containing an eight-membered ring. The dimer extends into three-dimensional supramolecular structures through π···π interactions, C–H···F and C–H···Cl interactions.     

Hydrothermal syntheses and characterization of four 2-D lanthanide coordination polymers with glutarate and 1,10-phenanthroline

Four 2-D coordination polymers Ln₂(phen)₂(C₅H₆O₄)₃ [Ln?=?Pr(1), Eu(2), Er(3), Yb(4), phen?=?1,10-phenanthroline] were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data reveal that these complexes are isostructural. In the asymmetric unit, the two Ln(III) ions are nine-coordinate and have similar coordination environments. The Ln(III) ions are built into 2-D layers by three different coordination modes of glutarate. The resulting 2-D layer forms 3-D supramolecular architecture by two types of π···π stacking interactions. All the complexes were characterized by IR spectra and thermogravimetric analysis, and the emission spectrum shows that Eu₂(phen)₂(C₅H₆O₄)₃ possesses strong luminescence.     

Syntheses and structures of three chiral complexes derived from nucleophilic addition of L-proline to di-2-pyridyl ketone

In the presence of nickel acetate, a chiral ligand, (S)-Hdphp ((S)-N-[di(2-pyridyl)-hydroxy-methyl]-proline), was synthesized in situ by nucleophilic addition of L-proline to di-2-pyridyl ketone. Based on this ligand, three chiral mononuclear complexes, {Ni[(S)-dphp](DMF)(H₂O)}(ClO₄) (1), {Ni[(S)-dphp](H₂O)₂}(ClO₄)(H₂O)_1.5 (2), and {Ni[(S)-dphp](SCN)(H₂O)} (3), have been obtained and characterized by single-crystal X-ray diffraction, elemental analyses, and infrared spectra. By virtue of charge-assisted O–H?···?O hydrogen-bonding interactions, all the complexes possess double chain structures. The double chains were connected into 2-D networks via π?···?π stacking and CH?···?π interactions in 1. For 2, O–H?···?O hydrogen-bonding interactions between free water molecules and other oxygens as well as π?···?π stacking and CH?···?π interactions extend the chains into a 3-D network. Complex 3 exhibits 3-D structure via O–H?···?S interactions.     

Structural characterization,DFT studied,luminescent properties of cationic/neutral three-coordinated copper (I) complexes and application in warm-white light-emitting diode

A series of cationic/neutral copper (I) complexes, [Cu₂(Hbmb)(PPh₃)₄] (BF₄)₂ ( 1a ), [Cu₂(Hbmb)(DPEPhos)₂](BF₄)₂ ( 2a ), [Cu₂(Hbmb)(Xantphos)₂](BF₄)₂ ( 3a ), [Cu₂(bmb)(PPh₃)₄] ( 1b ), [Cu₂(bmb)(DPEPhos)₂] ( 2b ), [Cu₂(bmb)(Xantphos)₂] ( 3b ) (Hbmb = 1,4-bis (1H-benzimidazol −2-yl)benzene, PPh₃ = triphenylphosphine, DPEPhos = bis[2-(diphenylphosphino)-phenyl]ether, Xantphos =4,5-bis (diphenylphosphino)-9,9′-dimethyl-xanthene), have been synthesized and characterized by IR, TGA, XRD and X-ray crystal structure analysis. The structural analysis reveals that each Cu⁺ in all complexes adopts an almost ideal trigonal planar geometry, with three coordinate NP₂, and the C-H···π and π···π interactions are observed in the packing structures. DFT studied indicate the ingredients of the HOMOs and LUMOs for neutral copper (I) complexes 1b , 2b and 3b are different from cationic copper (I) complexes 1a , 2a and 3a , in accordance with the distribution of Mülliken atomic charges. Meanwhile, neutral copper (I) complexes 1b , 2b and 3b have fascinating broad blue-green emission bands at room temperature, while cationic copper (I) complexes 1a , 2a and 3a exhibit the existence of multiple emission peaks. Furthermore, the maximum phosphorescent lifetime and quantum yield at room temperature, for all copper (I) complexes, are 1143 μs and 8.82%, respectively. In addition, in order to measure the practical application of these complexes, the selection of complex 1b is used to fabricate the LED, which emits a bright warm-white light.     

Binuclear paddle-wheel platinum(II) and platinum(III) complexes containing 4-methyl-4H-1,2,4-triazole-3-thiol ligand: Synthesis,X-ray studies,and spectroscopic characterization

The complex [Pt₂(μ-mtrzt)₄(mtrzt)₂] (1) was synthesized from the reaction of a mixture of 4-methyl-4H-1,2,4-triazole-3-thiol (Hmtrzt) and ethylenediamine (en) with K₂PtCl₄ in CH₃OH/H₂O (2:1) as solvent. The complex [Pt₂(μ-mtrzt)₄] (2) was synthesized by the same procedure as described for preparation of complex 1 but in the absence of ethylenediamine. Both complexes were characterized by elemental analysis, IR,¹H NMR,¹³C{¹H}NMR, UV-Vis, as well as luminescence spectroscopy and their structures were analyzed by single-crystal X-ray diffraction method. The X-ray structure determinations show that complexes of 1 and 2 have binuclear structures in a paddle-wheel fashion with Pt-Pt distances of 2.6628(7) and 2.7977(16)Å, respectively. In complex 1, each platinum(III) atom has a distorted octahedral coordination geometry with the sulfur atom and the second platinum subunit in axial positions and two nitrogen and two sulfur atoms in equatorial positions. Also, in complex 2, each platinum(II) atom has a distorted square-pyramidal coordination geometry with the second platinum subunit in axial position and two nitrogen and two sulfur atoms in equatorial positions. In addition, intermolecular C?H···N and C?H···S hydrogen bonds in 1 and 2 as well as intermolecular anagostic C?H···Pt and C?H···π interactions in 2 are effective in the stabilization of the crystal packing of these complexes.     

Zn(II) Complexes with Quinoline Supported Amidate Ligands: Synthesis,Fluorescence, and Catalytic Activity

Zn(II) complexes of N-(quinolin-8-yl)picolinamide (HL¹) (1) and N²,N⁶-di(quinolin-8-yl)pyridine-2,6-dicarboxamide (H₂L²) (2) have been synthesized by deprotonation of the ligands and characterized by IR, NMR, and Single crystal X-ray crystallography. The mononuclear [Zn(L¹)₂] (3) and homodinuclear [Zn₂(L²)₂] (4) complexes are characterized by distorted octahedral geometries stabilized by hydrogen bonding and weak π···π interaction. The complexes demonstrate intense fluorescence bands in comparison with their corresponding ligands with well-distinguished intensity. The complexes act as efficient catalysts in various transesterification reactions. Among those, the best results have been achieved with complex 3 in conversion of 4-nitrophenylacetate into methyl acetate within 3 h.

     

Synthesis and Structure of New Trimethylplatinum(IV) Iodide Complexes of 2,2′‐Bipyridine Ligands

The synthesis and structural characterization of four new trimethylplatinum(IV) iodide complexes of 2,2′‐bipyridine ligands {[PtMe₃(4,4′‐Clbipy)I] ( 1 ), [PtMe₃(4,4′‐Brbipy)I] ( 2 ), [PtMe₃(4,4′‐CNbipy)I] ( 3 ) and [PtMe₃(4,4′‐NO₂bipy)I] ( 4 )} are reported. The ¹H NMR spectra of the complexes reveal the presence of two chemically distinct methyl groups in the complexes. X‐ray crystal structures of complexes 1 – 4 show that the platinum metal center in each of the complexes form distorted octahedral structure being surrounded by methyl groups, bipyridine ligand, and iodine atom. Furthermore, the crystal packing study shows that self‐assembly of the complexes are governed by weak hydrogen bonding and other non‐covalent interactions such as π ··· π, halogen ··· π and C–H ··· π interactions. Complex 1 exhibits infinite one‐dimensional zigzag chain structure and other three complexes form infinite ladder type structures.     

Syntheses and structures of two NiIICoIINiII complexes of macrocyclic ligands

Two new linear trinuclear complexes, [Co(NiL¹)₂(SCN)₂] (1) and [Co(NiL²)₂(H₂O)₂](ClO₄)₂?·?2C₂H₅OH (2), have been prepared by using Co(ClO₄)₂?·?6H₂O and two macrocyclic complex ligands NiL¹ and NiL². L¹ and L² are the doubly deprotonated forms of dimethyl 5,6,7,8,15,16-hexahydro-6,7-dioxodibenzo[1,4,8,11]tetraazabicyclo[12.4.0^15,16]13,18-dicarboxylate and dimethyl 5,6,7,8,15,16-hexahydro-15-methyl-6,7-dioxodibenzo[1,4,8,11]tetraazacyclotetradecine-13,18-dicarboxylate, respectively. X-ray single crystal analyses reveal the coordination geometries around Ni(II) in both 1 and 2 are identical and slightly distorted square planar with N₄ donors; all Ni–N bonds in the two complexes are very short. The Co(II) ions are at the centers of the trinuclear complexes and have distorted octahedral coordination geometries of O₄N₂ donors in 1 and an O₆ in 2. π?···?π interactions involving aromatic and non-aromatic π-systems join the trinuclear entities to form 2-D layers in the crystals of 1 and 2.     

Supramolecular Assembly of Triangulo Pd(II) Diimine Complexes Containing Triply‐Bridging Sulfide Ligands

We report here a substituent effect of diimines on the solid‐state assembly of interesting triangulo Pd(II) complexes, [(Pd(d‐t‐bpy))₃(μJ₃‐S)₂][NO₃]₂ 1 ·[NO₃]₂ and [(Pd(bpy))₃(μ₃‐S)₂][ClO₄]₂ 2 ·[ClO₄]₂ (d‐t‐bpy = 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine, bpy = 2,2′‐bipyridine). 2 ·[ClO₄]₂ shows the intermolecular π···π interactions leading to the formation of one‐dimensional frameworks, whereas 1 ·[NO₃]₂ only shows the discrete structure in the solid state, featuring an interesting herring‐bone arrangement. The variation in structural motifs from 1 ·[NO₃]₂ to 2 ·[ClO₄]₂ is expected to be dominated by the substituent's steric hindrance for the diimine ligand. Thus, the crystal‐engineering approach has proved successful in the solid‐state packing due to a substituent's modification of the diimine ligand.     

Post-synthetic modification of divalent nickel acetate cubanes with carboxylates

Starting from nickel(II) cubane [Ni^II₄(HL)₄(OAc)₄] (2a), five different tetranuclear cubic complexes [Ni^II₄(HL)₄(O₂CR)₄] (3) were generated simply by applying a post-synthetic cubane modification strategy via a complete acetate-to-carboxylate co-ligand exchange. This was achieved by stirring the parent complex 2a with a large excess of the corresponding sodium carboxylate salt 4 for three days in THF. Single-crystal X-ray structure analyses of Ni^II cubanes 3a·2 Et₂O and 3b·0.5 CH₂Cl₂·0.5 Et₂O reveal unequivocally that both are isostructural in terms of the [Ni₄(μ₃-O₄]⁴⁺ core and crystallize in the triclinic space group P-1 with two molecules in the unit cell. In the solid state, the cubic centers of 3a,b differ only slightly in bond lengths and angles mainly due to the different substituents in the carboxylate co-ligand and packing in the unit cell. The orientation of 3a,b and the formation of supramolecular aggregates in the crystal packing were controlled by π–π interactions as well as intra- and intermolecular O–H?O hydrogen bonds. Variable-temperature magnetic susceptibility measurements reveal that 3a–c show a ferrimagnetic coupling scheme that leads to a diamagnetic ground state for all investigated complexes.     

Syntheses and properties of two chiral multidentate carboxylate copper coordination compounds

A chiral ligand, (R)-2-(4-(carboxymethoxy)phenoxy)propanoic acid, is employed as building block to construct two chiral coordination compounds, [Cu(L)(bipy)(H₂O)] (1) and [Cu₂(L)₂(phen)₄(H₂O)₁₃] (2), by the solvent-thermal method and the volatilization method, respectively. The compounds are characterized by single-crystal X-ray diffraction (XRD), IR spectra, XRD, TGA, and circular dichroism spectra. Compound 1 is comprised of right-handed helical chains and 2 shows a separated structure, both of which extend to 3-D supramolecular framework by hydrogen bonds and π?···?π interactions. CD indicates both compounds retain original stereo character with strong fluorescence at room temperature.     

Syntheses,structures, and fluorescent properties of three Zn(II) and Cu(II) complexes of different ligands derived from 3,6-bis(2-pyridyl)-1,2-dihydro-1,2,4,5-tetrazine

Three supramolecular complexes [Zn(HL₁ )₂(H₂O)₂(ZnCl₄)₂] (1), [Cu(L₂ )₂Cl₂] (2), and [Zn(L₃ )Cl₂] (3) have been synthesized and characterized by single crystal X-ray diffraction analysis (L₁ = 3,5-di(2-pyridyl)-4-amino-1,2,4-triazole, L₂ = 3,5-di(2-pyridyl)-1,2,4-triazole, and L₃ = 2-pyridinecarboxylic acid (pyridin-2-ylmethylene)-hydrazide). In 1, anion–π interactions between Cl^? and the π-systems of L₁ are observed and anion–π, hydrogen bonding and π–π stacking interactions link the two complex units of [Zn(HL₁ )₂(H₂O)₂]⁴⁺ and [ZnCl₄]^2? to form a 3-D supramolecular network. In 2, π–π stacking interactions between aromatic rings of 1,2,4-triazole and pyridine rings are observed; in 3, hydrogen bonding of Cl ··· H–N and π–π stacking interactions between parallel pyridine rings of L ₃ are observed. The mechanisms of rearrangement reactions of L to L₁ –L₃ are discussed. The fluorescent properties for solid 1 and 3 are also investigated.     

Comparative study of two new grid complexes: synthesis,X-ray structure characterization,thermogravimetric, and spectroscopic properties

The synthesis and characterization of two new grid complexes, [Ni₄(L)₄(DMF)₄]?·?2H₂O (1) and [Mn₄(L)₄(DMF)₄] (2) (where L is the anion of 3,5-dichlorosalicylaldehyde pyridine-2-formyl hydrazone), were investigated. X-ray crystal structure analysis reveals that the metal centers in both complexes exhibit slightly distorted square-bipyramidal coordination geometry. The dominating interaction of two adjacent grids for 1 and 2 is Cl?···?H hydrogen bonds. The halogen–hydrogen bond is a key factor to stabilize the crystal structure of chloro-substituted grid compounds. Thermogravimetric curves of 1 and 2 exhibit distinct weight loss stages at different temperatures and reflect the thermal stability of the complexes. Both UV-visible and fluorescence spectra of 1 and 2 indicate they have a stronger conjugated system and the same significant quenching ability compared with H₂L. The ESI-MS spectra of 1 and 2 prove that the tetranuclear grids decompose in methanol/water solution.     

Hydrothermal Synthesis,Crystal Structures and Effect of Non Bonding Interactions in Crystal Packing of Two Mixed‐Ligand Metal Complexes with Glycolato and 2,2′‐Dipiridylamine and with Benzilato and Imidazole

Two new mixed‐ligand complexes [Fe(HG)₂(dipyam)] ( 1 ) (HG = glycolato and dipyam = 2,2′‐dipyridylamine) and [Cu(HB)₂(im)₂]·2H₂O ( 2 ) (HB = benzilato and im = imidazole) have been hydrothermally synthesized and structurally characterised by X‐ray diffraction. In both cases the metallic centre is in an octahedral environment, strongly distorted in 2 (4+2 coordination). The α‐hydroxycarboxylato ligands (glycolato or benzilato) present different coordinative behaviour, bidentade chelate through the hydroxyl oxygen and one carboxy oxygen in 1 and through the two oxygen atoms of the carboxylate group in 2 . The complexes are extended into 2D frameworks through hydrogen bonding and π···π or C‐H···π interactions. The complexes were also characterized by elemental analysis, FT‐IR and UV‐vis spectroscopy and room temperature magnetic measurements.     

X-ray crystal structure,spectral and magnetic properties of end-to-end di-μ-thiocyanatobis(imidazole)M(II) polymeric complexes (M=Co,Mn): supramolecular network structure based on N–H ··· S hydrogen bonding and π ··· π stacking

Two isomorphous one-dimensional chain complexes Co(NCS)₂(Him)₂ (1) and Mn(NCS)₂(Him)₂ (2) (Him?=?imidazole) have been prepared and characterized structurally. Both 1 and 2 crystallize in the monoclinic system, space group P2₁/n, and the structures consist of one-dimensional polymeric chains in which metal ions are bridged by two thiocyanate groups bonding in end-to-end fashion. Both 1 and 2 exhibit two-dimensional sheet structures with N–H?···?S hydrogen bonds and three-dimensional supramolecular network structure with π?···?π stacking interactions. IR spectra indicate the presence of bridging thiocyanate groups in both 1 and 2, confirmed by their structures. The variable temperature magnetic susceptibility, measured in the 2–300?K range, indicates weak antiferromagnetic exchange interactions in complex 2.