Synthesis,Structures, and Luminescent Properties of Three Alkaline Earth Metal‐based MOFs Assembled from 3‐(3‐Carboxyphenoxy) Phthalic Acid Ligand

Three two‐dimensional (2D) coordination complexes, namely [Ca₂(HL)₂(H₂O)₅]_n · 2nH₂O ( 1 ), [Sr(HL)(H₂O)₃]_n · nH₂O ( 2 ), and [Ba(HL)(H₂O)₃]_n · nH₂O ( 3 ) [H₃L = 3‐(3‐carboxy‐phenoxy) phthalic acid], were synthesized by using the ligand H₃L and alkaline earth metals. Structural analysis reveals that the structures of complexes 1 – 3 can be described as 2D networks with the point (Schälfli) symbol for net: {3¹² · 4¹⁴ · 5²} topology. Additionally, the thermal stability and solid‐state luminescent properties of compounds 1 – 3 were investigated at room temperature. The quantum yield (QY) of compound 2 is 10.75 %, which is much higher than the QY of the free H₃L ligand (QY_H3L < 1 %).     

Mixed‐Ligand Complexes of Copper(II) with α‐Hydroxycarboxylic Acids and 1,10‐Phenanthroline

Eight new two‐ligand complexes of copper(II) with 1,10‐phenanthroline and one of four different α‐hydroxy‐carboxylic acids (glycolic, lactic, mandelic and benzylic) were prepared. The complexes of general formula [Cu(HL)₂(phen)] · nH₂O (HL = monodeprotonated acid) ( 1 – 4 ) were characterized by elemental analysis, IR, electronic and EPR spectroscopy, magnetic measurements and thermo‐gravimetric analysis. The complexes of general formulae [Cu(HL)(phen)₂](HL) · H₂L · nSolv [ 1 a (HL = HGLYO^–, n = 1, Solv = MeCN) and 3 a (HL = HMANO^–, n = 0)] and [Cu(L)(phen)(OH₂)] · nH₂O [ 2 a (L = LACO^2–, n = 4) and 4 a (L = BENO^2–, n = 2)] were characterized by X‐ray diffractometry. In all these latter a pentacoordinated copper atom has a basically square pyramidal coordination polyhedron, the distortion of which towards a trigonal bipyramidal configuration has been evaluated in terms of the parameter τ. In 1 a and 3 a there are three forms of α‐hydroxycarboxylic acid: a monodentate monoanion, a monoanionic counterion, and a neutral molecule lying in the outer coordination sphere; in 2 a and 4 a the α‐hydroxycarboxylic acid is a bidentate dianion coordinating through carboxyl and hydroxyl oxygens.     

Syntheses,Structures, and Catalytic Properties of Three Copper(II) Coordination Polymers Based on 2,3,5,6‐Tetrafluoro‐1,4‐bis(triazole‐ylmethyl)benzene and Benzene Carboxylate Ligands

Three new mixed‐ligand coordination polymers of Cu^II, namely, [Cu(Fbtx)(L1)(H₂O)]_n ( 1 ), [Cu(Fbtx)_0.5(HL2)(H₂O)₂]_n ( 2 ), and {[Cu(Fbtx)_1.5(HL3)(H₂O)] · H₂O}_n ( 3 ) [Fbtx = 2,3,5,6‐tetrafluoro‐1,4‐bis(1,2,4‐triazole‐1‐ylmethyl)benenze, H₂L1 = terephthalic acid, H₃L2 = trimesic acid, NaH₂L3 = 5‐sulfoisophthalic acid monosodium salt], were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectra, and single‐crystal and powder X‐ray diffraction techniques. All the complexes have a two‐dimensional (2D) coordination layer structure. Of these, 1 displays a planar 4⁴‐ sql structure whereas both 2 and 3 are highly undulated 6³‐ hcb nets. Moreover, their thermal stability and catalytic behaviors in the aerobic oxidation of 4‐methoxybenzyl alcohol were also investigated as well. The results indicate that the benzene dicarboxylate ligands have an effective influence on the structures and catalytic properties of the resulting coordination polymers.     

REACTION BETWEEN [PdCl4]2- AND 5,5-DIMETHYL-2-THIOXOIMIDAZOLIDIN-4-ONE

Abstract

The reaction between 5,5-dimethyl-2-thioxoimidazolidin-4-one (H2L) and [PdCl₄]^2- has been studied in aqueous solution by potentiometric and spectrophotometric measurements. In the presence of the palladium salt, H₂L is completely monodeprotonated (HL^?); from spectrophotometric measurements, only two complexes having 1:1 and 1:2 Pd/ligand mol ratios have been identified. Potentiometric titrations, carried out on solutions with 1:1, 1:2, 1:3 and 1:4 metal/ligand mol ratios, show that these complexes must be formulated as Pd(HL)₂ and [Pd₂(HL)₂(μ-H₂O)(μ-OH)]⁺. Ionization constants of the pure ligand and formation constants of the complexes give pH distribution curves of the various species and the spectra of the two complexes. From MeOH, S-coordinated Pd(H₂L)_nCl₂ (n = 2–4) complexes have been separated in the solid state; from water, two complexes of formula Pd(H₂L)(HL)Cl and Pd(HL)Cl have been obtained with HL^? N,S-coordinated to the metal.     

Hydrothermal Syntheses and Characterizations of Three ZnII Coordination Polymers Tuned by pH Value and Base

Three new Zn^II coordination polymers, [Zn(bpe)(HL)₂(H₂O)]_n ( 1 ), {[Zn(bpe)(L)] · H₂O}_n ( 2 ), and [Zn₂Ca(bpe)(HL)₂(L)₂]_n ( 3 ) [H₂L = 5‐methoxyisophthalic acid and bpe = 1,2‐dis(4‐pyridyl) ethylene], were hydrothermally synthesized under different pH values and bases. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analyses and IR spectroscopy. Polymer 1 is formed at pH = 4 and has a 1D chain structure. These 1D chains are linked by hydrogen bonds to afford a 1D double chain and further to form a threefold interpenetrating network. At pH = 7, a 2D layer structure of 2 with sql topology is formed. By using calcium hydroxide as base for the synthesis of 3 , a 3D network with pcu topology is obtained. These structural differences among 1 – 3 indicate that pH value and the identity of the base play important role in defining the overall structures of metal‐organic frameworks. In addition, the fluorescent properties of 1 – 3 are discussed.     

Crystal Structure and Luminescent Properties of Diverse Cadmium(II) Coordination Polymers Based on A Semirigid Multicarboxylate Ligand

Four Cd^II metal coordination polymers, namely, [Cd(HL)(H₂O)₃]_n ( 1 ), [Cd(HL)(4,4′‐bpy)]_n · nH₂O ( 2 ), [Cd₃(L)₂(2,2′‐bpy)₃(H₂O)₃]_n · 2nH₂O ( 3 ), and [Cd₃(L)₂(phen)₂(H₂O)]_n · 2.5nH₂O ( 4 ) [H₃L = 3‐(3‐carboxyphenoxy) phthalic acid, 4,4′‐bpy = 4,4′‐bipyridine, 2,2′‐bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline], were synthesized and structurally characterized by X‐ray diffraction, elemental analysis, and IR spectroscopy. Single‐crystal X‐ray analyses reveal that complexes 1 – 3 have different one‐dimensional (1D) chain structures including zigzag chain, ladder chain, and helical chain, whereas complex 4 shows a 0D trinuclear motif. These low‐dimensional complexes are further extended to 3D supramolecular networks by intermolecular π–π interactions and hydrogen bonds. The ligand H₃L exhibits five coordination modes: μ₁‐η²‐chelating/μ₁‐η²‐chelating, μ₁‐η²‐chelating/μ₁‐η²‐chelating/μ₁‐η²‐chelating, μ₁‐η²‐chelating/μ₁‐η²‐chelating/μ₁‐η¹‐bridging, μ₁‐η²‐chelating/μ₂‐η²‐bridging/μ₂‐η¹:η¹‐bridging, and μ₂‐η²‐chelating:η¹‐bridging/μ₂‐η²‐chelating:η¹‐bridging/μ₁‐η¹‐bridging. Moreover, the photoluminescent properties of complexes 1 – 4 were studied in the solid‐state at room temperature.     

Six Coordination Polymers based on 4‐(1H‐Imidazol‐1‐yl)phthalic Acid: Structural Diversities,Magnetism and Luminescence Properties

The coordination polymers (CPs), [Ni(L)(H₂O)₄]_n ( 1 ), [Co(HL)₂(H₂O)₂]_n ( 2 ), {[Cu(L)(H₂O)₃] · H₂O}_n ( 3 ), [Mn(L)(H₂O)₂]_n ( 4 ), [Cd(L)(H₂O)₂]_n ( 5 ), and {[Zn₂(L)₂] · H₂O}_n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H₂L). Single‐crystal X‐ray diffraction indicated that the L^2–/HL^– ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.     

The reactivity of N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine towards copper(II) ions

The acid–base properties of the N-substituted amino acid HL [HL = N-2-(4-amino-1,6-dihydro-1-methyl-5-nitroso-6-oxopyrimidinyl)-L-histidine] and its reactivity towards the Cu^II ion have been measured by potentiometric and spectrophotometric techniques in aqueous solution at 25 °C and 0.1 M KCl ionic strength. These studies show that the neutral HL compound is present in aqueous solution (3–7 pH range) in the zwitterionic form with the diprotonated imidazolic residue. Studies of HL/Cu^II mixtures reveal the existence of complex species with the neutral ligand, HL and containing the deprotonated L ligand. By controlling the reaction conditions, four solid phases of stoichiometry: CuLCl(H₂O)₆, Cu₂LCl₃(H₂O)₈, CuL₂(H₂O)₆ and Cu(HL)₂Cl₂(H₂O)₆ were isolated and characterised by i.r. and electronic spectroscopy, thermal techniques and magnetic measurements.     

The d metal-sulfosalicylate complexes: Herring-bone, ladder and double-stranded chain frameworks with green luminescences

Assembly of 5-sulfosalicylic acid (H₃L) and d¹⁰ transition metal ions (Cd^II, Ag^I) with the neutral N-donor ligands produces five new complexes: [Cd₂(HL)₂(4,4′-bipy)₃]_n·2nH₂O (1), {[Cd₂(μ₂-HCO₂)₂(4,4′-bipy)₂(H₂O)₄][Cd(HL)₂(4,4′-bipy)(H₂O)₂]}_n (2), {[Cd(4,4′-bipy)(H₂O)₄][HL]·H₂O}_n (3), [Cd(HL)(dpp)₂(H₂O)]_n·4nH₂O (4), {[Ag(4,4′-bipy)][Hhbs]}_n (5) (4,4′-bipy=4,4′-bipyridine, dpp=1,3-di(pyridin-4-yl)propane, H₂hbs=4-hydroxybenzenesulfonic acid, the decarboxylation product of H₃L). Complex 1 adopts a 5-connected 3D bilayer topology. Complex 2 has the herring-bone and ladder chain, which are extended to a 3D network via hydrogen bonding. In 3–4 complexes, 3 is a 3D supermolecular structure formed by polymeric chains and 2D network of HL²⁻, while 4 gives the double-stranded chains. In 5, ladder arrays are stacked with the 2D networks of Hhbs⁻ anions in an –ABAB– sequence. Complexes 1–4 display green luminescences in solid state at room temperature, while emission spectra of 3 and 4 show obvious blue-shifts at low temperature.     

Strained Ruthenium Complexes Bearing Tridentate Guanidine-Derived Ligands

The dimer [{(η⁶-p-cymene)RuCl}₂(μ-Cl)₂] (cymene=MeC₆H₄ⁱPr) reacts with N,N′-bis(p-tolyl)-N′′-(2-pyridinylmethyl)guanidine ( H₂L1 ) and N,N′-bis(p-tolyl)-N′′-(2-diphenylphosphanoethyl)guanidine ( H₂L2 ), in the presence of NaSbF₆, giving rise to chlorido compounds of formula [(η⁶-p-cymene)RuCl( H₂L )][SbF₆] ( H₂L = H₂L1 ( 1 ), H₂L2 ( 2 )) in which the guanidine ligand adopts a κ² chelate coordination mode. The related ligand (S)-N,N′-bis(p-tolyl)-N′′-(1-isopropyl, 2-diphenylphosphano ethyl)guanidine ( H₂L3 ) affords mixtures of the corresponding chlorido compound [(η⁶-p-cymene)RuCl( H₂L3 )][SbF₆] ( 3 ) together with the complexes [(η⁶-p-cymene)RuCl₂( H₃L3 )][SbF₆] ( 4 ) and [(η⁶-p-cymene)Ru(κ³N,N′,P- HL3 )][SbF₆] ( 10 ) which contain phosphano-guanidinium and phosphano-guanidinate ions acting as monodentate and tridentate ligand, respectively. Compounds 1 , 2 and mixture of 3 / 4 / 10 react with AgSbF₆ rendering the cationic aqua-complexes [(η⁶-p-cymene)Ru( H₂L )(OH₂)][SbF₆]₂ ( H₂L = H₂L1 ( 5 ), H₂L2 ( 6 ), H₂L3 ( 7 )). These aqua-complexes exhibit a temperature-dependent fluxional process in solution. Experimental NMR studies and DFT theoretical calculations on complex 6 suggest that the process involves the exchange between two rotamers around one of the C−N guanidine bonds. Treatment of 5 – 7 with NaHCO₃ renders the complexes [(η⁶-p-cymene)Ru(κ³N,N′,N′′- HL1 )][SbF₆] ( 8 ) and [(η⁶-p-cymene)Ru(κ³N,N′,P- HL )][SbF₆] ( HL = HL2 ( 9 ), HL3 ( 10 )), respectively, in which the HL ligand adopts a fac κ³ coordination mode. The new complexes have been characterized by analytical and spectroscopic means, including the determination of the crystal structures of the compounds 1 , 2 , 5 , 9 and 10 , by X-ray diffractometric methods.     

A new octahedral cobalt(III) complex of (1,8)- bis (2-hydroxybenzamido)-3,6-diazaoctane incorporating phenolate-amide-amine coordination: synthesis, X-ray crystal structure, ligand substitution and redox activity with sulfur(IV) and l -ascorbic acid

The octahedral complex, [Co^III(HL)]·9H₂O (H₄L = (1,8)-bis(2-hydroxybenzamido)-3,6-diazaoctane) incorporating bis carboxamido-N-, bis sec-NH, phenolate, and phenol coordination has been synthesized and characterized by analytical, NMR (¹H, ¹³C), e.s.i.-Mass, UV–vis, i.r., and Raman spectroscopy. The formation of the complex has also been confirmed by its single crystal X-ray structure. The cyclic voltammetry of the sample in DMF ([TEAP] = 0.1 mol dm⁻³, TEAP = tetraethylammonium perchlorate) displayed irreversible redox processes, [Co^III(HL)] → [Co^IV(HL)]⁺ and [Co^III(HL)] → [Co^II(HL)]⁻ at 0.41 and −1.09 V (versus SCE), respectively. A slow and H⁺ mediated isomerisation was observed for the protonated complex, [Co^III(H₂L)]⁺ (pK = 3.5, 25 °C, I = 0.5 mol dm⁻³). H₂Asc was an efficient reductant for the complex and the reaction involved outer sphere mechanism; the propensity of different species for intra molecular reduction followed the sequence: [{[Co^III(HL)],(H₂Asc)}–H]⁻ <<< {[Co^III(H₂L)],(H₂Asc)}⁺ < {[Co^III(HL)],(H₂Asc)}. A low value (ca. 3.7 × 10⁻¹⁰ dm³ mol⁻¹ s⁻¹, 25 °C, I = 0.5 mol dm⁻³) for the self exchange rate constant of the couple [Co^III(HL)]/[Co^II(HL)]⁻ indicated that the ligand HL³⁻ with amido (N-) donor offers substantial stability to the Co^III state. HSO₃⁻ and [Co^III(HL)] formed an outer sphere complex {[Co^III(HL)],(HSO₃⁻)}, which was slowly transformed to an inner sphere S-bonded sulfito complex, [Co^III(H₂L)(HSO₃)] and the latter was inert to reduction by external sulfite but underwent intramolecular S^IV → Co^III electron transfer very slowly. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Synthesis,Structures, and Luminescent Properties of Three Coordination Polymers Constructed from Tricarboxylate and Bisbenzoimidazole Ligand

The hydrothermal reaction of the tricarboxylate ligand 5‐(carboxymethoxy)isophthalic acid (H₃L) with Zn^II, Cd^II, and Sn^II salts in the presence of the bisbenzoimidazole coligand 1, 3‐bis(benzimidazol‐2‐yl)‐2‐oxapropane (bbop) afforded the coordination polymers, [Zn(HL)(bbop)]_n ( 1 ), [Cd(HL)(bbop)]_n ( 2 ), and {[H₂(bbop)][Sn₂L₂]}_n ( 3 ). The complexes were characterized by elemental analyses, IR spectroscopy, single‐crystal X‐ray diffraction analyses, thermogravimetric analyses, and fluorescence properties. The structures of complexes 1 and 2 are constructed by 1D chains and show strong blue luminescence emission. The structure of complex 3 is a 2D anionic dilayer, and shows a vase‐like porous structure occupied by the bulky [H₂(bbop)]²⁺ cation, which is an uncommon structural feature in transition metal coordination polymers. The three complexes are further connected by hydrogen bonds to form 3D supramolecular architectures.     

Homo- and heterometallic complexes based on polytopic carboxylic acid: synthesis,characterization, and property

Two heterometallic [K₄M₄(HL)₄(H₂O)₁₂] (M=Co (1), Ni (2)) and two homometallic [M₂L(H₂O)₇]?·?2H₂O ((M=Co (3), Ni (4)) (H₄L?=?(2-(bis(carboxymethyl)amino) terephthalic acid) have been synthesized and characterized by elemental analysis, FT-IR spectrum, and single-crystal X-ray diffraction. The isomorphous 1 and 2 contain K⁺ and M²⁺, in which K⁺ were bridged with M²⁺ through μ-HL^3? and μ-H₂O, leading to 2-D layer structures. The isomorphous 3 and 4 show homometallic binuclear complexes with μ-HL^3? as the bridging ligand. Various H-bonds including different H-bond helical chains form, by which 3 and 4 assemble into 3-D supramolecular frameworks. TG analysis indicates that the decomposition temperatures are [K₄M₄(HL)₄(H₂O)₁₂] (1)?>?[M₂L(H₂O)₇]?·?2H₂O (3)?>?H₄L.     

Hydrothermal Synthesis, Crystal Structures of Three New Metal (Ⅱ) Complexes with 1-Adamantaneacetic Acid

Three new complexes constructed by 1‐adamantaneacetic acid (HL), [Zn₂L₄]_n ( 1 ), [MnL₂(4,4′‐bipy)(H₂O)₂]_n· 2n(HL) ( 2 ) and MnL₂(2,2'‐bipy)(H₂O)₂ ( 3 ), have been hydrothermally synthesized. X‐ray single crystal diffraction analyses reveal that both 1 and 2 are infinite 1D chains along b axis. 2 and 3 have an octahedral coordination and show the supramolecular structures which are formed on the basis of the connectivity of intermolecular hydrogen bonds. The deprotonated L^? ligands coordinate the M(II) atoms with many coordination modes in the title complexes.     

Benzotriazol-based structure assemble directed by transition metals

Two coordination polymers, namely [Mn(L)₂(H₂O)₂]_n (1) and [Cd₂(L)₄(H₂O)₄]_n (2) {HL?=?(benzotriazol-1-yloxy)-acetic acid}, have been synthesized and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy and elemental analysis. The results reveal that CP1 has 1D double chain structure, while CP2 features a 1D infinite chain structure. Additionally, there both exist O–H···O and O–H···N hydrogen bonds in CP1 and CP2, forming 3D supramolecular structures, respectively. UV-vis absorption spectra of CP1, and photoluminescence property of CP2, have been examined in solid state at room temperature. The result on optical energy gap of 2.80 eV indicates that CP1 is a potential semiconductive material.

     

Exploring the Interactions of Atomic Oxygen on Silver Clusters with Hydrogen

The interactions between Ag_nO^-(n=1-8) and H₂ (or D₂) were explored by combination of the mass spectroscopy experiments and density function theory (DFT) calculations. The experiments found that all oxygen atoms in Ag_nO^-(n=1-8) are inert in the interactions with H₂ or D₂ at the low temperature of 150 K, which is in contrast to their high reactivity with CO under the same condition. These observations are parallel with the preferential oxidation (PROX) of CO in excess hydrogen catalyzed by dispersed silver species in the condensed phase. Possible reaction paths between Ag_nO^-(n=1-8) and H₂ were explored using DFT calculations. The results indicated that adsorption of H₂ on any site of Ag_nO^-(n=1-8) is extremely weak, and oxidation of H₂ by any kind of oxygen in Ag_nO^-(n=1-8) has an apparent barrier strongly dependent on the adsorption style of the "O". These experiments and theoretical results about cluster reactions provided molecule-level insights into the activity of atomic oxygen on real silver catalysts.     

Calculation of the Gibbs Energy of the Reaction OH-·(H2O)n-1 + H2O = OH-·(H2O)n by the Monte-Carlo Method

The energy, the Gibbs energy of the reaction OH^-·(H₂O) _{n- 1} + H₂O = OH^-·(H₂O) _n are calculated by the Monte-Carlo method with a large canonical ensemble for n = 1, ..., 20. The ion-waternonpair interaction potential was obtained by numerical fitting of calculated Gibbs energy and entropy of (H₂O)_n clusters (n = 1, ..., 5) to experimental ones. A good fit to experiment both of the internal energy and the Gibbs energy can be obtained in terms of a model allowing for nonpair interaction. It is shown that constructing an ion-water interaction potential without allowance for the entropy factor can lead to considerable errors in the Gibbs energy of cluster formation and in the nucleation rate.     

基于2,3,5,6-四氟对苯二甲酸构筑的两个超分子网络结构的合成、结构和荧光性质(英文)

在水热条件下合成了基于四氟对苯二甲酸的2个二维微孔配位聚合物{[Cd2(IP)2(tfBDC)2(H2O)2]·H2O}n(1)和{[Mn2(IP)2(tfBDC)2(H2O)2]·H2O}n(2)(tfBDC=2,3,5,6-四氟对苯二甲酸,IP=1-H-咪唑[4,5-f][1,10]-菲咯啉)。二维层状结构是44-网状结构,三维超分子结构是由氢键连接相邻的二维层状结构而形成的。2个配位聚合物均用元素分析、热重分析(TGA)、粉末衍射(PXRD)、红外光谱(FT-IR)进行了表征,且对配合物1的荧光性质进行了详细的分析。     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Theoretical studies on the structure and protonation of Cu(II) complexes of a series of tripodal aliphatic tetraamines: Good correlations with the experimental data

DFT(B3LYP) studies on first protonation step of a series of Cu(II) complexes of some tripodal tetraamines with general formula N[(CH₂)_nNH₂][(CH₂)_mNH₂][(CH₂)_pNH₂] (n = m = p = 2, tren; n = 3, m = p = 2, pee; n = m = 3, p = 2, ppe; n = m = 3, tpt; n = 2, m = 3, p = 4, epb; and n = m = 3, p = 4; ppb) are reported. First, the gas‐phase proton macroaffinity of all latter complexes was calculated with considering following simple reaction: [Cu(L)]²⁺(g) + H⁺(g) → [Cu(HL)]³⁺(g). The results showed that there is a good correlation between the calculated proton macroaffinities of all complexes with their stability constants in solution. Then, we tried to determine the possible reliable structures for microspecies involved in protonation process of above complexes. The results showed that, similar to the solid state, the [Cu(L)(H₂O)]²⁺ and [Cu(HL)(H₂O)₂]³⁺ are most stable species for latter complexes and their protonated form, respectively, at gas phase. We found that there are acceptable correlations between the formation constants of above complexes with both the ? and ? of following reaction: [Cu(L)(H₂O)]²⁺(g) + H⁺(g) + H₂O(g) → [Cu(HL)(H₂O)₂]³⁺(g). The ? of the latter reaction can be defined as a theoretically solvent–proton macroaffinity of reactant complexes because they have gained one proton and one molecule of the solvent. The unknown formation constant of [Cu(epb)]²⁺ complex was also predicted from the observed correlations. In addition, the first proton affinity of all complexes was studied in solution using DPCM and CPCM methods. It was shown that there is an acceptable correlation between the solvent–proton affinities of [Cu(L)(H₂O)]²⁺ complexes with formation constants of [Cu(HL)(H₂O)₂]³⁺ complexes in solution. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010