Density functional theory of chemical reactivity indices in some ion—molecule reaction systems

Three isoelectronic reactions, proton transfer (PT ), hydrogen abstraction (HA ), and electron transfer (ET ), of NH⁺₃ with NH,₃ H₂O, and HF have been studied using ab initio molecular orbital calculations. For the reaction of NH⁺₃ + H₂O, the energy of the transition state (TS) is higher than that of the reactants. This is consistent with the experimental observation that the rate constant is less than the average dipole orientation (ADO) rate constant. It seems reasonable that the reaction rate for the reaction NH⁺₃ + H₂O would hardly depend on the v₂ mode of NH⁺₃ at least for low-lying excited states (E_int≤ 0.714 eV) of the v₂ mode, because the v₂ mode contributes mainly to the normal mode orthogonal to the reaction coordinate at the TS . This is consistent with experimental observation. A similar prediction can be made for the NH⁺₃ + HF reaction. The electron-transfer processes for the HA reactions have been examined in terms of the intrinsic reaction coordinate (IRC ). The order of reactivity with NH⁺₃ is NH₃ > H₂O > HF. It is found that the degree of the electron transfer and the reactivity are correlated with the absolute hardness (η) of NH₃, H₂O, and HF. This is in accord with the softness as the chemical reactivity index in the density functional theory. © 1996 John Wiley & Sons, Inc.     

Theoretical study of the structure and stability of cage-substituted icosahedral closo-boranes, alanes, and gallanes MiM′12 ? iH 122? (M, M′ = B, Al, and Ga; i = 0–12)

The equilibrium geometric parameters and energetic and spectroscopic characteristics of low-lying conformers for several series of model cage-substituted (mixed) borane, alane, and gallane closo-dianions M _i M′_{12 − i} H₁₂²⁻(M, M′ = B, Al, Ga), as well as of “bare” gallium-aluminum anions Ga _i Al_12−i ⁻ with i = 0–12, were calculated within the B3LYP approximation of the density functional theory using 6–31G* and 6–311+G** basis sets. Differences in structure and stability between alanoborane clusters of similar composition are revealed. In clusters where the M and M’ heteroatoms are close in size and electronegativity (in gallonoalanes and gallium-aluminum anions), successive substitutions of M′ for M are accompanied by small energy changes and occur quasi-stochastically in different positions of the cage. When the substituents are significantly different (in alanoboranes), mixed clusters are unstable against disproportionation into homonuclear “predecessors” M₁₂H₁₂²⁻ and M′₁₂H₁₂²⁻, and the most favorable M _i M′_{12 − i} H₁₂²⁻ structures among them are those in which M _i M′_{12 − i} the cages are subdivided into homonuclear “subclusters” M _i and M′t′_12−i with a maximal number of homonuclear bonds (M-M and M′-M′) and a minimal number of heteronuclear bonds (M-M′).     

(Imido)vanadium Complexes as Efficient Catalyst Precursors for Olefin Polymerization/Oligomerization

(Arylimido)vanadium(V) complexes containing anionic ancillary donor ligands of type, V(NAr)Cl₂(L) (Ar = 2,6-Me₂C₆H₃, L = aryloxo, ketimide phenoxyimine, etc.) exhibited high catalytic activities for ethylene polymerization in the presence of Al cocatalyst; V(NAr)Cl₂(O-2,6-Me₂C₆H₃) showed the exceptionally high activities in the presence of halogenated Al alkyls such as Et₂AlCl, EtAlCl₂, etc. (Arylimido)vanadium(V)-alkylidene complexes, V(CHSiMe₃)(NAr)(L′) (L′ = N=C ^t Bu₂, O-2,6- ⁱ Pr₂C₆H₃) exhibited the remarkable catalytic activities for ring-opening metathesis polymerization of norbornene. (Imido)vanadium(V) complexes containing the (2-anilidomethyl)pyridine ligand, V(NR)Cl₂[2-Ar′NCH₂(C₅H₄N)] (R = 1-adamantyl, cyclohexyl, phenyl, Ar′ = 2,6-Me₂C₆H₃, 2,6- ⁱ Pr₂C₆H₃), exhibit the remarkable activities for ethylene dimerization in the presence of MAO, affording 1-butene exclusively (selectivity 90.4 to >99%). The steric bulk of the imido ligand plays an important role in the selectivity, and the electronic nature directly affects the activity.     

Formation of phosphonates and pyrophosphates in the reactions of chlorophosphate esters with strong organic bases

The compounds S(6-t-Bu-4-Me-C₆H₂O)₂P(O)Cl (1), CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)Cl (2) and (2,2′-C₂₀H₁₂O₂)P(O)Cl (3) react with diazabicycloundecene (DBU) to give rise to, predominantly, the phosphonate compounds [S(6-t-Bu-4-Me-C₆H₆O)₂P(O)(DBU)]⁺[Cl]⁻ (4), [CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O) (DBU)]⁺[Cl]⁻ (5) and [(2,2′-C₂₀Hi₂O₂)P(0)(DBU)]⁺[Cl]^- (6). The first two compounds could be isolated in the pure state. In analogous reactions of 1 and 2 with diazabicyclononene (DBN) or N-methyl imidazole, only the pyrophosphates [S(6-t-Bu-4-Me-C₆H₂O)₂P(O)]₂O (7) and [CH₂(6-t-Bu-4-Me-C₆H₂O)₂P(O)]₂O (8) could be isolated, although the reaction mixture showed several other compounds in the phosphorus NMR. A possible pathway for the formation of phosphonate salts is proposed. The X-ray crystal structures of4,7 and8 are also discussed.     

Agitation requirement for synthesis of micron-sized monodisperse polymer particles in soap-free polymerization method

Single-stage polymerization recently proposed for producing micron-sized polymer particles in aqueous media by Gu, Inukai and Konno (2002) was carried out under the control of agitation with styrene monomer, an amphoteric initiator, 2,2′-azobis [N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate and a pH buffer NH₃/NH₄Cl at a monomer concentration of 1.1 kmol/m³ H₂O, an initiator concentration of 10 mol/m³ H₂O and a buffer concentration of [NH₃] = [NH₄Cl] = 10 mol/m³ H₂O. In the polymerizations, impeller speed was ranged from 300 to 500 rpm to satisfy complete dispersion of the monomer phase and not to introduce the gas phase from the free surface. Polymerization experiments under steady agitation indicated that impeller speed was an important factor for size distribution of polymer particles. An increase in impeller speed promoted particle coagulation during the polymerization to enlarge the average size of polymer particles but widen the size distribution. To produce polymer particles with narrow size distribution, stepwise reduction in impeller speed was examined in the polymerization experiments. It was demonstrated that this method was more effective than the steady agitation. The impeller speed reduction could produce highly monodisperse particles with an average size of 2 μm and a coefficient of variation of size distributions of 2.2% that was much smaller than typical monodispersity criterion of 10%.     

Alkylation of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with alkyl halides and dimethyl sulfate

Salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides, RCH(OH)CH₂N(O)=NO⁻ M⁺ (R=Me, Prⁱ, or Bu^t; and M=Li, Na, K, Ag, NH₄, or Me₄N), were prepared. Their alkylation with alkyl halides R′X (X=Cl, Br, or I) and dimethyl sulfate was studied. Generally, alkylation afforded mixtures ofN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides RCH(OH)CH₂N(O)=NOR′ andO-alkyl-N-(β-hydroxyalkyl)-N-nitrosohydroxylamines RCH(OH)CH₂N(NO)OR′. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1996–2001, October, 1998.     

Transition metal substituted polyoxometalates supported on amine-functionalized silica

A series of transition metal substituted polyoxometalates (POM) have been anchored to propylamine-functionalized mesoporous silica (silicaNH₂). These include V, Co and Mn Keggin-type anions such as [PMo₁₀V₂O₄₀]⁵⁻ and [PMo₁₁VO₄₀]⁴⁻, or [SiW₁₁Co^II(H₂O)O₃₉]⁶⁻ and [SiW₁₁Mn^III(H₂O)O₃₉]⁵⁻, and sandwich-type anions, [(PW₉O₃₄)₂ Co ₄ ^II (H₂O)₂]¹⁰⁻ and [(PW₉O₃₄)₂Mn ₄ ^II (H₂O)₂]¹⁰⁻. Experiments at different initial pH_i of aqueous suspension of silica were performed for the Co and Mn substituted Keggin anions. The novel silicaNH₂-POM materials having between 12–17% (w/w) of polyoxometalate were characterized by elemental analysis, solid-state ²⁹Si, ¹³C and ³¹P n.m.r., diffuse reflectance spectroscopy, FTIR spectroscopy, thermal analyses, and BET surface area measurements. The elemental analyses and spectroscopic results pointed to the integrity of POM structures after immobilization on the silica support while the latter one showed a slight decrease of BET surface area. Results of the visible diffuse reflectance spectroscopy for the Co-substituted Keggin anion revealed the coordination of cobalt centers in the cluster with the nitrogen atom of amine groups in modified silica at pH_i ≥ 5.5 or the electrostatic bonding between polyoxoanion and protonated C₃H₆NH ₃ ⁺ group at pH_i = 3.5. For the Co-substituted sandwich anion, external Co centres of the polyoxoanion have coordinated with the amine groups of modified silica under the experimental conditions used. ³¹P MAS n.m.r. showed a shifting of phosphorus atom resonances in H₅[PMo₁₀V₂O₄₀] and H₄[PMo₁₁VO₄₀] to a single resonance at ca. − 4.1 ppm (Δv _1/2 ~ 70 Hz) when these POM were immobilized on the functionalized silica under weak acidic conditions (pH 3), evidencing electrostatic interaction of POM clusters with the C₃H₆NH ₃ ⁺ groups.     

Crystal Structure and EPR Spectra of cis—Dioxo—molybdenum（V） Complex with o—Aminophenol

ＩｎｔｒｏｄｕｃｔｉｏｎＭｏｌｙｂｄｅｎｕｍｉｓｗｉｄｅｌｙｕｓｅｄｉｎｂｉｏｌｏｇｉｃａｌｓｙｓｔｅｍｓｄｕｅｔｏｔｈｅｔｗｏｂａｓｉｃｆｏｒｍｓ :ｎｉｔｒｏｇｅｎａｓｅｓａｎｄｏｘｏｔｒａｎｓｆｅｒａｓｅｓｏｒｏｘｏｍｏｌｙｂｄｏｅｎｚｙｍｅｓ .Ｔｈｅｌａｔｔｅｒａｓｔｈｅｍｏｎｏｎｕｃｌｅａｒａｃｔｉｖｅｓｉｔｅｓｏｆａｍｕｃｈｍｏｒｅｄｉｖｅｒｓｅｇｒｏｕｐｏｆｅｎｚｙｍｅｓｉｎｇｅｎｅｒａｌｆｕｎｃｔｉｏｎｃａｔａｌｙｔｉｃａｌｌｙｔｒａｎｓｆｅｒａｎｏｘｙｇｅｎａｔｏｍｅｉｔｈｅｒｔ…     

Cationic polymerization of isobutylene by complexes of alkylaluminum dichlorides with diisopropyl ether: An activating effect of water

The RAlCl₂ × OⁱPr₂‐co‐initiated (R = ⁱBu or Et) cationic polymerization of isobutylene in the presence of externally added water (0.016–0.1 mM) in nonpolar n‐hexane at 10 °C and high monomer concentration ([IB] = 5.8 M) has been investigated. It was shown that the sequence of H₂O introduction into the system had the crucial effect on the polymerization rate, saturated monomer conversion, and, to a lesser extent, the content of exo‐olefin end groups. Particularly, the highest polymerization rate (>70% of monomer conversion in 10 min) and acceptable exo‐olefin end groups content (～83%) were observed when ⁱBuAlCl₂ × 0.8OⁱPr₂ reacted with suspended in n‐hexane H₂O before the monomer addition. Better functionality can be obtained when H₂O is introduced into the system in the course of the polymerization (after 3–10 min since the initiation of reaction). Under these conditions, highly reactive polyisobutylenes (exo‐olefin content is 86–89%) with desired low molecular weight (M_n = 1000–2000 g mol^?1) in a high yield (75–90% of monomer conversion in 20 min) were readily synthesized. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2386–2393     

Chelating Phosphorus–An O,C, O-Coordinating Pincer-Type Ligand Coordinating PIII and PV Centres

The sequence of reactions of the phosphorus-containing aryllithium compound 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂Li (ArLi) with Ph₂PCl, KMnO₄, elemental sulfur and elemental selenium, respectively, gave the aryldiphenylphosphane chalcogenides 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂P(E)Ph₂ ( 1 , E=O; 2 , E=S; 3 , E=Se). Compound 1 partially hydrolysed giving [5-t-Bu-1-{(P(O)(O-i-Pr)₂}-3-{(P(O)(OH)₂}C₆H₂]P(O)Ph₂ ( 4 ). The reaction of ArLi with PhPCl₂ provided the benzoxaphosphaphosphole [1(P), 3(P)-P(O)(O-i-Pr)OPPh-6-t-Bu-4-P(O)(O-i-Pr)₂]C₆H₂P ( 5i ) as a mixture of the two diastereomers. The oxidation of 5i with elemental sulfur gave the benzoxaphosphaphosphole sulfide [1(P), 3(P)-P(O)(O-i-Pr)OP(S)Ph-6-t-Bu-4-P(O)(O-i-Pr)₂]C₆H₂ ( 5 ) as pair of enantiomers P1(R), P3(S)/P1(S), P3(R) of the diastereomer (RS/SR)- 5 ( 5b ). The aryldiphenylphosphane 5-t-Bu-1,3-[(P(O)(O-i-Pr)₂]₂C₆H₂PPh₂ ( 6 ) was obtained from the reaction of the corresponding aryldiphenylphosphane sulfide 2 with either sodium hydride, NaH, or disodium iron tetracarbonyl, Na₂Fe(CO)₄. The oxidation of the aryldiphenylphosphane 6 with elemental iodine and subsequent hydrolysis yielded the aryldiphenyldioxaphosphorane 9-t-Bu-2,6-(OH)-4,4-Ph₂-3,5-O₂-2,6-P₂-4λ⁵-P-[5.3.1.0]-undeca-1(10),7(11),8-triene ( 7 ). Both of its diastereomers, (RR/SS)- 7 ( 7a ) and (RS/SR)- 7 ( 7b ), were separated as their chloroform and i-propanol solvates, 7a ⋅2CHCl₃ and 7b ⋅i-PrOH, respectively. DFT calculations accompanied the experimental work.     

N-(n-Alkyl)-N′-diphenylphosphorylureas as a new type of extractants for preconcentration of actinides and lanthanides

N-(n-Alkyl)-N′-diphenylphosphorylureas Ph₂P(O)NHC(O)NHC _n H_2n+1 (n = 6–10) were synthesized by the reaction of diphenylphosphoryl isocyanate with primary n-alkylamines C _n H_2n+1NH₂. The products (especially N-diphenylphosphoryl-N′-n-octylurea) are efficient extractants capable of extracting actinides and lanthanides from nitric acid solutions with high distribution coefficients. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 374–379, February, 2008.     

Synthesis and characterization of bis(<Emphasis Type="Italic">O,O</Emphasis>′-diisopropylmonothiophosphato)nickel(II) adducts and molecular structures of bis(pyridine)bis(<Emphasis Type="Italic">O,O</Emphasis>′-diisopropylmonothiophosphato)nickel(II) complex

The present work demonstrates the synthesis and characterization of adducts with bis(O,O′-diisopropylmonothiophosphato)nickel(II) complex, Ni{S(O)P(OⁱPr)₂}₂(L) _n (n = 2, L = pyridine, 2-picoline, 3-picoline; n = 1, L = 2,2′-bipyridyl and 1,10-phenanthroline). The crystallographic investigation of Ni{S(O)P(OⁱPr)₂}₂(C₅H₅N)₂ reveals distorted octahedral geometry around the central nickel(II) atom. The monothiophosphate moieties show anisobidentate coordination to the central metal, while the pyridine ligands are in cis positions. These nickel(II) adducts were characterized by elemental analysis, a range of spectroscopic techniques, and magnetic susceptibility measurement.     

Nucleophilic addition of alcohols to the C-N multiple bonds of the nitrilium substituent in the anion [2-B10H9(N≡CMe)]−

The reactions of salts of the anion [2-B₁₀H₉(N≡CMe)]⁻ with aliphatic alcohols ROH (R = C _n H_2n+1 (n = 1–6) CH₂CH₂(OEt), Prⁱ, Buⁱ, Bu^t, i-C₅H₁₁) are studied. These reactions result in hydrolytically stable imidates [2-B₁₀H₉{NH=C(OR)Me}]⁻. Their structures were confirmed by the data from mass spectrometry, IR, ¹H, ¹¹B, and ¹³C NMR spectroscopy. The molecular geometry of [2(Z)-B₁₀H₉{NH=C(OBu)Me}]⁻, which formed in nucleophilic addition reaction of n-butyl alcohol to [2-B₁₀H₉(N≡CMe)]⁻, was established by X-ray diffraction analysis.     

Quenching of Li (2P) by H2: potential energy surfaces, conical intersection seam, and diabatic bases

The quenching of Li (1s ²2p; ²P) to Li (1s ²2s; ²S) by H₂ is considered using coupled-cluster and multireference configuration-interaction techniques. C _{2 v} (²A₁, ²B₂) and C _{∞ v} (²Π,²Σ⁺) sections of the 1²A^′ and 2²A^′ potential energy surfaces are determined. The C _{2 v} portion of the 1²A^′−2²A^′ seam of conical intersection is studied. Perhaps the most significant finding is a surprising trifurcation of this seam into a portion with only C _s symmetry and the aforementioned C _{2 v} portion. The adiabatic-to-diabatic state transformation is considered in the vicinity of the seam of conical intersection using both perturbation theory and the dipole moment operator. The ²B₂ section of the 2²A^′ potential energy surface exhibits an exciplex in the general vicinity of the seam of conical intersection. The ²Π section of the 2²A^′ potential energy surface possesses a global minimum lying 1.86kcal/mol below the Li (²P)+H₂ asymptote. A van der Waals-like minimum with C _{∞ v} symmetry was found on the 1²A^′ potential energy surface. Received: 14 August 1998 / Accepted: 20 August 1998 / Published online: 11 November 1998     

Diffuse reflectance infrared Fourier transform spectral study of the interaction of 3-aminopropyltriethoxysilane on silica gel. Behavior of amino groups on the surface

 Three silica gel sample systems, modified with 3-amino-propyltriethoxysilane (APTS), were prepared by sequentially sampling the reaction mixture at various time intervals, and the diffuse reflectance infrared Fourier transform (DRIFT) spectra of these samples were measured in the regions 2700–3500 and 1300–2000 cm^-1. The IR bands observed at 1597 and 1629–1633 cm^-1 were assigned to the deformation modes of NH₂ and NH⁺ ₃ groups, respectively. The intensities of these two bands are dependent on both the APTS concentration used in the preparation and the reaction time. The results are summarized as fol-lows. For the sample systems in which smaller APTS concentration were used, most of the NH₂ groups of the aminopropyl segments are converted into the NH⁺ ₃ groups on the surface, showing that the SiO^-…H⁺NH₂-type structure is predominantly stabilized on the surface of the silica gel. As the APTS concentration in the reaction mixture increases, the population of NH₂ groups in the silane layer coated onto the surface increases. Interpretation of the CH stretch region further suggests that cyclic structures may be formed on the surface as a consequence of the formation of NH⁺ ₃ groups. Received: 18 November 1996 Accepted: 14 February 1997     

Syntheses, structures and properties of two new neodymium complexes with N-P-acetamidobenzenesulfonyl-glycine acid

Two new neodymium complexes, [Nd₂(abglyH)₆(2,2′-bipy)₂(H₂O)₂] · 4H₂O 1 and {[Nd(abglyH)₃(H₂O)₂] · (4,4′-bipy) · 7H₂O}_n 2 (abglyH₂ = N-P-acetamidobenzenesulfonyl-glycine acid, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine), have been synthesized and their structures have been measured by X-ray crystallography. In 1, nine-coordinated Nd(III) ions are bridged by two syn–syn bidentate and two tridentate bridging carboxylate groups from four different abglyH⁻ anions to form dinuclear motifs, which are further connected into a 3-D supramolecular framework via hydrogen bonds between the binuclear motifs and the uncoordinated water molecules. In 2, eight-coordinated Nd(III) ions are linked by six carboxylate groups adopting a syn–syn bidentate bridging fashion to form a 1-D inorganic–organic alternating linear chain. These polymeric chains generate microchannels extending along the a direction, and these cavities are occupied by discrete tetradecameric water clusters, which interact with their surroundings and finally furnish the 3-D supramolecular network via hydrogen bonds. At the same time, π–π stacking interactions between benzene rings from abglyH⁻ anions also play an important role in stabilizing the network.     

121,123Sb NQR study of solid phases formed in systems (MF)1−x −(M′F) x −SbF3−H2O (M, M′=Na, K, Rb, Cs, and NH4)

Crystalline substances formed in the (MF)_1−x −(M′F) _x −SbF₃−H₂O systems (M, M′=Na, K, Rb, Cs, and NH₄;x=0 to 1) were investigated by^121,123Sb NQR spectroscopy at 77 K. The formation of individual Sb^III complexes NaCs₃Sb₄F₁₆·H₂O and NaKSbF₅·1.5H₂O, and statistically disordered mixed crystals M_1−x −M′ _x −SbF₄ (M, M′=K, Rb, Cs, and NH₄) was established. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 109–112, January, 1999.     

Solubilities and Transfer Chemical Potentials for Cobalt(III) Complexes in <Emphasis Type="BoldItalic">t</Emphasis>-butanol– <Emphasis Type="BoldItalic">i</Emphasis>-propanol–, and ethanol–water Mixtures

Solubilities in t-BuOH–, i-PrOH–, and EtOH–H₂O mixtures at 298.2 K are reported for a number of salts of mono- and bi-nuclear cobalt(III) complexes. From these solubilities and published single ion transfer chemical potentials, on the TATB (Ph₄As ⁺≡ BPh₄^-) assumption, transfer chemical potentials have been derived for most of these cobalt(III) complexes. The results and trends are discussed in relation to those for other ions and complexes. Effects of ligand nature for transfer to t-BuOH–H₂O mixtures are detailed and, for a selection of complexes, trends for transfer of a given complex to t-BuOH–, i-PrOH–, EtOH– , and MeOH– H₂O mixtures are compared.     

Syntheses of the eight-coordinate NH4[ErIII(Cydta)(H2O)2] · 4.5H2O and (NH4)2[Er 2III (Pdta)2(H2O)2] · 2H2O complexes and their structural investigation

In this work, the title complexes, NH₄[Er^III(Cydta)(H₂O)₂] · 4.5H₂O (I) (H₄Cydta = trans-1,2-cyclo-hexanediamine-N,N,N′,N′-tetraacetic acid) and (NH₄)₂[Er₂^III(Pdta)₂(H₂O)₂] · 2H₂O (II) (H₄Pdta= propylene-diamine-N,N,N′,N′-tetraacetic acid), were prepared, respectively, and their composition and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques. Complex I selects a mononu-clear structure with pseudosquare antiprismatic geometry crystallized in the triclinic crystal system with space group $ P\bar 1 $ P\bar 1 and the central Er³⁺ ion is eight-coordinated by the hexadentate Cydta ligand and two water molecules. The crystal data are as follows: a = 8.568(3), b = 10.024(3), c = 14.377(4) ?, α = 88.404(4)°, β = 75.411(4)°, γ = 88.332(4)°, V = 1194.2(6) ?³, Z = 1, ρ _c = 1.793 g/cm³, μ = 3.586 mm⁻¹, F(000) = 648, R = 0.0257, and wR = 0.0667 for 4169 observed reflections with I ≥ 2σ(I). Complex II is eight-coordinated as well, which selects a binuclear structure with two pseudosquare antiprismatic geometry and crystallizes in the monoclinic crystal system with space group P2₁/n. The central Er³⁺ ion is coordinated by two nitrogens and four oxygens from one hexadentate Pdta ligand. Besides, two oxygens come from one carboxylic group of the neighboring Pdta ligand and one water molecule, respectively. The crystal data are as follows: a = 12.7576(8), b = 9.3151(6), c = 14.3278(9) ?, β = 96.1380(10)°, V = 1692.93(19) ?³, Z = 4, ρ _c = 2.054 g/cm³, μ = 5.015 mm⁻¹, F(000) = 1028, R= 0.0228, and wR = 0.0534 for 2984 observed reflections with I ≥ 2σ(I).