A study of [C7H8]+˙ and [C7H8]2+ ions formed from different precursor molecules

On the basis of unimolecular and collisionally activated decompositions, as well as their charge stripping behaviour, [C₇H₈]⁺˙ and [C₇H₈]²⁺ ions from a variety of precursors have been studied. In particular, structural characteristics of molecular ions of toluene, cycloheptatriene, norborna-2,5-diene and quadricyclane have been compared to those of [C₇H₈]⁺˙ and [C₇H₈]²⁺ rearrangement fragment ions obtained from n-butylbenzene, 2-phenylethanol and n-pentylbenzene. Severe interferences from [C₇H₇]^2+˙ ion fragmentations have been observed and rationalized.     

Self‐Assembled Multimetallic/Peptide Complexes: Structures and Unimolecular Reactions of [Mn(GlyGly−H)2n−1]+ and Mn+1(GlyGly−H2n]2+ Clusters in the Gas Phase

The unimolecular chemistry and structures of self‐assembled complexes containing multiple alkaline‐earth‐metal dications and deprotonated GlyGly ligands are investigated. Singly and doubly charged ions [M_n(GlyGly?H)_n‐1]⁺ (n=2–4), [M_n+1(GlyGly?H)_2n]²⁺ (n=2,4,6), and [M(GlyGly?H)GlyGly]⁺ were observed. The losses of 132 Da (GlyGly) and 57 Da (determined to be aminoketene) were the major dissociation pathways for singly charged ions. Doubly charged Mg²⁺ clusters mainly lost GlyGly, whereas those containing Ca²⁺ or Sr²⁺ also underwent charge separation. Except for charge separation, no loss of metal cations was observed. Infrared multiple photon dissociation spectra were the most consistent with the computed IR spectra for the lowest energy structures, in which deprotonation occurs at the carboxyl acid groups and all amide and carboxylate oxygen atoms are complexed to the metal cations. The N?H stretch band, observed at 3350 cm^?1, is indicative of hydrogen bonding between the amine nitrogen atoms and the amide hydrogen atom. This study represents the first into large self‐assembled multimetallic complexes bound by peptide ligands.     

Structures and stabilities of [C3H2]+ ˙ and [C3H2]2+ ions

Ab initio molecular orbital theory using basis sets up to 6-311G^{* *}, with electron correlation incorporated via configuration interaction calculations with single and double substitutions, has been used to study the structures and energies of the C₃H₂ monocation and dication. In agreement with recent experimental observations, we find evidence for stable cyclic and linear isomers of [C₃H₂]^{+ ˙}. The cyclic structure (, a) represents the global minimum on the [C₃H₂]^{+ ˙} potential energy surface. The linear isomer (, b) lies somewhat higher in energy, 53 kJ mol^?1 above a. The calculated heat of formation for [HCCCH]^{+ ˙} (1369 kJ mol^?1) is in good agreement with a recent experimental value (1377 kJ mol^?1). For the [C₃H₂]²⁺ dication, the lowest energy isomer corresponds to the linear [HCCCH]²⁺ singlet (h). Other singlet and triplet isomers are found not to be competitive in energy. The [HCCCH]²⁺ dication (h) is calculated to be thermodynamically stable with respect to deprotonation and with respect to C? C cleavage into CCH⁺ + CH⁺. The predicted stability is consistent with the frequent observation of [C₃H₂]²⁺ in mass spectrometric experiments. Comparison of our calculated ionization energies for the process [C₃H₂]^{+ ˙} → [C₃H₂]²⁺ with the Q_min values derived from charge-stripping experiments suggests that the ionization is accompanied by a significant change in structure.     

Evidence for long-lived excited states of [CnH2]2+ carbodications

The energetics, structures, stabilities and reactivities of[C_nH₂]²⁺ ions have been investigated using computational methods and experimental mass spectrometric techniques. Spontaneous decompositions of [C_nH₂]²⁺ into [C_nH]⁺ + H⁺ products, observed for ions with odd-n values, have been explained by invoking the formation of excited triplet states. Even-n [C_nH]⁺ ions possess triplet ground states with low-lying excited states, whereas odd-n ions have triplet states with energies several eV above ground singlet states. Radiationless transitions of vibrationally excited long-lived triplet state ions into singlet state continua are suggested as possible mechanisms for spontaneous deprotonation processes of odd-n [C_nH₂]²⁺ ions. Evidence for these long-lived excited states has been obtained in bimolecular single electron transfer reactions.     

Crystal-chemical functions of [Hg2]2+ and [Hg3]4+ groups in inorganic structures

About 20 structures of natural and synthetic inorganic compounds containing a [H_g2] (dumbbell) pair (Hg-Hg = 2.47?2.56 å) or a [H_g3] triangle (Hg-Hg_av = 2.7 å) are analyzed. From crystal-chemical viewpoint, it is reasonable to consider these groups as a single cation with coordinates of its geometrical center. In all cases, the coordination polvhedra are convex polxhedra with 8–14 vertices and with distances from the center to the vertex of 3.00?3.91 å, which makes the [H_g2]²⁺ and [Hg3]⁴⁺ cations analogs of Cs. Examples are given to demonstrate the advantages of the suggested analysis of structures with a [Hg_n] group. This approach extends classical crystal chemistry to compounds with nonuniform chemical bonds, in particular, to compounds with pseudocluster and cluster groups inserted in the ionic structure; therefore, it is especially useful for comparison and classification purposes and for analysis of structure-foming factors.     

Asymmetric salt effects on anion/cation reactions: A comparative study of the [Fe(CN)6]4− + [Co(NH3)5pz]3+ and [Ru(NH3)5pz]2+ + [Co(C2O4)3]3− reactions

The kinetics of electron transfer reactions between [Fe(CN)₆]^4? and [Co(NH₃)₅pz]³⁺ and between [Ru(NH₃)₅pz]²⁺ and [Co(C₂O₄)₃]^3? was studied in concentrated salt solutions (Na₂SO₄, LiNO₃, and Ca(NO₃)₂). An analysis of the experimental kinetic data, k_obs, permits us to obtain the true (unimolecular) electron transfer rate constants corresponding to the true electron transfer process (precursor complex → successor complex), k_et. The variations of both, k_obs and k_et, with salt concentrations are opposite for these reactions. These opposite tendencies can be rationalized by using the Marcus–Hush treatment for electron transfer reactions. The conclusion is that the negative salt effect found for the first reaction ([Fe(CN)₆]^4? + [Co(NH₃)₅pz]³⁺) is due to the increase of the reaction and reorganization free energies when the concentration of salt increases. In the case of the second reaction ([Ru(NH₃)₅pz]²⁺ + [Co(C₂O₄)₃]^3?), the positive salt effect observed is caused by the fact that the driving force becomes more favorable when the concentration of salt increases. Thus, it is shown that for anion/cation electron transfer reactions the kinetic salt effect depends on the charge sign of the oxidant (and the reductant). © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 81–89, 2005     

Theoretical study in [C2H4–Tl]+ and [C2H2–Tl]+ complexes

We studied the attraction between [C₂H_n] and Tl(I) in the hypothetical [C₂H_n–Tl]⁺ complexes (n = 2,4) using ab initio methodology. We found that the changes around the equilibrium distance C–Tl and in the interaction energies are sensitive to the electron correlation potential. We evaluated these effects using several levels of theory, including Hartree–Fock (HF), second‐order Møller–Plesset (MP2), MP4, coupled cluster singles and doubles CCSD(T), and local density approximation augmented by nonlocal corrections for exchange and correlation due to Becke and Perdew (LDA/BP). The obtained interaction energies differences at the equilibrium distance R_e (C–Tl) range from 33 and 46 kJ/mol at the different levels used. These results indicate that the interaction between olefinic systems and Tl(I) are a real minimum on the potential energy surfaces (PES). We can predict that these new complexes are viable for synthesizing. At long distances, the behavior of the [C₂H_n]–Tl⁺ interaction may be related mainly to charge‐induced dipole and dispersion terms, both involving the individual properties of the olefinic π‐system and thallium ion. However, the charge‐induced dipole term (R^?4) is found as the principal contribution in the stability at long and short distances. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Zur Dimorphie von Nd3Cl[SiO4]2

On the Dimorphism of Nd₃Cl[SiO₄]₂ On reacting NdCl₃, Nd₂O₃, and SiO₂ (molar ratio: 1 : 4 : 6) at 850 °C in evacuated silica tubes, pale violet, hydrolysis resistant neodymium(III) chloride ortho‐silicate Nd₃Cl[SiO₄]₂ can be obtained within seven days. If equimolar amounts of NaCl are added as flux, rod‐ or platelet‐shaped, transparent single crystals of two modifications accumulate simultaneously. The one with the higher density (A‐Nd₃Cl[SiO₄]₂) crystallizes monoclinically (C2/c, no. 15; a = 1416.6(1), b = 638.79(6), c = 872.21(9) pm, β = 98.403(7)°; V_m = 117.55 cm³/mol, Z = 4), whereas the one with the lower density (B‐Nd₃Cl[SiO₄]₂) exhibits orthorhombic symmetry (Pnma, no. 62; a = 709.36(7), b = 1815.7(2), c = 631.48(6) pm; V_m = 122.45 cm³/mol, Z = 4). Two crystallographically independent Nd³⁺ cations exist in each of both crystal structures, which in the A type are surrounded by nine (1 Cl^– + 8 O^2–) and ten (2 Cl^– + 8 O^2–), whilst those in the B type by only two times eight (1 Cl^– + 7 O^2– and 2 Cl^– + 6 O^2–) anions, respectively. Thereby all oxygen atoms of both forms represent members of discrete ortho‐silicate tetrahedra ([SiO₄]^4–). Although both crystal structures are built of alternating anionic double layers {(Nd1)₂[SiO₄]₂}^2– and cationic single layers {(Nd2)Cl}²⁺, there is a higher cross‐linkage of the building units in the A‐type lattice, where the cations are coordinated by three and four tetrahedra edges of ortho‐silicate anions, compared to only two times two of them in the B type. From this an about 4% higher density of Nd₃Cl[SiO₄]₂ results for the A‐type structure (D_x = 5.55 g/cm³) in comparison with B‐type Nd₃Cl[SiO₄]₂ (D_x = 5.33 g/cm³).     

Strukturen von planaren und tetraedrischen TetrafulminatoMetallkomplexen: [N(C3H7)4]2 [Ni(CNO)4], [N(C3H7)4]2 [Pt(CNO)4] und [N(C3H7)4]2 [Zn(CNO)4]

Pseudohalogeno Metal Compounds. LXXVIII. Structures of Planar and Tetrahedral Tetrafulminato Metal Complexes: [N(C₃H₇)₄]₂ [Ni(CNO)₄], [N(C₃H₇)₄]₂ [Pt(CNO)₄], and [N(C₃H₇)₄]₂ [Zn(CNO)₄] The crystals contain the tetrafulminatometallates of an ideal square planar structure ([Ni(CNO)₄]^2–, [Pt(CNO)₄]^2–) with D_4h symmetry at the nickel and platinum atom and a tetrahedron ([Zn(CNO)₄]^2–) with perfect T_d symmetry at the zinc atom and with linear C≡N–O ligands. The metal carbon bonds (Ni–C: 187 pm, Pt–C: 200 pm, Zn–C: 201 pm) of the metal fulminates are very close to those of the corresponding cyano complexes. In the crystals the anions ([Ni(CNO)₄]^2–, [Pt(CNO)₄]^2–, [Zn(CNO)₄]^2–) are separated by the cations ([N(C₃H₇)₄]⁺) which explains the thermal stability of these compounds.     

[C6H6, C3H7 +]and [C6H7 +, C3H6] ion-neutral complexes intermediate in the reactions of protonated propylbenzenes

From the mass-analysed ion kinetic energy spectra of labelled ions, kinetic energy releases and thermodynamic data, it is proved that protonated n-propylbenzene (1) isomerizes into protonated isopropyl benzene (2). It is also shown that the dissociation of the less energetic metastable ions of (2), leading to [iso-C₃H₇]⁺ and [C₆H₇]⁺ product ions, is preceded by H exchange. This H exchange involves two interconverting ion-neutral complexes [C₆H₆, iso-C₃H₇⁺] (2π) and [C₆H₇⁺, C₃H₆] (2α).     

Analysis of vibrational spectra (FT-IR and VCD) and nonlinear optical properties of [Ru(L)3]2+ complexes

Density functional theory calculations were performed on [Ru(L)₃]²⁺ (L = 1,10-phenanthroline, 2,2′-bipyridine, 2,2′-bipyrimidine, 2,2′-bipyrazine) complexes by employing B3PW91 functional and LAN2DZ basis set to predict their spectra and nonlinear optical response. The geometrical and coordination energy studies explained that the stability of [Ru(L)₃]²⁺ metal complexes depends on the extent of interaction of the dπ orbitals of Ru²⁺ with the π* ligand orbitals, which is maximum for 1,10-phenanthroline. The two enantiomers of the [Ru(L)₃]²⁺ show IR absorption peaks in the region of 1100–1800 cm^?1, and a slight shift occurs to lower frequency by solvent. The vibrational circular dichroism peaks of [Ru(phen)₃]²⁺ had major contribution from out-of-phase stretching of 1,10-phenanthroline rings and a minor contribution from H–C=C–H wagging and C=C stretching of rings. Maximum hyperpolarizability was observed for [Ru(phen)₃]²⁺ due to stronger anharmonicity in the π-electron system. Among the [Ru(L)₃]²⁺ (L = bpy, bpm, and bpz) complexes, [Ru(bpm)₃]²⁺ shows enhanced hyperpolarizability due to increase in the dipole along the X-direction. In derivative Ru²⁺ complexes, we found that hyperpolarizability depends on electron-donating capability of the substituent. As per FMOs study, the HOMO is predominantly metal fragment based, the LUMO is primarily ligand based, and the larger value of hyperpolarizability corresponds to the lower E_LUMO–E_HOMO gap, reflecting that nonlinear optical response is a consequence of additive dipolar responses of charge transfer and hyperpolarizability.     

[3+2] Cycloadditions of Metallo Nitrile Ylides and Metallo Nitrile Imines with Metal Carbonyl,Thiocarbonyl, and Isocyanide Complexes: Heterodimetallic Systems with Bridging Heterocycles [1]

The reactions of [Re(CO)₆]⁺, [FeCp(CO)₂CS]⁺ and [FeCp(CNPh)₃]⁺ with the metallo nitrile ylides [M^–{C⁺=N–C^–(H)CO₂Et}(CO)₅]^– (M = Cr, W) and the chromio nitrile imine [Cr^–{C⁺=N–N^–H}(CO)₅]^– (generated by mono‐α‐deprotonation of the parent isocyanide complexes) to give neutral 5‐metallated 1,3‐oxazolin‐ ( 1 ), 1,3‐thiazolin‐ ( 2 ), imidazolin‐ ( 3 , 4 ), 1,3,4‐oxdiazolin‐ ( 5 ), 1,3,4‐thiadiazolin‐ ( 6 ) and 1,3,4‐triazolin‐2‐ylidene ( 8 ) chromium and tungsten complexes represent the first all‐organometallic versions of Huisgen’s 1,3‐dipolar cycloadditions. The formation of 6 and 8 is accompanied by partial decomposition to (OC)₅Cr–C≡N–FeCpL₂ {L = CO ( 7 ), CNPh ( 9 )}. The structures of 4a and 5 have been characterized by X‐ray diffraction.     

A structural investigation of [C6H6]2+ and [C6H6]+˙ ions involved in charge exchange reactions

Mass-analysed ion kinetic energy spectra for collisional activation (CA) of [C₆H₆]⁺˙ formed via electron capture by [C₆H₆]²⁺ ions in collision with neutral benzene molecules have been compared for the C₆H₆ isomers benzene, 1,5-hexadiyne and 2,4-hexadiyne. Comparisons of fragment abundance and total CA fragment yields were also made for [C₆H₆]⁺˙ ions generated by electron ionization (EI). CA conditions of ion velocity and collision gas pressure were identical in these comparisons. In general the fragment abundance patterns for the ions formed by charge exchange were very similar to those for singly charged benzene ions generated by EI. However, significant variations in CA fragment yield (the ratio of the total CA fragment ion abundance to the abundance of the incident unfragmented ions) were observed. It is not clear from the results whether these variations reflect structurally different ions or ions of different internal energies. The CA spectra of [C₆H₆]⁺˙ ions derived from charge exchange reactions between the benzene dication and the target gases He, Ne, Ar, Kr and Xe have also been recorded and, once again, very similar fragment abundance patterns were observed along with large variations in total CA fragment yields. Charge exchange efficiency measurements are reported for reactions between the benzene dication and the targets He, Ne, Ar, Kr, Xe and C₆H₆ (benzene) and also for the doubly charged ions derived from the linear C₆H₆ isomers. In the latter case Xe and benzene targets were used. The energetics and efficiency measurements for the former reactions suggest that for targets such as He and Ne the processes probably involve excited states of the doubly charged ions. The efficiencies measured for the latter reactions were distinctly different for the three C₆H₆ isomers and may indicate a strong dependence of charge exchange cross-section on doubly charged ion structure.     

The negative ion mass spectra of mixtures of sulphur and organic compounds. II—the formation of [C5H5 + Sn]− from the mixture of sulphur and ferrocene

The negative ion mass spectra of ferrocene and of a mixture of ferrocene with sulphur were studied. In the spectrum of the mixture, characteristic peaks of [C₅H₅ + S_n]^? (n = 1, 2, 3 etc.) were observed. The structures of these ions are discussed.     

Ce2[SeO3]3 and Pr2[SeO3]3: Non‐Isostructural Oxoselenates(IV) of the Light Lanthanoids

The crystal structures of Ce₂[SeO₃]₃ and Pr₂[SeO₃]₃ have been refined from X‐ray single‐crystal diffraction data. The compounds were obtained using stoichiometric mixtures of CeO₂, SeO₂, Ce, and CeCl₃ (molar ratio 3:3:1:1) or Pr₆O₁₁, SeO₂, Pr, and PrCl₃ (molar ratio 3:27:1:2) heated in evacuated sealed silica tubes at 830 °C for one week. Ce₂[SeO₃]₃ crystallizes orthorhombically (space group: Pnma), with four formula units per unit cell of the dimensions a = 839.23(5) pm, b = 1421.12(9) pm, and c = 704.58(4) pm. Its structure contains only a single crystallographically unique Ce³⁺ cation in tenfold coordination with oxygen atoms arranged as single‐face bicapped square antiprism and two different trigonal pyramidal [SeO₃]^2? groups. The connectivity among the [CeO₁₀] polyhedra results in infinite sheets of face‐ and edge‐sharing units propagating normal to [001]. Pr₂[SeO₃]₃ is monoclinic (space group: P2₁/n) with twelve formula units per unit cell of the dimensions a = 1683.76(9) pm, b = 705.38(4) pm, c = 2167.19(12) pm, and β = 102.063(7)°. Its structure exhibits six crystallographically distinct Pr³⁺ cations in nine‐ and tenfold coordination with oxygen atoms forming distorted capped square antiprisms or prisms (CN = 9), bicapped square antiprisms and tetracapped trigonal prisms (CN = 10), respectively. The [PrO₉] and [PrO₁₀] polyhedra form double layers parallel to (111) by edge‐ or face‐sharing, which are linked by nine different [SeO₃]^2? groups to build up a three‐dimensional framework. In both compounds, the discrete [SeO₃]^2? anions (d(Se⁴⁺–O^2?) = 166–174 pm) show the typical Ψ¹‐tetrahedral shape owing to the non‐bonding “lone‐pair” electrons at the central selenium(IV) particles. Moreover, their stereochemical “lone‐pair” activity seems to flock together in large empty channels running along [010] in the orthorhombic Ce₂[SeO₃]₃ and along [101] in the monoclinic Pr₂[SeO₃]₃ structure, respectively.     

Free radicals formed by ion beam neutralization of [DCO]+, [DOCO] +, [CD3OD2]+ and [(CD3)2COD] + on metal targets

A series of radicals formed when a fast beam of deuterated ions, [DCO] ⁺, [DOCO] ⁺, [CD₃OD₂]⁺ and [(CD) ₂COD] ⁺, is neutralized by electron transfer from K. Na and Zn atoms has been studied by a combination of charge stripping and beam scattering techniques For all systems studied, some fraction of The radicals from charge exchange are formed in excited dissociative states. Radical decomposition products have been identified and fragmentation energies have been measured. A metastable slate of CD3GD2 is observed with a lifetime greater than 0.5 μs. Stable radicals of DCO and (CD₃)₂ COD are formed by ion–Zn charge exchange. Indirect evidence indicates that [DCO] ⁺–K charge exchang; leads to an excited radiative state of the radical.     

Two New Modifications of [P(C6H5)4]2[Cu2I4]

Single crystals of two new modifications of [P(C₆H₅)₄]₂[Cu₂I₄] were obtained by reaction of granulated copper with iodine and [P(C₆H₅)₄]I in dry acetone under nitrogen atmosphere. They crystallise monoclinically, space group P2₁/n (No. 14), a = 11.550(6), b = 7.236(2), c = 27.232(13) Å, β = 98.13(3)°, V = 2253(2) ų, and Z = 2 ([P(C₆H₅)₄]₂[Cu₂I₄]-C), and space group Cc (No. 9), a = 17.133(5), b = 15.941(5), c = 18.762 (6) Å, β = 114.02(1)°, V = 4681(3) ų, and Z = 4 ([P(C₆H₅)₄]₂[Cu₂I₄]-D), respectively. In these compounds the [CuI₂]^? anions form dimers di-μ-iodo-diiodocuprate(I), which are either planar ( C ) or folded ( D ).     

Effect of External Pressure on the Excitation Energy Transfer from [Cr(ox)3]3− to [Cr(bpy)3]3+ in [Rh1−xCrx(bpy)3][NaM1−yCry(ox)3]ClO4

Resonant excitation energy transfer from [Cr(ox)₃]^3? to [Cr(bpy)₃]³⁺ in the doped 3D oxalate networks [Rh_1?xCr_x(bpy)₃][NaM^III_1?yCr_y(ox)₃]ClO₄ (ox=C₂O₄^?, bpy=2,2′‐bipyridine, M=Al, Rh) is due to two types of interaction, namely super exchange coupling and electric dipole–dipole interaction. The energy transfer probability for both mechanisms is proportional to the spectral overlap of the ²E→⁴A₂ emission of the [Cr(ox)₃]^3? donor and the ⁴A₂→²T₁ absorption of the [Cr(bpy)₃]³⁺ acceptor. The spin‐flip transitions of (pseudo‐)octahedral Cr³⁺ are known to shift to lower energy with increasing pressure. Because the shift rates of the two transitions in question differ, the spectral overlap between the donor emission and the acceptor absorption is a function of applied pressure. For [Rh_1?xCr_x(bpy)₃][NaM_1?yCr_y(ox)₃]ClO₄ the spectral overlap is thus substantially reduced on increasing pressure from 0 to 2.5 GPa. As a result, the energy transfer probability decreases with increasing pressure as evidenced by a decrease in the relative emission intensity from the [Cr(bpy)₃]³⁺ acceptor.     

[Mn(H2O)4(C4N2H4)][C6H4(COO)2] – Ein eindimensionales Koordinationspolymer mit kettenartigen [Mn(H2O)4(C4N2H4)]n2n+ Polykationen

[Mn(H₂O)₄(C₄N₂H₄)][C₆H₄(COO)₂] – An One‐Dimensional Coordination Polymer with Chain‐like [Mn(H₂O)₄(C₄N₂H₄)]_n²ⁿ⁺ Polycations Orthorhombic single crystals of [Mn(H₂O)₄(C₄N₂H₄)][C₆H₄(COO)₂] have been prepared in aqueous solution at room temperature. Space group Imm2 (no. 44), a = 1039.00(6) pm, b = 954.46(13) pm, c = 737.86(5) pm, V = 0.73172(12) nm³, Z = 2. Mn²⁺ is coordinated in a octahedral manner by four water molecules and two nitrogen atoms stemming from the pyrazine molecules (Mn–O 215.02(11) pm; Mn–N 228.7(4), 230.7(4) pm). Mn²⁺ and pyrazine molecules form chain‐like polycations with [Mn(H₂O)₄(C₄N₂H₄)]_n²ⁿ⁺ composition. The positive charge of the polycationic chains is compensated for by phthalate anions, which are accomodated between the chains. The phthalate anions are linked by hydrogen bonds to the polycationic chains. Thermogravimetric analysis in air revealed that the loss of water of crystallisation and pyrazine occurs in two steps between 130 and 245 °C. The resulting sample was stable up to 360 °C. Further decomposition yielded Mn₂O₃.     

A 3d‐4f Complex Constructed by the Assembly of a Cationic Template, [Cu(en)2]2+, and a 3D Anionic Coordination Polymer, [Sm2(C2O4)3(C5O5)(H2O)2]2–

A three‐dimensional (3D) 3d‐4f complex, [Cu(en)₂][Sm₂(C₅O₅)(C₂O₄)₃(H₂O)₂] · 8H₂O ( 1 ) (en = ethylenediamine, C₅O₅^2– = dianion of 4,5‐dihydroxycyclopent‐4‐ene‐1,2,3‐trione), were prepared via the in‐situ ring‐opening oxidation reaction of croconate in the presence of the template‐directed complex, [Cu(en)₂]²⁺ cation. The structural characterization determined by X‐ray diffraction determination reveals that the 3D anionic coordination polymer of [Sm₂(C₂O₄)₃(C₅O₅)(H₂O)₂]^2– in 1 can be describe in terms of in‐plane 2D honeycomb‐like [Sm₂(C₂O₄)₃] layered frameworks bridged by oxalate with bis‐chelating mode, being mutually interlinked via the bridge of μ_1,2,3,4‐croconate ligands with bis‐chelating coordination mode to complete the 3D open framework, which gives rise to 1D channels with pore size of 14.023 × 11.893 Å (longest atom–atom contact distances) along the b axis. The structure‐directing complex, [Cu(en)₂]²⁺, and solvated water molecules are resided into these honeycomb‐type hexagonal channels. The thermal stability of 1 was further studied by TGA and in‐situ powder X‐ray diffraction measurement.