Hydrothermal synthesis, crystal structure, and magnetic property of a three-dimensional inorganic-organic hybrid material: Mn(H2O)[HO3PCH2NH(CH2CO2)2]

A novel three-dimensional inorganic-organic hybrid compound, Mn(H₂O)[HO₃PCH₂NH(CH₂CO₂)₂] from a hydrothermal reaction of Mn (II) ion with N-(phosphonomethyl)iminodiacetic acid (H₄PMIDA) was reported. The compound crystallizes in the monoclinic P2₁/n with cell dimensions of a=5.215(5) Å, b=14.111(15) Å, c=12.727(12) Å, β=93.646(16)°, V=934.6(16) Å³ and Z=4. In this structure each Mn atom is six-coordinated with the carboxylic groups and phosphonic groups to form layers along the bc plane. These layers are further connected with the organic moieties of H₂PMIDA, resulting in a complicated three-dimensional network structure. Thermogravimetric analysis, IR spectrum and magnetic susceptibility of this compound are given.     

Inorganic-organic hybrid compounds: hydrothermal synthesis and characterization of a new three-dimensional metal tetraphosphonate Mn[(HO3PCH2)N(H)(CH2)4(H)N(CH2PO3H)2]

The new manganese tetraphosphonate, Mn[(HO₃PCH₂)₂N(H)(CH₂)₄(H)N(CH₂PO₃)₂] (1) was hydrothermally synthesized from MnCl₂ and N,N,N′,N′-tetrametylphosphono-1,4-diaminobutane, (H₂O₃PCH₂)₂N-(CH₂)₄-N(CH₂PO₃H₂)₂. The structure was determined from single-crystal X-ray diffraction data (Mn[(HO₃PCH₂)₂N(H)(CH₂)₄(H)N(CH₂PO₃)₂], monoclinic, P2₁/a, with a=9.6663(1), b=9.2249(2), c=10.5452(1) pm, β=105.676(1)°, V=905.35(3)×10⁶ pm, Z=2, R₁=0.051, wR₂=0.109 (all data). The structure contains the zwitter ions [(HO₃PCH₂)₂N(H)-(CH₂)₄-(H)N(CH₂PO₃)₂]²⁻ and is built from alternating corner-linked [MnO₆] and [PO₃C] polyhedra forming a two-dimensional net of eight-rings. These layers are connected to a pillared structure by the diaminobutane groups. Magnetic susceptibility data confirms the presence of Mn²⁺ ions. Thermogravimetric measurements show a stability of 1 up to ∼290°C. Between 290°C and 345°C a one-step loss of ∼7.0% is observed, and above 345°C the continuous decomposition of the organic part of the structures takes place.     

Ab-initio crystal structure of hydroxy adipate of nickel and hydroxy subarate of nickel and cobalt from synchrotron powder diffraction and magnetic properties

Organic-inorganic hybrid compounds Ni(II)₅(OH)₆(C₆H₈O₄)₂(1), Ni(II)₅(OH)₆(C₈H₁₂O₄)₂(2) and Co(II)₅(OH)₆(C₈H₁₂O₄)₂(3) have a similar layered structure as determined ab initio from synchrotron powder diffraction analysis. The metal sites are octahedrally coordinated by O atoms. The slabs are built from edge-sharing octahedra in such a way that channels with an average size of 4 Å are formed. Bis-bidentate and bridging dicarboxylate anions lead to a 3D framework. The compounds (1) and (2) order antiferromagnetically below T_N=26.5 and 19.3 K, respectively, while (3) is ferrimagnetic with T_C=16.2 K. Crystal data for compounds are as follows: (1)a=11.6504(1) Å, b=6.8021(3) Å, c=6.3603(1) Å, α=73.52(1)°, β=99.69(1)°, γ=96.16(1)°, R_B=0.070, 668 reflections; (2)a=13.9325(1) Å, b=6.7893(1) Å, c=6.3534(4) Å, α=73.63(1)°, β=95.14(1)°, γ=91.80(1)°, R_B=0.052, 804 reflections; (3)a=13.9806(1) Å, b=6.9588(1) Å, c=6.3967(1) Å, α=73.05(1)°, β=94.51(1)°, γ=92.19(1)°, R_B=0.048, 410 reflections. The space group is P−1 for the three compounds.     

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.     

Hydrothermal synthesis, crystal structure, and magnetic properties of a novel organo-templated iron(III) borophosphate: (C3H12N2)Fe 6(H2O)4[B4P8O32(OH)8]

The organo-templated iron(III) borophosphate (C₃H₁₂N₂)Fe^III ₆(H₂O)₄[B₄P₈O₃₂(OH)₈] was prepared under mild hydrothermal conditions (at 443 K) and the crystal structure was determined from single crystal X-ray data at 295 K (monoclinic, P2₁/c (No. 14), a=5.014(2) Å, b=9.309(2) Å, c=20.923(7) Å, β=110.29(2)°, V=915.9(5) Å³, Z=2, R1=0.049, wR2=0.107 for all data, 2234 observed reflections with I>2σ(I)). The title compound contains a complex inorganic framework of borophosphate trimers [BP₂O₈(OH)₂]⁵⁻ together with FeO₄(OH)(H₂O)- and FeO₄(OH)₂-octahedra forming channels with ten-membered ring apertures in which the diaminopropane cations are located. The magnetization measurements confirm the Fe(III)-state and show an antiferromagnetic ordering at T_N≈14.0(1) K.     

Synthesis and structural investigation of the compounds containing HF2 anions: Ca(HF2)2, Ba4F4(HF2)(PF6)3 and Pb2F2(HF2)(PF6)

Three new compounds Ca(HF₂)₂, Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF₅. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF₂)₂ was prepared by simply dissolving CaF₂ in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H₃F₄)₂. The compounds Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF⁺)_n besides PbF(AsF₆), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba₄F₄(HF₂)(PF₆)₃ crystallizes in a triclinic space group P1¯ with a=4.5870(2) Å, b=8.8327(3) Å, c=11.2489(3) Å, α=67.758(9)°, β=84.722(12), γ=78.283(12)°, V=413.00(3) Å³ at 200 K, Z=1 and R=0.0588. Pb₂F₂(HF₂)(PF₆) at 200 K: space group P1¯, a=4.5722(19) Å, b=4.763(2) Å, c=8.818(4) Å, α=86.967(10)°, β=76.774(10)°, γ=83.230(12)°, V=185.55(14) ų, Z=1 and R=0.0937. Pb₂F₂(HF₂)(PF₆) at 293 K: space group P1¯, a=4.586(2) Å, b=4.781(3) Å, c=8.831(5) Å, α=87.106(13)°, β=76.830(13)°, γ=83.531(11)°, V=187.27(18) Å³, Z=1 and R=0.072. Ca(HF₂)₂ crystallizes in an orthorhombic Fddd space group with a=5.5709(6) Å, b=10.1111(9) Å, c=10.5945(10) Å, V=596.77(10) Å³ at 200 K, Z=8 and R=0.028.     

Building three-dimensional metal phosphites from the corner-shared four-membered rings chain

Three new compounds, a one-dimensional (1D) zinc phosphite, (C₄H₈N₂H₄)[Zn(HPO₃)₂] (I), two three-dimensional (3D) metal phosphites (C₄H₈N₂H₄)[Zn₃(HPO₃)₄] (II) and (C₄H₈N₂H₄)[Zn_(3−x)Co_x(HPO₃)₄(H₂O)₂] (x≈0.83) (III) have been synthesized under hydrothermal conditions templated by piperazine and characterized by single-crystal X-ray diffraction, XRD, IR, UV-vis spectra and SQUID magnetometer. Compound I displays 1D chain-like structure, containing corner-shared (cs) four-membered rings. Interestingly, the structures of II and III show 1D chains similar to those observed in I. It is noteworthy that III represents the first cobalt-substituted zinc-phosphite. Crystal data: I, monoclinic, C2/c, a=17.748(2) Å, b=7.428(9) Å, c=8.8071(11) Å, β=105.345(3)°, V=1091.9 Å³, Z=4. II, Monoclinic P2₁/c, a=9.9435(4) Å, b=10.1438(3) Å, c=17.8164(5) Å, β=95.665(2)°, V=1788.27 Å³, Z=4, and III, Monoclinic P2₁/c, a=7.2338(2) Å, b=15.0238(5) Å, c=9.2153(3) Å, β=107.741(2)°, V=953.88(5) Å³, Z=2.     

Hydrothermal synthesis, structure, and magnetic properties of Pu(SeO3)2

The reaction between PuO₂ and SeO₂ under mild hydrothermal conditions results in the formation of Pu(SeO₃)₂ as brick-red prisms. This compound adopts the Ce(SeO₃)₂ structure type, and consists of one-dimensional chains of edge-sharing [PuO₈] distorted bicapped trigonal prisms linked by [SeO₃] units into a three-dimensional network. Crystallographic data: Pu(SeO₃)₂, monoclinic, space group P2₁/n, a=6.960(1) Å, b=10.547(2) Å, c=7.245(1) Å, β=106.880(9)°, V=508.98(17) Å³, Z=4 (T=193 K), R(F)=2.92% for 83 parameters with 1140 reflections with I>2σ(I). Magnetic susceptibility data for Pu(SeO₃)₂ are linear from 35 to 320 K and yield an effective moment of 2.71(5) μ_B and a Weiss constant of −500(5) K.     

Magnetism and Raman spectroscopy of the dimeric lanthanide iodates Ln(IO3)3 (Ln=Gd, Er) and magnetism of Yb(IO3)3

Colorless single crystals of Gd(IO₃)₃ or pale pink single crystals of Er(IO₃)₃ have been formed from the reaction of Gd metal with H₅IO₆ or Er metal with H₅IO₆ under hydrothermal reaction conditions at 180 °C. The structures of both materials adopt the Bi(IO₃)₃ structure type. Crystallographic data are (MoKα, λ=0.71073 Å): Gd(IO₃)₃, monoclinic, space group P2₁/n, a=8.7615(3) Å, b=5.9081(2) Å, c=15.1232(6) Å, β=96.980(1)°, V=777.03(5) Z=4, R(F)=1.68% for 119 parameters with 1930 reflections with I>2σ(I); Er(IO₃)₃, monoclinic, space group P2₁/n, a=8.6885(7) Å, b=5.9538(5) Å, c=14.9664(12) Å, β=97.054(1)°, V=768.4(1) Z=4, R(F)=2.26% for 119 parameters with 1894 reflections with I>2σ(I). In addition to structural studies, Gd(IO₃)₃, Er(IO₃)₃, and the isostructural Yb(IO₃)₃ were also characterized by Raman spectroscopy and magnetic property measurements. The results of the Raman studies indicated that the vibrational profiles are adequately sensitive to distinguish between the structures of the iodates reported here and other lanthanide iodate systems. The magnetic measurements indicate that only in Gd(IO₃)₃ did the 3+ lanthanide ion exhibit its full 7.9 μ_B Hund's rule moment; Er³⁺ and Yb³⁺ exhibited ground state moments and gap energy scales of 8.3 μ_B/70 K and 3.8 μ_B/160 K, respectively. Er(IO₃)₃ exhibited extremely weak ferromagnetic correlations (+0.4 K), while the magnetic ions in Gd(IO₃)₃ and Yb(IO₃)₃ were fully non-interacting within the resolution of our measurements (∼0.2 K).     

Syntheses, crystal structures and optical spectroscopy of Ln2(SO4)3·8H2O (Ln=Ho, Tm) and Pr2(SO4)3·4H2O

The lanthanide sulphate octahydrates Ln₂(SO₄)₃·8H₂O (Ln=Ho, Tm) and the respective tetrahydrate Pr₂(SO₄)₃·4H₂O were obtained by evaporation of aqueous reaction mixtures of trivalent rare earth oxides and sulphuric acid at 300 K. Ln₂(SO₄)₃·8H₂O (Ln=Ho, Tm) crystallise in space group C2/c (Z=4, a_Ho=13.4421(4) Å, b_Ho=6.6745(2) Å, c_Ho=18.1642(5) Å, β_Ho=102.006(1) Å³ and a_Tm=13.4118(14) Å, b_Tm=6.6402(6) Å, c_Tm=18.1040(16) Å, β_Tm=101.980(8) Å³), Pr₂(SO₄)₃·4H₂O adopts space group P2₁/n (a=13.051(3) Å, b=7.2047(14) Å, c=13.316(3) Å, β=92.55(3) Å³). The vibrational and optical spectra of Ho₂(SO₄)₃·8H₂O and Pr₂(SO₄)₃·4H₂O are also reported.     

Synthesis and crystal structure of a new open-framework iron phosphate (NH4)4Fe3(OH)2F2[H3(PO4)4]: Novel linear trimer of corner-sharing Fe(III) octahedra

A new iron phosphate (NH₄)₄Fe₃(OH)₂F₂[H₃(PO₄)₄] has been synthesized hydrothermally at HF concentrations from 0.5 to 1.2 mL. Single-crystal X-ray diffraction analysis reveals its three-dimensional open-framework structure (monoclinic, space group P2₁/n (No. 14), a=6.2614(13) Å, b=9.844(2) Å, c=14.271(3) Å, β=92.11(1)°, V=879.0(3) Å³). This structure is built from isolated linear trimers of corner-sharing Fe(III) octahedra, which are linked by (PO₄) groups to form ten-membered-ring channels along [1 0 0]. This isolated, linear trimer of corner-sharing Fe(III) octahedra, [(FeO₄)₃(OH)₂F₂], is new and adds to the diverse linkages of Fe polyhedra as secondary building units in iron phosphates. The trivalent iron at octahedral sites for the title compound has been confirmed by synchrotron Fe K-edge XANES spectra and magnetic measurements. Magnetic measurements also show that this compound exhibit a strong antiferromagnetic exchange below T_N=17 K, consistent with superexchange interactions expected for the linear trimer of ferric octahedra with the Fe-F-Fe angle of 132.5°.     

Syntheses, structures, and vibrational spectroscopy of the two-dimensional iodates Ln(IO3)3 and Ln(IO3)3(H2O) (LnYb, Lu)

The reaction of Lu³⁺ or Yb³⁺ and H₅IO₆ in aqueous media at 180 °C leads to the formation of Yb(IO₃)₃(H₂O) or Lu(IO₃)₃(H₂O), respectively, while the reaction of Yb metal with H₅IO₆ under similar reaction conditions gives rise to the anhydrous iodate, Yb(IO₃)₃. Under supercritical conditions Lu³⁺ reacts with HIO₃ and KIO₄ to yield the isostructural Lu(IO₃)₃. The structures have been determined by single-crystal X-ray diffraction. Crystallographic data are (MoKα, λ=0.71073 Å): Yb(IO₃)₃, monoclinic, space group P2₁/n, a=8.6664(9) Å, b=5.9904(6) Å, c=14.8826(15) Å, β=96.931(2)°, V=766.99(13), Z=4, R(F)=4.23% for 114 parameters with 1880 reflections with I>2σ(I); Lu(IO₃)₃, monoclinic, space group P2₁/n, a=8.6410(9), b=5.9961(6), c=14.8782(16) Å, β=97.028(2)°, V=765.08(14), Z=4, R(F)=2.65% for 119 parameters with 1756 reflections with I>2σ(I); Yb(IO₃)₃(H₂O), monoclinic, space group C2/c, a=27.2476(15), b=5.6296(3), c=12.0157(7) Å, β=98.636(1)°, V=1822.2(2), Z=8, R(F)=1.51% for 128 parameters with 2250 reflections with I>2σ(I); Lu(IO₃)₃(H₂O), monoclinic, space group C2/c, a=27.258(4), b=5.6251(7), c=12.0006(16) Å, β=98.704(2)°, V=1818.8(4), Z=8, R(F)=1.98% for 128 parameters with 2242 reflections with I>2σ(I). The f elements in all of the compounds are found in seven-coordinate environments and bridged with monodentate, bidentate, or tridentate iodate anions. Both Lu(IO₃)₃(H₂O) and Yb(IO₃)₃(H₂O) display distinctively different vibrational profiles from their respective anhydrous analogs. Hence, the Raman profile can be used as a complementary diagnostic tool to discern the different structural motifs of the compounds.     

The extended chain compounds Ln12(C2)3I17 (Ln=Pr, Nd, Gd, Dy): Synthesis, structure and physical properties

The title compounds are obtained in high yield from stoichiometric mixtures of Ln, LnI₃ and graphite, heated at 900-950 °C in welded Ta containers. The crystal structures of new Pr and Nd phases determined by single-crystal X-ray diffraction are related to those of other Ln₁₂(C₂)₃I₁₇-type compounds (C 2/c, a=19.610(1) and 19.574(4) Å, b=12.406(2) and 12.393(3) Å, c=19.062(5) and 19.003(5) Å, β=90.45(3)° and 90.41(3)°, for Pr₁₂(C₂)₃I₁₇ and Nd₁₂(C₂)₃I₁₇, respectively). All compounds contain infinite zigzag chains of C₂-centered metal atom octahedra condensed by edge-sharing into the [tcc]_∞ sequence (c=cis, t=trans) and surrounded by edge-bridging iodine atoms as well as by apical iodine atoms that bridge between chains. The polycrystalline Gd₁₂(C₂)₃I₁₇ sample exhibits semiconducting thermal behavior which is consistent with an ionic formulation (Ln³⁺)₁₂(C₂^6-)₃(I⁻)₁₇(e⁻) under the assumption that one extra electron is localized in metal-metal bonding. The magnetization measurements on Nd₁₂(C₂)₃I₁₇, Gd₁₂(C₂)₃I₁₇ and Dy₁₂(C₂)₃I₁₇ indicate the coexistence of competing magnetic interactions leading to spin freezing at T_f=5 K for the Gd phase. The Nd and Dy compounds order antiferromagnetically at T_N=25 and 29 K, respectively. For Dy₁₂(C₂)₃I₁₇, a metamagnetic transition is observed at a critical magnetic field H≈25 kOe.     

Synthesis, structure and magnetic behaviour of mixed metal leucophosphite

A synthetic analogue of leucophosphite, an iron phosphate, was synthesized hydrothermally at 180 °C and its chemical composition determined to be {K[(FeV)(PO₄)₂(OH)(H₂O)]·H₂O}. The compound crystallizes in the monoclinic P2₁/c space group, with a=9.7210(19) Å, b=9.6500(19) Å, c=12.198(4) Å and β=128.569(18)°. While the original all-iron compound is reported to be antiferromagnetic, the inclusion of substitutional vanadium(III) ions renders the structure ferrimagnetic. Diffraction studies and magnetic characterization show that iron and vanadium are disordered throughout the crystallographic sites. The magnetic behaviour of this system was interpreted in terms of a classic ferrimagnetic mean field model, consisting of two antiferromagnetically coupled non-crystallographic “sublattices”.     

New binuclear vanadium(III) and (IV) squarate species: synthesis, structure and characterization of [V(OH)(H2O)2(C4O4)]2·2H2O and (NH4)[(VO)2(OH)(C4O4)2(H2O)3]·3H2O

Two new vanadium squarates have been synthesized, characterized by infrared and thermal behavior and their structures determined by single crystal X-ray diffraction. Both structures are made of discrete, binuclear vanadium entity but in 1, [V(OH)(H₂O)₂(C₄O₄)]₂·2H₂O the vanadium atom is trivalent and the entity is neutral while in 2, (NH₄)[(VO)₂(OH)(C₄O₄)₂(H₂O)₃]·3H₂O, the vanadium atom is tetravalent and the entity is negatively charged, balanced by the presence of one ammonium ion. Both molecular anions are bridged by two terminal μ₂ squarate ligands. 1 crystallizes in the triclinic system, space group P-1, with lattice constants a=7.5112(10) Å, b=7.5603(8) Å, c=8.2185(8) Å, α=106.904(8)°, β=94.510(10)°, γ=113.984(9)° while 2 crystallizes in the monoclinic system, space group C2/c, with a=14.9340(15) Å, b=6.4900(9) Å, c=17.9590(19) Å and β=97.927(12)°. From the magnetic point of view, V(III) binuclear species show ferromagnetic interactions at low temperatures. However, no anomalies pointing to magnetic ordering are observed down to 2 K.     

Preparation and structures of copper(II) and zinc(II) complexes with 5-ferrocenylpyrimidine: Structural variation derived from flexible coordination ability of the ligand and metal ions

5-Ferrocenylpyrimidine (FcPM) reacts with dinuclear copper(II) carboxylates ([Cu₂(RCOO)₄]; R = C₆H₅, C₅H₁₁, CH₃) to produce one-dimensional coordination polymers [Cu₂(C₆H₅COO)₄(FcPM)]_n (1), [Cu₂(C₅H₁₁COO)₄(FcPM)]_n · nCH₃CN (2), and a discrete tetranuclear complex [Cu₂(CH₃COO)₄(FcPM)₂] (3). Compounds 1 and 2 show similar zigzag chain structures, comprising alternate linking of FcPM and dinuclear copper(II) units, whereas the structure of 3 corresponds to the local structural motifs of 1 and 2. Reaction of FcPM with zinc salts (ZnX₂; X = NO₃, SCN) affords zinc-centered ferrocenyl cluster complexes, [Zn(NO₃)₂(FcPM)₃] (4) and [Zn(SCN)₂(FcPM)₂] · 0.5H₂O (5), with varying M:L ratios. FcPM acts as a bidentate ligand in 1 and 2, and as a monodentate ligand in the others.     

Synthesis, structure, and characterization of hybrid materials: [Ce(H2O)]2[O2C(CH2)2CO2]3 and [Sm(H2O)]2[O2C(CH2)2CO2]3·H2O

The rare-earth dicarboxylate hybrid materials [Ce(H₂O)]₂[O₂C(CH₂)₂CO₂]₃ ([Ce(Suc)]) and [Sm(H₂O)]₂[O₂C(CH₂)₂CO₂]₃·H₂O ([Sm(Suc)]) have been hydrothermally synthesized (200°C, 3 days) under autogenus pressure. [Ce(Suc)] is triclinic, a=7.961 (3) Å, b=8.176 (5) Å, c=14.32 (2) Å, α=97.07° (7), β=96.75° (8), γ=103.73° (6), and z=2. The crystal structure of this compound has been determined using 3120 unique single crystal data. The final refinements let the agreement factors R₁ and wR₂(F²) converge to 0.0138 and 0.0363, respectively. [Ce(Suc)] is built up from infinite chains of edge-sharing nine-fold coordinated cerium atoms running along [100]. These chains are interconnected by the carbon atoms of the succinate anions, leading to a three-dimensional hybrid framework. The cell constants of [Sm(Suc)], isotypic with monoclinic C2/c [Pr(H₂O)]₂[O₂C(CH₂)₂CO₂]₃·H₂O ([Pr(Suc)]), were refined starting from X-ray powder data: a=20.275 (3) Å, b=7.919 (6) Å, c=14.130 (3) Å, and β=121.45° (1). Despite its lower symmetry, [Ce(Suc)] presents an important structural filiation with [Sm(Suc)]     

Synthesis, structure determination, and infrared spectroscopy of (NpO2)2(SO4)(H2O)4: Prevalence of cation-cation interactions and cationic nets in neptunyl sulfate compounds

The compound (NpO₂)₂(SO₄)(H₂O)₄ was synthesized by evaporation of a Np⁵⁺ sulfate solution. The crystal structure was determined using single crystal X-ray diffraction and refined to an R₁=0.0310. (NpO₂)₂(SO₄)(H₂O)₄ crystallizes in triclinic space group P-1, a=8.1102(7) Å, b=8.7506(7) Å, c=16.234(1) Å, α=90.242(2)°, β=92.855(2)°, γ=113.067(2)°, V=1058.3(2) Å³, and Z=2. The structure contains neptunyl pentagonal bipyramids that share vertices through cation-cation interactions to form a sheet or cationic net. The sheet is decorated on each side by vertex sharing with sulfate tetrahedra, and adjacent sheets are linked together through hydrogen bonding. A graphical representation of (NpO₂)₂(SO₄)(H₂O)₄ was constructed to facilitate the structural comparison to similar Np⁵⁺ compounds. The prevalence of the cationic nets in neptunyl sulfate compounds related to the overall stability of the structure is also discussed.     

Lanthanide N,N′-piperazine-bis(methylenephosphonates) (Ln=La, Ce, Nd) that display flexible frameworks, reversible hydration and cation exchange

Hydrothermal syntheses of lanthanide bisphosphonate metal organic frameworks comprising the light lanthanides lanthanum, cerium and neodymium and N,N′-piperazine bis(methylenephosphonic acid) (H₂L(1) and its 2-methyl and 2,5-dimethyl derivatives (H₂L(2) and H₂L(3)) gives three new structure types. At elevated starting pH (ca. 5 and above) syntheses give ‘type I’ materials with all metals and acids of the study (MLnLxH₂O, M=Na, K, Cs; Ln=La, Ce, Nd; x≈4: KCeL(1)·4H₂O, C2/c, a=23.5864(2) Å, b=12.1186(2) Å, c=5.6613(2) Å, β=93.040(2)°). The framework of structure type I shows considerable flexibility as the ligand is changed, due mainly to rotation around the -N-CH₂- bond of the linker in response to steric considerations. Type I materials demonstrate cation exchange and dehydration and rehydration behaviour. Upon dehydration of KCeL·4H₂O, the space group changes to P2₁/n, a=21.8361(12) Å, b=9.3519(4) Å, c=5.5629(3) Å, β=96.560(4)°, as a result of a change of the piperazine ring from chair to boat configuration. When syntheses are performed at lower pH, two other structure types crystallise. With the ‘non-methyl’ ligand 1, type II materials result (LnL(1)H₂L(1)·4.5H₂O: Ln=La, P−1, a=5.7630(13) Å, b=10.213(2) Å, c=11.649(2) Å, α=84.242(2)°, β=89.051(2)°, γ=82.876(2)°) in which one half of the ligands coordinate via the piperazine nitrogen atoms. With the 2-methyl ligand, structure type III crystallises (LnHL(2)·4H₂O: Ln=Nd, Ce, P2₁/c, a=5.7540(9) Å, b=14.1259(18) Å, c=21.156(5) Å, β=90.14(2)°) due to unfavourable steric interactions of the methyl group in structure type II.     

Hydrothermal synthesis and structural characterization of two organically templated zincophosphites with three-dimensional frameworks, (C6H14N2)·[Zn3(HPO3)4] and (C4H12N2)·[Zn3(HPO3)4]

Two organically templated zincophosphites, (C₆H₁₄N₂)·[Zn₃(HPO₃)₄] and (C₄H₁₄N₂)·[Zn₃(HPO₃)₄] have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction. (C₆H₁₄N₂)·[Zn₃(HPO₃)₄] crystallizes in the triclinic space group , with cell parameters, a=9.363(4) Å, b=10.051(4) Å, c=10.051(4) Å, α=85.777(13)°, β=82.091(9)°, and γ=79.783(9)°. (C₄H₁₄N₂)·[Zn₃(HPO₃)₄] crystallizes in the monoclinic space group P2₁/c, with cell parameters, a=9.9512(3) Å, b=10.1508(3) Å, c=17.8105(5) Å, and β=95.6510(10)°. Although the two structures are different, they have the same anionic framework compositions of [Zn₃(HPO₃)₄]²⁻. Their frameworks are built up from strictly alternating ZnO₄ tetrahedra and HPO₃ pseudo pyramids by sharing vertexes. There exist channels with an eight-membered ring window along the a- and c-axis. Powder X-ray diffraction, IR spectroscopy, ³¹P MAS solid-state NMR, thermogravimetric and differential thermal analyses were also carried out.