A novel unexpected luminescent quarternary coordination polymer {Sm3(C8H4O4)4(C12N2H8)2(NO3)}n with three high asymmetrical central Sm fragments by hydrothermal assembly

A novel chain-like luminescent samarium coordination polymer {Sm₃(C₈H₄O₄)₄(C₁₂N₂H₈)₂(NO₃)}_n (C₈H₄O₄ = phthalate, C₁₂N₂H₈ = 1,10-phenanthroline) has been assembled by hydrothermal process. The title complex crystallizes in the monoclinic system, space group P2(1)/c, with lattice parameters a = 22.56(3) Å, b = 11.155(15) Å, c = 20.32(3) Å, β = 96.70(2)°, V = 5078(12) ų, F(000) = 2964, GOF = 0.857, R₁ = 0.0358, wR₂ = 0.0597, Z = 4. Samarium ions exhibit different coordination modes from each other and lead to the unexpected high asymmetrical structure. To our knowledge, it is the first example of lanthanide coordination polymers comprising the three asymmetrical central Sm³⁺ fragments. The photophysical properties have been studied with excitation and emission spectra.     

Hydrothermal synthesis and structure characterization of the first organically templated metal iodates

The first organically templated molybdenum iodates (C₅H₆N)₂Mo₂O₅(IO₃)₄(H₂O)₂ (1), (C₁₀H₈N₂)[MoO₂(IO₃)₃] · H₃O (2), and uranium iodate (C₅H₅N)₂[(UO₂)(IO₃)₃](IO₃) (3), have been successfully synthesized under mild hydrothermal conditions. Compound 1 is simple zero-dimensional units consisting of [(Mo₂O₅(IO₃)₄)]²⁻ anions, which can be described as a tetranuclear unit hanged on either side by two [IO₃] groups. The [Mo₂O₅(IO₃)₄]²⁻ anions are in a close connection through the water molecules and protonated pyridine cations, via hydrogen bonds and intermolecular actions. Compound 2 is built up from [MoO₆] octahedra and [IO₃] pyramids to two-dimensional layers, in which 4,4′-bipy molecules and water cations are located, forming strong hydrogen bonds with the inorganic framework, leading to pseudo three-dimensional structure. Compound 3 is one-dimensional ribbons containing {[(UO₂)(IO₃)₃](IO₃)}²⁻ anions and charge neutrality is achieved by the protonated 4,4′-bipy cations, which reside between two ribbons, forming hydrogen bonds with the inorganic framework and resulting in pseudo two-dimensional structure. Crystal data are as follows: (C₅H₆N)₂Mo₂O₅(IO₃)₄(H₂O)₂ (1), orthorhombic, Pnma, a = 24.097(5) Å, b = 13.532(3) Å, c = 7.836(16) Å, Z = 4, V = 2555.2(9) Å³; (C₁₀H₈N₂)[MoO₂(IO₃)₃] · H₃O (2), monoclinic, C2/c, a = 24.176(5) Å, b = 10.751(2) Å, c = 7.5074(15) Å, β = 107.44(3)°, Z = 8, V = 1861.6(6) Å³; (C₅H₅N)₂[(UO₂)(IO₃)₃](IO₃) (3), monoclinic, P2₁/n, a = 14.430(3) Å, b = 7.3459(15) Å, c = 19.811(4) Å, β = 106.70(3)°, Z = 4, V = 2011.3(7) Å³.     

Bifunctional chelates with mixed aromatic and aliphatic amine donors for labeling of biomolecules with the {Tc(CO)3} and {Re(CO)3} cores

A series of tridentate ligands consisting of mixed aromatic and aliphatic amine derivatives of single amino acid chelates and phenylpiperazine have been developed, and their reactions with [NEt₄]₂[ReBr₃(CO)₃] have been investigated. The compounds [Re(CO)₃{(NC₅H₄CH₂)NCH₃(C₂H₄)NHCH₃}]Br (4), [Re(CO)₃{(NC₅H₄CH₂)NCH₃(C₂H₄)NCH₃(CH₂)_xCOOC₂H₅}]Br (x = 1, 5; x = 4, 6) [Re(CO)₃{(NC₅H₄CH₂)NH(C₂H₄)N(CH₃)₂}]Br (7), [Re(CO)₃{(NC₅H₄CH₂)N(CH ₂COOC₂H₅)(C₂H₄)N(CH₃)₂}]Br (8) and [Re(CO)₃(NC₅H₄CH₂)(C₂H₄NH₂)N(CH₂)₃-CH₃Ophenpip]Br (9) (phenpip: phenylpiperazine, -C₆H₄-(CH₂CH₂)₂N-) were prepared and characterized by elemental analysis, NMR, IR, HSMS and X-ray crystallography. All complexes exhibit fac-{Re(CO)₃N₃} coordination geometry in the cationic molecular unit. Crystal data for C₁₃H₁₇BrN₃O₃Re (4): orthorhombic, Pbca, a = 13.4510(8) Å, b = 10.5728(6) Å, c = 22.5378(13) Å, V = 3205.2(3) ų, Z = 8; C₁₇H₂₃BrN₃O₅Re (5): orthorhombic, Pcca, a = 16.5907(7) Å,b = 14.8387(6) Å, c = 16.7075(7) Å, V = 4113.1(3) ų, Z = 8; C₁₃H₂₅BrN₃O₇Re (7 · 4H₂O): monoclinic, P2₁/n, a = 14.0698(17) Å, b = 9.6760(12) Å, c = 15.6099 (19) Å, β = 114.930(2)°, V = 1927.1(4) ų, Z = 4; C₁₇H₂₃BrN₃O₅Re (8): monoclinic, P2₁/n, a = 7.5312(5) Å, b = 16.0366(10) Å, c = 16.8741(10) Å, β = 98.9990(10)°, V = 2012.9(2) ų, Z = 4.     

Synthesis, crystal structure, magnetic properties and electrochemical behaviour of the mixed valence compound [Cu(CN)3Cu(C3H10N2)2]

The binuclear mixed valence copper(I/II) compound [Cu^I(CN)₃Cu^II(tn)₂] (1) (tn = propane-1,3-diamine) and its acetonitrile adduct [Cu^I(CN)₃Cu^II(tn)₂] · 2MeCN (2) have been synthesized. Complex 1 crystallizes triclinic, space group , a = 8.117(2) Å, b = 8.389(2) Å, c = 11.920(2) Å, α = 108.728(3)°, β = 100.024(3)°, γ = 104.888(4)°, Z = 2, and compound 2 monoclinic, space group P2₁/m, a = 8.752(2) Å, b = 13.243(3) Å, c = 9.549(2) Å, β = 114.678(4)°, Z = 2. In both crystal structures, the binuclear [Cu^I(CN)₃Cu^II(tn)₂] complex with slightly different bonding geometries is formed. One of the three nitrogen atoms of a Cu^I(CN)₃ moiety is coordinated to Cu(II) at the apex of a square-pyramid with two chelating ligands tn on its base. The shortest intramolecular Cu^II?Cu^II distance in 1 is 5.640(7) Å. The EPR behaviour of 1 has been investigated at room temperature and at 77 K. The magnetic properties were measured in the temperature range 1.8-300 K.     

Novel polynuclear thallium thiolates with cage structures

Yellow thallium(I)-tetra(2-butanethiolato)-thallium(III) Tl[Tl(SC₄H₉)₄] (1) crystallizes from a solution of thallium(I) carbonate and 2-butanethiol in DMF after heating under reflux in air. In the crystal structure (space group: , a = 8.941(3) Å, b = 11.078(4) Å, c = 13.458(4) Å, α = 70.81(3)°, β = 83.65(3)°, γ = 74.78(3)°, Z = 2) regular, TlS₄ tetrahedra are bridged by thallium(I) atoms to an one-dimensional framework. The thallium(I) atoms are in fivefold distorted coordination and are linked to four further TlS₄ tetrahedra. The resulting Tl₄(S-Bu)₈ units consist of two face-sharing Tl₃S₄ defect cubane entities.TlSC₃H₇ (2) was obtained from a solution of thallium(I) carbonate and 2-propanethiol in DMF after heating under reflux in air. The crystal structure (space group C2/c, a = 22.501(5) Å, b = 10.360(2) Å, c = 12.760(3) Å, β = 107.92(2)°, Z = 16) contains novel [Tl₄(SPr)₅]⁻ units which are linked via thallium atoms to one-dimensional molecular chains running parallel to [0 0 1].     

Structure and spectroscopic studies of cis-bis(bipyridine) ruthenium(II) complexes of phenylcyanamide ligands

New ruthenium(II) complexes with cyanamide ligands, cis-[Ru(bpy)₂(Ipcyd)₂] (1) and [Ru(bpy)₂(OHpcyd)₂] (2) (bpy = 2,2′-bipyridine, Ipcyd = 4-iodophenylcyanamide anion, OHpcyd = 4-(3-hydroxy-3-methylbut-1-ynil)phenylcyanamide), have been prepared and characterized by UV-Vis, IR and ¹H NMR spectroscopies as well as electrochemical technique (CV). The complex cis-[Ru(bpy)₂(Ipcyd)₂] (1) crystallized with empirical formula of C₃₄H₂₄I₂N₈Ru in a monoclinic crystal system and space group of P2₁/c with a = 11.769(7) Å, b = 24.188(12) Å, c = 11.623(2) Å, β = 91.63(3)°, V = 3308(3) ų and Z = 4.     

Synthesis of bimetallic fulvalene and bis(cyclopentadienyl)methane derivatives of niobium and tantalum tetracarbonyl

Ring coupled bimetallic derivatives (μ-η^5:5-C₅H₄C₅H₄)[Nb(CO)₄]₂ and [μ-CH₂(η⁵-C₅H₄)₂][M(CO)₄]₂, where M = Nb and Ta have been prepared. The molecular structures of the latter two compounds have been determined: , triclinic, , a = 8.028(2) Å, b = 11.414(1) Å, c = 12.711(2) Å, α = 75.020(8)°, β = 80.34(2)°, γ = 79.46(2)°, V = 1097.3(4) ų, Z = 2, R(F) = 2.79%; [μ-CH₂(η⁵-C₅H₄)₂][Ta(CO)₄]₂, triclinic, , a = 7.815(3) Å, b = 10.275(4) Å, c = 13.135(4) Å, α = 104.25(3)°, β = 100.26(4)°, γ = 96.86(3)°, V = 991.2(6) ų, Z = 2, R(F) = 3.00%.     

Synthesis and characterization of new coordination polymers generated from oxadiazole-containing ligands and IIB metal ions

The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L1) and 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2) with inorganic IIB metal salts have been investigated. Five new coordination polymers (1-5) were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Cd(L1)₂(CH₃CN)₂](ClO₄)₂ · (CH₃CN)₂ (1) crystallized in the monoclinic space group P2₁/c, a = 8.4028(5) Å, b = 21.3726(13) Å, c = 10.5617(7) Å, β = 95.1200(10)°, and Z = 2. In the solid state, it adopts an infinite two-dimensional polymeric structural motif with effective cross section of ca. 14.31 × 14.31 Å. Cd(L2)(H₂O)(NO₃)₂ (2) crystallized in the monoclinic space group Ia, a = 7.1203(5) Å, b = 22.2475(15) Å, c = 20.2652(16) Å, β = 90.6080(10)°, and Z = 8. In the solid state, the two Cd(II) centers are connected to each other by L2 ligands and bridging nitrates into a two-dimensional network. [ZnCl₂(L1)] (3) and [HgI₂(L1)] · CH₃CN (4) crystallized in the monoclinic crystal system (3: P2₁/c, a = 5.3702(3) Å, b = 20.4800(11) Å, c = 12.4093(7) Å, β = 94.7930(10)°, and Z = 4; 4: P2/n, a = 17.2733(11) Å, b = 5.2173(3) Å, c = 20.4069(13) Å, β = 102.8690(10)°, and Z = 4). In the solid state, Zn(II) and Hg(II) metal centers are connected to each other by L1 ligands into a zigzag chain motif. Compound 5 (HgBr₂(L2) is different from 3 and 4, monoclinic, P2(1)/n, a = 5.470(4) Å, b = 16.271(13) Å, c = 16.486(12) Å, β = 93.197(15)°, and Z = 4) adopts a novel one-dimensional helical chain motif which resulted from the relative different coordinated orientation of the two N-donors on L2 ligand.     

Homochiral metal-organic coordination networks from l-typtophan

Three homochiral metal-organic coordination networks [Co₂(l-Trp)₂(Py)₆] · Py · (ClO₄)₂ (1), [Ni(l-Trp)(Py)₃] · H₂O · ClO₄ (2) and [Co₂(l-Trp)(INT)₂(H₂O)₂(ClO₄)] (3), all containing natural amino acid l-HTrp (l-typtophan), were hydrothermally synthesized and structurally characterized. The compounds 1 and 2 crystallize in the orthorhombic space group C222₁, with a = 10.731(2) Å, b = 19.709(4) Å, c = 27.365(6) Å and Z = 4 for 1 and a = 10.710(10) Å, b = 20.088(18) Å, c = 27.63(3) Å and Z = 8 for 2, respectively. The compound 3 has the monoclinic space group P2₁, with a = 8.1934(14) Å, b = 13.209(2) Å, c = 12.464(2) Å, β = 104.107(3)° and Z = 2. Both 1 and 2 consist of 1D helical chains. Compound 3 is composed of 2D networks, which further assemble into a 3D supramolecular structure via weak interlayer interactions. The optically pure amino acid l-HTrp plays an important role leading to homochiral structures reported here.     

A novel inorganic and organic mixture cations templated indium phosphate: Synthesis and crystal structure

A novel mixture cations templated indium phosphates, Li(C₂N₂H₁₀)[In₂(HPO₄)₃(PO₄)], has been synthesized under mild hydrothermal conditions and characterized by elemental analysis and FT-IR spectrum. The crystal structure of title compound was determined by single crystal X-ray diffraction data. It belongs to monoclinic, space group P2/n with unit cell dimension a = 9.4692(13) Å, b = 9.1622(12) Å, c = 9.7063(14) Å, β = 117.5620(10)°. Its structure is characterized as a three-dimensional open-framework with 8-membered ring channels along a axis, where the inorganic lithium cation and organic double-protonated ethylenediamine cation are located and interact with the framework both electrostatically and via hydrogen bonds of N-H?O.     

Synthesis, characterization, and luminescence properties of magnesium coordination networks using a thiophene-based linker

By varying the solvents and temperatures under solvothermal conditions, two new magnesium based coordination networks were synthesized using 2,5-thiophenedicarbxoylate as a linker. Mg₃(TDC)₃(DMF)₃ [1; TDC = 2,5 thiophenedicarboxylate; space group P2₁/c, a = 17.747(4) Å, b = 9.805(2) Å, c = 21.359(4) Å, β = 103.13(3)°] is constructed by a combination of magnesium polyhedral trimers, which are connected by the TDC²⁻ linkers to form a 3-D network. Coordinated DMF molecules are present within the channels. Mg(TDC)(H₂O)₂ [2; space group Pnma, a = 7.296(4) Å, b = 17.760(4) Å, c = 6.6631(3) Å] is formed by 1-D chains of magnesium octahedra connected by the TDC²⁻ linker. Water molecules are coordinated at the axial positions of the magnesium octahedra. Compound 1 is formed using DMF as the synthesis solvent at 180 °C, while compound 2 is formed using ethanol as the synthesis solvent at 100 °C. Both compounds show enhanced photoluminescence intensity when excited at 397 nm compared to the free TDC ligand, suggesting a charge transfer between the ligand and the magnesium metal center.     

Hydrothermal synthesis and characterizations of a novel 2-D double-layers metal-organic coordination polymer involving in situ ligand synthesis

A novel 2-D metal-organic coordination polymer [Ni_0.5(apddica)(H₂O)] · H₂O 1 (Hapddica=2-(4-Amino-phenyl)-1,3-dioxo-2,3-dihydro-1H-isoindole-5-carboxylic acid) has been hydrothermally synthesized and structurally characterized by element analyses, IR and XPS spectra, TG analyses and single crystal X-ray diffraction. Crystal data: C₁₅H₁₃N₂Ni_0.5O₆, monoclinic, P2(1)/c, a=12.181(2) Å, b=7.9392(6) Å, c=14.835(3) Å, β=94.25(3) °, V=1430(75) ų, Z=4. Compound 1 exhibits a novel 2-D double-layers network based on apddica and Ni center. It is noteworthy that new ligand Hapddica was first prepared with hydrothermal technique involving in situ ligand synthesis and used for constructing coordination polymers. There are unusual parallelogram tunnels along a-axis in which the dissociative water molecules filled in. The magnetic property of compound has been studied.     

Octahedral cyanohydroxo cluster complex trans-[Re6Se8(CN)4(OH)2]: Synthesis, crystal structure, and properties

A hexarhenium cyanohydroxo anionic cluster complex [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was synthesized for the first time starting from [Re₆Se₈(OH)₆]⁴⁻, which was crystallized as a salt of the composition Cs_2.75K_1.25[Re₆Se₈(CN)₄(OH)₂]·H₂O (1). The reaction of the complex with Cu²⁺ in an aqueous ammonia or methylamine solutions afforded [Cu(NH₃)₅]₂[Re₆Se₈(CN)₄(OH)₂]·8H₂O (2) or [{Cu(CH₃NH₂)₄}₂Re₆Se₈(CN)₄(OH)₂] (3), respectively. All of these three compounds were characterized by a single-crystal X-ray diffraction method. Compound 1 is crystallized in the tetragonal space group I4/m with eight formula units per cell (a = b = 17.4823(14) Å, c = 19.430(2) Å, V = 5938.3(10) Å³); compound 2 is crystallized in the monoclinic space group P2₁/n with two formula units per cell (a = 12.1845(13) Å, b = 8.6554(9) Å, c = 19.2568(19) Å, β = 91.081(2)°, V = 2030.5(4) Å³); compound 3 is crystallized in the orthorhombic space group Cmcm with four formula units per cell (a = 19.816(4) Å, b = 14.611(3) Å, c = 13.751(3) Å, V = 3981.2(13) Å³). The luminescence properties of 1 were studied in both aqueous solution and solid state. In addition, the electronic structure of [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was elucidated by DFT calculations.     

Syntheses, structures, and magnetic properties of two new μ-alkoxo-μ-pyrazolato bridged dicopper(II) complexes

The syntheses, structures, and magnetic properties of two new μ-alkoxo-μ-pyrazolato heterobridged compounds, [Cu ^II₂(L¹-F)(μ-prz)] (1) and [Cu ^II₂(L¹-2OMe) (μ-prz)] · 0.5 CH₃CN (2) (prz=pyrazolato; H₂L¹-F=1,3-bis(3-fluorosalicylideneamino)-2-propanol; H₂L¹-2OMe=1,3-bis(4,6-dimethoxy salicylideneamino)-2-propanol) have been reported. Compound 1 crystallizes in triclinic space group with a=8.6392(10) Å, b=10.6431(9) Å, c=11.6809(13) Å, α=85.972(8)°, β=71.492(9)°, and γ=72.221(9)°, while the unit cell parameters of 2 are as follows: space group: monoclinic C2/c, a=28.2948(5) Å, b=7.3033(2) Å, c=26.3933(5) Å, and β=96.243(1)°. The variable-temperature magnetic susceptibility measurements reveal that the metal centers in both the compounds are antiferromagnetically coupled with J=−200 cm⁻¹ for 1 and J=−175 cm⁻¹ for 2. The magnetic behaviors have been explained on the basis of two opposing factors, complementarity and countercomplementarity of magnetic orbitals.     

An unprecedented (3,4)-connected self-penetrating network of zinc complex: In situ formation of a tetradentate N-heterocyclic ligand under POMs-mediated hydrothermal conditions

The reaction of lacunary polyanion [α-H₂P₂W₁₂O₄₈]¹²⁻, zinc acetate, bpp (1,3-bis(4-pyridyl)propane) and BTC (1,3,5-benzenetricarboxylate) in an acidic aqueous solution led to the isolation of a new complex [Zn₃(BTC)₂(chtpy)(H₂O)₂] · 2H₂O (1), which crystallizes in the space group C2/c with a = 28.988(6) Å, b = 11.254(2) Å, c = 17.347(4) Å, V = 4682.5(2) Å³, Z = 4. X-ray diffraction analysis reveals that there exists the generation of in situ ligand through simultaneous dehydrogenative coupling and hydroxylation of an N-heterocyclic ligand in complex 1. More interestingly, it exhibits an unprecedented (3,4)-connected (8².10)₂(8³)₂(8⁴.10.12)(8⁵.10) topology which has been reported for the first time and shows self-penetrating nature at the same time.     

A ferromagnetically coupled tetranuclear pseudo-cubane copper(II) cluster: magnetic and ESR studies

A tetranuclear copper(II) complex [Cu₄(NSI)₄] · 2C₂H₅OH · 2H₂O (NSI=hydroxethylsalicydeneimine) has been synthesized and characterized by X-ray diffraction analysis. The compound crystallizes in the monoclinic system, space group P2(1), a=9.494(3) Å, b=18.687(5) Å, c=13.149(4) Å, β=110.162(5)°, Z=2, R₁=0.0482 and wR₂=0.0978. The crystal structure contains a tetranuclear pseudo-cubane core based on an approximately cubane array of alternating copper and oxygen atoms. Each copper atom resides in a distorted square planar coordination environment with one nitrogen and three oxygen atoms from two NSI ligands. The tetranuclear units are linked in the crystal by O-H?O hydrogen bonds and weak Cu?O co-ordination bonds into one-dimensional structure. Variable temperature (5-300 K) magnetic measurements indicate the existence of ferromagnetic interactions among copper atoms. The IR and ESR spectra have also been investigated.     

Hydrothermal synthesis and structural investigation of silver magnesium complex of benzenehexacarboxylic acid (mellitic acid), Ag2Mg2[C6(COO)6] · 8H2O with two-dimensional layered structure

Crystal and molecular structure of silver magnesium mellitate, Ag₂Mg₂[C₆(COO)₆] · 8H₂O, was synthesized hydrothermally and characterized by X-ray structure analysis. The complex crystallizes in the monoclinic system, space group P2/n, with unit cell dimensions of a=7.4347(2), b=9.9858(2), c=14.4248(3) Å, β=99.2429(5)°, V=1055.01(4) ų, and Z=2. The structure was solved and refined to R=0.036 (R_w=0.045) for 1707 independent reflections [I_o>2σ(I_o)]. The Ag cations are coordinated by six carboxylic oxygen atoms of mellitate anions with composition of [C₆(COO)₆]⁶⁻ on the (1 0 1) plane; each mellitate anion linking three neighboring Ag distorted trigonal prisms produces a two-dimensional layered structure parallel to (1 0 1). The Mg cations, which are coordinated by four water molecules and two carboxylic oxygen atoms, are intercalated between the two-dimensional layer stacks. The carboxylate group coordinated to Mg and Ag cations serve as a tridentate ligand in that structure. The number of water molecules incorporated into the mellitate compound is controlled mainly by ionic radii of metal cation in the structure. Furthermore, the ionic radii of metal cations in the mellitate compound play an essential role in arrangement of mellitate anions in the structure, whether as a one-dimensional infinite chain, a two-dimensional layered structure, or a three-dimensional framework structure.     

Hydrothermal syntheses and structures of a novel zincophosphite, [C6N2H18] · [Zn3(HPO3)4]

A novel three-dimensional organically templated zincophosphite, [C₆N₂H₁₈] · [Zn₃(HPO₃)₄], was synthesized under milder hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, differential thermal-thermogravimetric analysis, powder X-ray diffraction, ³¹P MAS NMR spectrum, and IR spectroscopy. It crystallizes in the monoclinic system, space group C2/c with cell parameters: a = 8.7820(4) Å, b = 14.9417(7) Å, c = 15.4943(5) Å, β = 92.940(2)°, and Z = 4. The structure consists of a network of strictly alternating ZnO₄ tetrahedra and pseudo-pyramid, forming 4-membered ring chains. The structure has a 4.8.16-net and 8- and 16-membered ring channels where completely protonated N,N,N′,N′-tetramethylenediamine cations are encapsulated. The structure is stabilized by template-to-framework hydrogen bonding. In phosphites system, this compound possesses extra-large-pores.     

Structure and electrochemistry of the bridging-ligand mono-substituted diruthenium compound, [Ru2(II,III)(O2CCH3)3(admpym)(Cl)(MeOH)] (Hadmpym=2-amino-4,6-dimethylpyrimidine)

The ligand substitution reaction of Ru₂(O₂CCH₃)₄Cl with 2-amino-4,6-dimethylpyrimidine (Hadmpym) under gentle refluxing conditions in methanol led to the formation of a bridging-ligand mono-substituted compound, [Ru₂(O₂CCH₃)₃(admpym)(Cl)(MeOH)] (1). Compound 1 crystallized in monoclinic space group P2₁/n (no. 14) with a=8.3074(8) Å, b=12.3722(8) Å, c=18.913(1) Å, β=95.559(3)°, V=1934.8(3) ų, and Z=4. Temperature dependence of the magnetic susceptibility of 1 revealed it to be in a spin ground state S=3/2 arising from the electronic configuration of σ²π⁴δ²(δ*π*)³. Compound 1 undergoes three metal-centered redox reactions in electrochemistry: E_1/2 ^(ox)=+0.72 V (I_a/I_c<1, ΔE_p=0.17 V); E_1/2 ^(1,red)=−0.65 V (I_a/I_c≈1, ΔE_p=0.10 V); and E_1/2 ^(2,red)=−1.80 V (I_a/I_c?1, ΔE_p=0.16 V). Then, the redox species produced by electrolysis were characterized by spectroscopic studies.     

Octahedral hexanuclear complexes involving light lanthanide ions

Two new hexanuclear complexes involving two of the lightest lanthanide ions have been synthesized and structurally described. Their chemical formula is [Ln₆(μ₆-O)(μ₃-OH)₈(NO₃)₆(H₂O)₁₄] · 2NO₃ · 2H₂O with Ln = Pr or Nd. The structure has been solved for the Pr³⁺-containing compound. It crystallizes in the monoclinic system, space group P21/n (no. 14) with a = 12.4163(2) Å, b = 10.51210(10) Å, c = 16.0389(2) Å, β = 95.7810(6)° and Z = 4. The chemical and thermal stabilities of both the compounds have been studied. These studies reveal that they can be used as molecular chemical precursors for further materials synthesis. To the best of our knowledge, this praseodymium-containing hexanuclear complex is the first ever reported.