Characterization of Ni(II) and Cu(II) complexes of 4-(2-Quinolylmethyleneamino)-1-phenyl-2,3-dimethyl-5-pyrazolone and their analytical applications

A synthesis of the new reagent 4-(2-quinolylmethyleneamino)-1-phenyl-2,3-dimethyl-5-pyrazolone (QPP) and of its complexes with Ni(II) and Cu(II) is described. The structure of the ligand itself and the nature of the bonding in complex molecules were determined by elemental analysis, IR, and mass spectrometry. The analysis of data showed that isolated crystal metal complexes are of the ML₂ type. The composition and stability constants of the complexes in water/methanol solutions, (methanol) = 0.16, at constant temperature 25 ±1 °C and ionic strength of 0.5 M (KNO₃) at different pH (4, 6, 8, and 10) have been determined spectrophotometrically. The results indicate that the metal complexes formed in the solution have a metal-to-ligand ratio 1:2. The reaction of QPP with Ni(II) and Cu(II) in solution was quantitatively studied. The lowest detection limit for the determination of Ni is 0.3 μg/ml while that for Cu is 0.05 μg/ml under the investigated experimental Conditions.     

Bis(trifluoroacetyl) peroxide, CF(3)C(O)OOC(O)CF(3)

Pure, highly explosive CF(3)C(O)OOC(O)CF(3) is prepared for the first time by low-temperature reaction between CF(3)C(O)Cl and Na(2)O(2). At room temperature CF(3)C(O)OOC(O)CF(3) is stable for days in the liquid or gaseous state. The melting point is -37.5 degrees C, and the boiling point is extrapolated to 44 degrees C from the vapor pressure curve log p = -1875/T + 8.92 (p/mbar, T/K). Above room temperature the first-order unimolecular decay into C(2)F(6) + CO(2) occurs with an activation energy of 129 kJ mol(-1). CF(3)C(O)OOC(O)CF(3) is a clean source for CF(3) radicals as demonstrated by matrix-isolation experiments. The pure compound is characterized by NMR, vibrational, and UV spectroscopy. The geometric structure is determined by gas electron diffraction and quantum chemical calculations (HF, B3PW91, B3LYP, and MP2 with 6-31G basis sets). The molecule possesses syn-syn conformation (both C=O bonds synperiplanar to the O-O bond) with O-O = 1.426(10) A and dihedral angle phi(C-O-O-C) = 86.5(32) degrees. The density functional calculations reproduce the experimental structure very well.     

OH(3) (-) and O(2)H(5) (-) double Rydberg anions: predictions and comparisons with NH(4) (-) and N(2)H(7) (-)

A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra.     

Chemically induced magnetism and magnetoresistance in La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4)

It is shown by magnetometry and microSR spectroscopy that short-range magnetic interactions between the Mn cations in the nonmetallic K(2)NiF(4)-like phase La(0.8)Sr(1.2)Mn(0.6)Rh(0.4)O(4) become significant below approximately 200 K. Negative magnetoresistance (rho/rho(0) approximately 0.5 in 14 T at 108 K) is apparent below this temperature. Neutron diffraction has shown that an applied magnetic field of 5 T is sufficient to induce saturated (3.38(7)mu(B) per Mn) long-range ferromagnetic ordering of the atomic moments at 2 K, and that the induced ordering persists up to a temperature of 50 K in 5 T. Spin glass behavior is observed below 20 K in the absence of an applied field. The induced magnetic ordering is attributed to the subtle changes in band structure brought about by the external field, and to the controlling influence of Rh(3+) over the relative strength of competing magnetic exchange interactions.     

New layered materials: syntheses, structures, and optical properties of K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiaAg(2)S(4), Cs(2)TiAg(2)sS(4), and Cs(2)TiCu(2)Se(4)

The new compounds K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiAg(2)S(4), Cs(2)TiAg(2)S(4), and Cs(2)TiCu(2)Se(4) have been synthesized by the reactions of A(2)Q(3) (A = K, Rb, Cs; Q = S, Se) with Ti, M (M = Cu or Ag), and Q at 823 K. The compounds Rb(2)TiCu(2)S(4), Cs(2)TiAg(2)S(4), and Cs(2)TiCu(2)Se(4) are isostructural. They crystallize with two formula units in space group P4(2)/mcm of the tetragonal system in cells of dimensions a = 5.6046(4) A, c = 13.154(1) A for Rb(2)TiCu(2)S(4), a =6.024(1) A, c = 13.566(4) A for Cs(2)TiAg(2)S(4), and a =5.852(2) A, c =14.234(5) A for Cs(2)TiCu(2)Se(4) at 153 K. Their structure is closely related to that of Cs(2)ZrAg(2)Te(4) and comprises [TiM(2)Q(4)(2)(-)] layers, which are separated by alkali metal atoms. The [TiM(2)Q(4)(2)(-)] layer is anti-fluorite-like with both Ti and M atoms tetrahedrally coordinated to Q atoms. Tetrahedral coordination of Ti(4+) is rare in the solid state. On the basis of unit cell and space group determinations, the compounds K(2)TiCu(2)S(4) and Rb(2)TiAg(2)S(4) are isostructural with the above compounds. The band gaps of K(2)TiCu(2)S(4), Rb(2)TiCu(2)S(4), Rb(2)TiAg(2)S(4), and Cs(2)TiAg(2)S(4) are 2.04, 2.19, 2.33, and 2.44 eV, respectively, as derived from optical measurements. From band-structure calculations, the optical absorption for an A(2)TiM(2)Q(4) compound is assigned to a transition from an M d and Q p valence band (HOMO) to a Ti 3d conduction band.     

Cyclotriphosphazene hydrazides as efficient multisite coordination ligands. eta(3)-fac-non-geminal-N(3) coordination of spiro-N(3)P(3)[O(2)C(12)H(8)][N(Me)NH(2)](4) (L) in L(2)CoCl(3) and L(2)M(NO(3))(2) (M = Ni, Zn, Cd)

The cyclophosphazene tetrahydrazide spiro-N(3)P(3)[O(2)C(12)H(8)][N(Me)NH(2)](4) (L) functions as a multisite coordination ligand and affords L(2)CoCl(3).2CH(3)OH (4), L(2)Ni(NO(3))(2).2CHCl(3).2.5H(2)O (5), L(2)Zn(NO(3))(2).2CH(3)CN.2H(2)O (6), and L(2)Cd(NO(3))(2) (7). Each of the cyclophosphazene ligands that is involved in coordination to the metal functions as a non-geminal-N(3) donor coordinating through one ring nitrogen atom and two non-geminal-NH(2) nitrogen atoms. The coordination geometry around the metal ion in 4-6 is approximately octahedral while it is severely distorted in the case of 7.     

Synthesis of bis(diethyldithiocarbamato)manganese(II) and tris(diethyldithiocarbamato)manganese(III)

An ideal undergraduate introduction to the challenges of synthesis and characterization of air-sensitive compounds is accomplished in the preparation of bis(diethyldithiocarbamato)manganese(II). This economical experiment employs a glovebag, low-cost and low-toxicity chemicals, and is completed in one undergraduate laboratory period. For comparison purposes, the synthesis and characterization of air-stable tris(diethyldithiocarbamato)manganese(III) is also described.     

Further Examples of the P-O-P Connection in Borophosphates: Synthesis and Characterization of Li(2) Cs(2) B(2) P(4) O(15) , LiK(2) BP(2) O(8) , and Li(3) M(2) BP(4) O(14) (M=K, Rb)

A new series of anhydrous mixed alkali-metal borophosphates-Li(2) Cs(2) B(2) P(4) O(15) (1), LiK(2) BP(2) O(8) (2), Li(3) K(2) BP(4) O(14) (3), and Li(3) Rb(2) BP(4) O(14) (4)-have been successfully synthesized by using the conventional solid-state reaction method. Compound 1 contains a novel fundamental building unit (FBU), [B(4) P(8) O(30) ], with B/P=1:2. Compound 2 contains an FBU of [B(2) P(4) O(16) ] with B/P=1:2. Compounds 3 and 4 are isotypic, and they have a [B(P(2) O(7) )(2) ] unit as their FBU. In all four compounds, their FBUs are connected through corner sharing to generate layered anionic partial structures, and then further linked with metallic polyhedra to form three-dimensional (3D) frameworks. Most interestingly, three of the four compounds contain direct P-O-P connections in their structures, which is extremely rare among borophosphates. Thermal analyses, IR spectroscopy, and UV/Vis/near-IR diffuse reflectance spectroscopy have also been performed on the four title compounds.     

Tris(dimethylamino)oxosulfonium difluorotrimethylsilicate, (Me(2)N)(3)SO(+)Me(3)SiF(2)(-) (TAOS Fluoride)

In the OSF(4)/Me(2)NSiMe(3) system besides the long known Me(2)NS(O)F(3) only the trisubstituted derivative is isolated as (Me(2)N)(3)SO(+)Me(3)SiF(2)(-) (3). Similar to (Me(2)N)(3)S(+)Me(3)SiF(2)(-) compound 3 is an excellent fluoride ion donor. With AsF(5) and HF the corresponding hexafluoroarsenate (Me(2)N)(3)SO(+)AsF(6)(-) (4) and the hydrogen bifluoride (Me(2)N)(3)SO(+)HF(2)(-) (5) are formed in almost quantitative yield. X-ray structure determinations of 3-5 surprisingly showed two different types of structures for the cation. In 3 and 5 this cation has C(3) symmetry, while in the hexafluoroarsenate 4 a (Me(2)N)(3)S(+)-like structure with C(s)() symmetry is determined. The experimental results for (Me(2)N)(3)SO(+) and (Me(2)N)(3)S(+) are compared with theoretical calculations for these cations and their isoelectronic neutral counterparts, the phosphorus amides (Me(2)N)(3)PO and (Me(2)N)(3)P, respectively.     

Silver(I) undecafluorodiantimonate(V)

The reaction between AgBF4 and excess of SbF5 in anhydrous hydrogen fluoride (aHF) yields the white solid AgSb2F11 after the solvent and the excess of SbF5 have been pumped off. Reaction between equimolar amounts of AgSb2F11 and AgBF4 yields AgSbF6. Meanwhile, oxidation of solvolyzed AgSb2F11 in aHF by elemental fluorine yields a clear blue solution of solvated Ag(II) cations and SbF6- anions. AgSb2F11 is orthorhombic, at 250 K, Pbca, with a=1091.80(7) pm, b=1246.28(8) pm, c=3880.2(3) pm, V=5.2797(6) nm3, and Z=24. The crystal structure of AgSb2F11 is related to the already known crystal structure of H3OSb2F11. Vibrational spectra of AgSb2F11 entirely match the literature-reported vibrational spectra of beta-Ag(SbF6)2, for which a formulation of a mixed-valence AgI/AgIII compound was suggested (AgIAgIII(SbF6)4). On the basis of obtained results it can be concluded that previously reported beta-Ag(SbF6)2 is in fact Ag(I) compound with composition AgSb2F11.     

{H(3-(t)Bupz)B(3-(t)Bupz)(2)-eta(2)}AlEt(2) and {H(3-(t)Bupz)B(3-(t)Bupz)(5-(t)Bupz)-eta(2)}AlEt(2). Structure, Dynamic Solution Behavior, and the 1,2-Borotropic Shift

HB(3-(t)Bupz)(3)Tl and AlEt(3) in benzene yield {H(3-(t)Bupz)B(3-(t)Bupz)(2)-eta(2)}AlEt(2), 1, as a hydrocarbon-soluble crystalline solid. Compound 1 is also obtained in a related reaction involving ClAlEt(2) via a preferential metathesis of the Al-Cl bond. Crystal data for 1 at -101 degrees C: a = 11.770(3) ?, b = 11.054(3) ?, c = 21.973(6) ?, beta = 95.57(1) degrees, Z = 4, space group P2(1)/a. In 1 the Al center is four-coordinate with Al-C = 1.97(1) ? and Al-N = 1.99(1) ? and with C-Al-C = 127 degrees and N-Al-N = 101 degrees being the largest and smallest angles, respectively. The average N-B-N angle is 109(1) degrees. In toluene-d(8) and tetrahydrofuran-d(8), 1 shows two types of 3-(t)Bupz groups in the integral ratio 2:1 and two distinct ethyl ligands. At low temperature there is a broadening of the 3-(t)Bupz singlet that is assigned to the eta(2)-(t)Bupz ligands. Up to +60 degrees C, compound 1 is nonfluxional on the NMR time scale but does isomerize to {H(3-(t)Bupz)B(3-(t)Bupz)(5-(t)Bupz)-eta(2)}AlEt(2), 2. Crystal data for 2 at -172 degrees C: a = 29.235(5) ?, b = 11.298(1) ?, c = 22.033(3) ?, beta = 129.66(1) degrees, Z = 8, space group = C2/c. In 2 there is a pseudotetrahedral Al center with Al-C = 1.97(1) ? (average) and Al-N = 1.95(1) ? (average) and with C-Al-C = 119 degrees and N-Al-N = 98 degrees as the largest and smallest angles, respectively. The average N-B-N angle is 108(1) degrees. In 2 the eta(2)-tris(alkylpyrazolyl)borate ligand isomerizes by a 1,2-borotropic shift to give one 5-(t)Bupz fragment that is part of the eta(2)-N,N' aluminum-bonded ligand. Variable-temperature (1)H NMR spectra of 2 in toluene-d(8) and THF-d(8) reveal temperature-dependent exchange involving the 3-(t)Bupz moieties, with more rapid site exchange in toluene-d(8) than in THF-d(8). At low temperature there are two ethyl signals, one of which indicates diastereotopic methylene protons, as well as three (t)Bu signals in the ratio 1:1:1. The dynamic behavior of 2 is consistent with an eta(2) right harpoon over left harpoon eta(3) exchange process as opposed to an eta(2) right harpoon over left harpoon eta(1) exchange wherein the Al center is transiently three-coordinate. The isomerization of 1 to 2 has been studied in benzene-d(6) (DeltaH() = 21.0(2) kcal/mol, DeltaS() = -15(1) eu) and THF-d(8) (DeltaH() = 18.3(4) kcal/mol, DeltaS() = -15(1) eu) and compared to a related isomerization involving {H(2)B(3-(t)Bupz)(2)-eta(2)}AlMe(2) reported by Parkin and Looney [Polyhedron 1990, 9, 265] in benzene-d(6) (DeltaH() = 34.5(8) kcal/mol, DeltaS() = 6(2) eu). It is proposed that the rate-determining 1,2-borotropic shift in the 1 --> 2 reaction occurs in a noncoordinating (t)Bupz group and that this is followed by a rapid associative interchange of pz groups wherein the sterically less demanding 5-(t)Bupz moiety remains bound to the metal.     

Rhodium-catalyzed dehydrocoupling of the sterically encumbered phosphine-borane adduct tBu(2)PH.BH(3): synthesis of the linear dimers tBu(2)PH-BH(2)-tBu(2)P-BH(3) and tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl

The dehydrocoupling of the sterically hindered phosphine-borane adduct tBu(2)PH.BH(3) above 140 degrees C is catalyzed by the rhodium complexes [Rh(1,5-cod)(2)][OTf] or Rh(6)(CO)(16) to give the four-membered chain tBu(2)PH-BH(2)-tBu(2)P-BH(3) (1), which was isolated in 60% yield and characterized by multinuclear NMR spectroscopy, mass spectrometry, and elemental analysis. Thermolysis of 1 in the temperature range 175-180 degrees C led to partial decomposition and the formation of tBu(2)PH.BH(3). When the dehydrocoupling of tBu(2)PH.BH(3) was performed in the presence of [[Rh(mu-Cl)(1,5-cod)](2)] or RhCl(3) hydrate, the chlorinated compound tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl (2) was formed which could not be obtained free of 1. The molecular structures of tBu(2)PH.BH(3), tBu(2)PH-BH(2)-tBu(2)P-BH(3) (1), and tBu(2)PH-BH(2)-tBu(2)P-BH(2)Cl (2) together with 1 were determined by single-crystal X-ray diffraction studies.     

Solid state NMR characterization of individual compounds and solid solutions formed in Sc(2)O(3)--V(2)O(5)--Nb(2)O(5)--Ta(2)O(5) system

In this study, (51)V, (45)Sc and (93)Nb MAS NMR combined with satellite transition spectroscopy analysis were used to characterize the complex solid mixtures: VNb(9(1-x))Ta(9x)O(25), ScNb((1-x))Ta(x)O(4) and ScNb(2(1-x))Ta(2x)VO(9) (x = 0, 0.3, 0.5, 0.7, 1.0). This led us to describe the structures of Sc and V sites. The conclusions were based on accurate values for (51)V quadrupole coupling and chemical shift tensors obtained with (51)V MAS NMR/SATRAS for VNb(9)O(25), VTa(9)O(25) and ScVO(4). The (45)Sc NMR parameters have been obtained for Sc(2)O(3), ScVO(4), ScNbO(4) and ScTaO(4). On the basis of (45)Sc NMR and data available from literature, the ranges of the (45)Sc chemical shift have been established for ScO(6) and ScO(8). The gradual change of the (45)Sc and (51)V NMR parameters with x confirms the formation of solid solutions in the process of synthesis of VNb(9(1-x))Ta(9x)O(25) and ScNb((1-x))Ta(x)O(4), in contrast to ScNb(2(1-x))Ta(2x)VO(9). The cation sublattice of ScNb((1-x))Ta(x)O(4) is found to be in octahedral coordination. The V sites in VNb(9(1-x))Ta(9x)O(25) are present in the form of slightly distorted tetrahedra. The (93)Nb NMR parameters have been obtained for VNb(9)O(25).     

Syntheses and structures of the infinite chain compounds Cs(4)Ti(3)Se(13), Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14)

The alkali metal/group 4 metal/polychalcogenides Cs(4)Ti(3)Se(13), Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14) have been synthesized by means of the reactive flux method at 823 or 873 K. Cs(4)Ti(3)Se(13) crystallizes in a new structure type in space group C(2)(2)-P2(1) with eight formula units in a monoclinic cell at T = 153 K of dimensions a = 10.2524(6) A, b = 32.468(2) A, c = 14.6747(8) A, beta = 100.008(1) degrees. Cs(4)Ti(3)Se(13) is composed of four independent one-dimensional [Ti(3)Se(13)(4-)] chains separated by Cs(+) cations. These chains adopt hexagonal closest packing along the [100] direction. The [Ti(3)Se(13)(4-)] chains are built from the face- and edge-sharing of pentagonal pyramids and pentagonal bipyramids. Formal oxidation states cannot be assigned in Cs(4)Ti(3)Se(13). The compounds Rb(4)Ti(3)S(14), Cs(4)Ti(3)S(14), Rb(4)Hf(3)S(14), Rb(4)Zr(3)Se(14), Cs(4)Zr(3)Se(14), and Cs(4)Hf(3)Se(14) crystallize in the K(4)Ti(3)S(14) structure type with four formula units in space group C(2)(h)()(6)-C2/c of the monoclinic system at T = 153 K in cells of dimensions a = 21.085(1) A, b = 8.1169(5) A, c = 13.1992(8) A, beta = 112.835(1) degrees for Rb(4)Ti(3)S(14);a = 21.329(3) A, b = 8.415(1) A, c = 13.678(2) A, beta = 113.801(2) degrees for Cs(4)Ti(3)S(14); a = 21.643(2) A, b = 8.1848(8) A, c = 13.331(1) A, beta = 111.762(2) degrees for Rb(4)Hf(3)S(14); a = 22.605(7) A, b = 8.552(3) A, c = 13.880(4) A, beta = 110.919(9) degrees for Rb(4)Zr(3)Se(14); a = 22.826(5) A, b = 8.841(2) A, c = 14.278(3) A, beta = 111.456(4) degrees for Cs(4)Zr(3)Se(14); and a = 22.758(5) A, b = 8.844(2) A, c = 14.276(3) A, beta = 111.88(3) degrees for Cs(4)Hf(3)Se(14). These A(4)M(3)Q(14) compounds (A = alkali metal; M = group 4 metal; Q = chalcogen) contain hexagonally closest-packed [M(3)Q(14)(4-)] chains that run in the [101] direction and are separated by A(+) cations. Each [M(3)Q(14)(4-)] chain is built from a [M(3)Q(14)] unit that consists of two MQ(7) pentagonal bipyramids or one distorted MQ(8) bicapped octahedron bonded together by edge- or face-sharing. Each [M(3)Q(14)] unit contains six Q(2)(2-) dimers, with Q-Q distances in the normal single-bond range 2.0616(9)-2.095(2) A for S-S and 2.367(1)-2.391(2) A for Se-Se. The A(4)M(3)Q(14) compounds can be formulated as (A(+))(4)(M(4+))(3)(Q(2)(2-))(6)(Q(2-))(2).     

二—(2,2''''—联吡啶)—三—(硝酸)合镧(Ⅲ)La(C_(10)H_8N_2)_2(NO_3)_3的电子结构和化学键

引 言 希土化合物由于涉及f轨道,用分子轨道方法有一定困难,前人曾采用过多种处理方法。文献[8]报导了希土-2,2’-联吡啶配位方法和性质研究。文献[8],[9]对镧与2,2—联吡啶,硝酸配合物的合成,性质和结构亦作过研究。本文采用适用于镧系元素化合物电子结构计算的自旋非限制的INDO方法来研究La(C_(10)H_8N_2)_2(NO_3)_3的电子结构和化学键。     

Phosphine-boranes as bidentate ligands: formation of [8,8-eta(2)-(eta(2)-(BH(3)).dppm)-nido-8,7-RhSB(9)H(10)] and [9,9-eta(2)-(eta(2)-(BH(3)).dppm)-nido-9,7,8-RhC(2)B(8)H(11)] from [8,8-(eta(2)-dppm)-8-(eta(1)-dppm)-nido-8,7-RhSB(9)H(10)] and [9,9-(eta(2)-dppm)-9-(eta(1)-dppm)-nido-9,7,8-RhC(2)B(8)H(11)], respectively

The two clusters [8,8-(eta(2)-dppm)-8-(eta(1)-dppm)-nido-8,7-RhSB(9)H(10)] (1) and [9,9-(eta(2)-dppm)-9-(eta(1)-dppm)-nido-9,7,8-RhC(2)B(8)H(11)] (2) (dppm = PPh(2)CH(2)PPh(2)), both of which contain pendant PPh(2) groups, react with BH(3).thf to afford the species [8,8-eta(2)-(eta(2)-(BH(3)).dppm)-nido-8,7-RhSB(9)H(10)] (3) and [9,9-eta(2)-(eta(2)-(BH(3)).dppm))-nido-9,7,8-RhC(2)B(8)H(11)] (4), respectively. These two species are very similar in that they both contain the bidentate ligand [(BH(3)).dppm], which coordinates to the Rh center via a PPh(2) group and also via a eta(2)-BH(3) group. Thus, the B atom in the BH(3) group is four-coordinate, bonded to Rh by two bridging hydrogen atoms, to a terminal H atom, and to a PPh(2) group. At room temperature, the BH(3) group is fluxional; the two bridging H atoms and the terminal H atom are equivalent on the NMR time scale. The motion is arrested at low temperature with DeltaG++ = ca. 37 and 42 kJ mol(-1), respectively, for 3 and 4. Both species are characterized completely by NMR and mass spectral measurements as well as by elemental analysis and single-crystal structure determinations.     

Six-fold oxygen-coordinated triplet (S = 1) palladium(II) moieties templated by tris(bipyridine)ruthenium(II) ions

Tris(bipyridine)ruthenium(II) is used as a templating agent to insert palladium(II) into three-dimensional oxalate-based networks. The templated-assembly of [Ru(bpy)(3)][Pd(2)(ox)(3)] (Pd(2)) and [Ru(bpy)(3)][PdMn(ox)(3)] (PdMn) is described. The latter compound is structurally characterized by powder X-ray diffraction and X-ray absorption spectroscopy. These techniques reveal an unusual 6-fold oxygen environment around the Pd(II) atoms with two short (2.02 Angstrom) and four long (2.17 Angstrom) Pd-O distances. As stated by magnetometry, this environment is associated with a triplet ground state (S = 1) of the palladium(II) ion: when the temperature is decreased, the chiMT product shows a monotonous decrease from 5.54 cm(3) K mol(-1) at 300 K, a value which is slightly lower than the one expected for independent paramagnetic Pd(II) (S = 1, g = 2) and Mn(II) (S = 5/2, g = 2) ions. This thermal variation is due to antiferromagnetic exchange interactions between the two spin bearers. Nevertheless, no long-range magnetic order is detected down to 2 K. These results are confirmed by an analysis of the [MII(C(2)O(4))(3)](4-) (M = Ni, Pd, Pt) complex and of a [Pd(II){mu-(C(2)O(4))Mn(II)(OH(2))(4)}(3)](2+) tetranuclear model using density functional theory.     

Hexaaquacobalt(II) bis(hypophosphite) and hexaaquacobalt(II)/nickel(II) bis(hypophosphite)

The title compounds, hexa­aqua­cobalt(II) bis­(hypophosphite), [Co(H₂O)₆](H₂­PO₂)₂, and hexa­aqua­cobalt(II)/nickel(II) bis(hypophosphite), [Co_0.5Ni_0.5(H₂O)₆](H₂PO₂)₂, are shown to adopt the same structure as hexa­aqua­magnesium(II) bis­(hypophosphite). The packing of the Co(Ni) and P atoms is the same as in the structure of CaF₂. The Co^II(Ni^II) atoms have a pseudo‐face‐centred cubic cell, with a = b～ 10.3 Å, and the P atoms occupy the tetrahedral cavities. The central metal cation has a slightly distorted octahedral coordination sphere. The geometry of the hypophosphite anion in the structure is very close to ideal, with point symmetry mm2. Each O atom of the hypophosphite anion is hydrogen bonded to three water mol­ecules from different cation complexes, and each H atom of the hypophosphite anion is surrounded by three water mol­ecules from further different cation complexes.     

Synthesis and Crystal Structure of Trans-diaquabis(hexamethylenetetramine-N)bis(isothiocyanato)cobalt(Ⅱ) trans-tetraaquabis(isothiocyanato)cobalt(Ⅱ) dihydrate

1 INTRODUCTION Supramolecular compounds assembled by coordination covalent bonding or hydrogen bonding are of considerable interest due to their potential applications in developing new materials with magnetic, optical and catalytic properties[1]. One of the synthesis methods used to construct the functional compounds is that octahedral metal ion connects to polydentate ligand such as 4, 4?bipyridine, pyrazine and so on to form multi-dimensional supramolecular polymer[2]. Hmt (hexamethyl…