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1.
Yi-Shan Song 《Inorganica chimica acta》2005,358(1):191-195
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) Å3, 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. 相似文献
2.
Duncan E.K. SutherlandKelly L. Summers Martin J. Stillman 《Biochemical and biophysical research communications》2012,426(4):601-607
Mammalian metallothioneins (MTs) are a family of small cysteine rich proteins believed to have a number of physiological functions, including both metal ion homeostasis and toxic metal detoxification. Mammalian MTs bind 7 Zn2+ or Cd2+ ions into two distinct domains: an N-terminal β-domain that binds 3 Zn2+ or Cd2+, and a C-terminal α-domain that binds 4 Zn2+ or Cd2+. Although stepwise metalation to the saturated M7-MT (where M = Zn2+ or Cd2+) species would be expected to take place via a noncooperative mechanism involving the 20 cysteine thiolate ligands, literature reports suggest a cooperative mechanism involving cluster formation prior to saturation of the protein. Electrospray ionization mass spectrometry (ESI-MS) provides this sensitivity through delineation of all species (Mn-MT, n = 0-7) coexisting at each step in the metalation process. We report modeled ESI-mass spectral data for the stepwise metalation of human recombinant MT 1a (rhMT) and its two isolated fractions for three mechanistic conditions: cooperative (where the binding affinities are: K1 < K2 < K3 < ··· < K7), weakly cooperative (where K1 = K2 = K3 = ··· = K7), and noncooperative, (where K1 > K2 > K3 > ··· > K7). Detailed ESI-MS metalation data of human recombinant MT 1a by Zn2+ and Cd2+ are also reported. Comparison of the experimental data with the predicted mass spectral data provides conclusive evidence that metalation occurs in a noncooperative fashion for Zn2+ and Cd2+ binding to rhMT 1a. 相似文献
3.
Michael J. Vasbinder 《Inorganica chimica acta》2008,361(11):3193-3198
Oxidation of the title complexes with ozone takes place by hydrogen atom, hydride, and electron transfer mechanisms. The reaction with (NH3)4(H2O)RhH2+ is a two electron process, believed to involve hydride transfer with a rate constant k = (2.2 ± 0.2) × 105 M−1 s−1 and an isotope effect kH/kD = 2. The oxidation of (NH3)4(H2O)RhOOH2+ to (NH3)4(H2O)RhOO2+ by an apparent hydrogen atom transfer is quantitative and fast, k = (6.9 ± 0.3) × 103 M−1 s−1, and constitutes a useful route for the preparation of the superoxo complex. The latter is also oxidized by ozone, but more slowly, k = 480 ± 50 M−1 s−1. 相似文献
4.
Reaction of the rhenium(IV) compound, [Bu4N]2ReCl4ox, with the highly unsaturated tetraazabismacrocyclic copper(II) complex cation [CuCuL]4+ (L = 6,13-Bis(dodecylaminomethylidene)-1,4,8,11-tetraazacyclotetradeca-4,7,11,14-tetraene) produced a new kind of heterobimetallic compound: [CuCuL][ReCl4ox]2 · 2DMF in which [ReCl4ox]2− anions and [CuCuL]4+ cations are linked by electrostatic forces. The crystal structure of this compound was determined at 173(2) K. It crystallizes triclinic, space group , with a = 9.441(4), b = 11.032(5), c = 15.261(7) Å, α = 89.05(1)°, β = 88.93(1)°, γ = 77.09(1)°, Z = 1, R1 = 0.0557, wR2 = 0.1332. The magnetic behavior of this compound has been investigated over the temperature range 1.72-300 K. The compound behaves as a ferrimagnetic CuIIReIV bimetallic, chain with intrachain antiferromagnetic coupling. 相似文献
5.
Jian-Ying Zhang Cai-Ming Liu De-Qing Zhang Dao-Ben Zhu 《Inorganica chimica acta》2007,360(11):3553-3559
Two new binuclear radical complexes derived from a new long nitronyl nitroxide ligand, 2-[4-(5-pyrimidyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (4-NITPhPyrim), and M(hfac)2 (M2+ = Cu2+, Mn2+; hfac− = hexafluoroacetylacetonato), [Cu(hfac)2(4-NITPhPyrim)]2 · 4H2O (1) and [Mn(hfac)2(4-NITPhPyrim)]2 · 4H2O (2), were synthesized as well as characterized structurally and magnetically. X-ray analysis indicates that 1 and 2 are rectangle-like centrosymmetric dimer M2L2 complexes. Magnetic measurements indicate that there are two types of magnetic exchanges in 1: the ferromagnetic (FM) exchange between the Cu(II) ion and the directly bonded nitroxide unit (J1 = 24.20 cm−1) and the weak FM exchange of Cu-NIT through the pyrimidine and phenyl rings (J2 = 0.62 cm−1). Besides the strong antiferromagnetic (AFM) coupling between the Mn(II) ion and the directly bonded nitroxide unit (J = −87.61 cm−1), there is a weak FM interaction between the two Mn-NIT pairs (θ = 0.39 K) in 2. 相似文献
6.
Hybrid density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations have been carried out for ozone-water clusters O3(H2O)n (n = 1-4) in order to obtain hydration effects on the absorption spectrum of ozone. The first water molecule in n = 1 is bound to the ozone molecule by an oxygen orientation form in which the oxygen atom of H2O orients the central oxygen atom of O3. In n = 2, the water dimer is bound to O3 and then the cyclic structure is formed as the most stable structure. For n = 3 (or n = 4), the cyclic water trimer (or tetramer) is bound by a hydrogen bond to the ozone molecule. The TD-DFT calculations of O3(H2O)n (n = 0-4) show that the first and second excitation energies of O3 are blue-shifted by the interaction with the water clusters. The magnitude of the spectral shift is largest in n = 2, and the shifts of the excitation energies are +0.07 eV for S1 and +0.13 eV for S2 states. In addition to the spectral shifts (S1 and S2 states), it is suggested that a charge-transfer band is appeared as a low-lying excited state above the S1 and S2 states. The origin of the spectrum shifts was discussed on the basis of theoretical results. 相似文献
7.
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. 相似文献
8.
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) Å3, 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) Å3, 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) Å3, 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) Å3, Z = 4. 相似文献
9.
Yuri V. Mironov Konstantin A. Brylev Sung-Jin Kim Svetlana G. Kozlova Vladimir E. Fedorov 《Inorganica chimica acta》2011,370(1):363-368
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 Cs2.75K1.25[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. 相似文献
10.
S. Max Bessey 《Inorganica chimica acta》2010,363(1):279-7422
The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate, Et3PAu(SC6H4NO2-4), is reported. Et3PAu(SC6H4NO2-4) displays a low energy visible electronic absorption band which is solvent dependent: EtOH (λmax = 385 nm), acetonitrile (λmax = 391 nm), THF (λmax = 395 nm), and DMSO (λmax = 402 nm). The corresponding low energy visible electronic absorption band of 4-nitrobenzenethiolate, 4-NO2C6H4S− also shows solvent dependency: acetonitrile, (λmax = 484 nm), DMSO (λmax = 502 nm), dimethylformamide (λmax = 505 nm). The positive solvatochromic shifts for Et3PAu(SC6H4NO2-4) and 4-NO2C6H4S− are consistent with an intraligand (IL) charge transfer transition, i.e. π(S) → ∗π (C6H4NO2-4) or n(S) → ∗π (C6H4NO2-4). Assignment of 4-NO2C6H4S− was aided by a DFT calculation. 相似文献
11.
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. 相似文献
12.
Three kinds of copper(II) azide complexes have been synthesised in excellent yields by reacting Cu(ClO4)2 · 6H2O with N,N-bis(2-pyridylmethyl)amine (L1); N-(2-pyridylmethyl)-N′,N′-dimethylethylenediamine (L2); and N-(2-pyridylmethyl)-N′,N′-diethylethylenediamine (L3), respectively, in the presence of slight excess of sodium azide. They are the monomeric Cu(L1)(N3)(ClO4) (1), the end-to-end diazido-bridged Cu2(L2)2(μ-1,3-N3)2(ClO4)2 (2) and the single azido-bridged (μ-1,3-) 1D chain [Cu(L3)(μ-1,3-N3)]n(ClO4)n (3). The crystal and molecular structures of these complexes have been solved. The variable temperature magnetic moments of type 2 and type 3 complexes were studied. Temperature dependent susceptibility for 2 was fitted using the Bleaney-Bowers expression which led to the parameters J = −3.43 cm−1 and R = 1 × 10−5. The magnetic data for 3 were fitted to Baker’s expression for S = 1/2 and the parameters obtained were J = 1.6 cm−1 and R = 3.2 × 10−4. Crystal data are as follows. Cu(L1)(N3)(ClO4): Chemical formula, C12H13ClN6O4Cu; crystal system, monoclinic; space group, P21/c; a = 8.788(12), b = 13.045(15), c = 14.213(15) Å; β = 102.960(10)°; Z = 4. Cu(L2)(μ-N3)(ClO4): Chemical formula, C10H17ClN6O4Cu: crystal system, monoclinic; space group, P21/c; a = 10.790(12), b = 8.568(9), c = 16.651(17) Å; β = 102.360(10)°; Z = 4. [Cu(L3)(μ-N3)](ClO4): Chemical formula, C12H21ClN6O4Cu; crystal system, monoclinic; space group, P21/c; a = 12.331(14), b = 7.804(9), c = 18.64(2) Å; β = 103.405(10)°; Z = 4. 相似文献
13.
Adrienne Hammerschmidt 《Inorganica chimica acta》2005,358(14):4247-4252
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]. 相似文献
14.
Gašper Tav?ar 《Inorganica chimica acta》2011,377(1):69-76
Pure H3OCd(SbF6)(Sb2F11)2 is prepared by the reaction of CdO with nSbF5 (n ? 5) or by reaction of H3OSbF6, Cd(SbF6)2 and nSbF5 (n ? 2) in anhydrous hydrogen fluoride. H3OCd(SbF6)(Sb2F11)2 crystallizes in the monoclinic space group P21/a (No. 14) with a = 986.1(4) pm, b = 1257.3(5) pm, c = 1826.8.4(8) pm, β = 98.062(4)° and Z = 4.Reaction of CdO with SbF5 (n ? 3) in anhydrous HF yields only a mixture of H3OSbF6 and Cd(SbF6)2. No reactions were observed also when different ratios of H3OSbF6 and Cd(SbF6)2 were used as starting materials. However, the re-crystallization of these mixtures yielded single crystals of new phases: (H3O)2Cd(SbF6)3(Sb2F11) and (H3O)2Cd2F(SbF6)5. The former crystallizes in the orthorhombic Pcca space group (No. 54) with a = 2189(2) pm, b = 1121.2(8) pm, c = 1894(1) pm and Z = 8 and the latter in the monoclinic P21/a space group a = 1019(4) pm, b = 1112(1) pm, c = 1147(1) pm, β = 107.81(1)° and Z = 2. The attempt to prepare single crystals of Cd(SbF6)2 resulted in the preparation of few single crystals of (H3O)[Cd(HF)]4(SbF6)9, which crystallizes in the monoclinic space group C2/c (No. 15) with a = 2087(3) pm, b = 1021(5) pm, c = 2112(2) pm, β = 99.36(2)° and Z = 4. 相似文献
15.
Milorad Stojanovic 《Inorganica chimica acta》2011,376(1):414-421
The synthesis of a number of lanthanide tetracyanometallate (TCM) compounds have been carried out by reaction of Ln3+ nitrate salts and potassium tetracyanometallates in solvent systems containing dimethylsulfoxide and water. These reactions result in the isolation of three distinct structure types: (1) monoclinic [Ln(DMSO)4(H2O)3M(CN)4](M(CN)4)0.5·2H2O (Ln = Eu, Tb and M = Pd, Pt), (2) orthorhombic {La(DMSO)3(H2O)2(NO3)M(CN)4}∞·H2O (M = Pd, Pt), and (3) orthorhombic {Ln(DMSO)3(H2O)(NO3)M(CN)4}∞ (Ln = Tb and M = Pd, Pt; Ln = Er, Yb and M = Pt) in the form of single crystals. Single-crystal X-ray diffraction has been used to investigate their structural features. Structure type 1 is a zero dimensional ionic compound with a M/Ln ratio of 1.5:1. It contains coordinated as well as uncoordinated [M(CN)4]2− (M = Pd, Pt) anions and features relatively long platinophilic interactions. Structure types 2 and 3 differ quite drastically from structure type 1, but they are very similar to each other. Both of the latter are one-dimensional in nature due to chains containing linkage of Ln3+ coordination spheres with trans-bridging [M(CN)4]2− anions. These coordination polymers both have a M/Ln ratio of 1:1, a lack of platinophilic interactions, and incorporation of a bidentate NO3− for charge balance. Photoluminescence properties for select Eu3+ and Tb3+ compounds have been investigated. They show characteristic absorption and emission for the Ln3+ ions, but no significant influence of the tetracyanometallate anions. 相似文献
16.
Ya-Guang Chen Li-Kai Yan Xiang-Rong Hao Kun Liu Xiao-Hong Wang Ping-Ping Lu 《Inorganica chimica acta》2006,359(8):2550-2554
Organoammoinium polyoxomolybdate [(enH)2(H2Mo6O20)]∞ was formed in autogeneous pressure at 160 °C for 120 h. The colorless crystals of polyoxomolybdate were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The crystals are in monoclinic system with a space group P21/n and a = 8.0844(16), b = 14.413(3), c = 8.9153(18) Å, β = 98.12(3)°, V = 1013.8(4) Å3, Z = 4. The final R = 0.0375, wR = 0.0706 for 2370 reflections [I > σ(I0)].The crystals are constructed by one-dimension infinite inorganic chains with Mo6O20 unit as building block and protonated ethylenediamine cations located in between the inorganic chains. There are many hydrogen bonds between the chains and between the chains and the cations. IR spectrum of the title compound exhibited the vibration absorption of MoO, Mo-O-Mo bonds and protonated ethylenediamine cations, and suggests the presence of N-H-O and O-H-O hydrogen bonds. Quantum calculation gives the distribution of charges and the composition of frontier molecular orbits. From the calculation results, it can be inferred that protonation must have occurred on the terminal oxygen atom (O3) due to its smallest charge value and the terminal oxygen atom (O3) forms hydrogen bonds with the O12 atoms of the adjacent chain (2.936 Å); and that Mo1 atom will first receive the reduced electron. The electron transition taking place between HOMO and LUMO belongs basically to O → Mo charge transfer transition. 相似文献
17.
Ring coupled bimetallic derivatives (μ-η5:5-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) Å3, 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) Å3, Z = 2, R(F) = 3.00%. 相似文献
18.
G. Calvez C. Daiguebonne P.-E. Car V. Guillerm Y. Gérault F. Le Dret N. Mahé 《Inorganica chimica acta》2008,361(8):2349-2356
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. 相似文献
19.
The complexation of Al3+, Zn2+, Cd2+ and Pb2+ by the 3-hydroxyflavones: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-one (H1) and 3-hydroxy-2-(4-methoxyphenyl)-4H-1-benzopyran-4-one (H2), and by the 3-methoxythioflavone: 3-hydroxy-2-(2-methoxyphenyl)-4H-1-benzopyran-4-thione (H3) have been studied spectrophotometrically and fluorimetrically to determine the corresponding complexation constants, Ksp and Kfl, in 5:95 water:ethanol (v/v) solution for which [HClO4] was either 10−2 or 10−5 mol dm−3 and I = 0.10 mol dm−3 (NaClO4) at 298.2 K. Complexation occurs dominantly through the deprotonated ligand for [Al(1)]2+ and [Al(2)]2+ for which log Ksp = 4.51 and 4.73, respectively, in 10−2 mol dm−3 HClO4 and 4.21 and 4.61 in 10−5 mol dm−3 HClO4. For Pb2+ complexation by H1, H2 and H3 is characterized by log Ksp = 2.20, 2.57 and 3.22, respectively, in 10−2 mol dm−3 HClO4 and 4.70, 5.38 and 5.74 in 10−5 mol dm−3 HClO4. Equilibrium mixtures of [Pb(H1)]2+ and [Pb1]+, [Pb(H2)]2+ and [Pb2]+, and [Pb(H3)]2+ and [Pb3]+ appear to be formed. Complexation of Zn2+ and Cd2+ by all three ligands was only detected in 10−5 mol dm−3 HClO4. For Zn2+ complexation by H1, H2 and H3 log Ksp = 3.22, 3.74 and 4.46 and for Cd2+ the corresponding values are 2.39, 2.40 and 3.72 for Cd2+. Only [Al1]2+ and [Al2]2+ show significant fluorescence and are characterized by log Kfl = 6.30 and 7.49 in 10−2 mol dm−3 HClO4. 相似文献
20.
The synthesis and characterization of several complexes of the composition [{M(terpy)}n(L)](ClO4)m (M = Pt, Pd; L = 1-methylimidazole, 1-methyltetrazole, 1-methyltetrazolate; terpy = 2,2′:6′,2″-terpyridine; n = 1, 2; m = 1, 2, 3) is reported and their applicability in terms of a metal-mediated base pair investigated. Reaction of [M(terpy)(H2O)]2+ with 1-methylimidazole leads to [M(terpy)(1-methylimidazole)](ClO4)2 (1: M = Pt; 2: M = Pd). The analogous reaction of [Pt(terpy)(H2O)]2+ with 1-methyltetrazole leads to the organometallic compound [Pt(terpy)(1-methyltetrazolate)]ClO4 (3) in which the aromatic tetrazole proton has been substituted by the platinum moiety. For both platinum(II) and palladium(II), doubly metalated complexes [{M(terpy)}2(1-methyltetrazolate)](ClO4)3 (4: M = Pt; 5: M = Pd) can also be obtained depending on the reaction conditions. In the latter two compounds, the [M(terpy)]2+ moieties are coordinated via C5 and N4. X-ray crystal structures of 1, 2, and 3 are reported. In addition, DFT calculations have been carried out to determine the energy difference between fully planar [Pd(mterpy)(L)]2+ complexes Ip-IVp (mterpy = 4′-methyl-2,2′:6′,2″-terpyridine; L = 1-methylimidazole-N3 (I), 1-methyl-1,2,4-triazole-N4 (II), 1-methyltetrazole-N3 (III), or 3-methylpyridine-N1 (IV)) and the respective geometry-optimized structures Io-IVo. Whereas this energy difference is larger than 70 kJ mol−1 for compounds I, II, and IV, it amounts to only 0.8 kJ mol−1 for the tetrazole-containing complex III, which is stabilized by two intramolecular C-H?N hydrogen bonds. Of all complexes under investigation, only the terpyridine-metal ion-tetrazole system with N3-coordinated tetrazole appears to be suited for an application in terms of a metal-mediated base pair in a metal-modified oligonucleotide. 相似文献