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Violet single-crystals of the complex [Cu(ox)(phen)2]·5H2O (1), where ox2− is oxalate and phen is 1,10-phenanthroline, were obtained by slow evaporation of a solution previously prepared by dissolving Cu(ox)·1/3H2O in a water–acetonitrile solution of phenantroline. Its crystal structure consists of neutral mononuclear [Cu(ox)(phen)2] units and crystallization water molecules which are held together by face-to-face stacking interactions between the phenantroline aromatic rings and an extensive three-dimensional network of Ow–HO/Ow hydrogen bonds. The copper atom is hexaco-ordinated to two oxygen atoms of a bidentate oxalato ligand and to four nitrogen atoms belonging to two phen ligands in a distorted octahedral cis arrangement. The e.p.r. Q-band spectrum of 1 shows an axial-type signal with g-tensor values of g=2.28 and g=2.06, which is consistent with the axially elongated octahedral geometry of the copper(II) chromophore found in the structural work. The relation gg>2.0 indicates a d(x2y2) ground state. Variable temperature susceptibility measurements (5–300 K) reveals the occurrence of magnetically isolated paramagnetic centers in the crystal structure. Thermal degradation of the compound 1 under synthetic air atmosphere starts between 50 and 110°C with an endothermic process attributable to the release of the crystallization water molecules.  相似文献   
3.

[cis-g-Cr(trien) C2O4)] Cl·2H2O (I) (CrC8H22N4O6Cl) crystallizes at 22°C, from deionized water solution as a racemate in space group Pn (No. 7). Lattice constants are: a = 7.193(2), b = 9.1545(12), c = 11.469(2) Å; g = 100.994(13)°; V = 741.3(3) Å3 and Dcalc = 1.603 gcm-3 (MW = 357.75, Z = 2). A total of 2251 data were collected, using MoK f radiation ( u = 0.71703 Å), over the range 4 h 2 è h 60°; of these, 1441 (independent and with I S 2 σ (I)) were used in the structural analysis. Data were corrected for absorption ( w = 9.81 cm-1) and the transmission coefficients ranged from 0.8676 to 0.9942. The final R (F) and Rw(F) residuals were 0.0338 and 0.0764, respectively. The cations of (II) exist in the lattice as enantiomeric pairs. [Cr2( w -OH)2( w -tren)2]Br4 ·2H2O (II) (Cr2C12H42N8O4Br4) crystallizes in the monoclinic space group P21/n (No. 14) with a = 10.835(2) Å, b= 7.859(3) Å, c = 16.397(2) Å, g = 105.45(2)°, V = 1345.7(5) Å33 and Dcalc = 1.940 g cm-1 (MW = 786.18, Z = 4). A total of 2467 data were collected, using MoK f radiation ( u = 0.71703 Å), over the range 4 h 2 è h 50°; of these, 1450 (independent and with I S 2 σ ( I )) were used in the structural analysis. Data were corrected for absorption ( w =67.79 cm-1) and the transmission coefficients ranged from 0.5589 to 0.9949. The final R(F) and Rw(F) residuals were 0.0481 and 0.1408, respectively for 2385 observed reflections with ( I S 2 σ ( I )). In the complex cation, the two Cr(III) centers are in a distorted octahedral environment and are bridged by two hydroxide groups and two ethylamine arms, one from each tren ligand, which spans over the binuclear core. Within the bridging moiety, the Cr···Cr separation is 3.005(2) Å, the ° Cr-OH-Cr = 101.3(2)° and ° O-Cr-O = 78.7(2)°, while the average Cr-N bond distance trans to the hydroxo groups (2.085(6) Å) is shorter than the corresponding cis Cr-N distance (2.104(5) Å).  相似文献   
4.
Reduction by NaBH4 of the imine functions of (5,7,7,13-tetramethyl-13-nitro-1,4,8,11-tetraazacyclotetradec-4-ene)-nickel(II) and -copper(II), and of their 13-ethyl-5,7,7-trimethyl-homologues, yield the nitro-substituted cyclic tetraamine cations (5,5,7,13-tetramethyl-13-nitro-1,4,8,11-tetraazacyclotetradecane)-nickel(II) and -copper(II), [M(neh)]2+, and (13-ethyl-5,5,7-trimethyl-homologues, [M(nph)]2+, respectively. The nickel(II) cations form square–planar, singlet ground, state salts with poorly coordinating anions and octahedral, triplet ground state, compounds with additional ligands, trans-β-[Ni(neh)A2], A = Cl, NCS and trans-β-[Ni(neh)A2](ClO4)2, X = NH3, MeCN, all with nitrogen configuration III, 1R,4R,8S,11S = β. With oxalate the chain-polymeric compound catena-trans-β-[Ni(neh)(μ-C2O4)]n · 3n(H2O) is formed. Folded macrocycle compounds cis-α-[Ni(neh)(C5H7O2)]ClO4 and cis-α-[{Ni(neh)}2(C2O4)](ClO4)2 are formed with the chelates acetylacetonate and oxalate, with configuration 1R,4R,8R,11R = α. These react with HClO4 to form metastable α-[Ni(neh)](ClO4)2 with retention of configuration. The copper(II) cations form crimson salts with poorly coordinating anions and compounds of the type β-[Cu(neh)A]ClO4 of varying shades of blue with coordinating anions. Structures of singlet ground state square–planar nickel(II) compounds β-[Ni(neh)](ClO4)2 · H2O, β-[Ni(neh)](ClO4)2, β-[Ni(neh)]2[ZnCl3(OH2)]2[ZnCl4] · H2O and α-[Ni(neh)](ClO4)2, the triplet ground state chain-polymeric compound catena-trans-β-[Ni(neh)(μ-C2O4)]n · 3n(H2O) and of square–pyramidal β-[Cu(nph)Cl]ClO4 are reported.  相似文献   
5.
The complex [Cu2(L)22‐C2O4)]·CH3OH ( 1 ) has been synthesized and characterized by IR, UV, ESR and variable temperature magnetic susceptibility measurement, where L = 1‐(ethylamino)‐2‐(salicylideneamino)ethane. The crystal X‐ray diffraction reveals that complex 1 has a μ2‐C2O42— bridge. The complex exhibits ferromagnetic couplings between the copper atoms bridged by oxalate dianion, which is rare in oxalato‐bridged copper complexes.  相似文献   
6.
The complexes, M[M(C2O4)3xH2 O, where x=4 for M=Cr(III), x=2 for M=Sb(III) and x=9 for M=La(III) have been synthesized and their thermal stability was investigated. The complexes were characterized by elemental analysis, IR and electronic spectral data, conductivity measurement and powder X-ray diffraction (XRD) studies. The chromium(III)tris(oxalato)chromate(III)tetrahydrate (COT), Cr[Cr(C2 O4)3]·4H2O, released water in a stepwise fashion. Removal of the last trace of water was accompanied by a partial decomposition of the oxalate group. Thermal investigation using TG, DTG and DTA techniques in air produced Cr2O3 at 858°C through the intermediate formation of Cr2O3 and CrC2O4 at around 460°C. While DSC study in nitrogen up to 670°C produced a mixture of Cr2O3 and CrC2O4. In antimony(III)tris(oxalato)antimonate(III)dihydrate (AOD), Sb[Sb(C2O4)3]·3H2O the dehydration took place during the decomposition of precursor at 170–290°C and finally at ca. 610°C Sb2 O5 along with trace amounts of Sb2O4 were produced. Trace amount of Sb2O3 and Sb along with Sb2O is proposed as the end product at 670°C of AOD in nitrogen. The oxide La2O3 is formed at 838°C from the study with TG, DTG and DTA in air of lanthanum(III)tris(oxalato)lanthanum(III)nonahydrate (LON), La[La(C2O4)3]·9H2O. Intermediate dioxycarbonate, La2O2CO3 was generated at 526°C prior to its decomposition to lanthanum oxide in air; whereas in N2 the formation of La2(CO3)3 at 651°C was proposed. The thermal parameters have been evaluated for each step of the dehydration and decomposition of COT, AOD and LON using five non-mechanistic equations i.e. Flynn and Wall, Freeman and Carroll, Modified Freeman and Carroll, Coats–Redfern and MacCallum–Tanner equations. Kinetic parameters, such as, E*, ko, ΔH*, ΔS* etc. were also supplemented by DSC studies in nitrogen for all the three complexes. Some of the intermediate species have been identified by analytical and powder XRD studies. Tentative schemes has been proposed for the decomposition of all three compounds in air and nitrogen.  相似文献   
7.
A copper(II) and two nickel(II) dinuclear oxalato‐bridged compounds of formulae [{Cu(bpdto)}2(μ‐ox)](ClO4)2 ( 1 ), [{Ni(bpdto)]2(μ‐ox)](ClO4)2( 2 ), and [{Ni(bpdto)}2(μ‐ox)](NO3)2·2H2O ( 3 ), where bpdto = 1, 8‐bis(2‐pyridyl)‐3, 6‐dithiaoctane and ox = oxalate = C2O42— anion, have been synthesized and characterized. The crystal structure of 3 was determined by single‐crystal X‐ray analysis. It is a dinuclear complex with i symmetry in which the oxalate ligand is coordinated in bis(didentate) fashion to the inversion centre‐related nickel atoms. The distorted octahedral environment of each nickel atom is completed by two sulphur atoms in the equatorial plane and by two pyridyl nitrogen atoms in axial positions. Magnetic susceptibility measurements over the range 5 — 299K, show antiferromagnetic interactions that are weak in 1 (J = —12.8 cm—1) and strong in 2 and 3 (J = —37.8 and —40.9 cm—1, respectively), which in the case of 3 is in keeping with the observed structural parameters.  相似文献   
8.
基于密度泛函理论结合对称性破损态方法,选择不同的泛函方法和基组研究吡唑/草酸根混合配位的非对称双核铜配合物的磁学性质。结果表明,在B3LYP/def2-TZVP水平计算的磁耦合常数为-127.24cm~(-1),与实验值-129cm~(-1)基本吻合,可准确描述吡唑/草酸根混合配位的非对称双核铜配合物的磁学性质。磁轨道和自旋布居分析表明,顺磁中心Cu(Ⅱ)与桥联配体草酸根离子间存在较强的轨道相互作用,其磁轨道主要由顺磁中心Cu(Ⅱ)的3d_x2_(-y)2轨道、桥联配体草酸根离子的π键组成,顺磁中心Cu(Ⅱ)主要是自旋离域机理。配合物磁性与结构关系的研究表明,随着结构参数τ的增加,顺磁中心HS态和BS态自旋密度的平方差和自然磁轨道间重叠积分的平方随之增大,反铁磁性相互作用的贡献增大,配合物磁耦合常数J值减小。  相似文献   
9.
The mixed metal oxalate precursors, calcium(II)bis(oxalato)cobaltate(II)hydrate (COC), strontium(II)bis(oxalato)cobaltate(II)pentahydrate (SOC) and barium(II)bis(oxalato)cobaltate(II)octahydrate (BOC) have been synthesized and their thermal stability was investigated. The complexes were characterized by elemental analysis, IR spectral and X-ray powder diffraction studies. Thermal decomposition studies (TG, DTG and DTA) in air showed that the compound COC decomposed mainly to CaC2O4 and Co3O4 at 340 °C, and a mixture of CaCO3 and Co3O4 identified at 510 °C. A mixture of CaCO3 and Ca3Co2O6 along with the oxides and carbides of both the cobalt and calcium were attributed at 1000 °C as end products. DSC study in nitrogen ascertained the formation of a mixture of CaO and CoO along with a trace of carbon at 550 °C. The mixture species, SrC2O4, CoC2O4 and Co3O4 were generated at 255 °C in case of SOC in air, which ultimately changed to CoSrO3, SrCO3 and oxides of strontium and cobalt at 1000 °C. The several mixture species also generated as intermediate at 332 and 532 °C. The DSC study in nitrogen indicated the formation of CoSrOx (0.5 < x < 1) as end product. In case of BOC in air, a mixture of BaCoO2, BaO, CoO and carbides are identified as end product at 1000 °C through the generation of several intermediate species at 350 and 530 °C. A mixture of BaO and CoO is identified as end product in DSC study in nitrogen. The kinetic parameters have been evaluated for all the dehydration and decomposition steps of all the three compounds using four non-mechanistic equations. Using seven mechanistic equations, the kind of dominance of kinetic control mechanism of the dehydration and decomposition steps are also inferred. The kinetic parameters, ΔH and ΔS of all the steps are explored from the DSC studies. Some of the decomposition products are identified by IR and X-ray powder diffraction studies.  相似文献   
10.
Synthesis and Crystal Structure of the Nitrido Oxalato Osmate PPh4{Na(15-Crown-5)[OsNCl3(C2O4)]} The title compound has been prepared by slow reaction of PPh4[OsNCl4] with sodium oxalate in boiling dichloromethane in the presence of 15-crown-5, forming violet crystals, which were characterized by an X-ray structure determination. Space group P21/c, Z = 4, 4 769 observed unique reflections, R = 0.035. Lattice dimensions at –80°C: a = 1 931.4, b = 1 178.7, c = 1 764.1 pm, β = 99.39°. The structure consists of PPh4+ ions and ion pairs {Na(15-crown-5)[OsNCl3(C2O4)]}?, in which the osmium atom is distortedly octahedrally coordinated by the nitrido ligand, by three chlorine atoms, and by two oxygen atoms of the oxalato group. The remaining oxygen atoms of the oxalato ligand are coordinated to the sodium atom, which, together with the five oxygen atoms of the crown ether molecule, gets coordination number seven.  相似文献   
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