半胱氨酸VO~(2+)络合物的结构及其ESR波谱的研究

本文考察了VOSO_4与半胱氨酸在不同酸度(pH=1-1.4)的乙二醇/水(1:1)溶液中,在液氮温度下的ESR波谱。发现在pH<2,pH>11范围内,半胱氨酸不能与VO~(2+)生成络合物,当pH<2时,A=118G,归属于[VO(H_2O)_5]~(2+);当pH>11时,A=90G,归属于[VO(OCH_2CH_2O)_2)~(2-];pH=3-4时,A=116G,归属于VO~(2+)与半胱氨酸1:1单齿络合物,[VO(H_2O)_3(CysH)]~(2+);pH=5.0～5.5,A=102G,归属于1:1双齿螫合物[VO(H_2O)_2(Cys)]~+;pH=7.O～7.5,A=87G;pH=8-10,A=85G,分别归属于V0~(2+)与半胱氨酸1:2双齿顺式和反式螯合物[VO-(Cys)_2]~(2-)。利用测得的波谱参数,计算了键参数和电子能级。     

库仑滴定法测定钒电池电解液中钒(Ⅲ)与钒(Ⅳ)的含量

钒电池是利用不同价态的钒离子在硫酸电解质溶液中发生氧化还原反应,实现化学能与电能之间的相互转换,从而具有大容量的快速充放电且功率和容量可调节等优点,被相关行业认为是最佳新能源储存介质[1-2]。该电池的容量和充放电效率,与电解液中不同价态的钒离子浓度有关,而该电解液中的钒离子的起始状态通常为钒(Ⅲ,V3+)和钒(Ⅵ,VO2+)混合态,当两种离子浓度的比值为1时,电池比容量达到最大[3-4],因此如何简便、快速且高效的测定V3+和VO2+的含量,对产品的质量控制意义重大。     

一种硒桥连的四核锰取代的类Dawson硒钨酸盐

在水溶液中合成了一种新型硒桥连的四核锰取代的类Dawson硒钨酸盐[H_2N(CH_3)_2]_4 KH_7[Mn_4(H_2O)_6(SeO)_2(Se_2W_(12)O_(46))_2]·45H_2O (1),并通过红外光谱,热重分析和X射线单晶衍射对其结构进行了表征.1中二聚的[Mn_4(H_2O)_6(SeO)_2(Se_2W_(12)O_(46))_2]~(12-)阴离子由两个六缺位类Dawson的[Se_2W_(12)O_(46)]~(12-)片段通过两个[Mn(H_2O)_2(SeO)]~(4+)和两个[Mn(H_2O)_2]~(2+)离子连接而成.值得注意的是两种不同配位方式的锰原子在连接两个[Se_2W_(12)O_(46)]~(12-)片段时发挥着重要的作用.一类Mn~(2+)离子和Se~(4+)离子结合作为桥占据[Se_2W_(12)O_(46)]~(12-)片段的"极位",另一类Mn~(2+)离子占据了"赤道位".此外,对其磁性进行了研究.     

N-氧化吡啶-2-甲醛衍生物的配合物研究——(Ⅱ)与二胺生成的双希夫碱铜配合物的电子结构

用CNDO/2方法计算N-氧化吡啶-2-甲醛缩1,3-丙二胺合铜离子[Cu(piotn)(H_2O)_2]~(2+)和N-氧化吡啶-2-甲醛缩乙二胺合铜离子[Cu(pioen)(H_2O)]~(2+)的电子结构。以原子净电荷的变化和配合物大π键的形成说明配合物形成后红外谱中~vN-o波数少减和~vC=N波数增加的原因。     

Cu(Ⅱ)—苯并-15-冠-5在溶液中的磁共振研究

本文利用ESR和NMR谱对配合物Cu(II)—苯并-15-冠-5丙酮溶液的磁共振性质进行了研究.{[Cu(II)(C_(14)O_5H_(20))(H_2O)_2](ClO_4)_2}·3H_2O在丙酮中解离形成[Cu(II)(C_(14)O_5H_(20))(H_2O)_2]~(2+)和[Cu(H_2O)_6]~(2+)两种配位离子.其自旋哈密顿参量分别为g_∥=1.9887,g_⊥=2.3179,A_∥=0.0133cm~(-1),|A_⊥|<0.0032cm~(-1);(g')_∥=2.4143,(g')_⊥=2.0768,(A')_∥=0.0137cm~(-1),|(A')_⊥|<0.0016cm~(-1).基于ESR谱中g_∥相似文献   

三重桥氧三核铬脂肪酸配合物的快原子轰击质谱研究

本文报道三重桥氧三核铬脂肪酸配合物[Cr_3(μ_3-O)(μ-OOCH)_6(H_2O)_2OOCH]和[Cr_3(μ_3-O)(μ-OOCR)_6(H_2O)_3]~+(R=CH_3,C_2H_5和C_3H_7)的快原子轰击(FAB)质谱。当桥配体为甲酸基时获得完整的配位阳离子峰(其单晶结构见文献),由于质子亲电进攻端配体甲酸基的氧,从而形成了质子化的[Cr_3(μ_3-O)(μ-OOCH)_6(H_2O)_2HCOOH]~+离子。后者可以失去CO生成[Cr_3(μ_3-O)(μ-OOCH)_6(H_2O)_3]~+,进一步的断裂和乙酸配位时的情况相同,可连续脱三个配位水,分别生成[Cr_3O(OOCR)_6(H_2O)_2]~+、[Cr_3O(OOCR)_6(H_2O)]~+和[Cr_3O(OOCR)_6]~+离子;并可进一步脱桥配基或RCO,分别生成[Cr_3O(OOCR)_5]~+、[Cr_3O(OOCR)_4]~+、[Cr_3O(OOCR)_3]~+、[Cr_3O(OOCR)_5O]~+、[Cr_3O(OOCR)_4O]~+、[Cr_3O(OOCR)_3O]~+和[Cr_3O(OOCR)_2O]~+等碎片离子。当桥配体为丙酸和丁酸时,主要观察到[Cr_3O(OOCR)_6]~+离子及其进一步断裂所形成的碎片离子,断裂过程和乙酸配位时基本相似;另外这类配合物都还形成一系列由FAB底物参与的加成离子。基于以上分析,我们提出了这类配合物可能的断裂过程,并认为随着脂肪酸碳链的增长,整个配位阳离子的稳定性下降。     

一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐的合成、结构及表征

在水热条件下,成功合成了一例基于Keggin型多酸阴离子的双加帽杂多铌酸盐[Ni(en)_3]_3[Ni(en)_2(H_2O)_2]_2H[VNb_(12)O_(40)(VO)_2]·10H_2O(1),并通过红外光谱、热重分析和X射线单晶衍射等方法对该化合物进行了表征.X射线单晶衍射分析表明,化合物1属于正交晶系,Pna2(1)空间群,晶胞参数a=3.051 7(3)nm,b=1.561 0(1)nm,c=2.271 9(3)nm,V=10.823(3)nm~3.化合物1包含1个Keggin型聚阴离子[VNb_(12)O_(40)(VO)_2]~(11-)和3个镍配离子.在阴离子结构中,中心钒原子被12个铌原子包围形成经典Keggin型结构的[VNb_(12)O_(40)]~(15-)阴离子,另外两个{VO}基团分别加帽于[VNb_(12)O_(40)]~(15-)阴离子的两端.     

3,5-二(2′，5′-苯二羧酸)苯甲酸构筑的金属有机配合物的荧光识别及磁性（英文）

设计合成了3种新颖的金属有机配合物(MOCs):{[Pb_2(HL)(phen)]·2H_2O)_n(1),{[Ni(H_3L)(4,4'-bipy)_(1.5)(H_2O)_4]·(6H_2O}_n(2)和{[Ni_2(HL)(1,4-bibb)(H_2O)]·(CH_3CN)·H_2O)}_n(3)(H_5L=3,5-二(2',5'-苯二羧酸)苯甲酸,phen=1,10-菲咯啉,4,4'-bipy=4,4'-联吡啶,1,4-bibb=1,4-二(苯并咪唑)苯),并通过单晶X射线衍射、红外光谱(IR)、热重分析(TG)和粉末衍射对它们进行结构表征。结构分析表明1是基于[Pb_2(μ_2-COO)_2(μ_1-COO)_4] SBUs的一维链状结构;2是二维层状结构,其拓扑符号为{4.6~2)_2{4~2.6~2.8~2};3是一个3D网络结构,其拓扑符号为{6~2.8~4}{6~4.8~2}_2。进一步研究了配合物荧光和磁性能。荧光检测显示,配合物1在水溶液中可以高灵敏识别Fe~(3+)和Cr_2O_7~(2-)离子。同时研究了配合物1对Fe~(3+)和Cr_2O_7~(2-)猝灭机理。磁性分析表明配合物3中的Ni(Ⅱ)离子之间存在反铁磁相互作用。     

六元瓜环与配位聚合物[Cd(H2O)3 Cl(4-PCA)]的超分子自组装及光催化性能

本文用水热法合成得到一个六元瓜环(Q[6])与一氯三水(4-吡啶甲酸)合镉(Ⅱ)配位聚合物自组装作用形成的超分子自组装体Q[6]·[Cd(H_2O)_3Cl(4-PCA)]_2·22(H_2O)。自组装体的形成源于瓜环的外壁作用,即Q[6]正电性静电势外壁与配位聚合物中4-吡啶甲酸吡啶环和配位Cl~-离子间的超分子相互作用,以及配位聚合物镉(Ⅱ)离子上配位水分子与瓜环端口羰基氧原子间的氢键作用。该自组装体对溶液中染料具有吸附作用和光催化降解的性能。     

全钒氧化还原液流电池电解液

近年来,全钒氧化还原液流电池(VRFB)作为一种新型的储能电池备受关注。作为VRFB的核心材料,电解液的制备及优化一直都是研究的热点。高浓度和高稳定性电解液的制备是钒电池的关键技术之一。电解液性能的提高有助于加速VRFB的商业化进程。本文综述了VRFB电解液的研究进展,重点介绍了电解液的制备方法和影响电解液稳定性的因素,简述了电解液中钒离子浓度的分析方法和钒离子的存在形式,最后对电解液的进一步研究和应用前景进行了展望。     

Double silyl migration converting ORe[N(SiMe(2)CH(2)PCy(2))(2)] to NRe[O(SiMe(2)CH(2)PCy(2))(2)] substructures

The reaction of (R(2)PCH(2)SiMe(2))(2)NM (PNP(R)M; R = Cy; M = Li, Na, MgHal, Ag) with L(2)ReOX(3) [L(2) = (Ph(3)P)(2) or (Ph(3)PO)(Me(2)S); X = Cl, Br] gives (PNP(Cy))ReOX(2) as two isomers, mer,trans and mer,cis. These compounds undergo a double Si migration from N to O at 90 degrees C to form (POP(Cy))ReNX(2) as a mixture of mer,trans and fac,cis isomers. Additional thermolysis effects migration of CH(3) from Si to Re, along with compensating migration of halide from Re to Si. DFT calculations on various structural isomers support the greater thermodynamic stability of the POP/ReN isomer vs PNP/ReO and highlight the influence of the template effect on the reactivities of these species.     

Diverse evolution of [[Ph(2)P(CH(2))(n)PPh(2)]Pt(mu-S)(2)Pt[Ph(2)P(CH(2))(n)PPh(2)]] (n = 2, 3) metalloligands in CH(2)Cl(2)

The nucleophilicity of the [Pt(2)S(2)] core in [[Ph(2)P(CH(2))(n)PPh(2)]Pt(mu-S)(2)Pt[Ph(2)P(CH(2))(n)PPh(2)]] (n = 3, dppp (1); n = 2, dppe (2)) metalloligands toward the CH(2)Cl(2) solvent has been thoroughly studied. Complex 1, which has been obtained and characterized by X-ray diffraction, is structurally related to 2 and consists of dinuclear molecules with a hinged [Pt(2)S(2)] central ring. The reaction of 1 and 2 with CH(2)Cl(2) has been followed by means of (31)P, (1)H, and (13)C NMR, electrospray ionization mass spectrometry, and X-ray data. Although both reactions proceed at different rates, the first steps are common and lead to a mixture of the corresponding mononuclear complexes [Pt[Ph(2)P(CH(2))(n)PPh(2)](S(2)CH(2))], n = 3 (7), 2 (8), and [Pt[Ph(2)P(CH(2))(n)PPh(2)]Cl(2)], n = 3 (9), 2 (10). Theoretical calculations give support to the proposed pathway for the disintegration process of the [Pt(2)S(2)] ring. Only in the case of 1, the reaction proceeds further yielding [Pt(2)(dppp)(2)[mu-(SCH(2)SCH(2)S)-S,S']]Cl(2) (11). To confirm the sequence of the reactions leading from 1 and 2 to the final products 9 and 11 or 8 and 10, respectively, complexes 7, 8, and 11 have been synthesized and structurally characterized. Additional experiments have allowed elucidation of the reaction mechanism involved from 7 to 11, and thus, the origin of the CH(2) groups that participate in the expansion of the (SCH(2)S)(2-) ligand in 7 to afford the bridging (SCH(2)SCH(2)S)(2-) ligand in 11 has been established. The X-ray structure of 11 is totally unprecedented and consists of a hinged [(dppp)Pt(mu-S)(2)Pt(dppp)] core capped by a CH(2)SCH(2) fragment.     

Transformation of organic molecules on the low-valent [M(Ph(2)PCH(2)CH(2)PPh(2))(2)] moiety derived from trans-[M(N(2))(2)(Ph(2)PCH(2)CH(2)PPh(2))(2)] or related complexes (M = Mo, W)

A zero-valent [M(Ph(2)PCH(2)CH(2)PPh(2))(2)] moiety (M = Mo, W) generated in situ by dissociation of the N(2) ligands in trans-[M(N(2))(2)(Ph(2)PCH(2)CH(2)PPh(2))(2)] can activate pi-accepting organic molecules including isocyanides and nitriles, which undergo the electrophilic attack caused by a strong pi-donation from a zero-valent metal center. Cleavage of a variety of C-X bonds (X = H, C, N, O, P, halogen) also occurs at their electron-rich sites through oxidative addition to form reactive intermediates, which subsequently degradate to yield smaller molecules either bound to or dissociated from the metal center. The mechanism is substantiated unambiguously by isolation of numerous intermediate stages.     

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.     

Gas-phase coordination complexes of U(VI)O2(2+), Np(VI)O2(2+), and Pu(VI)O2(2+) with dimethylformamide

Electrospray ionization of actinyl perchlorate solutions in H₂O with 5% by volume of dimethylformamide (DMF) produced the isolatable gas-phase complexes, [An^VIO₂(DMF)₃(H₂O)]²⁺ and [An^VIO₂(DMF)₄]²⁺, where An = U, Np, and Pu. Collision-induced dissociation confirmed the composition of the dipositive coordination complexes, and produced doubly- and singly-charged fragment ions. The fragmentation products reveal differences in underlying chemistries of uranyl, neptunyl, and plutonyl, including the lower stability of Np(VI) and Pu(VI) compared with U(VI).     

Synthesis and Structural Characterization of Cu（pic）2[CO（NH2）2]2 and （picH2）2[Cu（pic）2（SCN）2]

1 INTRODUCTION The picolinic acid (picH), also called pyridine- 2-carboxylic acid, has a broad spectrum of physio- logical effects on the activity functions of both ani- mal and plant organisms. It is attributed increasing interest due to its ability to …     

Preparation of cis-Mo(CO)2(Ph2P(CH2)nPPh2)2 (n = 1, 2, 3) from cis-dicarbonylbis(norbornadiene)molybdenum and crystal structure of [cis-Mo(CO)2(Ph2P(CH2)3PPh2)2]

The complexes cis-Mo(CO)₂(Ph₂P(CH₂)_nPPh₂)₂ (n = 1, 2, 3) are synthesized by heating benzene solutions of cis-dicarbonylbis(norbornadiene)molybdenum and the corresponding diphosphines. The X-ray structural analysis of cis-Mo(CO)₂(Ph₂P(CH₂)₃PPh₂)₂ is reported, with the following crystal data: C₅₆H₅₂MoO₂P₄·2CH₂Cl₂·0.5C₆H₁₄, mol wt. 1189.81, monoclinic, space group P2₁/n, a 15.643(2), b 21.453(7), c 17.105(3) Å, β 100.75(1)°, V 5639.59 ų, Z = 4, D_c 1.39, D_m 1.36 g/cm³.     

Polymer imprinting with iron-oxo-hydroxo clusters: [Fe6O2(OH)2(O2CC(Cl)=CH2)12(H2O)2], [Fe6O2(OH)2(O2C-Ph-(CH)=CH2)12(H2O)2] and [{Fe(O2CC(Cl)=CH2)(OMe)2}10

We report the syntheses of imprinted polymers using iron-oxo-hydroxo clusters as templates. Three new iron clusters, [Fe(6)O(2)(OH)(2)(O(2)CC(Cl)=CH(2))(12)(H(2)O)(2)] (1), [{Fe(O(2)CC(Cl)=CH(2))(OMe)(2)}(10)] (2) and [Fe(6)O(2)(OH)(2)(O(2)C-Ph-(CH)=CH(2))(12)(H(2)O)(2)] (3) have been prepared from commercially-available carboxylic acids. Cluster-imprinted-polymers (CIPs) of 1, 2 and 3 were prepared with ethylene glycol dimethacrylate monomer, and of 1 with methyl methacrylate monomer. The imprinted sites within the CIPs were examined using EXAFS and diffuse reflectance UV/vis spectroscopy, demonstrating that the clusters 1, 2 and 3 were incorporated intact within the polymers. Extraction of the clusters from the CIPs imprinted with 1 and 3 gave new polymers that showed evidence of an imprinting effect.