首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
四氮杂大环配合物是生物体内一些金属酶结构单元的模拟物,四氮杂大环铜和镍的配合物可以催化化学振荡反应。近年来,此类反应被广泛地研究[1~4]。目前已报道的作为化学振荡反应催化剂的四氮杂大环配合物的配体都是单环。我们发现一种双四氮杂大环镍(Ⅱ)配合物Ni2L(ClO4)4[L为双(11,13二甲基1,4,7,10四氮杂10,13环十三二烯12亚甲基)]可以作为化学振荡反应的催化剂,本文研究了Ni2L(ClO4)4催化NaBrO3CH2(COOH)2(MA)H3PO4体系的化学振荡反应。1实验部分实验试剂:丙二酸…  相似文献   

2.
报道了一种反式Curtis环的镍(Ⅱ) 的配合物NiL(ClO4)2(L为2,4,4,9,11,11-六甲基-1,5,8,12-四氮杂环十四-1,5,8,12-四烯)催化NaBrO3-CH2(COOH)2(MA)-H3PO4体系的化学振荡反应。测得该体系的振荡范围,研究、分析了各物种浓度、自由基抑制剂和还原剂、Ag+、Hg2+以及温度对振荡反应的影响。结果表明Br-起重要动力学控制作用,在反应过程中有自由基、Br2产生并参与了反应。同时发现搅拌速度对反应有很大影响。该反应的振荡轨迹与经典BZ反应及其它四氮杂大环配合物催化的体系有所不同。  相似文献   

3.
四氮杂大环四烯镍(Ⅱ)配合物催化的化学振荡反应   总被引:2,自引:0,他引:2  
化学振荡反应是化学反应体系中某些状态量随时间或空间周期性变化。四氮杂大环配合物与存在生物体内的一些含有卟吩环的金属酶结构相似。目前,可以催化化学振荡反应的四氮杂大环配合物并不多,文献报道了一种具有C=N共轭双键的四烯型四氮杂大环配体(TIM)的Ni 的配合物可以催化BZ化学振荡反应[1-3]。然而以2,4,4,9.11,11一六甲基一1,5,8,12-四氮杂环十四一1,5, 8, 12一四烯(L)镍配合物[NiL(CIO4)2]这种具有四个孤立 C=N双键的四烯型四氮杂大环镍的配合物作为振荡反应催化…  相似文献   

4.
本文报道了四氮杂大环四烯镍(Ⅱ)配合物[Ni(TIM)]X[TIM为2,3,9,10-四甲基-1,4,8,11-四氮杂环十四-1,3,8,10-四烯;X=(ClO_4)_2,ZnCl_4,(SCN)_2]催化BrO_3~-CH_2(CO_2H)_2-(CO_2H)_2-H_2SO_4体系的新型振荡化学反应.对该振荡反应体系进行了多方面的研究,并提出了简要的机理.  相似文献   

5.
以甘氨酸为振荡底物,研究了四氮杂大环镍髤配合物[以NiL(ClO4)2表示](L为5,5,7,12,12,14-六甲基-1,4,8,11-四氮杂十四环-7,14-二烯)催化的氨基酸-KBrO3-H2SO4-丙酮体系的化学振荡反应。通过所获得的该振荡体系的振荡波形、振荡诱导期tin及振荡周期tp数据,估算了动力学参数(诱导期及周期的速率常数kin、kp,表观活化能Ein、Ep及指前因子Ain,Ap),进而依据Oregonator模型及不可逆过程热力学理论,获得了该振荡体系的热力学函数(ΔHin,ΔGin,ΔSin及ΔHp,ΔGp,ΔSp)。结果表明,四氮杂大环配合物不仅能催化丙二酸等有机羧酸参与的化学振荡反应,也是以甘氨酸为底物的B-Z(Belousov-Zhabotinskii)振荡反应的催化剂。该振荡体系的诱导期和周期的熵变ΔSin和ΔSp均为负值,从而进一步证明化学振荡反应是具有耗散结构的非平衡态体系。  相似文献   

6.
本文报道二价铜与叠氮、大环穴醚(C_(16)H_(38)N_6)配合物的合成和晶体结构.配合物组成为[Cu_2(N_2)_2(C_(16)H_(38)N_3)](ClO_4)_2,晶体属于空间群C_1~1-PI,晶胞参数a=17.669(10).b=13.355(5),c=6.414(3)A;β=103.85(4),β=100.40(4),γ=71.30(3)°;对1870个反射精修的最后一致性因子R=0.088.此配合物中Cu(Ⅱ)呈平面正方四配位结构形式,这在类似饱和大环穴醚双铜配合物中,还是首次发现.每个配位多面体由大环穴醚配体提供三个氮原子,叠氮离子提供一个氮原子,两个Cu(Ⅱ)离子之间不存在叠氮桥,间距为5.12A.  相似文献   

7.
本文报道了一种以四氮杂大环四烯镍(Ⅱ)配合物[Ni(TIM)](ClO4)2为催化剂,柠檬酸为有机底物的硫酸环境的新型的B-Z振荡反应体系。讨论了不同浓度的溴酸钠、硫酸、柠檬酸对振荡周期(tp)、振幅(A)、振荡次数(n)的影响,发现振荡周期tp与溴酸钠、硫酸、柠檬酸的浓度有关,关系表达式:tp(s)∝C0-2.003(NaBrO3)C0-2.881(H2SO4)C0-3.16(Citric acid)。研究了各种还原剂、自由基抑制剂、Ag+、Hg2+对该振荡反应的不同程度的影响。最后提出了该反应的反应机理。  相似文献   

8.
一种氮杂大环铜催化的新型振荡反应宋继梅(合肥地矿部石海局化探中心,,230022)倪诗圣,徐济德(安徽大学化学系,合肥,230039)四氮杂大环铜、镍配合物催化的Belousov-Zhabotinskii反应是一类新型的振荡反应 ̄[1],研究这类反应...  相似文献   

9.
本文报道了镧系离子Ln(Ⅱ)与1-氨基乙酸及1,10-二氮杂菲反应所形成的固态三元配合物,考察了这类配合物的红外光谱,荧光光谱,热谱。比较了X-射线粉末衍射及元素分析数据。确定该类配合物的组成为Ln·(Gly)·(phen)_2·H_2O(Gly为1-氨基乙酸,phen为1,10-二氮杂菲)。  相似文献   

10.
许志强  倪诗圣  徐济德  田玉鹏 《化学学报》1992,50(11):1085-1090
本文报道了四氮杂大环四烯镍(Ⅱ)配人事物[Ni(TIM]X[TIM为2,3,9,10-1,4,8,11-甲氮杂环十四-1,3,8,10-四烯;X=(ClO~4)~2,ZnCl~4,(SCN)~2]催化BrO CH~2(CO~H)~2-(CO~2H~2)-H~2SO~4体系的新型振荡化学反应.对该振荡反应体系进行了多方面的研究,并提出了简要的机理.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
14.
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.  相似文献   

15.
Huang FQ  Ibers JA 《Inorganic chemistry》2001,40(11):2602-2607
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.  相似文献   

16.
17.
Electrospray ionization of actinyl perchlorate solutions in H2O with 5% by volume of dimethylformamide (DMF) produced the isolatable gas-phase complexes, [AnVIO2(DMF)3(H2O)]2+ and [AnVIO2(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).  相似文献   

18.
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 …  相似文献   

19.
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.  相似文献   

20.
The reactions of UO(2)(C(2)H(3)O(2))(2).2H(2)O with K(2)TeO(3).H(2)O, Na(2)TeO(3) and TlCl, or Na(2)TeO(3) and Sr(OH)(2).8H(2)O under mild hydrothermal conditions yield K[UO(2)Te(2)O(5)(OH)] (1), Tl(3)[(UO(2))(2)[Te(2)O(5)(OH)](Te(2)O(6))].2H(2)O (2) and beta-Tl(2)[UO(2)(TeO(3))(2)] (3), or Sr(3)[UO(2)(TeO(3))(2)](TeO(3))(2) (4), respectively. The structure of 1 consists of tetragonal bipyramidal U(VI) centers that are bound by terminal oxo groups and tellurite anions. These UO(6) units span between one-dimensional chains of corner-sharing, square pyramidal TeO(4) polyhedra to create two-dimensional layers. Alternating corner-shared oxygen atoms in the tellurium oxide chains are protonated to create short/long bonding patterns. The one-dimensional chains of corner-sharing TeO(4) units found in 1 are also present in 2. However, in 2 there are two distinct chains present, one where alternating corner-shared oxygen atoms are protonated, and one where the chains are unprotonated. The uranyl moieties in 2 are bound by five oxygen atoms from the tellurite chains to create seven-coordinate pentagonal bipyramidal U(VI). The structures of 3 and 4 both contain one-dimensional [UO(2)(TeO(3))(2)](2-) chains constructed from tetragonal bipyramidal U(VI) centers that are bridged by tellurite anions. The chains differ between 3 and 4 in that all of the pyramidal tellurite anions in 3 have the same orientation, whereas the tellurite anions in 4 have opposite orientations on each side of the chain. In 4, there are also additional isolated TeO(3)(2-) anions present. Crystallographic data: 1, orthorhombic, space group Cmcm, a = 7.9993(5) A, b = 8.7416(6) A, c = 11.4413(8) A, Z = 4; 2, orthorhombic, space group Pbam, a = 10.0623(8) A, b = 23.024(2) A, c = 7.9389(6) A, Z = 4; 3, monoclinic, space group P2(1)/n, a = 5.4766(4) A, b = 8.2348(6) A, c = 20.849(3) A, beta = 92.329(1) degrees, Z = 4; 4, monoclinic, space group C2/c, a = 20.546(1) A, b = 5.6571(3) A, c = 13.0979(8) A, beta = 94.416(1) degrees, Z = 4.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号