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 31 毫秒
1.
The binary group 15 polyazides As(N(3))(3), Sb(N(3))(3), and Bi(N(3))(3) were stabilized by either anion or donor-acceptor adduct formation. Crystal structures are reported for [Bi(N(3))(4)](-), [Bi(N(3))(5)](2-), [bipy·Bi(N(3))(5)](2-), [Bi(N(3))(6)](3-), bipy·As(N(3))(3), bipy·Sb(N(3))(3), and [(bipy)(2)·Bi(N(3))(3)](2). The lone valence electron pair on the central atom of these pnictogen(+III) compounds can be either sterically active or inactive. The [Bi(N(3))(5)](2-) anion possesses a sterically active lone pair and a monomeric pseudo-octahedral structure with a coordination number of 6, whereas its 2,2'-bipyridine adduct exhibits a pseudo-monocapped trigonal prismatic structure with CN 7 and a sterically inactive lone pair. Because of the high oxidizing power of Bi(+V), reactions aimed at Bi(N(3))(5) and [Bi(N(3))(6)](-) resulted in the reduction to bismuth(+III) compounds by [N(3)](-). The powder X-ray diffraction pattern of Bi(N(3))(3) was recorded at 298 K and is distinct from that calculated for Sb(N(3))(3) from its single-crystal data at 223 K. The [(bipy)(2)·Bi(N(3))(3)](2) adduct is dimeric and derived from two BiN(8) square antiprisms sharing an edge consisting of two μ(1,1)-bridging N(3) ligands and with bismuth having CN 8 and a sterically inactive lone pair. The novel bipy·As(N(3))(3) and bipy·Sb(N(3))(3) adducts are monomeric and isostructural and contain a sterically active lone pair on their central atom and a CN of 6. A systematic quantum chemical analysis of the structures of these polyazides suggests that the M06-2X density functional is well suited for the prediction of the steric activity of lone pairs in main-group chemistry. Furthermore, it was found that the solid-state structures can strongly differ from those of the free gas-phase species or those in solutions and that lone pairs that are sterically inactive in a chemical surrounding can become activated in the free isolated species.  相似文献   

2.
1 INTRODUCTION The significance of cobalt coordination com- pounds in biological systems is recognized[1~3]. In many instances the cobalt coordination compounds of Schiff bases have been suggested as models to describe energy transfer in naturally occurring systems. In such cases the coordination sphere about the metal ion is believed to play an important role in determining the nature of the model system[4, 5]. In order to investigate the structures of such complexes, we report herein t…  相似文献   

3.
Schiff bases of isatin were reported to possess antibacterial, antifungal, antiviral, anti-HIV, antiprotozoal, and anthelmintic activities1. They also exhibit significantanticonvulsant activity, apart from other pharmacological properties2. Conductingsubs…  相似文献   

4.
2-(4′-Bromopyrazolyl-1′)-3-tosylaminopyridine (HL3) and its complex ZnL2 (I) are synthesized, and their structures are studied by IR, UV, and 1H NMR spectroscopy. The molecular structure of complex ZnL2 is determined by X-ray diffraction analysis. The atomic structure of ZnL2 is confirmed by the optimization of the molecular geometry using quantum-chemical calculations in the density functional theory approximation. The experimental bands in the absorption spectrum of complex I are interpreted on the basis of the calculations, and its photoluminescence properties are studied.  相似文献   

5.
Cu(II)-β-cyclodextrin-catalyzed synthesis of spiro[indoline-3,4′-pyrano[3,2-c]chromene]-3′-carbonitriles through the reaction of isatin derivatives, 4-hydroxycoumarin, and malononitrile in ethanol at room temperature.  相似文献   

6.
By treatment of 1,3-bis(3,4-dimethoxybenzyl)-3,4,5,6-tetrahydropyrimidinium chloride (1) with KOBu t and [PtCl2(PEt3)2]2 N-coordinated platinum complex (2) is obtained. The Pt atom is coordinated in square planar arrangements by two chloride ions in a trans-configuration, the N-formyl-N,N′-bisaryltrimethylenediamine nitrogen atom, and the phosphine P atom. An extensive three-dimensional network of three C-H…O hydrogen bonds, two C-H…π and one π…π interactions are responsible for the crystal stabilization. Intermolecular hydrogen bonds and C-H…π interactions produce R 2 2 (6), R 2 2 (22), R 2 2 (24), R 3 3 (23), R 4 4 (26), and R 4 4 (32) rings.  相似文献   

7.
《Polyhedron》1987,6(5):881-889
The crystal structures of diaquabis[(benzylthio)acetato]zinc(II), [Zn(BTA)2 (H2O)2] (1), catena-[diaqua-tetra[(benzylthio)acetato)]-bis[cadmium(II)], [Cd2(BTA)4 H2O)2]n (2), catena-{tetra-μ-[2-methyl-3-(phenylthio)propionato-O,O′]-bis[copper (II)]}, [Cu2(MPTP)4]n (3) and tetra-μ-[2-methyl-2-(phenylthio)propionato-O,O′]- bis[ethanol copper(II)], [Cu2(PTIBA)4(EtOH)2] (4) have been determined using X-ray diffraction techniques. Complex (1) is monomeric with distorted octahedral stereochemistry and lies on a two-fold rotational axis. The MO6 coordination involves four oxygens from two slightly asymmetric bidentate BTA car☐yl groups [ZnO, 2.138(3), 2.28(3)Å] and two cis-related waters [ZnOw, 1.996(3)Å]. The cadmium complex (2) is best described in terms of a polymer with the repeating unit consisting of two different centres, one seven, the other six-coordinate. With the first, the distorted MO6S coordination sphere has four oxygens from two asymmetric bidentate car☐ylate groups (ligands B and C) [CdO, 2.36, 2.56(1)Å; 2.26, 2.67(1)Å], an oxygen and a sulphur from a bidentate chelate ligand (A) [CdO, 2.36(1)Å; CdS, 2.773(4)Å] and an oxygen from a bridging car☐yl group (ligand D) [CdO, 2.28(1)Å]. Ligands C and D also bridge two Cd centres through sulphurs [CdS, 2.739, 2.723(4)Å]. The second car☐yl oxygen of ligand A also forms a bridge to the second Cd [(CdO, 2.30(1)Å], while the distorted octahedral MO4S2 stereochemistry is completed by two waters [CdO, 2.25(1), 2.49(1)Å] and a sulphur from ligand D [CdS, 2.723(4)Å] giving a polymer structure. Complexes (3) and (4) are centrosymmetric tetra-car☐ylate bridged dimers [for (3) Cu ··· Cu, 2.586(3)Å; mean CuO(equatorial), 1.957(11)Å; for the two independent dimers in (4), Cu ··· Cu, 2.596(1), 2.616(1)Å; CuO (equatorial), 1.952(4), 1.968(4)Åmean]. The axial positions of the dimer in (3) are occupied by car☐yl oxygens of adjacent dimers [CuO, 2.280(9)Å] forming a polymer structure. In contrast, these positions in (4) are occupied by ethanol molecules with CuO, 2.222(3) and 2.177(4)Årespectively for the two independent dimers.  相似文献   

8.
In the structure of the title compound, [Cu(C4O4)(C4H4N2)]n, each copper cation is surrounded by three squarate (3,4-di­hydroxy-3-cyclo­butene-1,2-dioate) anions and two pyrazine ligands, all of which are located in special positions. The copper cation and all atoms of the squarate anion are located on a mirror plane, whereas the pyrazine ligand is located around a mirror plane which is perpendicular to the ring plane. The cations are connected via the squarate anions and the pyrazine ligands, forming sheets parallel to (001).  相似文献   

9.
1 INTRODUCTION N,N?-Bis(salicylidene)-1,3-diaminopropane (BSDP) is a versatile tetradentate ligand, which forms stable complexes with a large number of transition metals[1~3]. However, the complexes related to the BSDP deriva- tive,N,N?-bis(3,5-dichlorosalicylidene)-1,3-diamino- propane (BCDP), have been seldom reported. The prime interest in these complexes is their ability to afford functional solid materials with potentially controllable properties and novel molecular struc- tur…  相似文献   

10.
<正> The title complex is of triclinic system space group P1 with its cell parameters: a = 9. 386(1), b = 9. 412(2), c=11. 549(2)(?), α=97. 91(2), β = 81.70(1), γ= 102. 63(1)°, V= 979.2(?)3, Z = l, Mr = 966. 01, Dx =1. 638 gcm-3, μ(MoKα) = 16. 896cm-1, F (000) = 478, final R = 0. 033 and Rw = 0. 046 for 3424 reflections with I≥3σ(I). The two O atoms of the ligand are bonded to two Sn atoms to form a bridged binuclear species which lies on the crystallographic centre of symmetry situated at the centre of the ethylene C -C bond. The unique Sn atom exhibits a trigonalbipyramidal geometry.  相似文献   

11.
We synthesized three copper(II) complexes with two structurally related polydentate ligands, quinoline-4-carboxylic acid (quCOOH) and quinoxaline (qux). The structures of these complexes were determined using X-ray single crystal crystallography. Complex 1, [Cu(quCOO)(N3)(H2O)] n , has a 2-D polymeric structure through di-μ1,1 azido groups forming (Cu2N2) dimeric units and di-μN,O quinoline carboxylate bridging the binuclear copper units. [Cu(quCOO)(N3)(H2O)] n · 0.87MeOH, (2), has the same structure as 1 in addition to MeOH molecules separating the 2-D sheets of [Cu(quCOO)(N3)(H2O)] n . [Cu(qux)(NO3)2] n , (3), has no coordinated azido groups, but the quinoxaline is a bidentate bridging ligand giving a 1-D chain, while the μO,O′ chelating nitrato groups stabilize the chain structure by forming a square planar coordination sphere around copper. IR and UV–Vis spectra of the complexes are in agreement with the crystal structures.  相似文献   

12.
The reaction of (1R,2R,5R)-3-[{2-[(2-hydroxybenzylidene)amino]ethyl}imino]-2,6,6-trimethylbicyclo[3.1.1]heptan-2-ol with lithium tetrachloropalladate was studied. A chiral palladium(II) complex was thus obtained and its structure was confirmed by NMR spectroscopy and X-ray diffraction analysis.  相似文献   

13.
The internal magnetic field (H n ) at57Fe nucleus was investigated for the mixed crystals, NBu4[Fe(II) x Mn(II)1-x Cr(III) (ox)3] (x=0.03?1) and NBu4[Fe(II) x Ni(II)1-x Fe(III)(ox)3]) (x=0?1) using Mössbauer spectroscopy, where NBu4/+=tetra(n-butyl)ammonium ion and ox2?=oxalate ion. With the decrease ofx, the direction ofH n at Fe(II) in NBu4[Fe(II) x Mn(II)1-x Cr(III)(ox)3] changed gradually from parallel to perpendicular, to the honeycomb layers consisting of an alternate array of the bivalent and tervalent ions through ox2? ligands. A variation of ca. 50° in direction was observed for theH n at Fe(III) in NBu4[Fe(II) x Ni(II)1-x Fe(III)(ox)3].  相似文献   

14.
Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of the type Na4[ML(H2O)2] of the ligand, 3,3′-bis[N,N-di(carboxymethyl)-aminomethyl]-o-cresol sulphonphthalein (Xylenol Orange, Na4H2L), have been synthesized and characterized by different physico-chemical (elemental analyses, solubility, electrolytic conductances, magnetic susceptibility measurements) and spectral (u.v.-vis, i.r., e.s.r., and powder X-ray diffraction) techniques for their structure determination. The data suggest 1?:?1 (M?:?L) compositions and octahedral geometries around M(II) except for Cu(II). Antifungal activity of the complexes measured against ten fungi show significant activity against Alternaria brassicicola, Alternaria solanai, Cercospora species and Helminthosporium oryzae and moderate antifungal activity against Curvularia species, Curvularia lunata, Curvularia penniseti, Colletotrichum capsici, Aspergillus niger, Aspergillus flavus Erysiphae pisi and Fusarium udum fungi.  相似文献   

15.
Copper(II) and zinc(II) complexes with the condensation derivative of 2-acetylpyridine and hydrolyzed ethyl hydrazinoacetate were synthesized in a one pot reaction. Crystal structure of the zinc(II) complex was determined by single-crystal X-ray diffraction. In this binuclear complex, the ligand is coordinated via pyridine and imine nitrogen, while carboxylate oxygen is a bridge between metal centers. The fifth coordination site is occupied by a chloride, giving a distorted square pyramidal geometry around each zinc(II). The molecular structure of the copper(II) complex was determined from elemental analysis, infrared and electron paramagnetic resonance spectroscopy, molar conductivity, mass spectrometry, and measurements of the magnetic moment. Thermal behavior of both complexes was studied by thermogravimetric analysis coupled with mass spectrometer.  相似文献   

16.
17.
Abstract

The symmetric 'end-off' compartmental proligand 2,6-[N,N′-bis(2-hydroxy-phenylmethyl)-N,N′-bis(2-pyridylmethyl)aminomethyl]-4-methylphenol (H3L) has been used to generate homodinuclear nickel(II) and zinc(II) complexes. The crystal structures of the complexes reveal that the di-nickel(II) complex is donor asymmetric and the di-zinc(II) complex is coordination number asymmetric. In both complexes non-coordinated acetic acid molecules are tightly hydrogen-bonded to the pendant phenols of the ligand generating a double acid salt of the type[CH3COO…H…L…H…OOCCH3]3? in the dinickel complex and a single acid salt of the type [CH3COO…H…L]3? in the dizinc complex. In both cases the ligand periphery has been extended to provide a supraligand in which the donor potential of the original ligand has been enhanced.  相似文献   

18.
正确的能级次序应与分子的活性位置一致.实验证实,铁硫蛋白或模型化合物Fe_2S_2(SR)~(2-)及Fe_4S_4(SR)_4~(2-)的活性位置在端基,易于发生多种取代反应,而Fe_2S_2和Fe_4S_4实一般是稳定的.但是,经过电化学还原生成的Fe_2S_2(SR)_4~(3-),却不可逆地二聚化,生成Fe_4S_4(SR)_4~(2-)  相似文献   

19.
3‐Iodothyronamine (T1AM) is a novel metabolite of thyroid hormone. In HEK‐293 cells expressing an orphan G‐protein coupled receptor, the trace amine receptor, T1AM, potently increased cAMP accumulation. In mice, T1AM rapidly induced hypothermia and bradycardia within minutes of administration. These results suggest the existence of a new signaling pathway, the stimulation of which leads to rapid physiological and behavioral consequences. Isotope‐labeled T1AM derivatives would be useful to study the biology and pharmacology of T1AM. Herein we describe efficient syntheses of [125I]‐, [2H]‐, and [3H]‐T1AM.  相似文献   

20.
以2-氨基-4-三氟甲基-5-甲基-噻吩-3-羧酸乙酯(1)为起始原料制得膦亚胺2.在碳酸钾的催化下,膦亚胺2与芳基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上2,2’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]3;膦亚胺2与烷基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上3,3’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]4.化合物3的核磁共振氢谱表明关环反应在嘧啶环的2,2’位;化合物4的核磁共振氢谱表明关环反应在嘧啶环的3,3’位.对合成反应机理的推导及目标产物核磁共振氢谱数据的分析解释了此合成反应的选择性.  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