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 15 毫秒
1.
Nucleophilic substitution of Pd(RaaiR′)Cl2 [(RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2NN-1-R′; where R = H(a)/ Me(b)/ Cl(c) and R′ = Et(1)/Bz(2)] with 2-Mercaptopyridine (2-SH-Py) in acetonitrile (MeCN) at 298 K, to form [Pd2(2-S-Py)4], has been studied spectrophotometrically under pseudo-first-order conditions and the analyses support the nucleophilic association path. The reaction follows the rate law, Rate = {k 0 + k [2-SH-Py] 0 2 }[Pd(RaaiR′)Cl2]: first order in Pd(RaaiR′)Cl2 and second order in 2-SH-Py. The rate of the reaction follows the order: Pd(RaaiEt)Cl2 (1) < Pd(RaaiBz)Cl2 (2) and Pd(MeaaiR′)Cl2 (b) < Pd(HaaiR′)Cl2 (a) < Pd(ClaaiR′)Cl2 (c). External addition of Cl (LiCl) and HCl suppresses the rate (Rate ∝ 1/[Cl]0 & ∝1/[HCl]0). The reactions have been studied at different temperatures (293–308 K) and activation parameters (Δ H° and Δ S°) of the reactions were calculated from the Eyring plot and support the proposed mechanism.  相似文献   

2.
Dechlorination of M(RaaiR′) n Cl2 by AgNO3 produced [M(RaaiR′) n (MeCN)2]+2 [M = Ru(II), n = 2; Pt(II), n = 1; RaaiR′ = 1-alkyl-2-(arylazo)imidazole)] which upon reaction with the nucleobase cytosine (C) in MeCN solution gave cytosinato bridged dimeric compounds which were isolated as perchlorate salts [M2(RaaiR′) n (C)2](ClO4)2 · H2O. The products were characterized by IR, u.v.–vis., 1H-n.m.r. spectroscopy and cyclic voltammetry. In MeCN solution the ruthenium complexes exhibit a strong MLCT band at 550–555 nm and two redox couples positive to SCE due to two metal-center oxidation along with ligand reduction, negative to SCE. The platinum complexes show a weak transition at 500–520 nm in MeCN and exhibit only ligand reduction in cyclic voltammetry. The coordination of the ligand was supported by 1H-n.m.r. spectral data.  相似文献   

3.
Silver-assisted aquation of blue cis-trans-cis-RuCl2(RAaiR’)2 (I) leads to the synthesis of solvento species, blue-violet cis-trans-cis-[Ru(OH2)2(RAaiR’)2](ClO4)2 (II), where RAaiR’ = p-R-C6H4-N=N-C3H2-NN, abbreviated as N,N′ chelator (N(imidazole) and N(azo) represent N and N′, respectively); R = H (a), p-Me (b), p-Cl(c); R′ = Me (III), Et (IV), Bz (V), that reacted with NCS in warm EtOH resulting in red-violet dithiocyanato complexes of the type [Ru(NCS)2(RAaiR)2] (IIIa–Vn). These complexes were studied by elemental analysis, UV-Vis, IR, and 1H NMR spectroscopy and cyclic voltammetry. The solution structure and stereoretentive transformation in each step have been established from 1H NMR results. All the complexes exhibit strong MLCT transitions in the visible region. They are redox active and display one metal-centered oxidation and successive ligand-based reductions. Linkage isomerisation was studied by changing the solvent and then by UV-Vis spectral analysis.  相似文献   

4.
Iron (II) complexes of 1-alkyl-2-(arylazo)imidazoles (p-R-C6H4-N=N-C3H2NN-1-R′, R = H (a), Me (b), Cl (c) and R′ = Me (1/3), Et (2/4) have been synthesized and formulated astris-chelates Fe(RaaiR′) 3 2+ . They are characterized by microanalytical, conductance, UV-Vis, IR, magnetic (polycrystalline state) data. The complexes are low spin in character,t 2g 6 (Fe(II)) configurations.  相似文献   

5.
The hetero-tris-chelates of the formula [Ru(Phen)(RAaiR′)2](ClO4)2 (Phen = 1,10-phenanthroline, RAaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2-NN-1-R′, where R = H (a), Me (b), Cl (c) and R′ = Me (II), Et (III), CH2Ph (IV)) have been isolated from the reaction of ctc-[RuCl2(RAaiR′)2] with AgNO3 + Phen or [Ag(Phen)2](ClO4) in acetone at 40°C in dark followed by the addition of NaClO4 (aq). The stereo-chemistry of the complexes have been supported by 1H NMR data. Considering the arylazoimidazole and phenanthroline moietie there are twenty different carbon atoms in the molecule which gives a total of twenty different peaks in the 13C NMR spectrum of complex Ia. Cyclic voltammograms show Ru(III)/Ru(II) couple at 1.3–1.4 V vs SCE along with three successive ligand reductions. The article is published in the original.  相似文献   

6.
Ag+ assisted aquation of blue cis-trans-cis-RuCl2(RaaiR′)2 (4–6) leads to the synthesis of solvento species, blue-violet cis-trans-cis-[Ru(OH2)2(RaaiR′)2](ClO4)2 [Raai R′=p-R-C6H4 N=N–C3H2–NN–1–R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), OMe (b), NO2 (c) and R′ = Me (1/4/7/10), CH2CH3 (2/5/8/11), CH2Ph (3/6/9/12)] that have been reacted with NO2in warm EtOH resulting in violet dinitro complexes of the type, Ru(NO2)2(RaaiR′)2 (7–9). The nitrite complexes are useful synthons of electrophilic nitrosyls, and on triturating the compounds, (7b–9b) with conc. HClO4 nitro-nitrosyl derivatives, [Ru(NO2)(NO)(OMeaaiR′)2](ClO4)2 (10b–12b) are isolated. The solution structure and stereoretentive transformation in each step have been established from 1H n.m.r. results. All the complexes exhibit strong MLCT transitions in the visible region. They are redox active and display one metal-centred oxidation and successive ligand-based reductions. The redox potentials of Ru(III)/Ru(II) (E1/2M) of (10b–12b) are anodically shifted by ∼ ∼0.2 V as compared to those of dinitro precursors, (7b–9b). The ν(NO) >1900 cm−1 strongly suggests the presence of linear Ru–NO bonding. The electrophilic behaviour of metal bound nitrosyl has been proved in one case (12b) by reacting with a bicyclic ketone, camphor, containing an active methylene group and an arylhydrazone with an active methine group, and the heteroleptic tris chelates thus formed have been characterised.  相似文献   

7.
Two transition metal complexes with azide and 3,4-di(2′-pyridyl)-1,2,5-oxadiazole (dpo), [Cu2(dpo)2(N3)4] (1), and [Mn(dpo)2(N3)2] (2), have been synthesized and characterized by single-crystal X-ray diffraction. The Cu(II) complex is binuclear with double end-on (EO) azido bridges, in which each Cu(II) ion assumes a distorted square pyramidal geometry, and each EO azido bridge adopts a quasi-symmetric fashion. In contrast, the Mn(II) complex is mononuclear, in which the Mn(II) ion is ligated by two dpo ligands and two terminal azide ions, with a distorted octahedron geometry. Magnetic studies on the Cu(II) complex revealed that the double EO azido bridge mediates ferromagnetic coupling with J=12.8 cm−1.  相似文献   

8.
The reaction of ctc-[Ru(RaaiR′)2Cl2] (3a–3i) [RaaiR′=1-alkyl-2-(arylazo)imidazole, p-R—C6H4—N=N— C3H2NN(1)—R′, R=H, OMe, NO2, R′=Me, Et, Bz] with KS2COR′′ (R′′=Me, Et, Pr, Bu or CH2Ph) in boiling dimethylformamide afforded [RuII{o-S—C6H4(p-R-)—N=N—C3H2NN(1)—R′}2] (4a–4i), where the ortho-carbon atom of the pendant phenyl ring of both ligands has been selectively and directedly thiolated. The newly formed tridentate thiolate ligands are bound in a meridional fashion. The solution electronic spectra exhibit a strong MLCT band near 700 nm and near 550 nm, respectively in DCM. The molecular geometry of the complexes in solution has been determined by H n.m.r. spectroscopy. Cyclic voltammograms show a Ru(II)/Ru(III) couple near 0.4 V and an irreversible oxidation response near 1.0 V due to oxidation of the coordinated thiol group, along with two successive reversible ligand reductions in the range −0.80–0.87 V (one electron), −1.38–1.42 V (one electron). Coulometric oxidation of the complexes at 0.6 V versus SCE in CH2Cl2 produced an unstable Ru(III) congener. When R=Me the presence of trivalent ruthenium was proved by a rhombic e.p.r. spectrum having g1=2.349, g2=2.310.  相似文献   

9.
Reaction of [Pd(dppe)Cl2/Br2] with AgOTf in a dichloromethane medium followed by ligand addition led to [Pd(dppe)(OSO2CF3)2] and then [Pd(dppe)(RaaiR)](OSO2CF3)2 [RaaiR′ = p-R-C6H4-N=N-C3H2-NN-1-R′, (1–3), abbreviated as a N,N′-chelator, where N(imidazole) and N(azo) are represented by N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3 (2), CH2Ph (3), OSO2CF3 is the triflate anion, dppe = 1,2-bis-(diphenylphosphinoethane)]. 31P “1H” NMR confirmed that due to the two phosphorus atom interaction in the azoimine symmetrical environment one sharp peak was formed. The 1H NMR spectral measurements suggest that azo-imine link with lot of phenyl protons in the aromatic region. 13C (1H) NMR spectrum, 1H, 1H COSY and 1H, 13C HMQC spectrum assign the solution structure and stereo-retentive conformation in each complex.  相似文献   

10.
[Ni(NaiR)2(X)2] (X = N3 (3, 4) and NCS (5, 6) complexes are synthesized from the reaction of Ni(ClO4)2 · 6H2O with 1-alkyl-2-(naphthyl-α/β-azo)imidazole (α/β-NaiR) and sodium azide (NaN3) or ammonium thiocyanate (NH4NCS) (1:2:2 molar ratio) in methanol solution. The complexes are characterized by elemental, spectroscopic and magnetic study. The distorted octahedral structure has been confirmed by single crystal X-ray diffraction study of [Ni(β-NaiEt)2(NCS)2] (6b). Cyclic voltammogram exhibits quasireversible oxidation response at 0.3–0.4 V which is corresponding to Ni(III)/Ni(II) couple along with ligand reductions at negative potential to SCE reference electrode.  相似文献   

11.
Reaction of [Ni(dppe)Cl2/Br2] with AgOTf in CH2Cl2 medium following ligand addition leads to [Ni(dppe)(OSO2CF3)2] and then [Ni(dppe)(RaaiR)](OSO2CF3)2 [RaaiR′ = p–R–C6H4–N=N–C3H2–NN-1–R′,(1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3 (2), CH2Ph (3), OSO2CF3 is the triflate anion]. 31P{1H}-NMR confirm that stable bis-chelated square planar Ni(II) azoimine–dppe complex formation with one sharp peaks. The 1H NMR spectral measurements suggest azoimine link is present with lot of phenyl protons in the aromatic region. Considering all the moities there are a lot of different carbon atoms in the molecule which gives many different peaks in the 13C(1H)-NMR spectrum. In the 1H-1H COSY spectrum in the present complexes and contour peaks in the 1H-13C-HMQC spectrum in the present complexes, assign the solution structure and stereoretentive conformation in each complexes.  相似文献   

12.
Reaction of [AuIII(C6F5)3(tht)] with RaaiR′ in dichloromethane medium leads to [AuIII(C6F5)3 (RaaiR′)] [RaaiR′=p-R-C6H4-N=N-C3H2-NN-l-R′, (1-3), R = H (a), Me (b), Cl (c) and R′= Me (1), CH2CH3 (2), CH2Ph (3), tht is tetrahydrothiophen]. The nine new complexes are characterised by ES/MS as well as FAB, IR and multinuclear NMR (1H,13C,19F) spectroscopic studies. In addition to dimensional NMR studies as1H,1H COSY and1H13C HMQC permit complete assignment of the complexes in the solution phase.  相似文献   

13.
Reaction of [Au(PPh3)2(tht)2](OSO2CF3)3 with RaaiR′ in CH2Cl2 medium following ligand addition leads to [Au(PPh3)2(RaaiR′)](OTf)3 [RaaiR′ = p-R–C6H4–N=N–C3H2–NN–1–R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3 (2), CH2Ph (3), PPh3 is triphenylphosphine, OSO2CF3 is the triflate anion, tht is tetrahydrothiophen]. The maximum molecular peak of the corresponding molecule is observed in the ESI mass spectrum. The 1H-nmr spectral measurements suggest methylene, –CH2–, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph it shows AB type quartets. 13C-nmr spectrum suggests the molecular skeleton. In the 1H–1H COSY spectrum as well as contour peaks in the 1H–13C heteronuclear multiple-quantum coherence (HMQC) spectrum assign the solution structure. Electrochemistry assign ligand reduction part rather than metal oxidation.  相似文献   

14.
Reaction of Mn(NCS)2 with 4-picoline (4-methylpyridine) leads to the formation of [Mn(NCS)2(4-picoline)4] · 0.67 · 4-picoline · 0.33 · H2O ( 1 - Mn ) reported in literature, Mn(NCS)2(4-picoline)2(H2O)2 ( 2-Mn/H2O ), and of [Mn(NCS)2(4-picoline)2]n ( 2-Mn/I ). 1-Mn and 2-Mn/H2O consist of discrete complexes, in which the metal cations are octahedrally coordinated, whereas in 2-Mn/I the metal cations are linked by pairs of μ-1,3-bridging thiocyanate anions into corrugated chains. Measurements using thermogravimetry and differential scanning calorimetry as well as temperature dependent X-ray powder diffraction on 1-Mn and 2-Mn/H2O reveal that upon heating both compounds transform into [Mn(NCS)2(4-picoline)]n ( 3-Mn ) via 2-Mn/I as intermediate. 3-Mn shows a very rare chain topology in which the metal cations are linked by μ-1,3,3 (N,S,S) coordinating anionic ligands which was never observed before with MnII. From these investigations there is no hint that a further modification of 2-Mn can be prepared as recently observed for [M(NCS)2(4-picoline)2]n (M = Fe, Cd) and such a form is also not available if the metastable forms of the FeII or CdII compounds were used as template during thermal decomposition. Magnetic investigations on 2-Mn/H2O show only paramagnetic behavior, whereas for 2-Mn/I antiferromagnetic ordering is observed. Finally, the crystal structure of Mn(NCS)2 was determined from XRPD data, which shows that it is strongly related to that of 3-Mn .  相似文献   

15.
Reaction of [Au(C6F5)(tht)2Cl](OTf) with RaaiR′ in CH2Cl2 medium leads to [Au(C6F5)(RaaiR′)Cl](OTf) [RaaiR′ = p-R–C6H4–N=N–C3H2–NN-1-R′, (1–3), abbreviated as N,N′-chelator, where N(imidazole) and N(azo) represent N and N′, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (1), CH2CH3 (2), CH2Ph (3), tht is tetrahydrothiophen]. The maximum molecular peak of [Au(C6F5)(MeaaiMe)Cl] is observed at m/z 599.51 (100 %) in the FAB mass spectrum. Ir spectra of the complexes show –C=N– and –N=N– stretching near at 1590 and 1370 cm−1 and near at 1510, 955, 800 cm−1 due to the presence of pentafluorophenyl ring. The 1H-NMR spectral measurements suggest methylene, –CH2–, in RaaiEt gives a complex AB type multiplet while in RaaiCH2Ph shows AB type quartets. 13C-NMR spectrum of complexes confirm the molecular skeleton. In the 1H-1H-COSY spectrum as well as contour peaks in the 1H-13C HMQC spectrum for the present complexes, assign the solution structure and stereoretentive conformation. The electrochemistry gives the ligand reduction peaks.  相似文献   

16.
The reaction of [Ni(dppa)(Cl)2] or [Ni(dppa)(Br)2] with AgOTf gives [Ni(dppa)(OTf)2], which then form [Ni(dppa)(RaaiR)](OSO2CF3)2 under the action of arylazoimidazole(RaaiR) in a dichloromethane medium [RaaiR′ = p-R-C6H4-N=N-C3H2-NN-1-R′, (I–III), abbreviated as N,N′-chelating agent, where N(imidazole) and N(azo) represent N and N’, respectively; R = H (a), Me (b), Cl (c) and R′ = Me (I), CH2CH3 (II), CH2Ph (III), OSO2CF3 is the triflate anion]. The 1H NMR spectral measurements suggest that a bound azoimine is responsible for a number of signals of phenyl protons in the aromatic region. The molecules of the complexes contain a number of different carbon atoms which gives a number of different peaks in the 13C (1H) NMR spectrum. The text was submitted by the author in English. The text was submitted by the author in English.  相似文献   

17.
Two new Mn(II) coordination polymers formed with molecular formula [Mn(H2O)2(HBTC)·(H2O)] 1 and [Mn(H2O)2(4,4′bipy)(HBTC)2]·(H4,4′bipy)2 2, where BTC = 1,2,4-benzenetricarboxylate and 4,4′bipy = 4,4′bipydine, have been synthesized via hydrothermal approach and characterized by single crystal X-ray diffraction techniques. 1 is composed of Mn–H2O–Mn 1D chains and further the chains are linked by HBTC ligands to form a 2D network in the ab plane; 2 is constructed by Mn–4,4′bipy–Mn 1D chains along the b direction with Mn2+ ions coordinated to H2BTC and water as terminal ligands to form a 2D network. We also prepared a third compound with the molecular formula of [Mn(H2O)(HBTC)·(H2O)] which has been recently structurally reported elsewhere. The magnetic properties of the three compounds have been studied in detail under variable temperatures.  相似文献   

18.
The reaction of [Ru(OH2)2(RaaiR′)2]2+ (RaaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C6H4-N=N-C3H2NN(1)-R′, R = H (1), Me (2), Cl (3); R′ = Me (a), Et (b), CH2Ph (c)) with 8-quinolinol (HQ) in acetone solution followed by the addition of NH4PF6 has afforded violet coloured mixed ligand complexes of the composition [Ru(Q)(RaaiR′)2](PF6). The maximum molecular peak of 1b is observed at m’z 790 (50%) in the ESI mass spectrum. Ir spectra of the complexes show -C=N- and -N=N- stretching near at 1590 and 1370 cm−1. The 1H NMR spectral measurements suggest methylene, -CH2−, in RaaiEt gives a complex AB type while in RaaiCH2Ph it shows AB type quartets. Considering the arylazoimidazole and oxine moitie there are twenty different carbon atoms in the molecule which gives a total of twenty different peaks in the C13 NMR spectrum of complex 1a. In the 1H-1H COSY spectrum of the present complexes, absence of any off-diagonal peaks extending from δ = 14.12 and 9.55 ppm confirm their assignment of no proton on N(1) and N(3) respectively. Contour peaks in the 1H-13C HMQC spectrum in the present complexes, the absence of any contours at δ = 157.12, 160.76, 155.67 ppm and 157.68–160.2 ppm assign them to the C(2), C(6), C(g) and C(h), C(i) carbon atoms respectively. The solution structure and stereoretentive transformation in each step have been established from n.m.r. results. Cyclic voltammograme show a Ru(III)/Ru(II) couple at 1.0–1.1 V versus SCE along with three successive ligand reductions.  相似文献   

19.

The synthesis, characterisation and X-ray structure of an Mn(II) compound, [Mn(ClL)2(NCS)2], is described. Oxidation of the compound by H2O2 leads to a mononuclear Mn(IV) compound [Mn(ClL)(ClL')(NCS)2]ClO4·2H2O where one of the ClL ligands is oxidised to the corresponding amide ClL'. Oxidation of [Mn(ClL)2(NCS)2] by Ce(IV), however, leads to a binuclear Mn(IV) compound [Mn2O(ClL')3(ClL)(H2O)2](NCS)2ClO4·2MeCN. Electron transfer behaviour of the compounds was investigated by cyclic voltammetry and differential pulse voltammetry.  相似文献   

20.
Two hexa-coordinate copper(II) complexes formulated as [Cu(phen)(4-dmampy)2(ClO4)2] and [Cu(bpy)(3-ampy)2(ClO4)2] · 0.5CH3OH · 0.5H2O (phen = 1,10–phenanthroline bpy = 2,2′-bipyridine, 3-ampy = 3-aminopyridine, 4-dmampy = 4-dimethylaminopyridine), and one low-spin ferrous complex formulated as [Fe(dmbpy)3](ClO4)2 · H2O (dmbpy = 4,4′-dimethyl-2,2′-bipyridine), were synthesized by in situ ligand substitution at room temperature, and characterized by X-ray single-crystal diffraction. This is the first structural report where either 4-dmampy and phen molecules, or 3-ampy and bpy molecules, are located simultaneously around one metal center.  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