共查询到20条相似文献,搜索用时 31 毫秒
1.
By using the hindered tris(pyrazolyl)borate ligand TpiPr2 (hydrotris(3,5-diisopropyl-1-pyrazolyl))borate, both mono- and binuclear complexes of cobalt [TpiPr2Co](X) (X = NO3 and OBz) and [TpiPr2Co]2(μ-X)(μ-OBz) (X = OH, N3) were synthesized. The nitrato complex, [TpiPr2Co](NO3) (1), which could be converted to (2), was prepared by reaction of KTpiPr2 with hydrated Co(NO3)2 and its molecular structure was determined by X-ray crystallography. The dinuclear di(μ-hydroxo) complex, [TpiPr2Co]2(μ-OH)2 (2), which was obtained by treatment of 1 with aqueous NaOH, reacted with one equivalent of benzoic acid to give the (μ-benzoato)(μ-hydroxo) complex, [TpiPr2Co]2(μ-OH)(μ-OBz) (3). X-ray crystallography shows the presence of both hydroxy and carboxylate group as bridging ligands and both cobalt metals are in five coordination environment in 3. The μ-azido complex, [TpiPr2Co]2(μ-N3)(μ-OBz) (5), was prepared by reaction of 3 with one equivalent of aqueous sodium azide. The spectroscopic studies suggested μ-1,1-bridging nature of group in this complex. The reaction of 2 with excess amount of benzoic acid resulted in the destruction of the bimetallic core to give the mononuclear carboxylato complex, [TpiPr2 Co](OBz) (4), which was characterized by X-ray crystallography. 相似文献
2.
Udai P. Singh Asish K. Sharma Hidehito Komatsuzaki Munetaka Akita 《Inorganica chimica acta》2006,359(13):4407-4411
A mononuclear side-on peroxo managanese (III) complex, TpiPr2Mn(η2-O2)(imMeH) (3) was prepared by the reaction of [TpiPr2Mn(O)]2 with excess amount of H2O2 in the presence of 2-methylimidazole (imMeH). Its X-ray structure clearly demonstrated the involvement of intermolecular hydrogen bonding interaction between η2-peroxide and imidazolyl N-H functional group. Complex 3 was stable, green in color and unable to oxygenate triphenylphosphine and ethyl vinyl ether. 相似文献
3.
A new type of multidentate ligand with both acetylacetonate and bis(2-pyridyl) units on the 1,3-dithiole moiety, 3-[2-(dipyridin-2-yl-methylene)-5-methylsulfanyl-[1,3]dithiol-4-ylsulfanyl]-pentane-2, 4-dione (L), has been prepared. Through reactions of the ligand with Re(CO)5X (X = Cl, Br), new rhenium(I) tricarbonyl complexes ClRe(CO)3(L) (2) and BrRe(CO)3(L) (3), have been obtained. With the use of 2 or 3 as the precursors, the further reactions with (TpPh2)Co(OAc)(HpzPh2) (TpPh2 = hydrotris(3,5-diphenylpyrazol-1-yl)borate); HpzPh2 = 3,5-diphenyl-pyrazole) or M(OAc)2(M = Mn, Zn), afford four new heteronuclear complexes: ClRe(CO)3(L)Co(TpPh2) (4), BrRe(CO)3(L)Co(TpPh2) (5), [ClRe(CO)3(L)]2Mn(CH3OH)2 (6) and [ClRe(CO)3(L)]2Zn(CH3OH)2 (7), respectively. Crystal structures of complexes 2 and 4-7 have been determined by X-ray diffraction. Their absorption spectra, photoluminescence and magnetic properties have been studied. 相似文献
4.
The coordination chemistry and reactivity of zinc(II) complexes supported by monoanionic hydrotris(pyrazolyl)borate ligands substituted by 3,3,3-mesityl groups (TpMs) and 3,3,5-mesityl groups (TpMs∗) have been investigated. Salt metathesis of ZnCl2, ZnEt2, and Zn(OAc)2 with Tl[TpMs] or Tl[TpMs∗] cleanly afforded the corresponding compounds TpMsZnCl (1), TpMsZnEt (2), TpMs∗ZnEt (3), and TpMsZnOAc (5). Compound 3 slowly disproportionates in benzene solution to afford the bis(ligand) complex (κ2-TpMs∗)2Zn (4). Acetate complex 5 as well as TpMsZnOCOPh (6) and [TpMs∗ZnOAc]2 (7) were alternatively prepared by acidolysis of the parent ethyl complexes (2, 3) with the corresponding carboxylic acid. No reaction was observed between 2 and 3 and alcohols (ROH; R = Et, iPr, Bn), while salt metathesis reactions of ZnEt(OR) with Tl[TpMs] led to 2 instead of the desired zinc-alkoxide complex. Compounds 1-7 were characterized by elemental analysis, 1H and 13C NMR spectroscopy, as well as by X-ray diffraction studies for 1, 2, 4, 5 and 7. The former compounds adopt a monomeric structure in the solid state while [TpMs∗ZnOAc]2 (7) exists as an anti-syn bridged acetate dimer. Complex 4 is four-coordinated, featuring a rare bidentate coordination mode of the TpMs∗ ligands. The results are rationalized in terms of the variable steric constraint around the zinc atom provided by the TpMs and TpMs∗ ligands. 相似文献
5.
Salvador Conejero 《Inorganica chimica acta》2009,362(12):4539-172
The synthesis of a series of rhodium and iridium complexes bearing bulky cyclopentadienyl or hydro(trispyrazolyl)borate ligands is described. The rhodium cyclopentadienyl and hydrotris(pyrazolyl)borate diene compounds, [(η5-C5Me4But)Rh(η4-2,3-MeRC4H4] (R = H, 1; Me, 2) and TpMsRh(η4-2,3-MeRC4H4) (R = H, 3; Me, 4; TpMs is hydrotris(3-mesitylpyrazol-1-yl)borate), respectively, have been prepared from the corresponding Rh(I) diene precursors and Zn(C5Me4But)2 (for 1 and 2), or TlTpMs (for 3 and 4), as effective C5Me4But or TpMs transfer reagents. In contrast with these results, attempts to obtain a bis(ethylene) derivative of the TptolIr(I) unit (Tptol stands for hydrotris(3-p-tolylpyrazol-1-yl)borate) have provided instead the Ir(III) complex [(κ4-N,N′,N″,C-Tptol)-Ir(C2H5)(C2H4)] (5), whose formation requires C-H bond activation of a molecule of ethylene and of one of the Tptolp-tolyl substituents. In refluxing toluene 5 experiences metalation of a second p-tolyl substituent to give [(κ5-N,N′,N″,C,C′-Tptol)-Ir(C2H4)] (6), which features unusual κ5-Tptol coordination. The latter compound reacts with carbon monoxide to yield the corresponding carbonyl, 7. 相似文献
6.
Two new mononuclear peroxo complexes of tungsten of the formula (gu)2[WO2(O2)2] (1) and (gu)[WO(O2)2(quin-2-c)] (2a) (where gu+ = guanidinium ion, and quin-2-c = quinoline-2-carboxylate ion) have been synthesized and characterized by elemental analysis, infrared, Raman, UV-visible and 1H NMR spectroscopies. The crystal structure of (gu)[WO(O2)2(quin-2-c)] · H2O (2b) determined by X-ray diffraction indicates that the side-on peroxo groups and the bidentate quinaldate ligand bind the W(VI) centre leading to an hepta coordination mode. The guanidinium ion occurring as a counterion and the hydrogen-bound interactions stabilize the complexes. The in vitro insulin-mimetic effect of the complexes has been evaluated by the inhibitory effect on free fatty acid release in isolated fat adipocytes treated with epinephrine. Moreover the niobate analogues, synthesized and characterized previously, (gu)3[Nb(O2)4] and (gu)2[Nb(O2)3(quin-2-c)] · H2O have been tested for the insulin-like activity. 相似文献
7.
Using a phosphorus based Mannich condensation reaction the new pyridylphosphines {5-Ph2PCH2N(H)}C5H3(2-Cl)N (1-Cl) and {2-Ph2PCH2N(H)}C5H3(5-Br)N (1-Br) have been synthesised in good yields (60% and 88%, respectively) from Ph2PCH2OH and the appropriate aminopyridine. The ligands 1-Cl and 1-Br display variable coordination modes depending on the choice of late transition-metal complex used. Hence P-monodentate coordination has been observed for the mononuclear complexes AuCl(1-Cl) (2), AuCl(1-Br) (3), RuCl2(p-cymene)(1-Cl) (4), RuCl2(p-cymene)(1-Br) (5), RhCl2(Cp∗)(1-Cl) (6), RhCl2(Cp∗)(1-Br) (7), IrCl2(Cp∗)(1-Cl) (8), IrCl2(Cp∗)(1′-Cl) (8′), IrCl2(Cp∗)(1-Br) (9), cis-/trans-PdCl2(1-Cl)2 (10), cis-/trans-PdCl2(1-Br)2 (11), cis-PtCl2(1-Cl)2 (12) and cis-PtCl2(1-Br)2 (13). Reaction of Pd(Me)Cl(cod) (cod = cycloocta-1,5-diene) with either 1 equiv. of 1-Br or the known pyridylphosphines 1′-Cl, 1-OH or 1-H gave the P/N-chelate complexes Pd(Me)Cl(1-Br-1-H) (14)-(17). All new compounds have been fully characterised by spectroscopic and analytical methods. Furthermore the structures of 4, 5, 10 and 16 · (CH3)2SO have been elucidated by single crystal X-ray crystallography. A crystal structure of the dinuclear metallocycle trans,trans-[PdCl2{μ-P/N-{Ph2PCH2N(H)}C5H4N}]2 · CHCl3, 18 · CHCl3, has also been determined. Here 1-H bridges, using both P and pyridyl N donors, two dichloropalladium centres affording a 12-membered ring with the PdCl2 units adopting a head-to-tail arrangement. 相似文献
8.
cis,trans-Fe(CO)2(PMe3)2(p-Y-C6H4)X [X=Br, Y=H (4a), MeO (4b), Cl (4c), F (4d), Me (4e); X=I, Y=H (5); X=Cl, Y=H (6)] and cis,trans-Fe(CO)2(PMe3)2(σ-CHCH2)X [X=Br (7); X=I (8); X=Cl (9)] are prepared by reacting dihalide complexes cis,trans,cis- Fe(CO)2(PMe3)2X2 [X=Br (1), X=I (2), X=Cl (3)] with Grignard reagents p-Y-C6H4-MgBr (Y=H, OMe, Cl, F, Me) or CH2CH-MgBr and with lithium reagents PhLi, CH2CH-Li. With both reagents, the reaction proceeds following two parallel pathways: one is the metallation reaction which yields alkyl derivatives, the other affords 17 electron complexes [Fe(CO)2(PMe3)2X] via monoelectron reductive elimination. The influence of the halides and organometallic reagents on the yield of the metallation reaction is discussed. The solution structure of the complexes is assigned on the basis of IR and 1H, 13C, 19F, 31P NMR spectra. The solid state structure of complexes 4a, 5 and 6 is determined by single crystal X-ray diffractometric methods. 相似文献
9.
Jing Han 《Inorganica chimica acta》2006,359(1):99-108
Four novel Mo(II) and Rh(II) complexes with cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene (cis-dbe) or closed-dbe were synthesized and characterized. Employing [M(O2CCF3)4] (M = Mo, Rh) with cis-dbe or closed-dbe afforded complex [Mo2(O2CCF3)4(cis-dbe)](benzene) (1), [Rh2(O2CCF3)4(cis-dbe)](benzene) (2), [{Mo2(O2CCF3)4}2(closed-dbe)] (3), and [Rh2(O2CCF3)4(closed-dbe)](p-xylene) (4). The structures of four metal complexes were revealed by X-ray crystallographic analyses and the correlation between the crystal structures and the photochromic performance was discussed. In all complexes, two cyano groups of the ligand bridged two dimetal carboxylates to give a 1-D zigzag infinite chain structure. Upon irradiation with 405 nm light, complex 1 turned into reddish purple from yellow, and the color reverted to initial yellow on exposure to 563 nm light, indicating the reversible cyclization/ring-opening reaction in the crystalline phase. However, the Rh(II) complex 2 did not display similarities in reaction induced by light, which is attributable to the lower ratio of photoactive anti-parallel conformers compared with complex 1 and coordination effect of metal ions on photochromism of diarylethenes. The complexes of Rh(II) ions did not exhibit the expected reversible photoinduced behavior. 相似文献
10.
A series of cyanide-bridged binuclear complexes, (‘S3’)Ni-CN-M[TptBu] (‘S3’ = bis(2-mercaptophenyl)sulfide, TptBu = hydrotris(3-tert-butylpyrazolyl)borate, M = Fe (2-Fe), Co (2-Co), Ni (2-Ni), Zn (2-Zn)) was prepared by the coupling of K[(‘S3’)Ni(CN)] with [TptBu]MX. The isostructural series of complexes was structurally and spectroscopically characterized. A similar coupling strategy was used to synthesize the anionic copper(I) analogue, Et4N{(‘S3’)Ni-CN-Cu[TptBu]}, 2-Cu.An alternative synthesis was devised for the preparation of the linkage isomers of 2-Zn, i.e. of cyanide-bridged linkage isomers. X-ray diffraction, 13C NMR and IR spectral studies established that isomerization to the more stable Ni-CN-Zn isomer occurs. DFT computational results buttressed the experimental observations indicating that the cyanide-bridged isomer is ca. 5 kcal/mol more stable than its linkage isomer. 相似文献
11.
Monika Moszner 《Inorganica chimica acta》2004,357(12):3613-3620
The decaaqua-di-rhodium(II) cation has been found to be an interesting starting material in the preparation of dioxygen complexes with different N-donor ligands. Treatment of aqueous HClO4 solution of [Rh2(H2O)10]4+ with NH4OH/NH3, py and/or en results in water exchange and the formation of corresponding [Rh2II(H2O)10−m(base)n(OH)m](4−m)+ derivatives. Reaction of the latter with dioxygen afforded superoxo and/or peroxo complexes, depending on reaction conditions: [Rh2III(O2 −)(NH3)8(OH)2](ClO4)3 (1), [Rh2III(O2 −)(NH3)8(OH)(H2O)](ClO4)4 (2), [Rh2III(O2 2−)(NH3)10](ClO4)4 · 6H2O (3), [Rh2III(O2 −)(py)8(H2O)2](ClO4)5 (4), [Rh2III(O2 2−)(en)4(H2O)2](ClO4)4 (5) and [Rh2III(O2 −)(en)4(H2O)2](ClO4)5 (6). All the obtained complexes were characterized by elemental analysis, mass spectrometry, UV-Vis, IR and ESR spectroscopies and magnetic measurements. 相似文献
12.
Hai-Yan Zhao Yong-Heng Xing Zhang-Peng Li Mao-Fa Ge Shu-Yun Niu 《Inorganica chimica acta》2009,362(11):4110-4118
A series of oxo-vanadium(IV) complexes: Tp∗VO(pzH∗)(CH3COO) (1), Tp∗VO(pzH∗)(CCl3COO) (2), Tp∗VO(pzH∗)(C6H5COO) (3), Tp∗VO(pzH∗)(m-NO2-C6H4COO)·CH3CN (4) and [Tp∗VO(pzH∗)(H2O)]+[m-NO2-C6H4-SO3]−·CH3OH (5) (Tp∗ = hydrotris(3,5-dimethylpyrazolyl)borate; pzH∗ = 3,5-dimethylpyrazole) are synthesized in methanol solution under physiological conditions. They are characterized by elemental analysis, IR, UV-Vis and X-ray crystallography. Structural analyses show that the vanadium atoms in complexes 1-5 are all in a distorted-octahedral environment with the N4O2 donor set, and intra- or inter-hydrogen bonding linkages have been also observed in each complex. Bromination reaction activity of the complexes has been evaluated by the method with phenol red as organic substrate in the presence of H2O2, Br− and phosphate buffer, indicating that they can be considered as potential functional model vanadium-dependent haloperoxidases. In addition, thermal analysis and quantum chemistry calculations were also performed and discussed in detail. 相似文献
13.
Two new, potentially cyclometalating terdentate ligands bearing phosphonate substituents, Et2O3P-N^C(H)^N (5) and Et2O3P-C(H)^N^N (7), have been prepared. The corresponding ruthenium complexes, [1]+ and [2]+, respectively, were obtained by reaction with [RuCl3(tpy)]. Complexes [1]+ and [2]+ display electronic properties characteristic for cyclometalated ruthenium complexes. The platinum complex [3], of N^C(H)^N ligand 5, was also prepared and is highly phosphorescent in solution. In general, the phosphonate group electronically behaves equivalent to a carboxylate moiety. 相似文献
14.
Patrick W. Blosser 《Inorganica chimica acta》2005,358(7):2341-2348
A synthetic and mechanistic study is reported on ligand substitution and other reactions of six-coordinate ruthenium(II) carbonyl complexes containing tridentate PhP(CH2CH2CH2PCy2)2 (Cyttp). Carbonylation of cis-mer-Ru(OSO2CF3)2(CO)(Cyttp) (1) affords [cis-mer-Ru(OSO2CF3)(CO)2(Cyttp)]O3SCF3 (2(O3SCF3)) and, on longer reaction times, [cis-mer-Ru(solvent)(CO)2(Cyttp)](O3SCF3)2 (solvent = acetone, THF, methanol). 2(O3SCF3) reacts with each of NaF, LiCl, LiBr, NaI, and LiHBEt3 to yield [cis-mer-RuX(CO)2(Cyttp)]+ (X = F (3), Cl (4), Br (5), I (6), H (7)), isolated as 3-7(BPh4). These conversions proceed with high stereospecificity to afford only a single isomer of the product that is assigned a structure in which the Ph group of Cyttp points toward the CO trans to X (anti when X = F, Cl, Br, or I; syn when X = H). Treatment of 2(O3SCF3) with NaOMe and CO generates the methoxycarbonyl complex [cis-mer-Ru(CO2Me)(CO)2(Cyttp)]+ (8), whereas addition of excess n-BuLi to 2(O3SCF3) in THF under CO affords mer-Ru(CO)2(Cyttp) (9). The two 13C isotopomers [cis-mer-Ru(OSO2CF3)(CO)(13CO)(Cyttp)]O3SCF3 (2′(O3SCF3): 13CO trans to PC; 2″(O3SCF3): 13CO cis to all P donors) were synthesized by appropriate adaptations of known transformations and used in mechanistic studies of reactions with each of LiHBEt3, NaOMe/CO, and n-BuLi. Whereas LiHBEt3 reacts with 2′(O3SCF3) and 2″(O3SCF3) to replace triflate by hydride without any scrambling of the carbonyl ligands, the corresponding reactions of NaOMe-CO are more complex. The methoxide combines with the CO cis to triflate in 2, and the resultant methoxycarbonyl ligand ends up positioned trans to the incoming CO in 8. A mechanism is proposed for this transformation. Finally, treatment of either 2′(O3SCF3) or 2″(O3SCF3) with an excess of n-BuLi leads to the formation of the same two ruthenium(0) isomers of mer-Ru(CO)(13CO)(Cyttp). These products represent, to our knowledge, the first example of a syn-anti pair of isomers of a five-coordinate metal complex. 相似文献
15.
Dioxo-MoVI complexes of general formula Tp∗MoO2(p-SC6H4Dn) (6a-6c) (where Tp∗ = hydrotris(3,5-dimethyl-pyrazol-1-yl)borate and Dn = dendritic unit) have been synthesized and characterized by spectroscopy and mass spectrometry. 1H NMR spectra of the metal complexes indicate that the Cs local symmetry about the metal core does not change by the incorporation of dendritic functionality at the thiophenolato ring. Electrochemical data show a ∼20 mV change in the redox potential in the complexes with dendritic ligands suggesting a very small perturbation in the redox orbital, which is also supported by small changes in the electronic spectra. The peak-to peak separation (ΔEp) increases from 125 mV in 6(a) to 240 mV in 6(c), suggesting sluggish electron transfer in molecules with larger dendritic ligands. 相似文献
16.
Kazuhiro Takenaka 《Inorganica chimica acta》2004,357(13):3895-3901
Novel upper-rim modified tetraphosphinocalix[4]arenes (5a-b) adopting 1,3-alternate conformation have been synthesized. Reaction of 5,11,17,23-tetrachloromethyl-25,26,27,28-tetrahydroxycalix[4]arene (1) with Ph2POEt gave 5,11,17,23-tetrakis(diphenylphosphinoylmethyl)-25,26,27,28-tetrahydroxycalix[4]arene (2). Tetra-O-substitution of 2 with n-propyl iodide or benzyl bromide in the presence of K2CO3 carried out to afford 5,11,17,23-tetrakis(diphenylphosphinoylmethyl)-25,26,27,28-tetrapropoxy-(3a) or -benzyloxycalix[4]arene (3b), whereas di-O-substituted calix[4]arene, 5,11,17,23-tetrakis(diphenylphosphinoylmethyl)-25,27-dipropoxy-26,28-dihydroxycalix[4]arene (4), was obtained exclusively when Na2CO3 was used as base. Reduction of 3a-b with PhSiHCl2 afforded 5,11,17,23-tetrakis(diphosphinomethyl)-25,26,27,28-tetrapropoxy-(5a) and -tetrabenzyloxycalix[4]arene (5b). 1H and 13C NMR analysis reveals that the phosphines (5a-b) and the tetra-O-substituted phosphine oxides (3a-b) adopt 1,3-alternate conformation, while the parent tetrahydroxy-(2) and the di-O-propylated phosphine oxide (4) adopt cone-conformation. The X-ray structure indicates that the calix[4]arene moieties in 4 a pinched-cone conformation in solid state. Complexation of the phosphine ligand (5a) with [RuCl2(p-cymene)]2 affords the tetranuclear complexes, [{RuCl2(p-cymene)}2 · 5a] (6), as 1,3-alternate conformer. 相似文献
17.
Yoshiyuki Misumi 《Inorganica chimica acta》2009,362(12):4409-4415
Treatment of the Rh(III) complex [Tp∗Rh(SPh)2(MeCN)] (1) with a series of late transition metal complexes resulted in the formations of thiolate-bridged di- and trinuclear complexes, which include the Rh(III)-Rh(I) complexes, [Tp∗RhCl(μ-SPh)2Rh(cod)] (2) and [Tp∗RhCl(μ-SPh)2Rh(PPh3)2], the Rh(III)-Pd(II) complexes, [Tp∗RhCl(μ-SPh)2Pd(η3-C3H5)] (4), [{Tp∗Rh(MeCN)}(μ-SPh)2PdCl2] (5), and [{Tp∗RhCl(μ-SPh)2}2Pd] (6), and the Rh(III)-Pt(II) complex [{Tp∗RhCl(μ-SPh)2}2Pt] (7). Early-late transition metal complexes containing the Rh(III)-Re(I) and Rh(III)-Mo(0) metal centers, [Tp∗RhCl(μ-SPh)2Re(CO)4] and [{Tp∗Rh(CO)}(μ-SPh)2Mo(CO)4] were also prepared from 1. The X-ray analysis has been carried out to confirm the structures for 2, 4, 5, 6, and 7. 相似文献
18.
Mohammad B KassimRowena L Paul John C JefferyJon A McCleverty Michael D Ward 《Inorganica chimica acta》2002,327(1):160-168
Reaction of [MoVI(TpMe,Me)(O)2Cl] with a variety of pyridine-based ligands [pyridine (py), 4,4′-bipyridine (bpy), 4-phenylpyridine (phpy) and 1,2′-bis(4-pyridyl)ethene (bpe)] in toluene in the presence of Ph3P affords the mononuclear oxo-Mo(IV) complexes [Mo(TpMe,Me)(O)Cl(L)] (L=py, phpy or monodentate bpy; abbreviated as Mo(py), Mo(phpy) and Mo(bpy), respectively) and the dinuclear complexes [{Mo(TpMe,Me)(O)Cl}2(μ-L)] (L=bpy, bpe; abbreviated as Mo2(bpy), Mo2(bpe), respectively). The complex Mo2(bpy), together with the by-product [{Mo(TpMe,Me)(O)Cl}2(μ-O)], have been crystallographically characterised. Electrochemical studies on the oxo-Mo(IV) complexes reveal the presence of reversible Mo(IV)/Mo(V) couples at around −0.3 V versus ferrocene/ferrocenium in every case. For the dinuclear complexes Mo2(bpy) and Mo2(bpe) these redox processes are coincident, indicating that they are largely metal-centred and not significantly delocalised across the bridging ligand. In contrast, Mo2(bpe) alone shows two reversible reductions, separated by 320 mV; these could be described as ligand-centred reductions of the bpe bridge, or as Mo(IV)/Mo(III) couples which—because of their separation—are substantially delocalised onto the bridging ligand. UV-Vis spectroelectrochemical studies using an OTTLE cell at 243 K revealed that oxidation of the complexes results in spectral changes (collapse of the Mo(IV) d-d transitions, loss in intensity of the Mo→pyridine MLCT transition) consistent with the formation of a Mo(V) state following metal-centred oxidation, but that one-electron reduction of Mo2(bpe) results in appearance of numerous intense transitions more characteristic of a ligand radical following ligand-centred reduction. 相似文献
19.
Linsheng Feng 《Inorganica chimica acta》2011,373(1):85-11358
Molybdenum tetramers: Mo4(μ3-O)4[μ-O2P(CH2Cl)2]4O4 (1), Mo4(μ3-O)4(μ-O2P(CH2OH)2)4O4 (2), Mo4(μ3-O)4[μ-O2P(PhOMe)2]4O4 (3), and Mo4(μ3-O)4[μ-O2P(o-C6H4(CH2)2)]4O4 (4) have been synthesized and characterized by IR, UV-Vis, and 31P NMR spectroscopy. Molybdenum tetramers 1 and 4 along with the ligands L2A and L4 were structurally characterized by single crystal X-ray crystallography. An infinite 2D polymeric sheet was formed via inter and intra hydrogen bonds in the crystals of L2A. The crystals of L4 consist of infinite polymeric chains formed through hydrogen bonding. All molybdenum tetramers were tested as catalysts for the epoxidation of cis-cyclooctene in the presence of H2O2. Compounds 1 and 2 resulted in more than 80% epoxide after 24 hours at 70 °C, and displayed superior catalytic activities over compounds 3 and 4 under identical conditions. The superior catalytic activities of compounds 1 and 2 may be attributed to their better solubility in the ethanol/H2O2 system. 相似文献
20.
Abdu Musad E Mohamed R Saeed BA Vishwanath BS Rai KM 《Bioorganic & medicinal chemistry letters》2011,21(12):3536-3540
Two series of five membered heterocyclic bis(1,3,4-oxadiazole) derivatives 2(a-h) and 3,5-bis(substituted)pyrazoles, isoxazoles 3(a,b,d-i), 4(a-c) were synthesized via oxidative cyclization of some diaroylhydrazones using chloramine-T and cyclocondensation reaction with hydrazine hydrate and hydroxylamine hydrochloride, respectively. The newly synthesized compounds were screened for antioxidant and anti-microbial activities. Compounds 2(b), 3(b), and 4(a) showed higher antioxidant activity at 10 μg/ml while compounds 2(a), 3(a), 3(f), and 4(a) exhibited better anti-microbial activity at 100 μg/ml compared with standard vitamin C and ciprofloxacin, respectively. Structures of newly synthesized compounds were confirmed by elemental analysis and spectral IR, 1H NMR, and 13C NMR data. 相似文献