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1.
Four molybdenum(VI) thiosemicarbazonato complexes have been synthesized and characterized. The dinuclear complexes [(MoO2L1)2] (1) and [(MoO2L2)2] (3) have been prepared by the reaction of [MoO2(acac)2] with 2-hydroxyacetophenone N(4)-cyclohexyl (H2L1) and N(4)-phenyl (H2L2) thiosemicarbazones in alcoholic medium. Mononuclear dioxomolybdenum(VI) complexes of the type [MoO2L1py] (2) and [MoO2L2py] (4) have been prepared by the reaction of 1 or 3 with pyridine (py) in alcoholic medium. In all the complexes, molybdenum is coordinated by two terminal oxo-oxygen atoms, (Ot), oxygen, nitrogen and sulfur atoms from the principal ligand and by an oxygen atom from the second unit in 1, and by a nitrogen atom from pyridine in complexes 2 and 4. All complexes have been spectroscopically characterized. The molecular structures of complexes 1, 2 and 4 have been determined by the single crystal X-ray diffraction method.  相似文献   

2.
The reaction of bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone with bis(acetylacetonato)dioxomolybdenum(VI) (MoO2(acac)2) in 1 : 3 molar ratio in EtOH : water mixture (95 : 5) affords a complex of composition [(MoO2)2(nsh)(H2O)2] · C2H5OH. The reaction of [(MoO2)2(nsh)(H2O)2] · C2H5OH with Lewis bases, namely pyridine, 2-picoline, 3-picoline, and 4-picoline, yields [(MoO2)2(nsh)(B)2] · C2H5OH (where B = pyridine, 2-picoline, 3-picoline, and 4-picoline). Further, when this complex was reacted with 1,10-phenanthroline and 2,2′-bipyridine in 1 : 3 molar ratio in anhydrous ethanol the binuclear complexes [(μ2-O)2(MoO2)2(H4nsh)(phen)] · C2H5OH and [(μ2-O)2(MoO2)2(H4nsh)(bpy)] · C2H5OH were obtained. All of the complexes have been characterized by analytical, magnetic moment, and molar conductivity data. The structures of the complexes have been discussed in the light of electronic, IR, 1H NMR, and 13C NMR spectroscopy.  相似文献   

3.
The oxido-pincer ligand pydotH2 (2,6-bis(1-hydroxy-1-o-tolyl-ethyl-η2O,O′)pyridine) forms two different CuII containing complexes when prepared from anhydrous CuCl2. A combination of EPR spectroscopy and EXAFS allowed to structurally characterise the light-green dimer of the formula [(pydotH2)CuCl(μ-Cl)2ClCu(pydotH2)] and the penta-coordinate olive-green monomer [(pydotH2)CuCl2]. The molecular entities imply that the ligand remains protonated upon coordination. When dissolved in DMF both compounds form monomeric species [(pydotH2)CuCl2(DMF)] which could be characterised in detail by EPR, UV-Vis/NIR spectroscopy and electrochemical measurements. The assignments were supported by comparison with CuII complexes of the related ligands 2,6-bis(hydroxymethyl)pyridine (pydimH2) and 2,6-bis(1-hydroxy-1-methyl)pyridine (pydipH2).  相似文献   

4.
Two new dioxomolybdenum(VI) complexes, [MoO2L1(CH3OH)] (1) and [MoO2L2(H2O)] (2), where L1 and L2 are dianionic form of N′-(2-hydroxy-3-methoxybenzylidene)-4methoxybenzohydrazide and N′-(2-hydroxy-3methoxybenzylidene)-2-hydroxybenzohydrazide, respectively, have been synthesized and structurally characterized by spectroscopic methods and single-crystal X-ray determination. The complexes are mononuclear molybdenum(VI) compounds. Mo in each complex is octahedral. The difference in the substituent groups in the benzohydrazides leads to coordination of different solvent molecules. Crystals of the complexes are stabilized by hydrogen bonds. The complexes are effective catalysts for sulfoxidation.  相似文献   

5.
The diamagnetic dioxomolybdenum(VI) complex [(MoO2)2(CH2L)(H2O)2]H2O (1) has been isolated in solid state from reaction of MoO2(acac)2 with bis(2-hydroxy-1-naphthaldehyde)malonoyldihydrazone (CH2LH4) in 3:1 molar ratio in ethanol at higher temperature. The reaction of the complex (1) with electron donor bases gives diamagnetic molybdenum(VI) complexes having composition [Mo2O5(CH2LH2)]·2A·2H2O (where A = pyridine (py, 2), 2-picoline (2-pic, 3), 3-picoline (3-pic, 4), 4-picoline (4-pic, 5)). Further, when the complex (1) is allowed to react with protonic bases such as isonicotinoylhydrazine (inhH3) and salicyloylhydrazine (slhH3), reduction of molybdenum(VI) centre occurs leading to isolation of homobimetallic molybdenum(V) complexes [Mo2(CH2L)(inh)2(H2O)2] (6) and [Mo2(CH2L)(slh)2] (7), respectively. The composition of the complexes has been established by analytical, thermo-analytical and molecular weight data. The structure of the molybdenum(VI) complexes (1)–(5) has been established by electronic, IR, 1H NMR and 13C NMR spectral studies while those of the complexes (6) and (7) by magnetic moment, electronic, IR and EPR spectral studies. The dihydrazone is coordinated to the metal centres in staggered configuration in complex (1) while in anti-cis configuration in complexes (2)–(7). The complexes (6) and (7) possess magnetic moment of 2.95 and 3.06 BM, respectively, indicating presence of two magnetic centre in the complexes per molecule each with one unpaired electron on each metal centre without any metal–metal interaction. The electronic spectra of the complexes are dominated by strong charge transfer bands. All of the complexes involve six coordinated molybdenum centre with octahedral arrangement of donor atoms except in the complex (6), in which the molybdenum centre has rhombic arrangement of ligand donor atoms. The probable mechanism for generation of oxo-group in the complexes (2)–(5) involving coordinated water molecule has been proposed.  相似文献   

6.
Two new dioxomolybdenum(VI) complexes, [MoO2(L1)] n · 0.5 n CH3OH (I) and [MoO2(L2)(CH3OH)] (II), where L1 and L2 are the dianionic form of N′-[1-(4-diethylamino-2-hydroxyphenyl)methylidene]isonicotinohydrazide and N′-(2-hydroxy-4-methoxybenzylidene)-3-methylbenzohydrazide, respectively, were prepared and structurally characterized by physicochemical and spectroscopic methods and single-crystal X-ray determination. For complex I, a polymeric structure is obtained, which is linked by coordination of the pyridine N atoms to the Mo atoms of other [MoO2(L1)] units. Complex II is a mononuclear molybdenum compound. In both complexes, the Mo atoms are in octahedral coordination. The catalytic properties of the complexes indicate that they are efficient catalysts for sulfoxidation.  相似文献   

7.
Summary cis-Dioxo(N-salicylidene-2-aminophenolato) (imidazole)-molybdenum(VI) complexes, [MoO2(Sap)(Im)], (Im = imidazole or its derivatives, sap = salicylidene-2-aminophenolate) are prepared by the ligand substitution of [MoO2(Sap)(EtOH)] with a unidentate imidazole ligand. All complexes are red or yellow, diamagnetic, non-electrolytes and possess an octahedral stereochemistry. The i.r. spectra shows two bands attributable tocis-MoO2 stretches in addition to the vibrations of the Schiff base ligand and the imidazole derivatives. Thermal degradation of the complexes result in successive loss of imidazole ligand followed by the Schiff base, with ultimate formation of MoO3 atca. 500 °C.  相似文献   

8.
The reactions of the sterically demanding group-13 alkyls ER3 (E = Al, Ga, In; R = CH2t-Bu, CH2SiMe3) with the platinum-complex [(dcpe)Pt(H)(CH2t-Bu)] were re-investigated. The bimetallic compounds [(dcpe)Pt(ER2)(R)] (3: E = Ga, R = CH2SiMe3; 5: E = In, R = CH2t-Bu; dcpe = bis(dicyclohexylphosphino)ethane) with direct σ(Pt-E) bonds were obtained by oxidative addition of an E-C bond to the coordinatively unsaturated fragment [(dcpe)Pt] produced in situ by thermolysis of the starting complex [(dcpe)Pt(CH2t-Bu)(H)]. The single crystal structure determination reveals a Pt-Ga bond length of 2.376(2) Å and a Pt-In bond length of 2.608(1) Å. All new compounds were characterised by elemental analysis, 31P and 195Pt NMR spectroscopy. Interestingly, the Pt-Ga compound 3 slowly transforms into the platinum alkyl/hydride isomer {(dcpe)Pt(μ2-H)[CH2Si(CH3)2 CH2Ga(CH2SiMe3)2]} (4) during crystallization from solution at room temperature. The X-ray single crystal structure analysis revealed both complexes 3 and 4 coexisting in the unit cell in a 1:1 relation. The inaccessibility of analytically pure samples of the Pt-Al complex {(dcpe)Pt[Al(CH2t-Bu)2](CH2t-Bu)} (6), postulated as intermediate of the reaction of [(dcpe)Pt(H)(CH2t-Bu)] with Al(CH2t-Bu) on the basis of 31P and 195Pt NMR data, is attributed to an enhanced tendency to isomerisation into the alkyl/hydride Pt/Al congener of 4. A brief DFT analysis of the bonding situation of the model complex [(dhpe)Pt(GaMe2)(Me)] (1M) revealed, that the contribution of π(Pt-Ga) back-bonding is negligible.  相似文献   

9.
The chiral (ONS) dianionic Schiff base ligand benzoin thiosemicarbazone (H2L) reacts with MoO2(acac)2 to give the polymeric complex [(MoO2L) n ] (1) (Type 1). The reaction of MoO2L with pyridine (py), 3-picoline (3-pic) or 4-picoline (4-pic) gives [MoVIO2LD] (D = py, 3-pic or 4-pic) (Type 1). Further, the reaction of [MoO2L] or [MoO2LD] with PPh3 or reaction of [MoO2L] with PPh3 (plus bpy or phen, D) in the presence of donor reagents D gives [MoIVOL] or [MoIVOLD] (Type 2). On the other hand, the reaction of [MoO2L] with hydrazides (zdhH3) such as benzoylhydrazine (bhH3), isonicotinoylhydrazine (inhH3), nicotinoylhydrazine (nhH3), salicyloylhydrazine (slhH3) and thiosemicarbazide (tscH3) produced non-oxo–diazenido complexes [MoL(zdh)] (Type 3). The complexes have been characterized by elemental analyses, molar conductance, magnetic moment, electronic, i.r. and e.s.r. spectroscopic measurements.  相似文献   

10.
We describe reactions of [99mTc(H2O)3(CO)3)]+ (1) with Diels-Alder products of cyclopentadiene such as “Thiele’s acid” (HCp-COOH)2 (2) and derivatives thereof in which the corresponding [(Cp-COOH)99mTc(CO)3)] (3) complex did form in water. We propose a metal mediated Diels-Alder reaction mechanism. To show that this reaction was not limited to carboxylate groups, we synthesized conjugates of 2 (HCp-CONHR)2 (4a-c) (4a, R = benzyl amine; 4b, R = Nα-Boc-l-2,3-diaminopropionic acid and 4c, R = glycine). The corresponding 99mTc complexes [(4a)99mTc(CO)3)] 6a, [(4b)99mTc(CO)3)] 6b and [(4c)99mTc(CO)3)] 6c have been prepared along the same route as for Thiele’s acid in aqueous media demonstrating the general applicability of this synthetic strategy. The authenticity of the 99mTc complexes on the no carrier added level have been confirmed by chromatographic comparison with the structurally characterized manganese or rhenium complexes.Studies of the reaction of 1 with Thiele’s acid bound to a solid phase resin demonstrated the formation of [(Cp-COOH)99mTc(CO)3)] 3 in a heterogeneous reaction. This is the first evidence for the formation of no carrier added 99mTc radiopharmaceuticals containing cyclopentadienyl ligands via solid phase syntheses. Macroscopically, the manganese analogue 5a and the rhenium complexes 5b-c have been prepared and characterized by IR, NMR, ESI-MS and X-ray crystallography for 5a (monoclinic, P21/c, a = 9.8696(2) Å, b = 25.8533(4) Å, c = 11.8414(2) Å, β = 98.7322(17)°) in order to unambiguously assign the authenticity of the corresponding 99mTc complexes.  相似文献   

11.
The reactions of the potentially tridentate Schiff bases 2-[(2-hydroxyphenyl)iminomethyl]phenol (H2ono) and 2-(2-aminobenzylideneimino)phenol (H3onn) with trans-[ReOBr3(PPh3)2] were studied, and the complexes [ReIIIBr(PPh3)2(ono)] (1) and [ReVBr(PPh3)2(onn)]Br (2) were isolated. In 1ono acts as a dianionic tridentate ligand, and in 2onn is coordinated as a tridentate trianionic imido-imino-phenolate. The complex [ReI(CO)3(ons)(Hno)] was isolated from the reaction of [Re(CO)5Br] with 2-[(2-methylthio)benzylideneimino]phenol (Hons; Hno = 2-aminophenol), with ons coordinated as a bidentate chelate with a free SCH3 group. These complexes were characterized by X-ray crystallography, NMR and IR spectroscopy.  相似文献   

12.
A series of mononuclear [M(EAr)2(dppe)] [M = Pd, Pt; E = Se, Te; Ar = phenyl, 2-thienyl; dppe = 1,2-bis(diphenylphosphino)ethane] complexes has been prepared in good yields by the reactions of [MCl2(dppe)] and corresponding ArE with a special emphasis on the aryltellurolato palladium and -platinum complexes for which the existing structural information is virtually non-existent. The complexes have crystallized in five isomorphic groups: (1) [Pd(SePh)2(dppe)] and [Pt(SePh)2(dppe)], (2) [Pd(TePh)2(dppe)] and [Pt(TePh)2(dppe)], (3) [Pd(SeTh)2(dppe)], (4) [Pt(SeTh)2(dppe)] and [Pd(TeTh)2(dppe)], and (5) [Pt(TePh)2(dppe)]. In addition, solvated [Pd(TePh)2(dppe)] · CH3OH and [Pd(TeTh)2(dppe)] · 1/2CH2Cl2 could be isolated and structurally characterized. The metal atom in each complex exhibits an approximate square-planar coordination. The Pd-Se, Pt-Se, Pd-Te, and Pt-Te bonds span a range of 2.4350(7)-2.4828(7) Å, 2.442(1)-2.511(1) Å, 2.5871(7)-2.6704(8) Å, and 2.6053(6)-2.6594(9) Å, respectively, and the respective Pd-P and Pt-P bond distances are 2.265(2)-2.295(2) Å and 2.247(2)-2.270(2) Å. The orientation of the arylchalcogenolato ligands with respect to the M(E2)(P2) plane has been found to depend on the E-M-E bond angle. The NMR spectroscopic information indicates the formation of only cis-[M(EAr)2(dppe)] complexes in solution. The trends in the 31P, 77Se, 125Te, and 195Pt chemical shifts expectedly depend on the nature of metal, chalcogen, and aryl group. Each trend can be considered independently of other factors. The 77Se or 125Te resonances appear as second-order multiplets in case of palladium and platinum complexes, respectively. Spectral simulation has yielded all relevant coupling constants.  相似文献   

13.
A reaction of [MoO2(acac)2] (where acac = acetylacetonate) with two hydrazone ligands in methanol yields two mononuclear molybdenum(VI) oxo complexes with the general formula [MoO2L(CH3OH)], where L = L1=(4-nitrophenoxy)acetic acid [1-(5-chloro-2-hydroxyphenyl)methylidene]hydrazide (H2L1) and L = L2=4-dimethylaminobenzoic acid [1-(2-hydroxy-3-methoxyphenyl)methylidene]hydrazide (H2L2). The crystal and molecular structures of the complexes are determined by the single crystal X-ray diffraction method. All of the investigated compounds are further characterized by the elemental analysis, FT-IR spectra, and thermogravimetric analysies. Single crystal X-ray structural studies indicate that hydrazone ligands coordinate to MoO2 cores through enolate oxygen, phenolate oxygen, and azomethine nitrogen atoms. The Mo atoms in both complexes are in octahedral coordination.  相似文献   

14.
The monomer molybdenum(VI) complex [MoO(2)(napoxlhH(2))].2H(2)O (1) has been synthesized from the reaction of MoO(2)(acac)(2) with bis(2-hydroxy-1-naphthaldehyde)oxaloyldihydrazone (napoxlhH(4)) in 1:1 molar ratio in ethanol under reflux. This complex on reaction with pyridine/3-picoline/4-picoline yielded the dimer molybdenum(VI) complexes [Mo(2)O(4)(napoxlhH(2))(2)(A)(2)].2H(2)O (A=py (2), 3-pic (3), 4-pic (4)), whereas reaction with isonicotinoylhydrazine (inhH(3)) and salicyloylhydrazine (sylshH(3)) lead to the reduction of the metal centre yielding monomeric molybdenum(V) complexes [Mo(napoxlhH(2))(hzid)].2H(2)O (where hzidH(3)=inhH(3) (5) and sylshH(3) (6)). The complexes have been characterized by elemental analyses, molecular weight determinations, molar conductance data, magnetic moment data, electronic, IR, ESR and (1)H NMR spectroscopic studies. The complexes (5) and (6) are paramagnetic to the extent of one unpaired electron. The electronic spectra of the complexes are dominated by strong charge transfer bands. In all of the complexes, the principal dihydrazone ligand has been suggested to coordinate to the metal centres in the anti-cis-configuration. The complexes (1), (5) and (6) are suggested to have six-coordinate octahedral stereochemistry around molybdenum(VI) and molybdenum(V) metal centres, respectively, while the complexes (2)-(4) are suggested to have eight coordinate dodecahedral stereochemistry around molybdenum(VI) metal centre.  相似文献   

15.
The molybdenum complexes of Schiff base ligands viz. [MoO2LH2O] where L1 = tris(hydroxymethyl)(salicylide-neamino)methane, L2 = tris(hydroxymethyl)(2,3-dihydroxybenzylideneamino)methane and L3 = tris(hydroxymethyl)(2,3,4-trihydroxybenzylideneamino)methane have been synthesized and characterized by spectroscopic and electrochemical techniques. The X-ray crystal structure of the complex [MoO2L1H2O] reveals a distorted octahedral geometry with one ligand and a water molecule coordinated to the MoO2 center. No previous complex of this type contains a coordinated water molecule. The complex undergoes an oxotransfer in the presence of Bu3P to form a -oxobridged molybdenum(V,V) dimer. This rules out Mo—S coordination as a prerequisite for oxotransfer in such molybdenum(VI) complexes.  相似文献   

16.
The new dibasic NNO ligand H2L (H2L = allyl N′-2-hydroxy-3-methoxybenzylidenecarbamohydrazonothioate) was synthesized by condensation of 2-hydroxy-3-methoxybenzaldehyde with the product resulting from the reaction of thiosemicarbazide with allyl bromide. Four dioxidomolybdenum(VI) complexes with the general formula [MoO2L(S)] (S=MeOH, EtOH, DMSO, and 1-methylimidazole) were synthesized and characterized by elemental analysis, FT-IR, EI-MS and UV-Vis spectroscopy, and by X-ray crystallography. Spectroscopic evidence indicates that the cis-MoO2 chelates have octahedral geometry in which H2L coordinates via the phenolate oxygen, azomethine nitrogen and deprotonated thioamide nitrogen. The other sites are occupied by two oxido and an additional ligand (S). Density functional theory calculations of spectral parameters were also carried out for these systems.  相似文献   

17.
18.
New dioxomolybdenum(VI) complexes were prepared by reacting S-methyl/allyl-4-phenyl-thiosemicarbazones of 2-hydroxy-1-naphthaldehyde (L 1 H2 and L 2 H2) and [MoO2(acac)2] in methyl, ethyl and propylalcohols. In the complexes the doubly deprotonated ligands are coordinated to molybdenum as tridentate ONN-donors through phenolic-oxygen, azomethine- and thioamide-nitrogen. The solid complexes of general formula [MoO2L(ROH)] which contain an alcohol (ROH) as second ligand were characterized by physico-chemical and spectroscopic methods. The fluorescence emission intensities of the compounds were recorded in chloroform, and the intensity changes were evaluated depending on chelation and time. The structure of the S-allyl-4-phenyl-thiosemicarbazone complex has been determined by the single crystal X-ray diffraction method. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

19.
Mononuclear [MoO2LD], and dinuclear [MoO2L]2 or [MoO2L]2 · D dixomolybdenum(VI) complexes have been prepared by the reaction of tridentate Schiff‐base ligands L with [MoO2(acac)2]. The Schiff‐base ligands have been synthesized from salicylaldehyde ( 1 , 1a , 1c , 1d ), 2‐hydroxy‐1‐naphthaldehyde ( 2 , 2c ) and 2‐hydroxy‐3‐methoxybenzaldehyde ( 3a , 3b , 3c , 3d , 3e ) with 2‐amino‐p‐cresol. All prepared complexes consist of cis‐MoO22+core coordinated by Schiff‐base ligand through two deprotonated hydroxyl groups and one imino nitrogen atom. The usual octahedral coordination around the molybdenum atoms is completed by the neutral ligand D (methanol, ethanol, dimethyl sulfoxide, imidazole or 4, 4′‐bipyridine). All compounds were characterized by elemental analyses, IR spectroscopy and some of them by X‐ray crystallography ( 1a , 2c , 3a , 3b , 3c and 3e ).  相似文献   

20.
Abstract

Eight new mixed ligand complexes of dioxomolybdenum(VI) with 2-hydroxy-3-methoxy/3,5-dibromo benzaldehyde 4-phenyl/ethyl-S-methyl/butyl thiosemicarbazones (L) were synthesized. The complexes of general formula [MoO2LD] (D: methanol, pyridine) were characterized by elemental analysis, IR, UV, and 1H-NMR spectroscopy. The structure of 3a was also determined by X-ray single-crystal diffraction. The thiosemicarbazone ligands are coordinated to dioxomolybdenum(VI) center through ONN set and the sixth coordinated site of the molybdenum is occupied by the second ligand (D). The in vitro antimicrobial activities of all thiosemicarbazones and their dioxomolybdenum(VI) complexes were tested against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.  相似文献   

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