Thermal studies of some aryloxides of titanium(IV)

Thermal behaviour of aryloxides of titanium(IV) of composition TiCl_n(OAr)_4?n (wheren=0→3 and OAr=OC₆Bu^t-4, OC₆H₄OMe-4 and OC₆H₂-Bu ₂ ^t -2,6?Me-4) has been studied by DTA and TG analysis. Multiple decomposition steps have been indicated by thermal weight losses which are both exothermic and endothermic as shown by DTA curves. Based upon the total % loss in weight; during entire decomposition titanium dioxide has been found to be the final residue in each case.     

Bis(alkyl) yttrium complex containing a new tridentate amidinate ligand: synthesis and structure

New potentially tridentate amidine containing the quinoline fragment in the lateral chain, viz., NC₉H₆-8-NHC(Bu^t)N-2,6-Prⁱ ₂-C₆H₃ (1), was synthesized by the reaction of chloroimine 2,6-Prⁱ ₂-C₆H₃-N=C(Bu^t)Cl and lithium derivative of 8-aminoquinoline NC₉H₆-8-NHLi. The elimination of alkane under the action of amidine 1 on Y(CH₂SiMe₃)₂(THF)₂ in THF affords bis(alkyl) yttrium complex [NC₉H₆-8-NC(Bu^t)N-2,6-Prⁱ ₂-C₆H₃]Y(CH₂SiMe₃)₂(THF) (2), monomeric in the crystalline state.     

Synthesis and characterization of heterobimetallic mixed-ligand complexes containing Zr(μ-OPri)2Al bridging units

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPrⁱ) _n }₂ (L)] (where M = Al, n = 4, L = OC₆H₄CH = NCH₂CH₂O (1); M = Nb, n = 6, L = OC₆H₄CH = NCH₂CH₂O (2); M = Al, n = 4, L = OC₁₀H₆CH = NCH₂CH₂O (3); M = Nb, n = 6, L = OC₁₀H₆CH = NCH₂CH₂O (4)), [Zr{Al(OPrⁱ)₄}₂Cl(OAr)] (where Ar = C₆H₃Me₂-2,5 (5); Ar = C₆H₂Me-4-Bu₂-2,6 (6), [Zr{Al(OPrⁱ)₄}₂(OAr)₂] (where Ar = C₆H₃Me₂-2,5 (7); Ar = C₆H₂Me-4-Bu₂-2,6 (8), [Zr{Al(OPrⁱ)₄}₃(OAr)] (where Ar = C₆H₃Me₂-2,5 (9); Ar = C₆H₃Me₂-2,6 (10), [ZrAl(OPrⁱ)_7-n (ON=CMe₂) _n ] (where n = 4 (11); n = 7 (12), [ZrAl₂(OPrⁱ)_10-n (ON=CMe₂) _n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPrⁱ)₄}₂{ON=CMe(R)} _n Cl_2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., ¹H-, and ²⁷Al- n.m.r.) studies.     

Synthesis and characterization of di- and triorganotin(IV) complexes of 2-tert-butyl-4-methyl phenol

The di- and trialkyltin(IV) complexes of composition R₂SnCl_2−x (OAr), and n-Bu₃Sn(OAr) (R = n-Bu and Me; x = 1 and 2; OAr = OC₆H₃Bu ^t -2-Me-4) have been synthesized by the reactions of di-n-butyl and dimethyltin dichlorides and tri-n-butyltin(IV) chloride with 2-tert-butyl-4-methylphenol and triethylamine in tetrahydrofuran. The reaction of triphenyltin chloride with trimethylsilyl-2-t-butyl-4-methylphenoxide in the same solvent however, gives a complex of composition Ph₃Sn(OAr). The complexes have been characterized by microanalyses, molar conductance measurements, molecular weight determinations and IR and ¹H, ¹³C and ¹¹⁹Sn NMR and mass spectral studies. Thermal behaviour of the complexes has been studied by TGA and DTA techniques. From the non-isothermal TG data, the kinetic and thermodynamic parameters have been calculated employing Coats-Redfern equation and the mechanism of decomposition has been computed using non-isothermal kinetic method. Thermal investigations on the blends of poly(methylmethacrylate). PMMA, with organotin(IV)-2-tert-butyl-4-methylphenoxides have shown increased thermal stability compared to pure PMMA suggesting thereby their potential as additives towards PMMA.     

Dilithium Hexaorganostannate(IV) Compounds

Hypercoordination of main‐group elements such as the heavier Group 14 elements (silicon, germanium, tin, and lead) usually requires strong electron‐withdrawing ligands and/or donating groups. Herein, we present the synthesis and characterization of two hexaaryltin(IV) dianions in form of their dilithium salts [Li₂(thf)₂{Sn(2‐py^Me)₆}] (py^Me=C₅H₃N‐5‐Me) ( 2 ) and [Li₂{Sn(2‐py^OtBu)₆}] (py^OtBu=C₅H₃N‐6‐OtBu) ( 3 ). Both complexes are stable in the solid state and solution under inert conditions. Theoretical investigations of compound 2 reveal a significant valence 5s‐orbital contribution of the tin atom forming six strongly polarized tin–carbon bonds.     

Thermoanalytical investigations of niobium(V) chloride aryloxides

Niobium(V) chloride aryloxides [NbCl₃(OAr)₂] and [NbCl₂(OAr)₃] (Oar = —OC₆H₄Bu ^t -4 and —OC₆H₄OMe-4) have been prepared by reacting NbCl₅ with two and three equivalents of the respective phenol in CCl₄. The complexes have been characterized by elemental analysis, molecular weight determination, i.r., ¹H-n.m.r., u.v.–vis. and MS techniques. Thermal behaviour (t.g.–d.t.) of the complexes has also been studied and decomposition schemes proposed. The kinetic and thermodynamic parameters namely, the activation energy 'E ^*', the frequency factor 'A', entropy of activation 'S' and specific rate constant 'kr' etc. have been calculated employing the Coats–Redfern equation. The non-isothermal t.g. data has also been utilized to determine the most probable mechanism and corresponding activation energy for the decomposition of niobium(V) complexes by testing seven different theoretically possible decomposition mechanisms.     

Titanium(IV) complexes with monocyclopentadienyl and phenoxy-alkoxo ligands: Synthesis,structures and catalytic properties for ethylene polymerization

Three monochlorotitanium complexes Cp′Ti(2,4-^tBu₂-6-(CPh₂O)C₆H₂O)Cl [Cp′ = η⁵-C₅H₅ (2), η⁵-C₅(CH₃)₅ (3), η⁵-C₅H₂Ph₂CH₃ (4)] have been synthesized in high yields (>90%) by the reaction of corresponding Cp′TiCl₃ with the dilithium salt of ligand 2,4-^tBu₂-6-(CPh₂OH)C₆H₂OH (1). When activated by [Ph₃C]⁺[B(C₆F₅)₄]⁻ and AlⁱBu₃, complexes 2–4 exhibit reasonable catalytic activity for ethylene polymerization, producing polyethylenes with moderate molecular weights and melting points. Addition of excess water to complex 2 gave the oxo-bridged complex [Ti(η⁵-C₅H₅)(2,4-^tBu₂-6-(CPh₂O)C₆H₂O)]₂O (5). Complexes 4 and 5 were characterized by single crystal X-ray diffraction.     

Thermonanalytical Investigations of Monochlorobis (2,4-Pentanedionato) Vanadium(IV) Aryloxides

The thermal decomposition of the complexes [Vcl (acac)₂(OAr)] (where acac=2,4-pentanedionato anion; OAr=–OC₆H₄O-M-4, OC₆H₄OBut-4) has been studied using non-isothermal techniques (DTA and TG). The TGA indicate that the substitution of chlorine in VCl₂(acac)₂ with aryloxide ligands results in an increase in the initial temperature of decomposition (IDT) of the new complexes. The role of the substituent at the aryloxide ring on the thermal stability of the complexes is depicted and hence described. The ultimate decomposition product in all the complexes has been identified as V₂O₅. The kinetic and thermodynamic parameters namely, the energy of activation E, the frequency factor A, entropy of activation S and specific reaction rate constant k _r etc. have been rationalized in relation to the bonding aspect of the aryloxide ligands. This revised version was published online in July 2006 with corrections to the Cover Date.     

Lanthanide(II) Complexes of the Dihydrotriazinido Ligand [N{C(Ph)=N}2C(tBu)Ph]−

The potassium dihydrotriazinide K(L^Ph,tBu) ( 1 ) was obtained by a metal exchange route from [Li(L^Ph,tBu)(THF)₃] and KOtBu (L^Ph,tBu = [N{C(Ph)=N}₂C(tBu)Ph]). Reaction of 1 with 1 or 0.5 equivalents of SmI₂(thf)₂ yielded the monosubstituted Sm^II complex [Sm(L^Ph,tBu)I(THF)₄] ( 2 ) or the disubstituted [Sm(L^Ph,tBu)₂(THF)₂] ( 3 ), respectively. Attempted synthesis of a heteroleptic Sm^II amido‐alkyl complex by the reaction of 2 with KCH₂Ph produced compound 3 due to ligand redistribution. The Yb^II bis(dihydrotriazinide) [Yb(L^Ph,tBu)₂(THF)₂] ( 4 ) was isolated from the 1:1 reaction of YbI₂(THF)₂ and 1 . Molecular structures of the crystalline compounds 2 , 3· 2C₆H₆ and 4· PhMe were determined by X‐ray crystallography.     

Synthesis and spectroscopic studies of homo- and heteroleptic N-arylsalicylaldiminates of titanium(IV), zirconium(IV) and chromium(III)

Homo- and heteroleptic N-arylsalicylaldiminate derivatives of Ti^IV and Zr^IV of the type, MX_4–x (OC₆H₄CH=NAr) _x (X = OPrⁱ, x = 2,3; X = Cl, x = 1,2,3,4; Ar = C₆H₃Me₂-2,6, C₆H₃Et₂-2,6) have been prepared by reactions in the desired molar ratios of: (i) Ti(OPrⁱ)₄/Zr(OPrⁱ)₄·PrⁱOH with N-arylsalicylaldimines in benzene, and (ii) MCl₄ (M = Ti, Zr) with Me₃SiOC₆H₄CH=NAr or HOC₆H₄CH=NAr in the presence of Et₃N as a base or the potassium salt of N-arylsalicylaldimines in benzene. The three homoleptic derivatives of Cr^III, Cr(OC₆H₄CH=NAr)₃ (Ar = C₆H₂Me₃-2,4,6, C₆H₃Et₂-2,6, C₆H₃Prⁱ ₂-2,6) have also been prepared by salt-elimination. All of these new derivatives have been characterized by elemental analyses, spectroscopic [i.r., ¹H and ¹³C-n.m.r. (Ti and Zr complexes), and electronic (for Cr complexes)] studies, as well as molecular weight measurements.     

Reactions of 1,2-catechol with Bu3M (M = Ga, In). Structures of intermediate products

Reactions of 1,2-catechol with ^tBu₃M (M = Ga, In) have been studied. Trinuclear compounds [^tBu₅M₃(OC₆H₄O)₂] [M = Ga (1), M = In (2)] were synthesised in the reaction of 2 equiv. of C₆H₄(OH)₂ with 3 equiv. of ^tBu₃M in refluxing solvents. At room temperature the reaction of 1,2-catechol with ^tBu₃In in Et₂O leads to the formation of a binuclear complex [^tBu₄In₂(OC₆H₄OH)₂ · 2Et₂O] (3) possessing a four-membered In₂O₂ core and two unreacted hydroxyl groups. The same reaction carried out in a non-coordinating solvent (CH₂Cl₂) results in formation a compound [^tBu₃In₂(OC₆H₄O)(OC₆H₄OH)] (4), which undergoes a reaction with ^tBu₃In to yield the product 2. Moreover two intermediate isomeric products 5 and 6 of formula [^tBu₃Ga₂(OC₆H₄O)(OC₆H₄OH)] were isolated from the post-reaction mixture of 1,2-catechol with ^tBu₃Ga. The compound 6 possessing a different coordination of gallium atoms than 5 is a result of the intramolecular rearrangement of the compound 5 to decrease the steric repultion between ligands. Compounds 3 and 6 were structurally characterised. According to the structure of intermediate products 3-6 a reaction pathway of 1,2-catechols with group 13 metal trialkyls was proposed.     

Flexidentate Coordination Behavior and Chemical Non-Innocence of a Bis(1,3-Diphosphacyclobutadiene) Sandwich Anion

The homoleptic 1,3-diphosphacyclobutadiene sandwich complex [Co(η⁴-1,3-P₂C₂tBu₂)₂]⁻ behaved as a versatile and highly flexible metalloligand toward Ni²⁺, Ru²⁺, Rh⁺, and Pd²⁺ cations, forming a range of unusual oligonuclear compounds. The reaction of [K(thf)₂{Co(η⁴-1,3-P₂C₂tBu₂)₂}] with [Ni₂Cp₃]BF₄ initially afforded the σ-complex [CpNi{Co(η⁴-1,3-P₂C₂tBu₂)₂}(thf)] ( 2 ), which converted into [Co(η⁴-CpNi{1,3-P₂C₂tBu₂-κP,κC})(η⁴-1,3-P₂C₂tBu₂)] ( 3 ) below room temperature. The structure of 3 contains an unprecedented 1,4-diphospha-2-nickelacyclopentadiene moiety formed by an oxidative addition of a ligand P−C bond onto nickel. At elevated temperatures, 3 isomerized to [Co(η⁴-CpNi{1,4-P₂C₂tBu₂-κ²P,P})(η⁴-1,3-P₂C₂tBu₂)] ( 4 ), which features a 1,3-diphospha-2-nickelacyclopentadiene unit. Transmetalation of [K(thf)₂{Co(η⁴-1,3-P₂C₂tBu₂)₂}] with [Cp*RuCl]₄ (Cp*=C₅Me₅) afforded tetranuclear [(Cp*Ru)₃(μ-Cl)₂{Co(η⁴-1,3-P₂C₂tBu₂)₂}] ( 5 ), in which the [Co(η⁴-1,3-P₂C₂tBu₂]⁻ anion acts as a chelate ligand toward Ru²⁺. The diphosphido complex [(Cp*Ru)₂(μ,η²-P₂)(μ,η²-C₂tBu₂)] ( 6 ) was formed as a byproduct. Pure compound 6 was isolated after prolonged heating of the reaction mixture. The reaction of [K(thf)₂{Co(η⁴-1,3-P₂C₂R₂)₂}] (R=tBu; adamantyl, Ad) with [RhCl(cod)]₂ (cod=1,5-cyclooctadiene) afforded unprecedented π-complexes [Rh(cod){Co(η⁴-1,3-P₂C₂R₂)₂}] ( 7 : R=tBu; 8 : R=Ad), in which one μ:η⁴:η⁴-P₂C₂R₂ ligand bridges two metal atoms. The pentanuclear complex [Pd₃(PPh₃)₂{Co(η⁴-1,3-P₂C₂tBu₂)₂}₂] ( 10 ), featuring a Pd₃ chain and a rare 1,4-diphospha-2-butene ligand, was synthesized by reacting [K(thf)₂{Co(η⁴-1,3-P₂C₂tBu₂)₂}] with cis-PdCl₂(PPh₃)₂. The redox properties of selected compounds were analyzed by cyclic voltammetry, whereas DFT calculations gave additional insight into the electronic structures. The results of this study revealed several remarkable and previously unrecognized properties of the [Co(P₂C₂tBu₂)₂]⁻ anion.     

Synthesis,characterization and acceptor behavior of n-butyltin(IV)-2,4-dimethylphenoxides

The n-butyltin(IV) complexes, n-BuSnCl_3?x(OC₆H₃(CH₃)₂-2,4) _x (where x?=?1–3), have been synthesized in quantitative yields by employing the reaction of n-BuSnCl₃ with 2,4-dimethylphenol and sodium acetate in methanol and benzene solvents at room temperature. The complexes have been characterized by elemental analysis, molar conductivity, and FT-IR, ¹H- and ¹³C-NMR, and mass spectral studies. Thermal behavior has been studied by TG–DTA techniques. Lewis acid character of n-BuSn(OC₆H₃(CH₃)₂-2,4)₃ has been investigated by reacting it with bases such as 2,2′-bipyridine and 1,10-phenanthroline (B), Ph₃PO and Ph₃AsO (LO) and phosphorus and arsenic donors Ph₃P, Ph₃As, and As(SPh)₃ (L). The formation of 1?:?1 and 1?:?2 (metal?:?base) coordination compounds [n-BuSn(OC₆H₃(CH₃)₂-2,4)₃·B] and n-[BuSn(OC₆H₃(CH₃)₂-2,4)₃·2LO/2L] has been authenticated by physicochemical and IR spectral studies. In order to infer the biological relevance of newly synthesized complexes, the antibacterial activity has been assayed against six bacterial strains Klebsiella pneumoniae, Staphylococcus epidermidis, Staphylococcus aureus, Salmonella typhi, Salmonella paratyphi, and Escherichia coli. In this study, n-BuSnCl₂(OC₆H₃(CH₃)₂-2,4) and n-BuSnCl(OC₆H₃(CH₃)₂-2,4)₂ showed better activity than precursor and ligand, while n-BuSn(OC₆H₃(CH₃)₂-2,4)₃ did not exhibit improved activity.     

Palladacyclic and platinacyclic catalysts for the allylation of aldehydes

A range of palladacyclic and platinacyclic catalysts have been tested for activity in the allylation of aldehydes with allyl tributyltin. The bulky, π-acidic palladacycle [{Pd(μ-Cl){κ²-P,C-P(OC₆H₂-2,4-^tBu₂)(OC₆H₃-2,4-^tBu₂)₂}}₂] shows particularly good activity at room temperature with a variety of unsaturated substrates.     

Palladium-catalyzed coupling of tetraphenylbismuth(V) derivatives with methyl acrylate

Tetraphenylbismuth(V) derivatives of the general formula Ph₄BiX [X = OSO₂C₆H₄Me-4, OC₆H₂(NO₂)₃-2,4,6, OC₆H₂(NO₂-4)(Br₂-2,6), OSO₂C₆H₃(OH)(COOH)] react with methyl acrylate in the presence of palladium dichloride (1:3:0.04 molar ratio) in acetonitrile at 20°C to form the cross-coupling products, methyl cinnamate (0.17–0.54 mol mol^?1 starting bismuth compound) and methylhydrocinnamate (0.10–0.73 mol mol^?1), diphenyl (0.06–0.80 mol mol^?1), and benzene (0.02–0.36 mol mol^?1). The highest C-phenylating activity is shown by Ph₄BiOSO₂C₆H₄Me-4. The mechanisms with the palladium-catalyzed cross-coupling reactions are suggested.     

β‐Diketiminatoytterbium aryloxides: synthesis,structural characterization,and catalytic activity for addition of amines to carbodiimides

The steric effect of an aryloxido group on the synthesis and molecular structures of ytterbium aryloxides supported by β‐diketiminato ligand L (L = [N(2,6‐Me₂C₆H₃)C(Me)]₂CH^?) is reported. Reactions of β‐diketiminatoytterbium dichloride, LYbCl₂(THF)₂, with NaOAr¹ in THF (Ar¹ = [2,6‐^tBu₂‐4‐MeC₆H₂], THF = tetrahydrofuran) at 60°C gave the corresponding ytterbium complexes LYb(OAr¹)Cl(THF) ( 1 ) and LYb(OAr¹)₂ (1), depending on the molar ratio of dichloride to sodium aryloxide, respectively, while the same reactions with NaOAr² and NaOAr³ (Ar² = [2,6‐ⁱPr₂C₆H₃], Ar³ = [2,6‐Me₂C₆H₃]) in 1:1 or 1:2 molar ratio in THF afforded only bisaryloxide complexes LYb(OAr²)₂(THF) (1) and LYb(OAr³)₂(THF) ( 4 ) in good yields, respectively. Complexes 1 , 2 , 3 , 4 were fully characterized, including X‐ray crystal structure analyses. All the complexes are efficient pre‐catalysts for the catalytic addition of amines to carbodiimides giving guanidines. Copyright © 2013 John Wiley & Sons, Ltd.     

Organometallic chemistry of chiral diphosphazane ligands: Synthesis and structural characterisation

The diphosphazane ligands of the type, (C₂₀H₁₂O₂)PN(R)P(E)Y₂ (R = CHMe₂ or (S)-*CHMePh; E = lone pair or S; Y₂ = O₂C₂₀H₁₂ or Y = OC₆H₅ or OC₆H₄Me-4 or OC₆H₄OMe-4 or OC₆H₄Bu^t-4 or C₆H₅) bearing axially chiral 1,1'-binaphthyl-2,2′-dioxy moiety have been synthesised. The structure and absolute configuration of a diastereomeric palladium complex, [PdCl₂{ηsu2}-((O₂C₂₀H₁₂)PN((S)-*CHMePh)PPh₂] has been determined by X-ray crystallography. The reactions of [CpRu(PPh₃)₂Cl] with various symmetrical and unsymmetrical diphosphazanes of the type, X₂PN(R)PYY′ (R = CHMe₂ or (S)-*CHMePh; X = C₆H₅ or X₂ = O₂C₂₀H₁₂; Y=Y′= C₆H₅ or Y = C₆H₅, Y′ = OC₆H₄Me-4 or OC₆H₃Me₂-3,5 or N₂C₃HMe₂-3,5) yield several diastereomeric neutral or cationic half-sandwich ruthenium complexes which contain a stereogenic metal center. In one case, the absolute configuration of a trichiral ruthenium complex, viz. [Cp*Ruη₂-Ph₂PN((S)-*CHMePh)*PPh (N₂C₃HMe₂-3,5)Cl] is established by X-ray diffraction. The reactions of Ru₃(CO)₁₂ with the diphosphazanes (C₂₀H₁₂O₂)PN(R)PY₂ (R = CHMe₂orMe; Y₂=O₂C₂₀H₁₂or Y= OC₆H₅ or OC₆H₄Me-4 or OC₆H₄OMe-4 or OC₆H₄Bu^t-4 or C₆H₅) yield the triruthenium clusters [Ru₃(CO)₁₀{η-(O₂C₂₀H₁₂)PN(R)PY₂}], in which the diphosphazane ligand bridges two metal centres. Palladium allyl chemistry of some of these chiral ligands has been investigated. The structures of isomeric η³-allyl palladium complexes, [Pd(η³-l,3-R′₂-C₃H₃){η²-(rac)-(0₂C₂₀H₁₂)PN(CHMe₂)PY₂}](PF₆) (R′ = Me or Ph; Y = C₆H₅ or OC₆H₅) have been elucidated by high field two-dimensional NMR spectroscopic and X-ray crystallographic studies.     

Preparation and Characterization of Aluminum Alkoxides and their Application to Ring‐Opening Polymerization of ϵ‐Caprolactones

The reaction of 2‐methoxybenzyl alcohol with one molar equiv of R₂AIX in diethyl ether at 0°C gives [(2‐MeOC₆H₄CH₂‐μ‐O)AlRX]₂ ( 1 : R = Et, X = Cl, 2 : R = X = Et). In addition, 2,4‐di‐tert‐butylphenol reacts with ⁱBu₃Al affording a four‐coordinated aluminum compound [(μ‐2,4‐^tBu₂‐C₆H₄O)Al(ⁱBu)₂]₂ ( 4 ). Single crystal X‐ray structure analysis of 4 shows a C_2h‐symmetry with a planar Al₂O₂ core. Ring‐opening polymerization (ROP) of caprolactones initiated by 1, 4 and [(μ‐OCH₂C₆H₄OMe)Al(ⁱBu)₂]₂ ( 3 ) is performed and polyesters with narrow molecular weight distributions were obtained from the “living” ROP of caprolactones. ¹H NMR spectroscopic studies of PCL reveal that the initiator of 1 and 3 is through the Al‐OAr function, but the initiator of 4 is through the Al‐ ⁱBu group.     

1,3-Diphosphacyclobutane-2,4-diyl-2-ylidenide: A Unique Carbene and Its Trimethylalane Complex

A unique bonding situation is displayed by the lithium 1,3-diphosphacyclobutane-2,4-diyl-2-ylidenide 2 ⋅[Li(thf)_n]⁺ (Ar=2,4,6-tBu₃C₆H₂) obtained by deprotonation of 1 . According to ab initio calculations, the anion 2 can viewed as a cyclic bis(phosphanyl)carbene. Reaction with trimethylaluminum gives the complex 3 ⋅[Li(thf)₄]⁺ , whose crystal structure is presented.     

Synthesis,characterization, reactivity,and antifungal activity of chlorobis(2,4-dinitrophenoxo) monooxovanadium(V)

[VOCl(OC₆H₃(NO₂)₂-2,4)₂] (1) has been synthesized by the reaction of VOCl₃ with bimolar amounts of Me₃SiOC₆H₃(NO₂)₂-2,4 in toluene and characterized by elemental analyses, molar conductance, infrared (IR), ¹H and ¹³C NMR and mass spectral, and thermal studies. Molecular modeling dynamics of the complex suggests tetrahedral geometry around vanadium. The reaction of 1 with sodium alkoxides, NaOR (OR?=?OMe (methoxy); OEt (ethoxy), OBuⁿ(n-butoxy); OPrⁱ (isopropoxy); and OAmⁱ(isoamyloxy)) afforded mixed alkoxo–phenoxo complexes, [VO(OR)(OC₆H₃(NO₂)₂-2,4)₂] authenticated by physicochemical and IR spectral studies. The antifungal activities of the ligand and complexes against three fungi, namely Aspergillus niger, Byssachlamys fulva, and Mucor circinelloides have been assayed by the minimum inhibitory concentration method. The complexes have improved antifungal activity compared to free ligand.