Schiff base derivatives of titanium(IV) and zirconium(IV)

The reactions of a few bifunctional and tridentate Schiff bases with titanium-(IV) and zirconium(IV) isopropoxides in equimolar and bimolar ratios are described. The resulting compounds have been obtained in almost quantitative yields and are of the general formulae M(SB)_x(OPrⁱ)_4?2X (where M = Ti or Zr; SB- = anion of the Schiff base SBH₂ and x = 1 or 2). Their molecular weights have been determined ebullioscopically and IR spectra recorded.     

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.     

Synthesis and characterization of a new class of heteronuclear derivatives of zirconium(IV)

Reactions of Zr{Al(OPrⁱ)₄}₂Cl₂ or Zr{Nb(OPrⁱ)₆}₂Cl₂ with KNb(OPrⁱ)₆/KAl(OPrⁱ)₄ and diethanolamines RN(CH₂CH₂OH)₂ [R=H(L^HH₂), Me(L^MeH₂), and Ph(L^PhH₂)] in the presence of two equivalents of Et₃N yield interesting hetero(bi- and tri-) nuclear derivatives (1)–(8) All of these new derivatives have been characterized by elemental analyses, molecular weight measurements, and spectroscopic studies.Ram C. Mehrotra - Deceased     

Synthesis and characterization of cyclophosphazene complexes of zirconium(IV)

Cyclophosphazene complexes of zirconium(IV) of the types and (R =??Ph or –SiMe₃, n =?1 or 2) have been synthesizedand isolated by reactions of acyclic bis-silylated phosphazene, [HN(PPh₂NSiMe₃)₂], or bis-phenylated phosphazene, [HN(PPh₂NPh)₂], with ZrCl₄ or ZrCl₂(OPrⁱ)₂ in different stoichiometries under anhydrous and inert conditions. These cyclozirconatriazadiphosphorines have been characterized by elemental analyses (C, H, N, Cl and Zr), molecular weight determination, IR and NMR (¹H, ¹³C and ³¹P) spectral studies, which indicated the monomeric nature of these complexes and a bidentate mode of bonding by the phosphazene ligand, leading to trigonal bipyramidal or octahedral geometries around the zirconium.     

Synthesis,spectroscopic characterization,and biological screening of levofloxacin based organotin(IV) derivatives

Four new organotin (IV) complexes with general formula R₃SnL/R₂SnL₂, where R = CH₃, n-C₄H₉, C₆H₅ and L = Levofloxacin, were synthesized and characterized by elemental analyses, FT-IR and NMR (¹H and ¹³C) spectroscopy. Spectroscopic data suggested a six-coordinated geometry for diorganotin(IV) derivatives and a five-coordinated geometry for triorganotin(IV) derivatives. The value of Me–Sn–Me bond angle for di- and trimethyltin complexes using the Lockhart equation, were 150° and 116°, respectively, that corresponded to six and five-coordinate geometry, accordingly. The ligand and its complexes were screened for their antibacterial, antifungal, cytotoxic, and free radical scavenging (DPPH) antioxidant activities. The biological data indicated those as potentially bioactive in each field of the study. Accumulated data of DNA interaction with the synthesized complexes based on UV-Vis, cyclic voltammetry and viscometry suggested an intercalative mode of the interaction.     

Synthesis to spectroscopy of titanium(IV) and zirconium(IV) chelates with biologically active ON donor systems

Summary A new class of 16 organotitanium(IV) and organozirconium(IV) chelates with biologically active monofunctional bidentate semicarbazones having the ON donor system were prepared by reacting 11 and 12 stoichiometric proportions of bis(cyclopentadienyl)titanium(IV) dichloride and bis(cyclopentadienyl)zirconium(IV) dichloride with the appropriate ligand, prepared by condensing heterocyclic ketones and semicarbazide hydrochlorides in presence of NaOAc. Trigonal bipyramidal and octahedral structures have been suggested for the 11 and 12 (ML) complexes of titanium(IV) and zirconium(IV), respectively, on the basis of spectral analyses.     

Synthesis and characterization of bis(indenyl) zirconium aryloxide derivatives and their use in α‐olefin polymerization

A series of new bis(indenyl) zirconium diaryloxides of general formula Ind₂Zr(OL)₂ (L = C₆H₅, 2 ; C₆F₅, 3 ; 2,6‐Me₂C₆H₃, 4; 2,4,6‐Me₃C₆H₂, 5 ; 4‐^tBuC₆H₄, 6 ) were synthesized by a metathesis reaction of Ind₂ZrCl₂ ( 1 ) with the appropriate thallium aryloxide salt, TlOL. The complexes 1–6 were characterized by ¹H and ¹³C NMR techniques. They were also examined as catalysts for ethene and 1‐hexene polymerization with methylalumoxane as co‐catalyst, and a trend of the polymerization activity as a function of aryloxide ligands was observed. An interpretation of this trend, considering both the electronic and steric effects of the substituents on the aryloxide rings, was proposed. Copyright © 2001 John Wiley & Sons, Ltd.     

Titanium(IV) and zirconium(IV) derivatives of tetradentate schiff bases

Summary Titanium and zirconium isopropoxides react with the tetradentate Schiff bases, I)is-salicylaldehyde-o-phenylenediimine (SBH₂ ) and bis-salicylaldehyde-p-phenylencdiimine (SBH₂) in anhydrous benzene in 1: 1 and 1 :2 molar ratios to give almost quantitative yields of M(OPr-i)₂ (SB) and M(OPr-i)2(SB)(SBH), where M = Ti or Zr and [SB]² is the anion of the corresponding Schiff base, SBH₂. The i.r. spectra of the completes have been recorded and tentative assignments for C=N and C-O stretching frequencies made.     

环戊二烯基二硫代氨基甲酸钛(Ⅳ), 锆(Ⅳ)配合物的合成及结构表征

(RCp)~2MCl~2, (RCp)TiCl~3分别与N-(4-苯基-2-噻唑基)二硫代氨基甲酸钾和3-苯基-5-(2-呋喃基)-吡唑啉-1-二硫代甲酸钠进行反应, 合成了三十二个未见报道的(RCp)M(S~2CNHR')~nCl~3~-~n,(RCp)~2M-(S~2CNHR')~nCl~2~-~n [R=H, Me; M=Ti, Zr; R'=4-苯基噻唑基(PTDTC), n=1,2,3] 以及(RCp)M(S~2CR^2)~nCl~3~-~n,(RCp)~2M(S~2CR^2)~nCl~2~n[R=H,Me;M=Ti,Zr,R^2=3-苯基-金-(呋喃-2)吡唑啉基(PFPDTC), n=1,2,3]型配合物。所有配合物经元素分析、UV、IR和^1H NMR谱证实, 二硫代氨基甲酸是以双齿配体键合的。     

Phospha(III)guanidinate complexes of titanium(IV) and zirconium(IV) amides

Two procedures for the synthesis of group 4 phosphaguanidine compounds M(R₂PC{NR′}₂)(NR″₂)₃ (M = Ti, Zr; R = Ph, Cy; R′ = ⁱPr, Cy; R″ = Me, Et) are described. Spectroscopic characterization indicated symmetrical bonding of the phosphaguanidinate ligand in solution for the P-diphenyl derivatives whereas the P-dicyclohexyl analogs adopt a more rigid geometry with inequivalent N_amidine substituents within the phosphaguanidinate ligand. X-ray diffraction studies show exclusively monomeric tbp metal centers for a series of derivatives, with a chelating phosphaguanidinate ligand that spans an axial and an equatorial position. Two different conformers have been identified in the solid-state that differ in the relative orientation of the phosphorus R₂P–C substituents with respect to the equatorial plane of the tbp metal. The synthetic protocol was extended to the bimetallic complex, [PhP(C{NⁱPr}₂Ti{NMe₂}₃)CH₂–]₂, which was characterized by crystallography as the meso-form.     

Synthesis and structural characterization of 1,2,4-diazaphospholide complexes of titanium(IV) and titanium(III)

Two 1,2,4-diazaphospholide complexes of [Ti(η(2)-3,5-Ph(2)dp)(4)] and paramagnetic [Ti(η(2)-3,5-tBu(2)dp)(3)] were prepared by the reaction of tetrakis(dimethylamido)titanium(IV) with 3,5-diphenyl-1,2,4-diazaphophole, H[3,5-Ph(2)dp], or by the treatment of 3,5-tert-butyl-1,2,4-diazaphopholide potassium, K[3,5-tBu(2)dp], with titanium trichloride. Complexes can be viewed as the core of P(σ(2)λ(3))-functionalized metallodendrimers, in which the metal atoms are exclusively η(2)(N,N) bonding to the 1,2,4-diazaphospholides while P atoms (σ(2)λ(3)) with electron lone pairs are located on the periphery of the molecules.     

Synthesis and characterization of bis(cyclopentadienyl)bis(hexafluoroantimonato) titanium(IV)

Reaction of titanocene dichloride with two equivalents of silver hexafluoroantimonate in sulphur dioxide quantitatively yields Cp₂Ti(SbF₆)₂ (Cp = η⁵-C₅H₅) and AgCl. The titanocene bishexafluoroantimonate was recrystallized from SO₂ and characterized by chemical analysis, ¹H NMR, IR and mass spectroscopy.     

Synthesis, structure, and catalytic activity of titanium(IV) and zirconium(IV) amides with chiral biphenyldiamine-based ligands

A new series of titanium(IV) and zirconium(IV) amides have been prepared from the reaction between M(NMe₂)₄ (M = Ti, Zr) and C₂-symmetric ligands, (R)-2,2′-bis(pyridin-2-ylmethylamino)-6,6′-dimethyl-1,1′-biphenyl (2H₂), (R)-2,2′-bis(pyrrol-2-ylmethyleneamino)-6,6′-dimethyl-1,1′-biphenyl (3H₂), (R)-2,2′-bis(diphenylphosphinoylamino)-6,6′-dimethyl-1,1′-biphenyl (4H₂), (R)-2,2′-bis(methanesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (5H₂), (R)-2,2′-bis(p-toluenesulphonylamino)-6,6′-dimethyl-1,1′-biphenyl (6H₂), and C₁-symmetric ligands, (R)-2-(diphenylthiophosphoramino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (7H) and (R)-2-(pyridin-2-ylamino)-2′-(dimethylamino)-6,6′-dimethyl-1,1′-biphenyl (8H), which are derived from (R)-2,2′-diamino-6,6′-dimethyl-1,1′-biphenyl. Treatment of M(NMe₂)₄ with 1 equiv. of N₄-ligand, 2H₂ or 3H₂ gives, after recrystallization from an n-hexane solution, the chiral zirconium amides (2)Zr(NMe₂)₂ (9), (3)Zr(NMe₂)₂ (11), and titanium amide (3)Ti(NMe₂)₂ (10), respectively, in good yields. Reaction of Zr(NMe₂)₄ with 1 equiv of diphenylphosphoramide 4H₂ affords the chiral zirconium amide (4)Zr(NMe₂)₂ (12) in 85% yield. Under similar reaction conditions, treatment of Ti(NMe₂)₄ with 1 equiv. of sulphonylamide ligand, 5H₂ or 6H₂ gives, after recrystallization from a toluene solution, the chiral titanium amides (5)Ti(NMe₂)₂·0.5C₇H₈ (13·0.5C₇H₈) and (6)Ti(NMe₂)₂ (15), respectively, in good yields, while reaction of Zr(NMe₂)₄ with 1 equiv. of 5H₂ or 6H₂ gives the bis-ligated complexes, (5)₂Zr (14) and (6)₂Zr (16). Treatment of M(NMe₂)₄ with 2 equiv. of diphenylthiophosphoramide ligand 7H or N₃-ligand 8H gives, after recrystallization from a benzene solution, the bis-ligated chiral zirconium amides (7)₂Zr(NMe₂)₂ (17) and (8)₂Zr(NMe₂)₂ (19), and bis-ligated chiral titanium amide (8)₂Ti(NMe₂)₂ (18), respectively, in good yields. All new compounds have been characterized by various spectroscopic techniques, and elemental analyses. The solid-state structures of complexes 10, 12, 13, and 17-19 have further been confirmed by X-ray diffraction analyses. The zirconium amides are active catalysts for the asymmetric hydroamination/cyclization of aminoalkenes, affording cyclic amines in good to excellent yields with moderate ee values, while the titanium amides are not.     

Bis(indenyl)titanium(IV) and zirconium(IV) complexes of monofunctional bidentate salicylidimines

Dichlorobis(indenyl)-titanium(IV) and -zirconium(IV), (C₉H₇)₂TiCl₂ and (C₉H₇)₂ZrCl₂, react with bidentate Schiff bases such as salicylidene aniline, salicylidene-o-toluidine, salicylidene-m-toluidine and salicylidene-p-toluidine in a 1:1 molar ratio in refluxing tetrahydrofuran in the presence of triethylamine to yield complexes of the type (C₉H₇)₂Ti(SB)Cl and (C₉H₇)₂Zr(SB)Cl, respectively where SB is the anion of the corresponding Schiff base, SBH. The new derivatives have been characterised on the basis of their elemental analyses, conductance measurements and spectral (IR, ¹H NMR and electronic) studies.     

New bis(diphenylphosphino)aniline derivatives: Synthesis and spectroscopic characterization

Six new multidentate bis(diphenyl‐phosphino)amine [R–N(PPh₂)₂] ligands have been prepared from the reaction of aniline derivatives, R–NH₂, with Ph₂PCl in the presence of triethylamine. All of the compounds were obtained in good yields and were characterized by NMR, IR, and microanalysis. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:613–616, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20362     

Determination of microamounts of zirconium(IV) and titanium(IV) with preliminary TLC separation

By the application of thin-layer chromatography on silica gel H and the solvent system consisting of 6 M HCl:acetylacetone: 9 M H₂SO₄ (60:2:1, v/v/v), zirconium and titanium have been quantitatively separated from each other, as well as from numerous other interfering ions. The efficiency of the chromatographic separation was evaluated by semiquantitative determination of zirconium and titanium by visual colorimetry of spots in situ, as well as by spectrophotometric determination of zirconium with rutin after its elution from silica gel H thin-layer.     

Isolation of dithiocarbazate salts as oxinato-complexes of titanium(IV), zirconium(IV) and hafnium(IV)

Summary Ionic chelate complexes of the type, [(⁵-R)₂ML][dtz] [R=cyclopentadienyl (Cp) or indenyl (C₉H₇); M=Ti^IV, Zr^IV or Hf^IV; HL=oxine; dtz=phenyldithiocarbazate (PhNHNHCS₂)] have been synthesised and characterised. Conductance measurements indicate that the complexes are 11 electrolytes. From i.r. and u.v. spectral studies we conclude that the oxinato-group is chelating. Consequently there is tetrahedral coordination around the metal ion.¹H and¹³C N.m.r. studies are consistent with the stoichiometries. X-ray powder diffraction studies have been made for [(⁵-Cp)₂ZrL][dtz]. For [(⁵-Cp)₂TiL][dtz] and [(⁵-Cp)₂ZrL][dtz] thermal (t.g. and d.t.a.) and mass spectral studies have been carried out.