Malti Sharma

Synthesis and Spectroscopic Characterisation of Six-Coordinate Complexes of Oxovanadium(V)

Complexes of the types VO(L)(R-deaH), VO(R-dea)(LH), and VO(L)(OGOH)[L = deprotonated form of N-(1-hydroxyethyl) naphthaldimine; R-dea = deprotonated form of a N-substituted diethanolamine, with R = H or Ph; G = CH2CH2, CHMeCHMe, CMe2CMe2, CHMeCH2CMe2, CMe2CH2CH2CMe2] have been prepared by the equimolar reactions of VO(OPri)3, LH2, and an appropriate diethanolamine or glycol in benzene. All of these coloured solid complexes have been characterised by elemental (C, H, N, and V) analyses and by spectroscopic (i.r., electronic, 1H-, 51V-n.m.r) studies. The relative lability of the hydroxy group(s) of N-(1-hydroxyethyl)naphthaldiamine, diethanolamine, and glycol has also been investigated.

PREPARATION, CHARACTERISATION, AND SPECTROSCOPIC STUDIES OF HOMO- AND HETEROBIMETALLIC PINACOLATE DERIVATIVES OF ALKALINE EARTH METALS

ABSTRACT Reactions of insoluble metal glycolates of the type with Al(OPr-i)3 in 1:2 molar ratio in C6H6 afford hydrocabon-soluble heterobimetallic pinacolate derivatives . All of these derivatives have been characterized by elemental analyses, molecular weight measurements, and spectroscopic [IR, NMR (1H, 13C, 27Al)] studies.

SYNTHESIS AND CHARACTERIZATION OF HOMO- AND HETEROBIMETALLIC TRIETHANOLAMINATES OF Ca, Sr AND Ba

The reactions of heavier alkaline earth metal alkoxides M(OPr) (Μ = Ca, Sr, Ba), with two equivalents of triethanolamine lead to the formation of insoruble products with the general formula, H4M{(OCH CH2)3N} . These insoluble products when treated with AliOPr) in 1:4 molar ratio afford soluble heterobimetallic derivatives of the type {Αΐ(ΟΡΓ72}4{Μ[(ΟΰΗ2ΟΗ2)3Ν]2}. All these derivatives have been characterized by elemental analysis, molecular weight measurements and spectroscopic [IR, NMR (Ή, C, AI)] studies. Introduction Recent interest in the synthesis of soluble alkoxides of alkaline earth metals due to their increasing applications as precursors for ceramic materials (e.g., superconductors), has led to interesting soluble homometallic derivatives with sterically demanding [15]/chelating [6-9]/fluorinated [7,10,11] alcohols. Although during the past few decades, triethanolamine (a strong chelating alcohol) has been used for the preparation of homometallic derivatives of a wide variety of e l e m e n t s [7] , on ly one heterobimetal l ic a lkox ide, triethanolaminate {Nb(OPr)4}3{La[(OCH2CH )3N]2} [12] appears to have been reported so far. In view of the above, the present research is focussed on the synthesis and characterization of novel homoand heterobi-metallic derivatives of Ca,Sr, and Ba with triethanolamine. Interestingly, the insoluble 1:2 triethanolaminate derivatives H4M{(OCH2CH )3N}2 react readily with Al(OPr) to yield heterobimetallic alkoxidetriethanolaminate products, the soluble nature of whicn is itself a strong evidence of a novel coordinated species in which the alkaline earth as well as all aluminium atoms attain six-coordination as revealed by NMR studies. Materials and Methods All manipulations were performed under a moisture-free environment. Solvents, benzene, hexane and toluene (BDH) were dried by refluxing over sodium benzophenone ketyl and distilled prior to use. Isopropyl alcohol was made anhydrous by refluxing over AI(OPr) followed by distillation. Triethanolamine was purified ana dried by keeping on 3A molecular sieves for 48 hr followed by distillation at 100°C/4mm. M(OPr)2 (M = Ca, Sr, Ba) [13] and AI(OPr)3 [14] were prepared by literature methods. Strontium and barium were estimated gravimetrically as sulphate, while aluminium was estimated by the oxinate method [15J. Calcium was estimated by complexometric titration using eriocnrome blackT as an indicator [15]. Nitrogen was estimated by KjeldaPs method [15]. Infrared spectra (4000-200 cm) were recorded on a Nicolet Magna-550 spectrophotometer in Nujol mulls. NMR spectra (Ή, C, AI) in CDCI DMSO-d or C6H were recorded on a JEOL FX 90Q spectrometer. Molecular weights were determined ebullioscopically in benzene using a Gallenkamp ebulliometer. (1) Preparation of H4Ba{(OCH2CH±NJ, Addition of triethanolamine f t . / f a , 0.0115 mole) solution in benzene (~ 35 ml) to a well stirred solution of freshly prepared BaiOPr^ (1.47g, 0.0057 mole) in benzene (~ 30 ml), led to instantaneous precipitation of a colourless solid. To ensure completion of the reaction, the contents of the flask were refluxed under a fractionating column and the a Nee Malti Bhagat H4 stands for the hydrogens of the coordinated hydroxy functionalities; the compound is actually not a hydride.

Synthesis and Characterisation of a New Class of Heterotrimetallic Isopropoxides of Strontium and Barium

Abstract New heterotrimetallic isopropoxides of the types {M2(OPr-i)9}M1{M11(OPr-i)5} (M = Zr, Sn(IV); M′ = Sr, Ba; M″ = Ti, Sn(IV)) and {Sn2(OPr-i)9}Sr{Al(OPr-i)4} have been synthesised for the first time by the single-pot reactions of metal isopropoxides (e.g., M1(OPr-i)2 (M′ = Sr, Ba), Ti(OPr-i)4, Sn(OPr-i)4.i-PrOH, or Al(OPr-i)3) in the desired molar ratios in refluxing benzene. All of these novel derivatives have been characterised by elemental analyses, molecular weight measurements, and spectroscopic [IR, NMR (1H, 13C, 27A1, 119Sn)] studies. Reactions of the derivative {Zr2(OPr-i)9}Ba{Sn(OPr-i)5} with alcohols (Me3CCH2OH and Me3COH) have been carried out to shed light on its possible structural features.

Synthesis and spectroscopic characterization of a new type of heterotrimetallic alkoxides of some bivalent metals

Heterotrimetallic isopropoxides of the composition [{Zr2(OPri)9}Ba{M(OPri)3}]2 have been prepared by the in situ reactions of MCl2 [M = Be, Mg, Zn, Sn(II], Co, Ni, Cu(II), KZr2(OPri)9 and KBa(OPri)3 in equimolar amounts. Reaction of [{Zr2(OPri)9}Ba{Zn(OPri)3}]2 with tertiary butyl alcohol has been studied to gain an insight into its structure. All new derivatives have been characterised by elemental analyses, spectroscopic [IR, UV–VIS, and NMR (1H, 13C, and 119Sn)] studies and molecular weight measurements.

Heterobimetallic diethanolaminate complexes of titanium and zirconium with alkaline earth metals

Ti(OPri)4 or Zr(OPri)4 · PriOH react with hydrocarbon-insoluble complexes M{(OCH2CH2)NH(CH2CH2OH)}2 (M = Mg, Ca, Sr, Ba) in a 2:1 molar ratio to yield hydrocarbon-soluble heterobimetallic diethanolaminate isopropoxide complexes [M{(OCH2CH2)2NH}2{M′(OPri)3}2] (M = Mg, Ca, Sr, Ba; M′ = Ti, Zr), which have been characterized by elemental analyses, molecular weight measurements and spectroscopic [i.r., n.m.r. (1H and 13C)] studies.