TITANIUM (IV) COMPLEXES 1231 pro kg Lösung in dem Gebiet, wo cD > cA ist. Die i 2) ppm. Die Fehlerangaben beziehen sich auf die nach (8) erwartete Linearität reicht von hohen Ablesegenauigkeit von K g und A0 aus der A jc^-A - Donatorkonzentrationen bis zu 61,0 Mol-% Geraden. Die Assoziationskonstante in Molenbruch- P4. Aus Abb. 4 kann die Assoziationskon­ einheiten errechnet sich nach Gl. (9) zu K m = 0,25 stante als negative Geradensteigung abgelesen wer­ ± 0,02. Dieser Wert in Gl. (6) eingesetzt, ergibt den zu K g = (0,031 i 0,002) kg/Mol. Extrapolation innerhalb der Fehlergrenzen mit PBr3 als Standard von A/cD gegen Null ergibt relativ zu reinem PBr3 für die chemische Verschiebung des Komplexes den eine Verschiebung des Komplexes von A0 = +(42 aus Abb. 4 ermittelten Wert. Titanium(IV) Complexes of Bifunctional Tridentate or Tetradentate Schiff Bases S. R. Gupta and J. P. Ta n d o n Chemical Laboratories, University of Rajasthan, Jaipur (India) (Z. Naturforsch. 25 b. 1231—1234 [1970] ; eingegangen am 30. Juni 1970) Reactions of titanium isopropoxide with bifunctional tridentate Schiff bases, such as sali- cylidene-o-aminophenol, acetylacetone-o-aminophenol and benzoylacetone-o-aminophenol and bifunc­ tional tetradentate Schiff bases, such as bis-acetylacetone ethylenediimine, bis-benzoylacetone ethylenediimine, bis-salicylaldehyde ethylenediamine and glyoxal-o-aminohpenol have been investi­ gated in different stoichiometrc ratios. The resulting products Ti(OPr')2(SB), Ti(SB)2, Ti(OPr*)2 (S'B'), Ti(OPr>)2(S"B") and Ti(OPr>) (S"B") (S"B"H) (where SBH2 = bifunctional tridentate Schiff base, S'B'H2 = bis-acetylacetone or bis-benzoylacetone ethylenediimine and S"B"H2 = bis-salicylaldehyde ethylenediamine or glyoxal-o-aminophenol) have been isolated in almost quanti­ tative yields. The molecular weights of the products soluble in benzene have been determined ebullioscopically and plausible structure indicated. The thermogravimetric analysis of the salicyl- idine-o-aminophenol derivatives has also been carried out. Reactions of titanium isopropoxide with bifunc­ Titanium (IV) derivatives of different types of tional tridentate Schiff bases, such as salicylidene- Schiff bases appear to be quite interesting. In o-aminophenol, acetylacetone-o-aminophenol and earlier publications1 from these laboratories, the benzoylacetone-o-aminophenol and bifunctional tetra­ synthesis of some new titanium (IV) derivatives of dentate Schiff bases, such as bis-acetylacetone bifunctional tridentate Schiff bases and their ethylenediimine, bis-benzoylacetone ethylenediimine, important properties were reported. In the present bis-salicylaldehyde ethylenediamine and glyoxal-o- study, some new compounds of titanium (IV) with aminophenol have been investigated in different bifunctional tridentate or tetradentate Schiff stoichiometric ratios. The resulting products bases have been synthesized with a view to make Ti(OPr')2(SB), Ti(SB)„, ^(OPrO^S'B'), Ti(0 comparative studies of the resulting derivatives. Pri) 2(S"B") and Ti(OPr!) (S"B") (S"B"H) (where Very recently, B ra d ley et al. 2 have also reported SBH2 = bifunctional tridentate Schiff base, some novel Ti (IV) -Schiff base compounds and S'B'Ho = bis-acetylacetone or bis-benzoylacetone confirmed the structure of one of these derivatives ethylenediimine and S//B//H2 = bis-salicylaldehyde with the help of X-ray crystallography. ethylenediamine or glyoxal-o-aminophenol) have In general, the reactions of titanium isopropoxide been isolated in almost quantitative yields. The with bifunctional tridentate Schiff bases in 1 : 1 molecular weights of the products soluble in ben­ and 1 : 2 molar ratios may be represented as given zene have been determined ebullioscopically and below: plausible structures indicated. The thermogravi­ metric analysis of the salicylidine-o-aminophenol T i (OPr!) 4 + SBHo - > T i (OPr') 2 (SB) + 2 P^OHf • derivatives has also been carried out. T i (OPr’) 4 + 2 SBH, - > T i (SB) 2 + 4 P^OHf . 1 P. Prashar and J. P. Tandon, J. Less-Common Metals Reprints request to Dr. J. P. T a n d o n , University of 13, 541 [1967] Rajasthan, Jaipur (Indien). 2 D. C. B r a d le y , M. B. Hursthouse, and I. F. R e n d a l l , Chemical Communication 13, 672 [1969]. 1232 S. R. GUPTA AND J. P. TANDON Heat was evolved and immediately a red coloured .c h 3 h 3c . / VC-0 0- compound started separating when the Schiff P r1 HQ .CH base was added to the benzene solution of titanium V Pr' ? , / ;c=n \ 0 1/ N=Q isopropoxide. The resulting derivatives were found h3c h2c/ v / \ \y c h 2 c h 3 Ti Ti I to be almost insoluble or sparingly soluble in H3Cx H2Cx /,\ \ / X x CH2 .cm benzene. However, diisopropoxy titanium (IV) ace- o HQ Pr' .CH tylacetone-o-aminophenol compound was found to V be quite soluble in benzene and showed a molarity H3C c h 3 of 1.5. Probably, an equilibrium exists between the H5C6 h 3c n monomer and dimer species as shown below: c— 0 C-0 HC^ HQ \ = = N C = N 'C — 0> H3C H2C V h 3c h 2c x He; ;T,i(OPr')2 h 3c c h 3 ,Ti(0Pr')2 Ti(0B ut )2 'X = N " 0 ;c-Ov 0 /N=C h3cx h2c // HS HS / / C = N ' h 3c ,CH HCnC=N 0 0 n 0—C H3C M Pr1 ch3 < ; / 0 — 0 h5c6 h 3c The reactions of titanium isopropoxide with bis- The reactions of titanium isopropoxide with bis- salicylaldehyde ethylenediamine and glyoxal-o- acetylacetone ethylenediimine or bis-benzoylacetone aminophenol were also carried out in molar ratios ethvlenediimine in 1 : 1 molar ratio may be shown of 1 : 1 and 1 : 2. The resulting derivatives were as follows: of the type, Ti(OPri) 2(S',B") and T ^O Pr1) (S"B") (S^B7 H ). With a view to prepare compounds of Ti (OPr1) 4 + S'B'H2 -> Ti (OPr1) 2 (S'B') + 2 Pr!OH f . the type Ti(S,/B,/) 2 , 1 : 2 molar reactions were also The reactions were also carried out in 1 : 2 molar carried out in presence of excess of Schiff base ratio and the resulting product dried under vacuum. or p-toluene sulphonic acid as catalyst, but were The analysis corresponded to the formula, found to be unsuccessful. Ti(OPr') 2(S,B/) (S B ’Ho) . On being washed with The TGA curve (fig. 1, curve A) of the Schiff ether a yellow filtrate of the Schiff base itself was base salicylidene-o-aminophenol does not show any obtained and the analysis of the resulting compound effect upto a temperature of 160 °C. Thereafter a corresponded to T i(0Pr1)2(S B ) . It, therefore, heavy loss in the weight was recorded, which is shows that even with excess of the Schiff base, probably due to the sublimation of the Schiff diisopropoxy titanium (IV)-S c h i f f base com­ base itself. pound is the final product. The molecular weights Diisopropoxy titanium(IV) salicylidene-o-amino­ of the diisopropoxy titanium (IV) bis-acetylacetone phenol was found to be stable upto 400 °C and ethylenediimine and diisopropoxy titanium (IV) thereafter a rapid decomposition was observed upto bis-benzoylacetone ethylenediimine corresponded to 460 °C. Finally, it gets converted into TiOo at the monomeric and dimeric state respectively. 690 °C (fig. 1, curve B ). Probably, the monomeric nature in the latter case The TGA curve (fig. 1, curve C) of titanium is due to the presence of bulkier phenyl group. This (IV) bis-salicylidene-o-aminophenol is almost simi­ could further be confirmed by reacting the benzene lar to that of diisopropoxy titanium(IV) salicyl- solution of diisopropyoxy titanium(IV) bis-acetyl­ idene-o-aminophenol. However, the complete con­ acetone ethylenediimine with excess of tertiary buta­ version into Ti02 takes place at 980 °C. nol. The resulting compound, tertiary dibutoxy tita­ nium (IV) bis-acetylacetone ethylenediimine was Experimental Section found to be a monomer. This also indicates that in Titanium isopropoxide was prepared by the am­ the diisopropoxy titanium (IV) bis-acetylacetone monia method3. It was distilled out (101°C/8mm) ethylenediimine, the dimerization takes place and then analysed: through the bridging isopropoxy groups*. Their Calc, for Ti(OPr!)4: Ti 16.85 OPrj 83.15, probable structure may be indicated as follows: Found: Ti 16.71 OPr1 82.15. TITANIUM (IV) COMPLEXES 1233 Schiff base Analysis Physical characteristics ““C H N [%] [%] [%] Salicylidene-o-aminophenol (a) 73.00 5.20 6.54 Orange solid, m.p. 188—189 °C, (C13H11NO2) (b) 73.21 5.20 6.57 sublimed at 188—190 °C/1.5—2.0 mm Acetylacetone-o-aminophenol (a) 68.83 6.81 7.25 Yellow needles, m.p. 189 — 191 °C (C11H13NO2) (b) 69.10 6.85 7.32 Benzoylacetone-o-aminophenol (a) 76.00 5.89 5.46 Yellow solid, m.p., 163 — 165 °C (Ci6Hi5N02) (b) 75.84 5.97 5.53 Bis-acetylacetone ethylene-diimine (a) 64.03 8.91 12.39 Straw coloured solid, m.p., (C12H20N2O2) (b) 64.27 8.98 12.48 118-119 °C. Bia-benzoylacetone ethylene-diimine (a) 75.97 6.92 7,97 Colourless solid, m.p., 180—181 °C. (C22H24N202) (b) 75.82 6.94 8.04 Bis-salicylaldehyde ethylene-diamine (a) 71.32 6.03 10.31 Yellow solid, m.p., 140—142 °C (C16H16N2O2) (b) 71.60 6.01 10.43 Glyoxal-o-aminophenol (a) 69.69 5.07 11.57 Colourless solid, m.p. ,213 — 215 °C (Ci4H12N202) (b) 69.98 5.03 11.66 Table 1. Schiff bases and their analyses, (a) = analysis of the compound, (b) = calculated for the formula. Isopropanol (B.D.H.) was dried over sodium and Thermogravimetric analysis was carried out on a then fractionated over aluminium isopropoxide.