Synthesis and Characterization of Some Trivalent and Tetravalent Derivatives of 2- Hydroxy-1-naphthoic Acid

ISSN: 0973-4945; CODEN ECJHAO E-Journal of Chemistry Vol. 1, No. 2, pp 110-114, April 2004 http://www.e-journals.net Synthesis and Characterization of Some Trivalent and Tetravalent Derivatives of 2- Hydroxy-1-naphthoic Acid DEEPTI JOSHI* and T. K. JOSHI§ * Chemical Laboratories, DSB Campus, Kumaun University, Nainital-263002, Uttranchal (INDIA). § Chemistry Department.CBS&H, G.B.Pant. University of Agriculture and Technology. Pantnagar. Received 22 February 2004; Accepted 10 March 2004 Abstract: The trivalent derivatives (B, Al, As, Sb & Fe) and tetravalent derivatives (Si,Ti & Se) of 2-hydroxy-1-naphthoic acid have been prepared by the interaction of their corresponding isopropoxide with letter in different molar ratio viz. 1:3 &1:4 in benzene medium. The prepared compounds generally obtained as coloured solids and amongst them those containing isopropoxy groups were found to be hygroscopic. All these compound were characterized by azeotrope and elemental analysis as well as by IR, PMR and mass spectral measurements. These spectral data have facilitated in elucidating the mode of bonding of the said metals and nonmetals in these compounds with 2-hydroxy-1-naphthoic acid. Keywords: Tri- and tetravalent derivatives, 2-Hydroxy-1-naphthoic acid, Alcoholysis reaction. Introduction The reactivity of metal / non metal alkoxides provides a simple and convenient method for preparations of a variety of metallo-organic / non-metallo-organic compounds. The ligating properties of 2-hydroxy-1-naphthoic acid containing hydroxy groups (-OH) adjacent to the carboxylic acid group(-COOH) have seen extensively examined1-3 owing to the favorable geometry of donor sites for stable 6-membered metal chelating ring formation. 111 DEEPTI JOSHI et al. These prepared trivalent and tetravalent compounds of 2-hydroxy-1-naphthoic acid (abbreviated as 2,1hna or LH2) (structure a) by alcoholysis reaction involving the interaction of the corresponding metal/non-metal isopropoxide with 2,1hna in appropriate stoichiometric ratios viz. 1:3 and 1:4 (1:1 and 1:2 were reported earlier4) in benzene as a reaction medium. Experimental Materials All the chemicals used during the study were of analytical grade reagents. The solvents were dried by standard procedures.5 2-Hydroxy-1-napthoic acid were used after re-crystallization from 50% (v/v) aqueous ethanol. B, Al, Fe, As or Sb triisopropoxides and Si and Se tetraisopropoxides were prepared by already reported methods6. Titanium tetraisopropoxides were used as such. General Procedure for the synthesis of trivalent and tetravalent derivatives The tri/tetravalent isopropoxide and 2,1 hna in appropriate stoichiometry in dry benzene are refluxed on a wax bath at 90-1000C. After several hrs (Table 1) of reflux, the isopropanolbenzene was fractionated out and the amount of isopropanol liberated was estimated by an oxidimetric method7,8 to monitor the completion of the reaction . This yielded colored solid which was washed with dry benzene followed by dry ether and finally dried under suction. Characterization Melting points were recorded on an electro thermal CAT No. IA 8103 digital m.p. apparatus. The IR spectra was recorded on a Bruker IFS 66 v FT-IR spectrometer, using KBr pellets in the region 4000-400 cm-1, while the PMR spectra were taken in DMSO- d6 solution and recorded on a JEO GSX 400 NB FT-NMR 400 MHz spectrometer, using TMS as an internal standard. The electrospray mass spectra were recorded on a Micromass Quatro II triple quadrapole mass electrospray spectrometer. Results and Discussion The reaction occurring between tri and tetravalent metal and non- metal isopropoxide and LH2 may be illustrated as under: M (OPri)3 + 3 LH2 M ( LH2)3 + 3 PriOH (1) (Where M = Bi, Al, Fe, As & Sb) M (OPri)4 + 3 LH2 M ( LH2)3 ( OPri) + 3 PriOH (2) i M (OPr )4 + 4 LH2 M ( LH2)4 + 4 PriOH (3) (M = Si, Ti & Se) IR and PMR spectrum of trivalent (III) and tetravalent (IV) compounds9,11 The IR and PMR spectrum are already known4. M(III) (LH2)3, M(IV) (LH2)4 shows weak and medium absorption in the region 3100-2880 cm-1 indicate the overlapping of free hydroxy and νC-H of the aromatic ring, while the other absorptions in the region 31002880 cm-1 corresponds to the overlapping of νC-H of the aromatic ring and isopropoxide group in case of M(IV) (LH2)3 (OPri). The absorption in the region 1645-1620 cm-1 shows the overlapping of νasCOO and νC=C of the aromatic ring and other absorption at 1440 -1420 cm-1 assigned to ν s COO of the carboxylate group. Thus a shift of 10-20 cm-1 ν s COO in comparison to the ligand suggests bonding of the carboxylate oxygen to the corresponding metal / non-metal. Further the separation value (ν as COO-ν s COO) Synthesis and Characterization of Some Trivalent and Tetravalent Derivatives 112 ∆νCOO, 185-230 cm-1 suggests the presence of a bridged or coordinated carboxylate group. The weak absorptions in the region 1390-1360 cm-1in M(IV) (LH)3(OPri) exhibits C-H bending of the gem–dimethyl structure of the isopropoxy group and other absorption in the region 1345-1210 cm-1because of the v C-O of the hydroxyl group, while the absorption in the region 1160-1140 cm-1 in M(IV) (LH2)3 (OPri) correspond to νC-O of the isopropoxy group. The new bands around 1360-1350 cm-1and 580-475 cm-1correspond to νB-O and νM-O (M = Br, Al, Sb, Fe, As, Si, Ti &, Se). Table 1. Analytical details of the compounds of 2-hydroxy-1-naphthoic acid. Compound S.No molar ratio 1 2 3 4 5 6 7 8 9 10 11 B(LH2)3 (1: 3) Al(LH2)3 (1: 3) Fe(LH2)3 (1: 3) As(LH2)3 (1: 3) Sb(LH2)3 (1: 3) Si(LH2)3 (Opri) (1: 3) Si(LH2)4 (1: 4) Ti(LH2)3 (OPri) (1: 3) Ti(LH2)4 (1: 4) Se(LH2)3 (OPri) (1: 3) Se(LH2)4 (1: 4) Reflux time, h M.P Colour 0 C 06 Light 240 yellow 08 Brown 270 12 Black 300 08 Yellow 220 10 White 250 10 White 270 12 09 10 Off white 280 Reddish 260 brown Reddish 240 brown 08 Off white 230 08 Off white 230 Azeotrope Analysis Found, Cald. Elemental Analysis Mol. Weight* 0.87 (0.87) 0.98 (0.98) 0.50 (0.50) 0.71 (0.71) 1.07 (1.08) C % H % M% Found Found Found, (Cal), (Cal), (Cal). 68.20 2.80 0.80 (69.25) (3.69) (1.90) 66.25 2.50 3.45 (67.35) (3.60) (4.58) 63.30 2.30 8.04 (64.20) (3.43) (9.04) 61.50 2.30 10.70 (62.28) (3.33) (11.77) 4.30 2.10 16.80 (58.00) (3.09) (17.81) 1.62 (1.63) 65.60 3.35 3.70 648.71 (66.65) (4.35) (4.33) 1.98 1.99 1.00 (1.01) 0.81 (0.82) 0.58 (0.58) 67.50 2.63 2.60 (68.04) (3.63) (3.60) 63.23 3.35 2.55 668.52 (64.68) (4.23) (7.17) 65.98 2.10 5.24 (66.34) (3.54) (6.01) 60.80 3.10 10.10 (61.81) (4.03) (11.29) 0.73 (0.73) 62.70 2.30 8.60 (63.85) (3.41) (9.54) 572.35 588.51 617.38 636.44 683.29 * Molecular weight obtained by Mass Spectrum in several representative cases. The multiplet between 7.20-8.15 corresponds to the naphthyl ring protons. The doublet and multiplet in the region 1.20-1.55 and 4.10-4.55 due to –CH3 and ≡CH protons of the isopropoxy group in M(IV)(LH2)3(OPri). A hump in the region 6.44-5.85 suggests that (...truncated)