International Journal of Scientific & Engineering Research, Volume 4, Issue 7, July-2013 28 ISSN 2229-5518 IJSER © 2013 http://www.ijser.org Synthesis and Characterisation of Some New Organoantimony (V) Aryloxyacetates Kiran Singhal, Dharmendra K. Srivastava, Prem Raj, A. Pandey Abstract— A series of new tri and tetra-organoantimony (V) aryloxyacetates of the general formula R3 Sb(OCOCH 2 OR’) 2 ; and R4 Sb(OCOCH2 OR’) [where R = p-OCH 3 C 6 H4 -, C 6 H5 - & R’ = p-CH3 C6 H4 -, m-CH 3 C6 H 4 -, o-CH3 C 6 H4 -, β-C10 H 7 -, o-ClC6 H 4 -], have been synthesised and characterised. These complexes are monomeric in benzene and non-electrolyte in acetonitrile. IR, NMR spectral data suggest the hepta-coordination with weak secondary interaction in between antimony and carbonyl oxygen of aryloxyacetate ligands. Keywords— Tri and tetra-organoantimony (V) aryloxyacetates, IR, 1 H NMR, 13 CNMR spectra, monomeric, non ionic, secondary interaction. ——————————  —————————— 1 INTRODUCTION The great variety of structural possibilities offered by organo- metal carboxylates perhaps is the main factor for the contin- ued interest in this class of compounds [27-34]. Despite a con- siderable interest in organometallic carboxylates and the varie- ty of metals for which such derivatives have been synthesized, corresponding aryl oxyacetates are mainly confined to tin. The etheral oxygen may or may not involve in coordination with metal atom and thus play an important role in changing the geometry of the complex. Studies on organotin complexes of aryloxy acetic acids indicate intramolecular O-Sn coordination particularly in case of alkyl tin derivatives with monomeric constitution in solid state. In sharp contrast to this triphenyltin derivatives having pentacoordination around tin were found to be polymeric with bridging carbonyl group. A perusal of literature reveals that the role of pentacoordination, partucu- larly in case of group 14 and group 15 elements in reaction mechanism is potentially one of the best method to explore the possibility of conformation extended from the ideal trigonal bipyramidal to the square or rectangular bipyramidal geome- try and the compounds of pentacoordinated phosphorus, ar- senic and antimony are probably the most interesting [1-10]. In case of thioacetate secondary bonding takes place through chelation [2, 6, 7 ]. Another important group of ligand which has not attracted much attention, but closely resembles to car- boxylates, is aryl oxy acetates. However unlike acetate or thio- acetate, aryl oxy acetates has one extra donor site i.e.; ArO, in addition to the  C = O functionality. It is note worthy that despite such a great variety of structural possibility, as discussed above, exhibit by organom et. al carboxylates and the variety of metals for which such derivatives have been synthesized corresponding aryloxyace- tates are mainly confined to transition metal derivatives [11] with an occasional reference to organotin 12 and organo anti- mony [12, 13]derivatives. It has been found that etheral oxy- gen of aryloxyacetates group may or may not involve in co- ordination with metal atom and thus play a great role in shap- ing the geometry of the complex. A perusal of the literature further reveals that the complexes of aryloxyacetic acids in case of organotin possess intermolecular O → Sn co-ordination, particularly for alkyltin derivatives and the compounds are monomeric in solid state. In sharp contrast to this triaryltin derivative having penta coordination around the tin were found to be polymer with bridging carboxylic group [12]. Although the aryloxy acetate of organophospho- rous and little known but the compound containing P-O, Sb- O, As-O have been studied to an appreciable extent [14, 15]. On the basis of ultraviolet and infrared spectra it has been concluded that aryloxyacetate behave as monodentate legend toward antimony (V) but slight decrease in IR frequencies for carbonyl group indelicate toward secondary interaction. A comparison of spectral data of the organoantimony acetate with those of free legends both in solid state and in solution rules out the likelihood of co-ordination of antimony through etheral oxygen of the aryloxy group [9]. However, there seems to be no systematic and comparative study of aryloxyacetate derivative of antimony in +5 oxidation state as yet. In conclu- sion, in the solid state it indicates that sterically disfavored conformations of TBPY antimony (V) complexes may be stabi- lized by secondary bonding interaction involving diaxially co- ordinated ester legends. The complex geometry accompanied by the expansion of the co-ordination sphere from five to sev- en [23]. Continuing our interest in the carboxylate derivatives of group 15 elements [16, 20], a series of aryloxyacetate derivatives of the general formula Ph3 Sb(OCOCH2 OR) 2 and (p-MeO- C6 H4 ) 3 Sb(OCOCH2 OR) 2 and Ph4 Sb(OCOCH2 OR) [where R = substituted aryl group; p-CH3 C6 H4 m-CH3 C6 H4 – , O – CH3 C6 H4 – , b - C10 H7 -, O-Cl-C6 H4 ] has been synthesized and characterized. The main objectives of this work were aimed at: ———————————————— • Corresponding author is Dr. (Mrs.) Kiran Singhal, Associate Professor, Chemistry Department, University of Lucknow, Lucknow and is the thesis supervisor of Mr. Dharmendra K. Srivastava. • Email: singhal.kiran@gmail.com Ph: +91-9415159894 • Contract Grant Sponsor: University Grants Commission, New Delhi, India Vide Letter No. 37-429/2009 SR. • Dr. Prem Raj is Senior Professor Chemistry Departrment, Lucknow University, Lucknow, U. P., India. IJSER