THERMODYNAMIC VS SUPRAMOLECULAR EFFECTS IN THE REGIOCONTROL OF THE FORMATION OF NEW CYCLOTRIPHOSPHAZENE-CONTAINING CHIRAL LIGANDS WITH 1,1'-BINAPHTHYL UNITS - SPIRO VS ANSA SUBSTITUTION AT THE N3P3 RING

Synthesis of new cyclophosphazene-containing chiral ligands (6-9) with 1, 1'-binaphthyl units has been achieved by stepwise dicyclosubstitut ion of hexachlorocyclotriphosphazene (1), with two sodium cation paire d dinucleophiles derived from bis-beta-naphthol (2) and tetraethylene glycol (3). The structures of the disubstitution products have been fo und to be addition order-dependent. In particular, the substitution pa ttern of the 1, 1'-binaphthalene-2, 2'-dioxy substituent in the N3P3 r ing [spiro (4 --> 6, 7) or ansa (8, 9)] was related to whether or not the crown substituent had been incorporated into 1 beforehand. Additio n of the phase transfer catalyst reagent, tetrabutylammonium bromide, to the reaction mixture of 5 + 2-Na-2 led to the parallel formation of both the spiro 6 and ansa 8 isomers. Spiro vs ansa regioisomerism of the binaphthalenedioxy derivatives formed is discussed in terms of the contributions of the respective thermodynamic and supramolecular effe cts to the regiocontrol of substitution in the N3P3 ring. It is found that there are two main factors determining the orientation of the bin aphthalenedioxy substitutent incoming to the N3P3 ring: the thermodyna mic stability of seven-membered spirocycles at the P-atoms and the cro wn-related cation assistance of the ansa substitution at the macrocycl e bearing P-atoms; the regiocontrol resulting from the supramolecular effects predominates, whenever possible. The structures of compounds 7 -9 were proven by X-ray crystallography. The metal cation complexing p roperties of compounds 6-9 were compared by a simple TLC method. The r esults show that the complexing properties of the chiral binaphthalene dioxy-containing PNP-crown ligands 6-9 toward alkali metal and silver cations are either similar (spiro-ansa derivative 6) or enhanced (bis- ansa derivatives 7-9) with respect to the parent tetrachloro PNP-crown 5.