TETRAHEDRON: ASYMMETRY Tetrahedron: Asymmetry 11 (2000) 3535–3541 Pergamon Efficient enantiorecognition of ruthenium(II) complexes by silica-bound teicoplanin Francesco Gasparrini, a Ilaria D’Acquarica, a Johannes G. Vos, b, * Christine M. O’Connor b and Claudio Villani c, * a Dipartimento di Studi di Chimica e Tecnologia delle Sostanze Biologicamente Attive, Universita ` di Roma, P.le A. Moro 5, 00185 Rome, Italy b Inorganic Chemistry Research Centre, School of Chemical Sciences, Dublin City University, Dublin 9, Ireland c Dipartimento di Scienze del Farmaco, Universita ` di Chieti, Via dei Vestini 31, 66013 Chieti, Italy Received 28 June 2000; accepted 25 July 2000 Abstract A series of chiral tris-diimine ruthenium(II) complexes have been resolved by HPLC on a chiral stationary phase. The stationary phase (CSP1) was prepared by covalent attachment of the glycopeptide antibiotic teicoplanin to isocyanate activated silica gel. CSP1 selectively retains the enantiomers of [Ru(L) 3 ] 2+ (L=2,2-bypyridine (bpy), 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline), with a preference for the  isomer. For the mixed-ligand complexes [Ru(bpy) 2 pztr] + and [Ru(bpy) 2 pytr] + (Hpztr=3-(pyrazin-2-yl)-1,2,4-triazole, Hpytr=3-(pyridin-2-yl)-1,2,4-triazole), where the triazole unit is bound to the metal centre either through the N 2 or the N 4 nitrogen of the ring, CSP1 discriminates both the enantiomers and the regioisomers. Diastereo- and enantioselective association was also observed between CSP1 and the stereoisomers of the dinuclear complex ((Ru(bpy) 2 ) 2 bpt] 3+ (Hbpt=3,5-bis(pyridin- 2-yl)-1,2,4-triazole), with differences in binding affinities of 1.4 kJ/mol between the homochiral enan- tiomers. © 2000 Elsevier Science Ltd. All rights reserved. 1. Introduction Transition metal complexes with polycyclic heteroaromatics have been extensively studied for their unique photochemical, photophysical and molecular recognition properties. 1–4 Enantioselective interactions are often observed between these chiral transition metal com- plexes and organized biological media, such as nucleic acids or oligonucleotides. The well defined, stereostable three-dimensional structure and the emissive properties of chiral tris- chelated metal complexes make them powerful tools in the elucidation of structural require- ments, energetics and dynamics of DNA recognition. * Corresponding authors. Tel: 003908713555262; fax: 00390649912780 (C.V.); e-mails: han.vos@dcu.ie; villani@ unich.it 0957-4166/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved. PII:S0957-4166(00)00292-5