GOLD(I) PHOSPHINE COMPLEXES AND THEIR POTENTIAL APPLICATION AS ANTI-TUMOUR AGENTS A dissertation submitted in fulfillment of the requirements of the degree of Master of Science MESSAI A. MAMO, B.Sc. (Hons.) School of Chemistry Faculty of Science University of the Witwatersrand February 2005 Abstract The monodentate phosphine complexes bui3PMX (2a: M = Cu, X = Cl, 2b: M = Cu, X = I, 2c: M = Ag, X = Cl, 2d: M = Au, X = Cl) were synthesised in high yields from bui3P and MX. Their reaction with [Li{?-N(R)C(but)C(H)R}]2 (R = SiMe3) gave the monomeric complexes bui3PCuN(R)C(but)=C(H)R (3a) and bui3PMC(H)RC(but)=NR (3b: M = Ag, 3c: M = Au) in moderate to high yields. The bonding mode in the 1-aza- allyl complexes 3a-c was found to depend strongly on the metal ion, with 3a being an enamide complex and 3b and 3c iminoalkyl complexes. The reaction of bidentate ligand dpmaaH2 (2,3-bis(diphenylphosphino)maleic acid) with R2Sn-precursors led to novel dialkyl tin dpmaa complexes (R2Sn)(O,O dpmaa) (6) (where 6a, R = Me; 6b, R = Bu) were synthesized. Complexation of the tin/phosphine complexes led to the heterobimetallic complexes {Au[(dpmaaO,O)(SnR2)]2}Cl (7a and 8a) {Au[(dpmaaO,O)(SnR2)][dpmaaH2]}Cl (7b and 8b) (where 7a and 8a, R = Me; 7b and 8b, R = Bu) and the mixed metal complexes {Au[(dpmaaO,O)(RuCl)]2}Cl (9a) {Au[(dpmaaO,O)(SnBu2)(dpmaaO,O)RuCl)]}Cl (9b) and {Au[(dpmaaO,O)(RuCl)][dpmaa]}Cl (9c). All compounds were fully characterised by multinuclear NMR spectroscopy and microanalysis (not 3a, 3b, 4 and 5) solid state IR spectroscopy (KBr-pellets) (4-9) and mass spectrometry (6-8). The solid state structures of complexes 2c, 2d, 3c, 6a and 6b (two polymorphs) have been determined by X-ray crystallography revealing the presence of rare trimeric macrocycles in the case of 6a and 6b. The anti-tumour activity of the metal complexes (6b and 7-9) was tested on a single cell- line (except 7a and 8a which were on eight cell-lines) and their activity was compared to cisplatin. ii Declaration I declare that this dissertation is my own, unaided work submitted for the degree of Master of Science in the University of the Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination in any other university. ?Messai A. Mamo?? (Name of Candidate) 18 day of February, 2005 iii Acknowledgements First and foremost I would like to give special thanks to my supervisors Dr. Marcus Layh and Dr. Richard J. Bowen for their help and guidance during the course of this research. It is also have the pleasure to acknowledge the assistance of the following people who have been kind enough to me in one way or other throughout this project; Manuel Frenandes for solving all the crystal structures in this project, Richard Mampa, the entire Inorganic Lab. occupants (B. Omondi, P. W. Gitari, Dr. J. Caddy, Dr. E. M. Coyanis, E. Kriel, S. D. Khanye), for the warm atmosphere they provided which made working in the laboratory enjoyable. Finally I would also like to thank the School of Chemistry for allowing me undertaking studies for a M.Sc. degree and Mintek for a scholarship. iv Table of contents Heading Page 1.0 Gold compounds as anti tumour agents 2 1.1 Early development 2 1.2 Relationship between structure and anti cancer activity 3 1.3 Mode of action 5 1.4 Recent development 6 1.4.1 Cationic anti tumour drugs 6 1.4.2 Lipophilicity, selectivity and anti tumour activity 8 1.4.3 Development of [Au(P-P)2]+type lipophilic cations anti tumour agents 9 1.4.4 Tin compounds as anti tumour agents 11 1.4.5 Ruthenium compounds as anti tumour agents 13 1.5 Mixed metal complexes of gold(I)/tin(IV) and gold(I)/ruthenium(III) 15 1.6 Objectives of the project 15 1.7 List of references 17 2.0 Results and discussion of 1-azaallyl complexes 22 2.1 Introduction 22 2.1.1 General methods of preparation of 1-azaallyl metal complexes 24 2.2 Synthesis 25 2.3 NMR-spectroscopic studies and solution behavior 26 2.4 Solid state structures of complexes 2c, 2d and 3c 28 2.4.1 Introduction 28 2.4.2 Crystal structure of compound 2c 29 2.4.3 Crystal structure of compound 2d 30 2.4.4 Crystal structure of compound 3c 32 2.5 List of references 34 v 3.0 Results and discussion of Tin Complexes 37 3.1 Synthesis of 2,3-bis(diphenylphosphino)maleic anhydride (dpma) 37 3.2 Synthesis of ClAuSMe2 38 3.3 Tin complexes 39 3.3.1 Synthesis of tin complexes 39 3.3.2 Spectroscopic studies 41 3.3.2.1 IR spectroscopy studies 41 3.3.2.2 NMR spectroscopy studies 42 3.3.3 Solid state structure 46 3.3.3.1 Crystallographic studies of 6 46 3.3.3.2 Crystal structure of [Au+(dpmaaH2)(dpmaaH-)] 52 3.4 List of references 56 4.0 Biological tests on selected compounds 58 4.1 Introduction 58 4.2 Results and Discussions 58 4.3 List of references 61 5.0 Conclusions 62 6.0 Experimental 64 6.1 General procedures 64 6.2 Synthesis 67 6.2.1 Preparation of finely divided gold powder 67 6.2.2 Synthesis of ClAuSMe2 67 6.2.3 Synthesis of buiPCuCl (2a) 67 6.2.4 Synthesis of buiPCuI (2b) 68 6.2.5 Synthesis of buiPAgCl (2c) 68 6.2.6 Synthesis of buiPAuCl (2d) 69 6.2.7 Synthesis of [buiPCuN(R)C(but)=CHR] (3a) 69 vi 6.2.8 Synthesis of [buiPAgCH(R)C(but)=NR] (3b) 70 6.2.9 Synthesis of [buiPAuCH(R)C(but)=NR] (3c) 70 6.2.10 Synthesis of Ph2PSiMe3 71 6.2.11 Synthesis of 2,3-bis(diphenylphosphino)maleic anhydride (dpma) 71 6.2.12 Synthesis of 2,3-bis(diphenylphosphino)maleic acid (dpmaaH2)?2Et2O (4) 72 6.2.13 Synthesis of [Au(dpmaa)2Cl?2thf] (5) 72 6.2.14 Synthesis of [(Me2Sn)(O,O dpmaa)] (6a) 73 6.2.15 Synthesis of [(Bu2Sn)(O,O dpmaa)] (6b) 73 6.2.16 Synthesis of{Au[(dpmaaO,O)(SnMe2)]2}Cl?H2O?Et2O (7a) 74 6.2.17 Synthesis of {Au[(dpmaaO,O) SnBu2]2}Cl (7b) 75 6.2.18 Synthesis of {Au[(dpmaaO,O)(SnMe2)][dpmaaH2]}Cl?Et2O(0.5) (8a) 76 6.2.19 Synthesis of {Au[(dpmaaO,O)(SnBu2)][dpmaaH2]}Cl?Et2O (8b) 76 6.2.20 Synthesis of {Au[(dpmaaO,O)(RuCl)]2}Cl (9a) 77 6.2.21 Synthesis of {Au[(dpmaaO,O)(SnBu2)(dpmaaO,O)RuCl)]}Cl?(H2O)2 ?(NEt3)1.5 (9b) 77 6.2.22 Synthesis of {Au[(dpmaaO,O)(RuCl)][dpmaaH2]}Cl (9c) 78 6.2.23 General method for Cytotoxicity assay 78 6.3 List of references 79 vii List of Tables Table Page 1. Selected NMR-spectroscopic data of 1-azaallyl metal complexes 26 2. Selected bond distances and angles for compound 2c 29 3. Selected bond distances and angles for compound 2d 31 4. Selected bond distances and angles for compound 3c 32 5. IR spectroscopic data of complexes 4 ? 8 41 6. NMR spectroscopy data at room temperature 4 ? 8 42 7. Selected bond lengths and angles for 6a and 6b 50 8. Selected bond lengths and angles for [Au(dpmaaH2)(dpmaaH)] 54 9. Hydrogen bonds distances and angles for [Au(dpmaaH2)(dpmaaH)] 55 10. IC50 values of the complexes 6a, 5 - 9 59 11. IR and NMR spectroscopic data of complexes 9 81 List of Figures Figure Page 1 Molecular structure of [bui3PAgCl]4 2c 29 2a. Molecular structure of bui3PAuCl 2d 30 2b. Molecular structure of bui3PAuCl, CH???Cl contacts 31 3 Molecular structure of bui3PAuLL? 3c 32 4 31P NMR of (Bu2Sn)(O,O dpmaa) at room temperature 43 5. P-XRD diffraction of (Bu2Sn)(O,O dpmaa) and dpmaaH2 44 6 31P NMR of complex 3b (Bu2Sn)(O,O dpmaa) at variable temperature 45 7. Molecular structure of (Me2Sn)(O,O dpmaa) (6a). 47 8a. Molecular structure of (Bu2Sn)(O,O dpmaa) (6b) polymorph 1 48 8b. Molecular structure of (Bu2Sn)(O,O dpmaa) (6b) polymorph 2 49 9. Molecular structure of [Au(dpmaaH2)(dpmaaH)] 59 10. H-bonding pattern of [Au(dpmaaH2)(dpmaaH)] in the solid state 55 viii Appendices Appendix Page A1. Mixed gold, tin and Ruthenium Complexes 80 A2. Crystal data and summary of data collection and refinement for compound for 2c, 2d and 3d 83 A3. Comprehensive crystallographic data for compound 2c 84 A4. Comprehensive crystallographic data for compound 2d 89 A5. Comprehensive crystallographic data for compound 3c 90 A6. Crystal data and summary of data collection and refinement for compound 6a, 6b (polymorph 1 and 2) and [Au(dpmaaH2)(dpmaaH)] 93 A7. Comprehensive crystallographic data for compound 6 94 A8. Comprehensive crystallographic data for Compound [Au (dpmaaH2)(dpmaaH)] 113 ix Abbreviations ? 1H NMR Proton Nuclear Magnetic Resonance ? 13C NMR 13 carbon isotope Nuclear Magnetic Resonance ? 31P NMR 31 Phosphorous Nuclear Magnetic Resonance ? 119 Sn NMR 119 tin isotope Nuclear Magnetic Resonance ? Bui iso butyl ? Bun normal butyl ? But tertiary butyl ? C6D6 deuterated benzene ? CDCl3 deuterated chloroform ? Cell lines 1. HCF-7 Breast carcinoma cells 2. A2780 Human ovarian carcinomia cels 3. A2780cis Human ovarian carcinomia cisplatin-sensitive sub line 4. COLO colon cancer cells 5. Hela cervical carcinoma cells 6. MCF-12A breast non-tumourogenic cells 7. B16 mouse melanoma 8. Fibroblasts primary human fibroblasts cells ? d2pype 2- pyridylphosphine ? d3pype 3- pyridylphosphine ? d4pype 4- pyridylphosphine ? d6-DMSO deuterated dimethyl sulphoxide ? depe Et2P(CH2)2PEt2 ? dme dimethoxyethane ? dpmaa 2,3-bis(diphenylphosphino)maleic acid ? dpma 2,3-bis(diphenylphosphino)maleic anhydride ? dppe 1,2-bis(diphenylphosphino)ethane ? dppey cis-1,2-bis(diphenylphosphino)ethylene ? DMSO dimethyl sulphoxide ? Et ethyl ? IR Infrared 1. b, broad 2. s, strong 3. m, medium 4. w, weak ? K Kelvin scale for Temperature (0K = -273.150C) ? LL? CH(SiMe3)(but)NSiMe3 ? mV millivolt ? Me methyl ? MHz Mega Hertz x ? NMR 1. d, dublet 2. dd, doublet of doublet 3. m, multiplet 4. s, singlet 5. bs, broad line ? ppm part per million ? P-XRD Powder X-ray Diffraction ? RT room temperature ? thf tetrahydrofuran ? TPA 1,3,5-triaza-7-phosphaadamantane ? XRD X-ray Diffraction ? 0C Degree Celsius xi