This dissertation has been 65—3852 microfilmed exactly as received FARONA, Michael Franklin, 1935— THIOCYANATO DERIVATrVES OF SOME METAL CARBONYLS. The Ohio State University, Ph.D., 1964 Chemistry, inorganic University Microfilms, Inc., Ann Arbor, Michigan THIOCYANATO DERIVATIVES OF SOME METAL CARBONYLS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Michael Franklin Farona, B.S., M ‘.Sc. ****** The Ohio State University 1964 Approved by Department of Chemistry ACKNOWLEDGMENTS The author is extremely grateful to his adviser^ Dr. Andrew Wojcicki^ not only for the suggestion of such- an interesting and productive project hut also for his invaluable guidance throughout the course of this research and in the preparation of this manuscript. The author is also appreciative of the funds received from Dr. Wojcicki's National Science Foundation grant. The Department of Chemistry is gratefully acknowledged by the author for salaries received through various teaching assistantships. Finally3 the author is appreciative of the patience and understanding of his wife, Jean. He is also indebted to her for her help in preparing the first draft of this dissertation. VITA January 30, 1935 . B o m - Cleveland, Ohio 1 9 5 6 .............. B.S., Western Reserve University, Cleveland, Ohio 1 9 5 8.......... Military Service, U.S. Army Medical Corps 1 9 5 9 -1 9 6 2 ........ Teaching Assistant, Department of Chemistry, The Ohio State University, Columbus, Ohio 1 9 6 3-1 9 6^ - ....... Research Fellow, Department of Chemistry, The Ohio State University, Columbus, Ohio PUBLICATIONS Farona, M. F., Sweet, T. R., and MacNevin, W. M., "A Chemical Investigation of the Lamprey Eel Venom." Arch. Biochem. Biophys. 9 8, 245 (1962). Gray, H. B., Billig, E., Wojcicki, A., and Farona, M. F., "The Electronic Structures and Reactivities of Mn(C0)j-X Complexes." Can. J. Chem. 4l, 1281 (19&3)* Wojcicki, A., and Farona, M. F., "Thiocyanato-S-penta- carbonylmanganese (I) and Some Derivatives." Inorg. Chem. 3, 151 (1964). Wojcicki, A., and Farona, M. F., "Thiocyanato Derivatives of Chromium, Molybdenum and Tungsten Hexacarbonyls." J. Inorg. Nucl. Chem., In press. FIELDS OF STUDY Major Field: Chemistry Studies in Inorganic Chemistry.' Professor Andrew Wojcicki Studies in Analytical Chemistry. Professor Thomas R. Sweet CONTENTS Page INTRODUCTION.................. '--- 1 HISTORICAL ......................... 3 EXPERIMENTAL....................................... 27 Starting Materials ............................... '27 Elemental Analyses and Physical Measurements ..... 34 Preparation of Mn(C0)5CNS ........................ 36 Attempted Preparations of Mn(CO)cSCN ............. 38 Preparation of the Derivatives or Mn(CO)cCNS ..... 42 Special Preparations of Some Derivatives ......... 59 Attempted Preparation of [Mn(CO)^CNS]o ........... 6l Preparation of the Thiocyanato Derivatives of the Group VIb Hexacarbonyls ........................ 62 Attempted Preparations of Fe(C0)i|(CNS)2 .......... 64 RESULTS AND DISCUSSION ............................. 68 Investigation of the Mn(CO)cCNS System........... 68 Investigation of the Derivatives of the Mh(C0)5CNS System .............................. 107 The Significance of the Metathesis Reactions ..... 131 Linkage Isomerism in the Derivatives ............. 131 Thiocyanato Derivatives of the Group VIb Hexacarbonyls .................................. 135 Investigation of the Thiocyanato Iron Carbonyl System............................... •......... l40 BIBLIOGRAPHY ....................................... 142 TABLES Table Page 1. X-Ray Structures of Thlocyanate Complexes ..... 4 2. Infrared Frequencies (cm-1) of Thiocyanate Group ....................................... 8 3. Analysis of the Derivatives of Mn(COLONS .... 60 4. Infrared Carbonyl Stretching Frequency Region of Mn(CO)^SCN in Various Media .............. 75 5. Comparison of the CO Stretching Frequencies of Mn(CO)^X Complexes ..... 83 6. The CS Stretching Frequency of Mh(CO)cCNS in Various Solvents ............................ 87 7. Change in Band Intensities with Rising Temperature ................................. 88 8. Approximate Secular Equations for the CO Stretching Modes in the Point Group Cij.v ..... 102 9 . Force Constants (mdynes/A) for Mn(C0)i-X Complexes ............................... 103 10. The A 1 (1) Stretching Modes and Values for MoL(CO)^ Molecules ............................ 106 11. Infrared Spectra of cis-[Mn(C0 )3L2 CNS] Complexes (cm-1) ............................ 113 12. Infrared Spectra of trans-[Mh(C0 )oL2 CNS] Complexes (cm-1) ............................ 118 1 3 . Infrared Spectra of Mh(C0)iiLCNS Complexes (cm-1) ...................................... 121 14. Infrared Spectra of (CH3 )aj.N[M(C0 )^CNS] (cm-1) .. 138 v FIGURES Figure Page I 1. The Carbonyl and CS Stretching Frequency Regions of the Infrared Spectrum of Mn(CO)5CNS ................................... 74 2. The Carbonyl and CS Stretching Frequency Regions of the Infrared Spectrum of Mn^CO^CNS in Acetonitrile ........... 7 8 3. Infrared Spectra of the Carbonyl Stretching Frequency Region Showing the Initial, Intermediate, and Final Bands of the Rearranging Mn(C0 )t5CNS In Acetonitrile ...... 85 4. The Carbonyl Stretching Frequency Region of the Infrared Spectra of Mh(CO)trCNS at Different Temperatures in Ethyl Acetate ..... 89 5. The Carbonyl Stretching Frequency Region of the Infrared Spectra of Mh(CO)cCNS in CH3CN at Different Temperatures ............. 91 6 . Assignment of the CO and CN Bands of Mn(C0 )5CNS in 1 ,2 -dichloroethane ............ 95 7. The Carbonyl and CS Stretching Frequency Regions of the Infrared Spectrum of Mn(C0)3py2CNS ................................. 114 8. The Carbonyl and CS Stretching Frequency Regions of the Infrared Spectrum of Mn(CO)3 (pfa)2CNS .............................. 115 9. The Carbonyl Stretching Frequency Region of the Infrared Spectrum of trans- .[Mn(CO)3 (AsPh3 )2 CNS] in CHCI3 ................ 1 2 -9 10. The Carbonyl Stretching Frequency Region of the Infrared Spectrum of Mn(CO)wAsPhoCNS in CHC1 3 ...... 7 ... 7 ......... 122 11. The Carbonyl Stretching Frequency Regions of the Infrared Spectra of Mh(COKAsPhqCNS in CHC13 and C H g C N ............. 7 .... 133 12. The Carbonyl and CS Stretching Frequency Regions of the Infrared Spectrum of (CH3 )4N[W(CO)5CNS] ............................ 1 39 vi INTRODUCTION Thiocyanato complexes of intermediate oxidation state transition metals have been studied extensively. The fact that so much work has been done on these systems is not surprising because as a ligand, thiocyanate ion is a very interesting species. For example* it is one of the few monodentate ligands which can coordinate to metal ions in one of three different ways. Thiocyanate ion may bond through either the sulfur or nitrogen ends, or bond simultaneously through both ends when it acts as a bridge between two metal ions. Although much time has been spent on synthesis, the truly interesting features of these complexes have been elucidated by means of various physical methods. For example, the purpose of the majority of the work has been to determine the mode of attachment of the thiocyanato group, and to apply modern theories of bonding to examine the factors which influence this attachment.. Until the work of this thesis was undertaken, no attempt had been reported to prepare and examine thiocyanate derivatives of low oxidation state transition metals. In particular, it has been the purpose of this work to 1 synthesize and characterize thiocyanato derivatives of some metal carbonyls. These systems were expected to be analogous in part to the known metal carbonyl halides. It was* then* of great interest to have compared and contrasted the results of this investigation with those of the corresponding carbonyl halides and the known thiocyanato complexes. HISTORICAL The thiocyanate ion is known to coordinate to transition metal ions in one of three different ways; through either the sulfur or nitrogen ends or as a bridge between two metal ions, when the sulfur and nitrogen ends coordinate simultaneously. These data have been supported by X-ray studies for the three modes of attachment. (l)3 (2), (3 )5 (^) Table 1 (1) shows some terminal thiocyanato complexes whose structures have been determined by X-ray analysis. Certain facts are noticed immediately from the table. For example, the only listed thiocyanato complexes which are N-bonded are those of the first row transition metals. The table also shows that the S-bonded complexes are those of the second and third row transition metals. This table is not complete and the above assignments do not represent strict conclusions. For example, although essentially all first row transition metals bond only 1 through nitrogen of terminal SCN groups, the second and third row metals may in some instances bond through Two exceptions have been found for Co(III) which bonds a terminal thiocyanato group through sulfur. The first example is in the vitamin Bto complex (5) and the second example is in the complex K^Co^CNj^SCN. (6) TABLE 1 X-RAY STRUCTURES OF THIOCYANATE COMPLEXES Stereochemistry Arrangement of (CNS) Compound of Central Atom Groups in Complex Ion Isothiopyanates [Cr(NH3 )2 (NCS)4 ]- Octahedral Co-planar, M-NC co-linear [Ni(NH3 )2 (NCS)4]2" Octahedral Co-planar, M-NC co-linear [Ni(NH3 )3(NCS)3r Octahedral M-NC co-linear [Ni(NH3 )4 (NCS)2] Octahedral trans-, M-NC co-linear [Nipy4 (NCS)2