Cis-Bis-(Alkyl, Aryv Or Diiodo Bis(Tri

THE PREPAHATION AND INVESTIGATION OF CIS-BIS-(ALKYL, ARYV OR DIIODO BIS(TRI PHENYLARSlNE) PLATINUM( II) COMPLEXES A Thesis Presented to the Graduate School Wisconsin State University La Crosse In Partial Fulfillment of the Requirements for the Degree Master of Science in Education by Jon D. Blackman August 1968 WISCONSIN STATE UNIVERSITY AT LA CROSSE GRADUATE SCHOOL Candidate: We recommend acceptance of this thesis to the Graduate College in partial fulfillment of this candidate's requirements for the degree of Master of Science. Thesis Committee Member t>- Date ;;:L4-4/ ~J Thesis Committee Member is approved for the Graduate College: 1.54890 _ TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION. • •• • • • •• • • • • • • •• •• • • • • • 1 II. HISTORICAL . · . • • 3 The Nature of the Olefin-Platinum Bond •• •• • • •• • • 3 Cyclic Polyolefin Platinum(II) Complexes and Their Reactions with Grignard Reagents • • •• • • • • • Stabilization of Aryl and Alkyl Platinum(II) Compounds with Tertiary Amines, Phosphines, Arsines and Stibines •• • • • •• • • • • • • • • •• • Reactions of Cyclooctatetraene Alkyl or Aryl Platinum(II) Complexes with Pyridine, Tri- phenylphosphine, Triphenylarsine and Triphenylstibine • • • • •• • • •• • • • • •• • ••• 6 III. EXPERIMENTAL • • • • • •• • • • •• • • •••• • • • • • 7 Analysis • • • • •• • • • • ••• • • • • • • • • •• • • 7 Supplied Chemicals • • • • • • •• • •• • • • • • • • • • 7 General Procedures •• • • •• • • • • • • •• • • • • •• 7 8 Preparation · .. • • • • • •• • • •• • • • •• • • • • Diiodo(cyclooctatetraene)Platinum(II) • •• ••• • • • 8 Alkyl and Aryl Derivatives of Cyclooctatetraene chelated Platinum(II) Complexes ••••••••••• 9 ~ -Cyclooctatetraene-bis-[bis-(methyl)-platinum(II)~. 11 ~ -Cyclooctatetraene-bis-Q?is-(phenyl)-platinum(II)]. 11 CHAPTER PAGE Cis-bis-(o-tolyl)(cyclooctatetraene)platinum(II) •• 11 Cis-bis-(m-tolyl)(cyclooctatetraene)platinum(II) •• 12 Cis-bis-(p-tolyl) (cyclooctatetraene)platinum(II) •• 12 Cis-bis-(triphenylarsine)Platinum(II) Aryl and Alkyl Derivatives ••••••••••••••• 13 Cis-bis-(methyl)bis-(triphenylarsine) platinum(II) * • 0 ••••••••• • • • • •• • 13 Cis-bis-(phenyl)bis-(triphenylarsine) platinum(II) •••••••••••• • • • • • • • Cis-bis-(o-tolyl)bis-(triphenylarsine) platinum(II) •••••••••••• •• • • • • • 14 Cis-bis-(m-tolyl)bis-(triphenylarsine) platinum(II} •••••••••••• • • • ••• • 15 Cis-bis-(p-tolyl)bis-(triphenylarsine) platinum.( II) ••••••••• •• • • • • • • • • 15 Cis-(diiodo}bis-(triphenylarsine)platinum(II) ••• 16 IV. RESULTS AND DISCUSSION ••••••••••• ••••••• 17 Stabilization of Bis(al~!l, aryJ)or diiodo Platinum(II) Complexes with Triphenylarsine ••• ••••••••• 17 Stabilization of the Series of Bis{alkyl, ary~ or diiodo Platinum(II) Complexes with Pyridine, Triphenyl phosphine, Triphenylarsine and Triphenylstibine •••• 18 CHAPTER PAGE Identification of the Bis(a1ky1, aryl) or diiodo Bis(triphenylarsine) Platinum(II) Complexes •••••• 19 BIBLIOORAPHY .... ••••••••••••••••••••••• 22 APPENDIX A ••• •••••••••••••••••••••• 23 APPENDIX B ••• •• •••••••••• 24 LIST OF FIGURES FIGURE PAGE 1. The Platinum-Olefin Bond •••••• ••••••• 3 2. Diiodo(cyclooctatetraene)platinum(II) ••••••••••• L 3. Bridged Structure ••••••••••••••••••••• it L. Inverse Grignard Apparatus ••••••••••••••••• 9 CHAPTER I INTRODUCTION Chatt and Shaw have reported the stabilisation of alkyl and aryl platinum(II) complexes with tertiaryphosphines and trialkylarsine& They reported that any ligand capable of producing a large crystal field splitting in the platinum(II) ion should similarly stabilize alkyl and aryl platinum(II) complexes. Also, it was reported that there was a difference in the stability of the o-substituted and p-substituted aryl phosphine derivatives.l ,2 Kistner andco-wom:rs have found that alkyl and aryl cyclicpoly olefin platinum(II) complexes react with pyridine and triphenylphosphine to give the corresponding pyridine and triphenylphosphine derivatives. They found that the triphenylphosphine derivatives have greater thermal stability than the corresponding pyridine derivatives.) Michaels and Kistner found that the bis(o-tolyl) platinum(II) triphenylarsine derivative is more stable than the corresponding pyridine and triphenylphosphine derivatives.Q Harris and Kistner reported the aryl and alkyl platinum(II) triphenylstibine derivatives. They reported a different trend in thermal stability for the triphenylstibine complexes.5 The following work was conducted to extend the study of the sta bilization of alkyl and aryl platinum(II) complexes with triphenylarsines and to further study the trends of stability in the series of pyridine, 2 triphenylphosphine, triphenylarsine and triphenylstibine alkyl or aryl platinum(II) complexes. .'-'- CHAPTER II HISTORICAL The Nature ~ ~ Olefin-Platinum ~. 6 Zeise reported the first platinum-olefin compound in 1821. Chatt's work led to a description of the nature of the platinum- olefin bond. He reported that there must be some sort of interaction of the d-orbitals besides the coordinate d-pi bond.7,8 It is proposed that a 5d6s6p2 hybrid orbital of the platinum ion overlaps the pi bond of the olefin forming a d-pi, sigma type bond. The additional interaction is a backband that is formed from the pi antibonding molecular orbitals of the olefin with a filled 5d orbital of the platinum ion. The double bond of --- the olefin is therefore most favorably oriented perpendicular to the plane of the square planar molecule. (See Figure 1.) a~4--'(- 5d orbital c '.:> PT\) (] C o 5d6s6p2 hybrid orbital FIGURE 1 THE PLATINUM-OLEFIN BOND -- L Cylic Polyolefin Platinum(II) Complexes and Their Reactions with Grignard Reagents. Jensen reported the preparation of diiodo(cyclooctatetraene)pla q tinum(II) and proposed a "tub" conformation for the cyclooctatetraene.' This "tub" conformation was reported by Karle10 and this orientation allows the double bonds of the olefin to arrange themselves in a favorable position to coordinate with the platinum. (Bee Figure 2.) FIGURE 2 DIIODO(CYCLOOOTATETRAENE)PLATINUM(II)' Binuclear methyl and phenyl platinum(II) cyclooctatetraene compounds were reported by Doyle and co-workers and a bridged structure was proposed.ll (See Figure 3.) FIGURE 3 BRIDGED STRUCTURE These were prepared by the reaction of diiodo(cyclooctatetraene)pla tinum( II) with methyl or phenyl Grignard reagents according to the equation: 2C8H8PtI2 + 4RMgI ~ R2PtC8HBPtR2 + CaHa + ltMgI2 R-Me or Ph Kistner and co-workers expanded the work done in this area and prepared other alkyl or aryl cyclooctatetraene platinum(IL) derivatives. Within the aryl series, the order of kinetic stability was shown to be l-napthyl .> o-tolyl >phenyl >p-tolyl. Investigation also showed that products containing aryl groups have greater stability than those that contain alkyl groups, with the exception of the methyl derivatives.) A similar sequence has also been noted2,l2 in the aryl series of platinum compounds containing substituted phosphines. Chatt credited the stability of the o-substituted aryl derivatives over the p-substituted aryl derivatives as being due to the orbital interaction of the sterically hindered rotation of the parallel rings. Stabilization .2! !!2! and Alkyl Platinum(II) Compounds ~ Tertiary Amines, Phosphines, Arsines and Stibines. Since most organo-platinum compounds were relatively unstable, Chatt reported the use of tertiary amines, phosphines and arsines to stabilize them. Chatt stated that the ligands create a strong enough crystal field splitting to stabilize the platinum(II) alkyl and aryl complexes. For example, as the ligands approach the x and y axis, the dx2-i- orbitals of the metal ion are elevated to a higher energy level 6 by electron repulsion and consequently the other d atomic orbitals fall 1 2 to lower levels. ' Kistner found that the phosphine derivatives were more stable thermally than the corresponding pyridine derivatives.3 Michaels pre pared cis-bis-(o-tolyl)bis-(triphenylarsine}platinum(II) and found it to have a higher decomposition point than the corresponding pyridine and phosphine derivatives.4 Harris, in the Research and Seminar course at Wisconsin State University La Crosse, reported aryl or alkyl triphenyl stibine platinum(II) complexes and found their decomposition points to be higher than the corresponding pyridine and phosphine compoun~s. He found the order of kinetic stability, within the aryl series, to be different from that established by Chatt and Kistner.' Reactions of Cyclooctatetraene Alkyl .2!: ~ Platinum(II) COmplexes with Pyridine, Triphenylphosphine, Triphenylarsine !E2 Triphenylstibine. Doyle and co-workers reported a general method for the pyridine and triphenylphosphine reactions as shown below.ll (Olefin)PtR2 + 2 Ligands~(Ligand)2PtR2 + Olefin R-Alkyl or Aryl Groups Michaels reported the o-tolyl triphenylarsine derivative, which was prepared by the same method. He attempted, but did not isolate the m-tolyl-arsine complex.4 Harris, also using the same method, reported the methyl, phenyl, o-tolyl, m-tolyl and p-tolyl derivatives of triphenylstibine.' CHAPTER III EXPERIMENTAL I. ANALYSIS The infra-red analyses are carried out using a Perkins-Elmer, #137 Infra-red Spectrophotometer. All spectra of the solid products are analyzed in KBr pellets. The Thomas Micro Carbon-Hydrogen Analyzer, model 35, is used in determining carbon-hydrogen analyses. II. SUPPLIED CHEMICALS The olefin, cyclooctatetraene (OsHa) is obtained from Chemical Intermediates and Research, Cuyahoga Falls, IDhio • ...;,;,;;.....;;..,;;,.;;.;;,;;.;;;;.,;;;,,;~..;;.;;.

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