310
JOHN
K.
J O YA N D ~ ~ I L T OORCI-IIN N
ITol. s1
Anal. Calcd.: C, 23.1; I{, 1.70; N, 3.37. Found: C , 0.01 molar anhydrous alcoholic hytlrochloric acid over the 23.7; 13, 2.02; N, 3.15. appropriate portion of t h e spectrum. A solution of the nlefinic reagent in 0.01 molar alcotiolic hydrnchlrn-ic acid W;I? 1,3-Bis-(4-nitrostyrene)-2,4-dichloro-fi-dichlorodiplatinum. -This compound was prepared in the same nianuer as the made from freshly distilled material,'4 usually on the clay hefore a run was ride. N o dilificulties were encountered froiii 3-nitrostyrene complex. The product was a yelloxv-orange polymerization of the styrenes. However, these srilution.: powder which decomposed above 160', without melting. checked to ensure that the absorbances were constant Anal. Calcd.: C , 23.1; H, 1.70; IC,3.37. Found: C, were from the time t h a t they were prepared until they were u s r d . 22.4; H, 1.67; N, 2.81. X solution of the freshly crystallized complex, usually 4 .O 1,3-Bis- (3-chlorostyrene) -2,4-dichloro-p-dichlorodipla- X molar, in 0.01 molar alcoholic hydrochloric acid, was tinurn.-This complex TWS prepared in the same manner as made just before a run was started. Xliquots of 5 ml. of this the styrene complex. The product w L i 5 a light orange powsdution were pipetted into five 50-1111. volumetric flasks. der which decomposed above 130°, nithout melting Aliquots of the olefin solution were added to the flasks in Anal. Calcd.: C , 23.3; H, 1.71. Found: C, 23.1; 11, progressing rolumc. Thus, when the flasks were brought to 2.08. volume, the total complex concentration was 4.0 X 1,3-Bis-(4-methylstyrene) -2,4-dichloro-fic-dichlorodiplat- molar in each case, whereas the total olefin concentrati~~ii inurn.-This compound was prepared, in toluene solution, varied over a rather wide range. Xs soon as the volutnc i i i each flask had been brought to 50 ml. with 0.01 nivlar :ilin the same manner as the 3-nitrostyrene complex. The prodcoholic hydrochloric acid, a sample was removed and its uct was a n orange pnmler which decomposed above 165', absorbance was measured in the spectrophotometer, tlierwithout melting. a t 25'. The flask was then suspended in a COIIAnal. Calcd.: C, 25.2; €1, 2.62. r o u n d : C, 09.2; €1, rnostated stant temperature bath at 25' for 1-2 hr. .-Isecond set of 2.91. measurements then was recorded. These usually differed 1,3-Bis- (I-dodecene) -2,4-dichloro-~-dichlorodiplatinum .very slightly from the initial readings, indicating that equilibOne millimole of ethylene platinous chloride 1% AS dissolved rium had been attained in the few minutes required to ptein the minimum volume of warm acetone. Two millimoles pare the snlutions. Absorbance measurements were takcii of 1-dodecene was added and the solution was warmed until a t two or three wave lengths as a check, althougli it wns nrcese\ olution of ethylene stopped. A large volume of petroleum sary to use only one value to determine the conccntratioiis of ether was added and the solution was boiled to reduce volall coniponrnts in equilibrium. ume, after which i t was cooled t o promote crystallimtioii. Acknowledgments.-This research was supT h e product was filtered and recrystallized from petroleum ether, yielding a pink-orange material having a soapy con- ported by a grant from the Petroleum Research sistency, m.p. 73-74', Tiitli deepening of color b u t no ap- Fund administered by the American Chemical Soparent decomposition. ciety. Grateful acknowledgment is hereby made ' l n a l . Calcd.: C, 33.2; H , 5.57 Found: C, 33.2; H,
to the donors of this fund. The authors also wish to thank Professor H. H. Jaffe for many helpful discussions and for a series of molecular orbital calculations on the energy levels of model styrene compounds. The authors are grateful to the American Platinuin byorks Co. and J. C. Wilcox, who iriade generous ciumtities of p h t j i i u ~ navail-
3.42. Ultraviolet Absorption Spectra.-The absorption spectra were obtained with a Reckman DU quartz spectrophotometer. Readings were taken at intervals of 2 nip or less in the regions of the spectrum showing appreciable absorption. The spectra of some of the dimeric complexes were obtained in both chloroform and t-butyl alcohol. T h e spectra of the ionic complexes were obtained by dissolving the corresponding dimers in a n acidic medium, either alcoholic or aqueous hG1rochloric acid. Soectroohotometric Evaluation of Eauilibrium Constants. -BAefore ihe study of a n equilibrium r e h i o n was made, the sprctra of the ahiorbing species involved were rechecked in
able. (14) 1-Dodecene w a s \Vilkinsm, I n c .
iiwd
