746 PITTMAN. et al.
Macromolecules
It is to be noted, however, that chain folding is a widely accepted mechanism for the crystallization of synthetic high polymers'O as well as many natural linear polymers. F o r these systems it is admitted that the extended chain form is unquestionably the most stable, since a fold usually represents molecular distortion and strain.
However, folding is tolerated since kinetic factors control the crystallization and, as a result of this, the effect of temperature is t o increase the length of chain segments between folds. This is clearly the opposite t o what has been observed in our case and suggests a n important influence of solvent o n the phenomenon.
Polymerization of Ferrocenylmethyl Acrylate and Ferrocenylmethyl Methacrylate. Characterization of Their Polymers and Their Polymeric Ferricinium Salts. Extension to Poly ( ferrocenylethylene) Charles U. Pittman, Jr.,'" J. C. Lai,'" D. P. Vanderpool,lc Mary Good,Id and Ronald Prado le
Department of Ciiemistry, Unicersity of Alabama, Unicersity, Alabama 35486, and Louisiana State Unicersity in New Orlenas, New Orleans, Louisiana 70122. Receiced June 15, 1970
ABSTRACT: Poly(ferrocenylmethy1 acrylate), poly(ferrocenylmethy1 methacrylate), and poly(ferroceny1ethylene) have been prepared by AIBN-catalyzed, free-radical polymerization in benzene solution. Treatment of these polymers with strongly electron attracting compounds such as tetracyanoethylene, dichlorodicyanoquinone, and o-chloranil leads to poly(ferricinium) salts, or polymeric charge-transfer derivatives. The characterization of these polymers was carried out by kinetic studies, infrared, nuclear magnetic resonance, ultraviolet, and Mossbauer spectroscopy, as well as gel permeation chromatography and viscosity studies. Some of these studies must be carried out before treatment with the electron acceptor. Mossbauer spectroscopy was found to be an excellent analytical technique to determine the percentage of ferrocene groups converted into ferricinium units, since iron in ferrocene groups exhibits a large quadrapole splitting (-2.4 mmjsec), while in ferricinium groups iron has a single peak. Each molecule of electron-attracting quinone in the poly(ferricinium) salts was present as its radical anion. Polysalts were prepared in which varying percentages of the ferrocene nuclei had been oxidized to ferricinium units. The homopolymerizations were first order in [monomer], half order in [AIBN], giving polymers with *Vn= 5-36 x lo3 before addition of electron acceptors. The activation energies were determined for the first-order polymerizations.
0
ver the past 15 years a large variety of polymers containing ferrocene has been prepared and reviewed.2 In spite of the large number of condensation polymers and unusual polymeric structures which have been prepared, references are rare t o addition polymers containing ferrocene, especially free-radicalinitiated addition polymers. One of the few exceptions is vinylferrocene which has been polymerized to poly(ferrocenylethylene), a tan powder melting a t 280285", by the use of azobisisobutyronitrile (AIBN) in bulk and in solution. However, even poly(ferroceny1(1) (a) To whom inquiries should be addressed at the University of Alabama; (b) University of Alabama, Graduate Student Research Associate (Petroleum Research Fund Fellow 19691970); (c) University of Alabama, Undergraduate Resedrch Paint Research Fellow 1970; (d) Louisiana State University; (e) Louisiana State University, Graduate Student Research Associate, N S F trainee. (2) C. U . Pittman, Jr., J . Paint Technol., 39 (513), 585 (1967); H. Valot, DoubleLiaison, 130,775 (1966); M. Dub, "Compounds of the Transition Metals," Vol. 1, Springer-Verlag, Berlin, 1966; E. W. Neuse in "Advances in Macromolecular Chemistry," Vol. 1, M. W. Pasika, Ed., Academic Press, New York, N. Y;: 1968; E. W. Neuse and H. Rosenberg, Ferrocene Polymers, Marcel Dekker, New York, N. Y., in press; T. P. Vishnyakova Usp. Khim., 36,2136 (1967). (3) F. S . Arimoto and A. C. Haven, J . Amer. Chem. Soc., 77, 6295 (1955); A. C. Haven, Jr., U. S . Patent 2,821,512 (1958); C . Y. Hua, F. Refojo, and H. G . Cassidy, J . Poljmm. Sci., 40, 433 (1959); M. G. Baldwin and Im.Sci., Part A - I , 1, 3209 (1963); M. G. Baldwin and I
