422
ADDITION
R
\c /
H = c
A N DCONDENSATION
Ph—Hg—CX Br
P O L Y M E R I Z A T I O N
PROCESSES
R
2
\
—Ph—Hg—Br CH -A/* 2
(A)
R = C H or H X = Cl or Br 3
(B)
Bu SnH 3
(B)
Bu = n-C Hg R = C H or H 4
(C)
3
Figure 1. Preparation of dihalocyclopropanes (reduction by tin hydrides) synthesized and compared with the macromolecular compounds in question. For this purpose, models of Structure A were used, and these reacted with dihalocarbenes. Models of type A are shown in Figure 2. Reasons for choosing these compounds were indicated when their syn thesis was described ( 18). Models Ia-Va reacted with dihalocarbenes prepared either by α-elimination (11) or by thermolysis of Ph-Hg-CX Br (22), giving rise to the corresponding dihalocyclopropane derivatives Ib-Vb (Figure 3). It was possible with these derivatives to characterize B, to study the reduction of Β (X = Br) toC.,and to characterize C. Characterization of B. This study was carried out on (macromolec ular and model) products in which all the double bonds were converted to 1,1-dihalocyclopropanes. Products obtained by adding CC1 and CBr to each of the model compounds were characterized by conventional methods. Their infrared spectra were examined and compared with those of the corresponding macromolecular compounds. None were found to absorb in the 3000-3100 cm." region [cyclopropane-CH — (25)], but all gave an intense absorption band in the C—halogen bond region (Table I): 790-850 cm." for chlorinated products and 700-770 cm.' for brominated products, this band having been reported for Β (17, 18). This band, therefore, seems to be characteristic of the dihalo-l,l-cyclo2
2
1
1
2
2
1
426
ADDITION
A N D CONDENSATION
P O L Y M E R I Z A T I O N
PROCESSES
All the compounds shown in Figure 4 give infrared absorption bands at 3050 and 1020 cm." , characteristic of — - C (25). The characteriCH zation of cyclopropane structures is confirmed by the NMR data given in Table III. 1
2
Table III. le CH —
