2.5. Metodología
2.5.3. Análisis Microbiológico
2.5.3.9. Pruebas Bioquímicas: Kligler, SIM, Urea y Citrato
i
5I 1P § § Í5I§§I£S3225555H
ëiUEëSKEKEKIKüüs
HSSSggggggggSSSSïïSîîsS
127
.
T a b le 2.15. D e v ia tio n s (A ) f r o « mean plan es (d e fin e d by s ta r re d
atoms; e . s . d . s . ♦/— 0 .0 0 5 A) in I (P E t 3 ) 2I 2P t(C 6H4CH2t 6H4 ) l . P la n e 1 P t 1.164 * C (13) 0.007 • C (14) 0.008 C (1 0 ) 0.678 *C (1 1 ) 0.008 •C (1 2 ) 0.007 P la n e 2 * C (1 ) 0.011 • C ( 2 ) 0.009 *C( 3 ) 0.007 * C (4 ) 0.165 • C (14) 0.036 •€ (1 3 ) 0.033 P la n e 3 • C (5 ) 0.008 •C (6 ) 0.027 •C (7 ) 0.019 * C (8 ) 0.007 * C (12) 0.025 *C (1 1 ) 0.017 P la n e 4 • P t 0.021 *C (1 0 ) 0.029 • C ( l l ) 0.058 • C ( 12) 0.058 P la n e 5 * P t 0.018 * C (1 0 ) 0.024 * C (1 4 ) 0.048 0.042 C ( 13)
The d ih e d ra l a n g le o f 1 1 0.5° s i g n i f i e s a la r g e d e g r e e o f
r i n g f o l d i n g and in d ic a t e s th a t th e b o a t c o n fo rm a tio n i s h ig h ly
puckered. I t i s th e s m a lle s t d ih e d r a l a n g le r e p o rte d f o r a 9 ,1 0 -
dih yd ro an th ra cen e compound.
2 .7 ATTEMPTED AROMATIS ATI ON OF [ ( P E t g J ^ i d ^ C H g C ^ ) ]
The compound [ ( P E t , ) _ P't(C_H.CH_C_H ] (2 .2 0 a ) was t r e a t e d 3 2 6 4 2 6 4
w ith a s e r i e s o f r e a g e n t s in an a ttem p t t o remove e i t h e r H* o r H~
from th e sp4 h y b r id is e d carbon w ith su bsequent fo r m a tio n o f a f u l l y
d e lo c a lis e d h e te ro a n th ra c e n e compound ( 2 . 2 5 ) o r (2 . 2 6 ) (Scheme
2 . 5 ) .
(2 .2 6 )
Scheme 2 .5 . A ttem pted a r o m a tis a tio n o f (2 .2 0 a ) by rem oval o f
Compound (2 .2 0 a ) was t r e a t e d w ith th e bases m e t h y llith iu m ,
b u t y llit h iu m , t e r t - b u t y l l i t h i u m and lith iu m b i s ( t r i m e t h y l s i l y l )
amide in an a ttem p t t o remove H+ , and w ith th e r e a g e n t t r i t y l t e t r a -
f l u o r o b o r a t e in an attem p t t o remove H~. A l l th e r e a c t io n s were
fo llo w e d by *H n .m .r. and 31P - { 1H > n .m .r. s p e c tr o s c o p y . However,
e v en a d d it io n s o f up t o 10 m ole e q u iv a le n t s o f each o f th e above
re a g e n t s and l e a v in g th e s o l u t i o n s f o r s e v e r a l hours o r days d id
n o t r e s u l t in th e d e s ir e d p ro d u c t b e in g form ed. In a l l c a s e s o n ly
d eco m p o sitio n t o o t h e r p la tin u m c o n ta in in g s p e c ie s was o b s e rv e d to
o c c u r .
In th e n .m .r. sp ectru m , one o f th e reso n a n ces due t o th e
tw o m ethylene p ro to n s would be e x p e c te d t o d is a p p e a r as l o s s o f
e i t h e r H* o r H o c c u rre d . The 31P - { 1H ) n .m .r. spectrum would be
e x p e c te d t o change s i g n i f i c a n t l y s in c e rem oval o f e i t h e r H* o r H~
w ould cause a change in th e b on din g in v o lv e d betw een th e platin u m
and th e 9 , 1 0 -d ih yd ro a n th ra cen e m o ie ty . T h is would i n d i r e c t l y a f f e c t
th e 31P ch em ica l s h i f t and * J ( P t P ) v a lu e s which a r e v e r y s e n s i t i v e
t o th e na tu re o f th e bon din g o f th e lig a n d tra n s t o th e phosphorus
n u c l e i . 271
S in ce a b s t r a c t io n o f e i t h e r H* o r H- from th e p la t i n u m ( I I )
com plex (2 .2 0 a ) was n o t s u c c e s s f u l, i t was reasoned th a t lo s s o f HX
fro m a p la tin u m (IV ) com plex such a s [ ( PE t3) j X j f i ( c 6H4CH2C6H4 ^
( 2 . 2 7 ) would be more e n e r g e t i c a l l y fa v o u r a b le (e q . 2 . 1 1 ).
X2(PEt3)2
e q . 2.11H
X{PEt3)2
(2 .2 7 )2 .8 SYNTHESIS AND CHARACTERISATION OF [ (P E t_ ) I P t(Ö H CH C H )1 3 2 2 6 4 2 6 4 and i ( d p p « ) I 2R t ( ^ H j 0 i ^ 5 6H4 ) ]
S e v e ra l a ttem p ts a t o x id a t iv e a d d itio n t o th e p la t in u m (I I )
complex (2 .2 0 a ) w ith su b stan ces such as m e t h y lio d id e . a c e t y l -
c h lo r id e and a l l y l c h l o r i d e were u n su cc e s s fu l. No r e a c t io n was
observed w ith a c e t y l c h l o r i d e and a l l y l c h lo r id e w h ils t r e a c t io n
w ith m eth y lio d id e ga v e [ P t I 2 (P E t3 ) 2 ] as e vid en ced by 3 l P - ( l H )
n .m .r. sp ec tro s c o p y . However a d d it io n o f one e q u iv a le n t o f io d in e
t o compound (2 .2 0 a ) produced the d e s ir e d p la tin u m (IV ) complex
(2 .2 1 ) (e q . 2 .1 2 ).
e q . 2 .12
(2 .2 0 a ) (2 . 2 1 )
The a d d itio n r e q u ir e d s e v e r a l hours s in c e a b u ild up in the
lo c a l c o n ce n tra tio n o f th e io d in e r e s u lt e d in th e fo rm a tio n o f
[ P t I 2 (P E t3 ) 2 ] r e s u lt in g from r e d u c tiv e e lim in a t io n . A s l i g h t excess
o f io d in e a ls o r e s u lt e d in c o n tam in atio n o f th e p ro d u ct w ith t h is
com plex. The p la tln u m (IV ) compound (2 .2 1 ) was i s o l a t e d as a b r ig h t
y e llo w , a i r - s t a b l e , c r y s t a l l i n e s o l i d which was c h a r a c t e r is e d by
*H, 3* P - { * H ), l3 C- (*H ) and 19^ P t- (* H ) n .m .r. s p ec tro s c o p y and
The e le m e n ta l a n a ly s is o f compound (2 .2 1 ) d id i n d ic a t e t h a t
o x i d a t i v e a d d it io n o f io d in e t o th e compound (2 .2 0 a ) had o c c u rre d .
The 31P - l V n . . . r . spectrum o f compound (2 .2 1 ) (d a t a g iv e n in
T a b le 2 .1 0 ) showed th a t th e t r ie t h y lp h o s p h in e lig a n d s were in a
t r a n s arrangement w ith th e tw o incom in g io d id e lig a n d s m u tu ally
c i s . I f the phosphine lig a n d s had rem ained m u tu a lly c i s , and tra n s
t o th e 9 ,10 -d ih yd ro a n th ra cen e m o ie ty on o x id a t iv e a d d it io n o f
i o d i n e , the 1(P t P ) v a lu e i n t h e r e s u lt in g p la tin u m (IV ) com plex
w o u ld be ex p ected t o be ca tw o t h ir d s th e m agnitude o f th e v a lu e o f
t h e c o u p lin g c o n sta n t in th e p l a t i n u m ( I I ) com plex278 ( i . e . c a 1200
H z ) . The observed 'J ( P t P ) v a lu e o f 1782 Hz in d ic a t e s t h a t th e
p h o sp h in e lig a n d s have re a rr a n g e d so th ey a r e tra n s t o each o t h e r .
P h o sp h in es have a lo w e r tra n s in flu e n c e than the
9 ,1 0 -d ih y d ro a n th ra c en e lig a n d and so t h i s r e s u lt s in th e h ig h e r
c o u p lin g c o n sta n t.
The 1H n .m .r . spectrum o f (2 .2 1 ) ( F i g . 2 .2 5 , d a ta g iv e n in
T a b le 2 .9 ) showed a s in g le reso n a n ce f o r th e two m ethylen e p ro to n s
o f th e 9 ,10 -d ih yd ro a n th ra cen e lig a n d s i g n i f y i n g th a t th e s i x
membered p la t in a c y c le was u n d e rgo in g r a p id r in g r e v e r s a l on the
n . m . r . tim e s c a le a t ambient tem p e ra tu re . T h e r e fo re o x id a t iv e
a d d i t i o n o f io d in e t o compound (2 .2 0 a ) has d ecrea sed th e a c t i v a t i o n
e n e r g y re q u ire d f o r r in g r e v e r s a l .
S in ce the c o n fo rm a tio n o f th e p l a t i n a c y c l i c r i n g was no
l o n g e r r i g i d in s o lu t io n o n ly on e resonan ce was o b s e rv e d f o r the
m eth y len e p ro ton s o f th e t r ie t h y lp h o s p h in e lig a n d s .
An i n t e r e s t in g fe a t u r e in th e *H n .m .r . spectrum o f (2 .2 1 )
F i * . 2 .2 5 . *H n .m .r. s p e c t r a (C D C lg, 100 M lz ) o f
[(P E t 3 ) 2I 2P t (C gHdCH2C6H4 ) ] show ing s e l e c t i v e p ro ton
a r o m a tic p ro ton resonan ces ( s e e F ig . 2 .2 5 ). The resonan ce showed
c o u p lin g t o one o t h e r p ro to n and had platinum s a t e l l i t e s ( 3J (P tH ) •
52 H z ) ] . Proton d e co u p lin g s t u d ie s ( F i g . 2 .2 5 ) enabled assignm ent
o f t h i s resonance t o th e p ro to n s on C ( l ) and C (8 ) o f th e a rom atic
g ro u p s in the 9 , 10-dih yd roa n th ra cen e m o ie ty . I t i s th ought th a t
th e s e two proton s a re d e s h ie ld e d by e i t h e r th e platinum atom o r th e
tw o io d in e lig a n d s by a th rough space e f f e c t . Such an e f f e c t i s
s e en in compound (2 .2 8 ) where th e arom a tic pro ton s o rth o t o the
r i g i d l y h eld P «0 group a r e d e s h ie ld e d and w e ll s e p a ra ted from th e
o t h e r arom atic p ro to n s . The c l o s e p ro x im ity o f th ese p ro to n s to th e
e q u a t o r ia l phosph inoyl oxygen atom g i v e s r i s e t o t h is e f f e c t . 279
(2 .2 8 )
O x id a tiv e a d d itio n o f io d in e t o the dppm complex (2 .2 0 g ) was
f o llo w e d by 31P - ( 1H ) n . a . r . s p e c tr o s c o p y . The 31P - ( l H) n .m .r.
spectrum o f the produ ct in s o lu t io n was c o n s is te n t w ith the
fo r m a tio n o f the p la tin u m (IV ) com plex ( 2 . 2 2 ) [ a 31P - 3 1.0 ppm,
1J ( P t P ) ■ 954 H z ]. The dppm lig a n d i s c h e la t in g , and hence th e two
io d in e lig a n d s a re tra n s to each o t h e r . The l J (P t P ) c o u p lin g
t h i r d s th e v a lu e found in th e p l a t i n u m ( I I ) com plex [ l J ( P t P ) * 1466
H z ] which would be e x p e c te d i f th e io d in e lig a n d s were in th e tra n s
p o s i t i o n s .
(2.2 2)
2 . 9 CONFORMATIONAL STUDIES O r [ ( P B t g ) 2 I g P t ( C6h4c h2<'6 H4 * ^
2 . 9 . 1 S o l u t i o n N .M .R . S t u d i e s o f l < P B t3 >2 I 2 ,it (< V i 4CH26 6H4 ) ^ The c r y s t a l s t r u c t u r e o f compound (2 .2 1 ) (S e c t io n 2 . 9 . 2 )
showed th a t i f th e b o a t c o n fo rm a tio n o f th e p l a t i n a c y c l i c r in g was
r i g i d in s o lu t io n , th e two phosph ine lig a n d s would n o t be
c h e m ic a lly e q u iv a le n t . One ph osph in e lig a n d would be above th e boat
and one would be b elow i t . Hence two s ig n a ls would be o b s e rv e d in
th e 31P - { 1H> n .m .r. spectrum . T h is prompted v a r ia b le low
tem pera tu re 31P - ( l H } n .m .r. s t u d ie s o f compound ( 2 . 2 1 ) . F i g . 2 .26
shows th a t as th e tem peratu re i s low ered th e phosphine lig a n d s a re