Efecto de la radiación gamma en la morfología de las películas

[ 9 , 9 ^ 4 0 ) ) ( l ^ )2-WIIX>-9<6 - f t a ^ -3 -C I-S -(P B l3 ) ] (4 ) A W 19j9<9 - (0 0 )(P t t i^2:jC TX)-916-R i<^gq^-7 -C l-S -(P T 9 ij) ] ( 5 ) ,

A minor product o f th e r e a c tio n o f [R u C l(00)(H )(PPh 3 ) 3 ] w ith U [ C »8H13] i s a c h lo rin a te d d e r iv a t iv e o f th e p re v io u s ly discussed nido ruthenacartoaborane ( 1 ) . The product i s form ulated as [9 .9 #9-(C P)(PPh3) : -nido-9.6-RuCB0H0-3 -C l-5 -(P P h 3 )1 ( 4 ) , where the decaborane(14) l i k e framework has the 6- and 9 - p o s itio n s s u b stitu ted by CH and [RuiPPhj^OD] fragm ents and has th e phosphine and c h lo rin e exo su bstitu en ts a t the 5 - and 3- p o s itio n s r e s p e c t iv e ly .

A fu rth e r c h lo rin a te d product can be produced by treatm ent o f th e n id o compound (1) w ith halogenated s o lv e n ts ( e . g . CJ^Clj) and i s form ulated as [9 .9 .9 -(Q 3 )(P P h3)2-n id o -9.6-RuCB0H j-7 -C l-5 -(P P h 3 )1 ( 5 ) . A s im il a r range o f n .m .r . measurements have been ob tained f o r th e two c h lo rin a ted ruthanacar b aboranes (4 ) and (5 ) as was requ ired f o r th e c h a ra c te ris a tio n o f ociqpound ( 1 ) , (shown in Ttable 1 0 ). Since th e c o r r e la tio n o f th e ob served n .m .r. data t o th e proposed s tru c tu re s ( v e r i f i e d by X-ray c r y s ta llo g r a p h y ) fo llo w s much th e same reasoning a s d escrib ed e a r l i e r f o r compound ( 1 ) a f u l l a n a ly s is i s not req u ired h ere. However, severed, i n t e r e s t in g fe a tu re s o f the observed 11B n .m .r. s p ectra are discussed b elcw a f t e r th e fo llo w in g stru c tu ra l d is c u s s io n , and a re o f in t e r e s t w ith r e s p e c t t o the r e l a t i v e e f f e c t s o f su b stitu en ts an th e chem ical s h i f t s o f th e cage atoms.

The c lu s te r boron-11 and proton resonances o f oaqpounda (4 ) and (5 ) a r e con sisten t w ith a n id o s tru ctu re analogous t o th a t o f the ruthenaoarbaborane ( 1 ) . The B (8 ,1 0 ) resonances a re r e a d ily assigned

BCRCN-1 1 A T P PROTON N .M .R . D ATA T e n ta tiv e Assignment Ccmpound(4 ) t e n t a t iv e Assignment Ocsqpound(5) 11B (p.p.m,. ) (p .p .m .)1H _{(P - P - *}11B. ) (p .p .m .)1H 8 21.5 4.12 8 24.5 3.95 3 14.8 B - d 7 18.4 B-Cl 1 9.8 3.62 1 10 .1 3.29 7 9 .8 3.57 3 5.5 3.10 10 -1 . 8 2.91 10 -4.7 2.71 5 -4 .7 B-P 5 -9.2 B-P 2 -1 2 .4 1.78 2 -1 1 . 6 2 .1 1 4 -1 7 .2 -0.17 4 -18.8 -0 .0 1 5.3 5.5 B (8)-H -R u (9) -8 .9 -8 .5 B(10)-H -Ru(9) -8.67 -8 .7 6.9 -7 .7 6 .9 -7 .5 PHD6PHCFUS-31 N.M.R. DATA ’t e n ta tiv e Assignment Ccnpound(4) 31p (p .p .m .) Oonqpound(S) 31p (p .p .m .) 49.2 50.4 Ru(PPh3 l « j u » t o r L a l 41.4 39.0 B -iP P h j) 10.5 8 .0

T b M * 10« Baron-11, proton and phospharus-31 n.ra.r. data (p .p .ra .) f a r th e n ld o m etallaaarbaboranes ( 4 ) and ( 5 ) .

from sharpening o f the b rid g in g B-H-Ru proton resonances in s e l e c t i v e 1H {1 1B} decou p lin g experim ents. The id e n t if ic a t io n o f a te r m in a l) hydrogen on B (8 ,1 0 ) a ls o e lim in a te s the p o s s i b i l i t y o f ex o s u b s titu tio n a t th ese s k e le t a l boron a tan s. The presence o f a c o r r e la t io n a t the B (2 ) and B (4 ) resonance group in th e proton-boron-11 s h i f t c o r r e la t io n p l o t (s e e F ig u re 68) f o r compounds ( 1 ) , (4 ) and ( 5 ) , a ls o reason ably e lim in a te s s u b s titu tio n a t these boron a tan s, as w e ll as a llo w in g a t e n t a t iv e assignment f o r these p o s itio n s .

The ex o phosphine su b stitu en t i s t h e r e fo r e in d ic a te d t o be p o s itio n e d a t th e B (5 ) o r B (7 ) boron, as was found f o r the n on -ch lorin a ted d e r iv a t iv e , w ith th e exo c h lo r in e p o s it io n in d ic a te d t o be attached t o the B (1 ), B (3 ) o r B (5 ,7 ) boron a ta n s . The d is p o s it io n o f th e two exo su b stitu en ts (PPh3 and C l) r e l a t i v e t o each o th e r and th e o r ie n ta tio n o f the liga n d s on th e ruthenium atom i s s im ila r ly unobtainable from th e n .ra.r. d ata. The asymmetry imposed by th e second s u b stitu en t a t the p o s itio n s noted above, would in p r in c ip le en able th e ligan d s on th e metal t o adopt th e o p p o s ite o r ie n t a t io n t o th a t found in compound (1) , w ithou t t h i s b ein g apparent from th e n .m .r. d a ta . However, assuming th e same stru c tu re as t h a t found f o r oonpound ( 1 ) , th e a lt e r n a t iv e stru ctu res f o r compounds (4 ) and (5 ) a re th e B (1 ), B (3 ) o r B {7 ) ch lo ro -s u b s titu te d p rodu cts. S ince the ex o phosphine could be in a syn o r a n t i p o s itio n w ith re s p e c t t o the Ru-(CD) lig a n d ( i . e . B tSi-PPhj o r B(7)-PPh3 ) th e re a re s i x p o s s ib le s tru c tu re s , in d is tin g u is h a b le from the n .m .r. data a lo n e .

In o rd e r t o determine unambiguously th e geom etry o f the m e ta l-lig a n d fracpnent, i t s d is p o s itio n w ith r e s p e c t t o th e carfaaborane cage and the d is t r ib u t io n o f exo phosphine and c h lo r in e su b stitu en ts In th e n id o -ruthenacarboranas (4 ) and ( 5 ) , each has been c h a ra c te ris e d

F ig u re 68. P roton-boron-11 s h ie ld in g c o r r e la t io n p l o t f o r

n jd e -(9 -< a > )-9 ,9 -< F I’h3)2-9 ,6 -R iiœ8H10-5 -< p n l3 ) ) (1) ( o ) , n id o - [9 - (a ))- 9 ,9 - (P P h3)2-9,6-RuCBaH3-3 -C l-5 -(P P h 3 ) ] (4 ) ( a ) and n id o - ig - IC D l- g ^ - IP P h jlj- g .e - R u C B jH j- T - C l- S - IP P h j»! (5 » ( a ) .

Schematic diagrams o f th e s i x p o s s ib le s tru c tu re s o f the F ig u re 69,

by s in g le - c r y s t a l X-ray d i f f r a c t i o n a n a ly s is . Drawings o f the c r y s t a llo g r a p h ic a lly determ ined m olecular s tru ctu res o f (4 ) and (5 ) and diagrams o f th e s k e le t a l bond d is ta n c e s cure g iv e n in Figu res 70-73, w ith o th e r c r y s ta llo g r a p h ic d e t a i l s g iv e n in Chapter 5.

The c r y s t a l m olecular s tru ctu res o f th e ruthenacarbaboranes (4) and (5 ) c o n s is t o f the p r e d ic te d nldo 6,9-MCBQ decaboranyl framework w ith th e c lu s t e r phosphine su b stitu en t on th e B (5) boron a ta n , as was found f o r compound (1) , w ith th e fu rth e r s i m i l a r i t y th a t, rega rd less o f th e p o s it io n o f the c h lo r in e s u b s titu e n t, th e exo phosphine i s syn w ith r e s p e c t t o th e metal carbon yl group. T h is o f course elim in a te s th ree o f th e p o s s ib le isom eric stru ctu res p o stu la ted above. O f the remaining 1 - , 3 - and 7 - c h lo r o s u b stitu ted isom ers p o stu la ted , the ruthenacarbaboranes (4 ) and (5 ) a re id e n t i f i e d a s 3-01 and 7-C l d e r iv a t iv e s r e s p e c t iv e ly .

N o ta b ly , th e le a s t sym m etrical isom er in terms o f liga n d d is t r ib u t io n , th e 1-C1 product i s not found. The syn th esis o f th e 7-C l isomer from th e p arent ruthenacarbaborane (1 ) i s thus seen t o proceed w ithout p e rtu rb a tio n o f th e m etal environment.

The replacem ent o f a term in a l hydrogen w ith a c h lo r in e atom does not a f f e c t th e number o f s k e le t a l e le c tr o n s a v a ila b le f o r bonding in the framework, hence the ruthenacarbaboranes (4 ) and (5 ) a re both 18 e le c tr o n d6 R u ( I l ) complexes, w ith the m etal c o n trib u tin g th ree o r b it a ls and two e le c tr o n s t o th e cage, w ith th e m etal cen tre possessing a q u a si-o cta h ed ra l bonding geom etry, as p o stu lated f o r the ls o e le c t r o n lc paren t compound (1) .

The r a th e r la r g e e . s . d 's a ss o c ia te d w ith th e in te r-a to m ic dista n ces d e r iv e d from the c r y s t a l stru c tu re a n a ly s is o f the chloro-ruthenacarbaboranes (4 ) and (5 ) l i m i t th e d iscu ssio n o f t h e ir

F ig u re 70. Drawing o f th e X -ra y c r y s t a llo g r a p h ic a lly determ ined m olecu lar s tru c tu re o f th e ruthenacarbaborane n id o -[9 -(C X ))-9 ,9 -(P P h3)2-9,6-RuCB8H9-3 -C l-5 -(P P h 3 ) ] ( 4 )

F igu re 71. Drawing o f th e X -ra y c r y s t a llo g r a p h ic a lly determ ined m olecu lar s tr u c tu r e o f th e ruthenacarbaborane n id o -[9 -(O Q )-9 .9 -(P P h j)j-9 .6 -R u C B0tij- 7 - C l- 5 - (P P h j) 1 ( 5 ) .

F igu re 72 S k e le ta l in te ra to m ic distan oee (pm) , w ith standard d e v ia tio n s in paren th esis, f o r th e ruthenacarfaaborane r ^ - [ 9 - ( C D ) - 9 , 9 - ( P P h3)2-9,6-«uCB0H9-3 -C l-5 -(P I> h 3 )] ( 4 ) .