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This study concerns t h e synthesis, s t r u c t u r e and r e a c t i v i t y of
6
8
complexes of d and d osmium. The r e a c t i v i t y of c e r t a i n ligands coordinated t o l o w v a l e n t osmium has a l s o been investigated,
Various hydride complexes of osmium(11) were prepared as p o t e n t i a l precursors of osmium(0). 0sH4(pph3) r e a c t s v i t h p-tolylisocyanide (TIC) and 4-ethyl-2,6,7-trioxa-I -phosphabicyclo[2,2.2]octane (ETPO) t o y i e l d 0sH2(L) ( P P ~ ~ ) from which were derived 0sH2
(L*)
(L) ( P P ~ ~ ) ~(L, L*
=
CO, TIC, ETPo), Attempts t o eliminate hydrogen from t h e dihydri des failed. OSHC~(CO) ( P P ~ ~ ) ~ r e a c t s with n e u t r a l l i g a n d s L(=
TICT ETPO, ~(0Me) 3, P ( O P ~ ) 3T P P ~ ~ M ~ ) t o give O S H C ~ (CO) (I) (PPh3) which, with s i l v e r perchlorate (L=
TIC, ETPO only) affordO S H ( C C ~ O ~ ) (CO) ( L ) ( P P ~ ~ ) ~ . The l a b i l e perchlorate ligand can be replaced by ligands L r affording
[OSH(CO)(L)(L*)(PP~~)~]C~O~ (I
= TIC, L* = CO, TIC, PPh3; L = ETPO, I* = CO, ETPO).
. O S H C ~ (CO) ( P P ~ ~ ) r e a c t s withs i l v e r perchlorate i n a c e t o n i t r i l e t o y i e l d [OSH(CO)
( c H ~ c N ) ~ ( P P ~ ~ ) ~ ] c ~ o ~
which i n t u r n r e a c t s with n e u t r a l ligands t o give [OSH(CO) ( C X ~ C N ) (L) ( P P ~ ~ ) ~ ] c ~ o ~ (L = COT TIC, ETPO, PPh3). Cationic [OSH(CO) (PPh3) 3]+ and [OSH (TIC) 2 ( ~ ~ h 3 ) 3]+
can
be prepared from t h e a c t i o n of PPh3 on[osH(co)~(cH~cN)(PP~~)~]+
and T I C on O . S R ( O $ C ~ ~ ~ ) ( ~ ? h ~ ) ~ respectively.With base, [OS~I(CO) ( C H ~ C N ) ( P P ~ ~ ) 3] ~ 1a f f o r d s 0 ~ OSH(OH) (CO) (PPh3)
from
which a series of hydroxide complexes O S H ( O H ) ( C O ) ( L ) ( P P ~ ~ ) ~ (I=
CO, T I C T ETPO) can be obtained. The hydroxide group i n OSH(OH)(CO) ( P P ~ ~ ) ~ i s cleaved by acids
HX
t o y i e l d O S B X ( C O ) ( P P ~ ~ ) ~ ( X=
F, B r , C1, I, CH3C02, CF3C02SC7H7, 0 ~ 1 0 ~ ) . m o s e members of the s e r i e s with X = CN, N3, OCN, SCN
I w e r e obtained from OSH ( ~ 1 0 ~ ) (CO) ( P P ~ ~ )
and
t h e appropriate anion.I
I
From t h e values of vCO f o r t h i s s e r i e s can be gained some understanding
I
of t h e bonding properties of t h e anionic ligands.
I
The n e u t r a l omium(0) complexes OS(CO) (TIC) ( P P ~ ~ ) ~ , Os(C0) 2 ( ~( P P ~ ~ ) ~ ~2, ~os(C0) ) 2 ( ~ ~ h 3 ) and OS(CO) (TIC) (PPh3) w e r e prepared by deprotonation of t h e corresponding c a t i o n s
[ o s ~ ( ~ o ) ,(TIC) (pph3),1+, [OSH(CO) (ETPo) ( P P ~ ~ ) 2]+, [OSH(CO) 2 ( ~ ~ h 3 )
1'
and [OSH(CO) (TIC) ( P P ~ ~ )
,I+.
Q i d a t i v e addition r e a c t i o n s of t h e s eJ
d m p l e x e s have
8
been investigated. Those of O S ( C O ) ~ ( T I C ) ( P P ~ ~ ) ~ andOS(CO) 2 ( ~ T P ~ ) (PPh3) c l o s e l y p a r a l l e l t h e r e a c t i o n s
of
OS(CO) 3 ( ~ ~ h 3 ) 2 with various oxidants, P r o t i c , a c i d s regenerate t h e hydride c a t i o n s as t h e t r a n s isomers. Halogens and mercuric h a l i d e s a l s o produce c a t i o n i c products, Dioxygen gives t h e chelated carbonate complexesO S ( C O ~ ) ( C O ) L ( P P ~ ~ ) ~
(I =
TIC,EZPO),
Whereas non-coordinating a c i d s with 0 s (CO) ( P P ~ ~ ) and OS(CO) (TIC) (PPh3) regenerate t h e hydride cations, h y d m h d i c acids afford OSHX(CO) ( P P ~ ~ ) 3, [OSX(CO) (TIC) ( P P ~ ~ ) 3]+ ( X=
C1,~ r ) and 0s12(C0) (TIC) ( P P ~ ~ ) ~ . Halogens y i e l d O S ) ~ ? ( C O ) ~ ( P P ~ ~ ) ~ (X = C1,
I),
[OsBr (CO) ( P P ~ ~ ) 3]*, [OSX(CO) (TIC) ( P P ~ ~ )3p
(X=
C1, B r ) andO S I ~ (CO) (TIC) ( P P ~ ~ ) ~ . Three isomeric f o m s of 0s1, (CO) ( P P ~ ~ ) ~ were i s o l a t e d , I n a novel reaction, sulphonyl c h l o r i d e s r e a c t with all four complexes affording [ O S C ~ ( C O ) (L) (L*) ( P P ~ ~ ) ~ ] R S O ~ (I = CO, IT
=
TIC, PPh3,OS(CO) 2 ( ~ ~ h 3 ) 3 and OS(CO) (TIC) ( P P ~ ~ ) undergo s u b s t i t u t i o n r e a c t i o n s
and
oxidatively add I$, C2H4 and CS2,These
r e a c t i o n s appear t oproceed
v A
d i s s o c i a t i o n of a l a b i l e phosphine t o form a t r a n s i e n t1 6 e l e c t r o n species:
-
a unique process i n osmiwn(0) chemistry, Adducts with PhC2H and PhC2Ph w e r e obtained only with O S ( C O ) ~ ( P P ~ ~ ) ~ , whicha l s o r e a c t s with dioxygen t o formthe first dioxygen adduct of osmium, 0s(02)
( c o ) ~ ( P P ~ ~ ) ~ .
This complex r e a c t s with SO2 and N204 t o give sulphate and d i n i t r a t e complexes of osmiwn(11),To study t h e s u s c e p t i b i l i t y towards nucleophilic a t t a c k of
carbon
monoxide and TIC coordinated t o osmium(11) a s e r i e s of complex c a t i o n s
(iii)
w a s chosen. OSHC~(CO) (TIC) ( P P ~ ~ ) ~ r e a c t s with perchloric acid t o give O s ~ l ( 0 ~ 1 0 ~ ) (CO) (TIC) ( P P ~ ~ ) ~ , of which two isomeric fonns were isolated, With n e u t r a l ligands, t h e perchlorate group can be displaced t o give [ O s C l (CO) (TIC) (L) ( P P ~ ~ ) 2 ] ~ 1 0 4
(I =
CO, TIC).[OsCl (CO) 2 ( ~ ~ ~ ) (PPh3) 2]+ r e a c t s with azide ions t o give
OsCl(NC0) (CO) (TIC) ( P P ~ ~ ) ~ ~ and reversibly w i t h primary amines yielding
0sCl (CONHI?) (CO) (TIC) ( P P ~ ~ ) 2. Basic alcohols afford 0sC1 ( C O ~ R ) (CO) (TIC) ( P P ~ ~ ) (R
=
Me, ~t), and with 2-chloroethanol a heterocyclic carbene complex[ O s C l (CO) (TIC) ( C C C ~ H ~ O )
-
( P P ~ ~ ) 2]+ results. [ O S C ~ (CO) (TIC) 2 ( ~ ~ h 3 )r e a c t s only with methoxide ions t o give [0s(OMe) (CO) ( T I C ) ~ ( P P ~ ~ ) ~ + which, with perchloric acid, affords [0s(0ClO3) (CO) (TIC) 2 ( ~ ~ h 3 ) 2]+.
[OsC1 (CO)
,
(TIC) (Pph3)2]+
r e a c t s with hydrosulphide ions a t t h e isocyanide ligand affording a n-isothiocyanate complex ~ ~ ( n - ~ ~ ~ p - t o l ~ l ) (CO) ( P P ~ ~ ) 2.This complex can be protonated and methylated a t nitrogen t o give
bident a t e thiocarboxamide complexes, [OS (h 4NRp-tolyl) (CO) 2 2 ~ +
(R = H, Me),
The ligand r e a c t i v i t y of ce.rtain rr-complexes has been investigated, O S ( C ~ H ~ ) (CO) 2 ( ~ ~ h 3 ) 2 r e a c t s with excess hydrochloric acid t o produce t h e hydroxycarbene complex 0sc12 (CO) (c[OH]C H
9
( P P ~ ~ ) which r e a c t s2 5
r e v e r s i b l y with base t o give 0sc1
( c ~ H ~ )
(CO) ( P P ~ ~ ) ~ . With other acids, t h e ethyl complexes OS(C A) x ( c o ) ~ ( P P ~ ~ ) ~
(X = I, CF3C02, 0 ~ 1 0 ~ ) r e s u l t .2 5
O S ( C ~ H ~ ) ( 0 ~ 1 0 ~ ) (CO) 2 ( ~ ~ h 3 ) 2 r e a c t s with n e u t r a l ligands and sodium d i e t h y l d i thiocarbamate affording [ O S ( C ~ H ~ C O ) (CO)
(I)
(PPh3) 2 ] ~ 1 0 4(I =
CO, TIC) and O S ( C ~ H ~ C O )( s ~ c N E ~ ~ )
(CO) ( P P ~ ~ ) respectively.O S ( ~ = C S ~ ) ( C ~ ) ~ ( P P ~ ~ ) ~ r e a c t s with methyl iodide t o give
O S I ( C S ~ M ~ ) (CO) ( P P ~ ~ ) 2 . ~ e ~ . The m e t h y l d i t h i o e s t g ligand of t h i s complex c h e l a t e s i n polar media affording [0s(h2-C[S] m e ) (CO) 2 ( ~ ~ h 3 ) 2 ] + .
With acids 10t, 0s(n-Cs2) (CO) 2 ( ~ ~ h 3 ) y i e l d s t h e first osmium thiocarbonyl complexes, 0sx2 (CO)
(CS)
( P P ~ ~ ) ~ (X = C l ,I).
Dibronoalkanes, B ~ ( c H ~ ) ~ B ~ , r e a c t w i t h O S ( ~ - C S ~ ) ( C O ) ~ ( P P ~ ~ ) ~ a f f o r d i n g complexes of
new
h e t e r o c y c l i c carbenes,~ o s B ~ ( c o ) ~ ( ~ s
[CH, J ~ ~ ) ( P P ~ ~ ) ~ ] ' ( n = 1,2,3), from which can bed e r i v e d 0sBr2(C0)
(6s [ c H ~ ] ~ ~ )
( P P ~ ~ ) ~ (n = 2,3). 0 s ( n 4 s 2 ) (CO) (TIC) (pPh3)*behaves sirnil a r l y i n g i v i n g [0s(h 2
-c[s]
S M ~ ) (CO) (TIC) ( P P ~ ~ ) ~ ] ' , O S C ~ ~ ( C S ) (TIC) ( P P ~ ~ ) and [Os~r (CO) (TIC) ( C S C ~ H ~ S )-
( P P ~ ~ ) ~ ] + .To i n v e s t i g a t e t h e r e a c t i v i t y of a complexed functionaL isocyan.de, various complexes of tosylrnethylisocyanide (TMIC) were synthesized.
Whereas deprotonation of [ O S K ( C O ) ~ ( ~ M I C ) ( P P ~ ~ ) ~ ] ' g i v e s
O S ( C ~ ) ~ ( T M I C ) ( P P ~ ~ ) ~ , attempted deprotonation of [OSH(CO) ( T M I C ) ( P P ~ ~ ) ~ ] + results i n t h e d e a l k y l a t i o n of TMIC t o y i e l d OSH(CN)
( c o ) ( P P ~ ~ ) ~ .
' O S H C ~ ( C O ) ( T I ~ I C ) ( P P ~ ~ ) ~ r e a c t s with base and carbonyl compounds t o
-
g i v e h e t e r o c y c l i c carbene complexes
O~HC~(CO)(CMHXIO)(PP~~)~,
XY=R1 =
Me, Et, R 2 = H, R3 = Me; R,=
R2 =R3 =
~ e ) . Under similarconditions, [ O S C ~ ( C O ) ~ ( T E ~ ~ C ) ( P P ~ ~ ) ~ ] ' y i e l d s OSC~(&~TH[TOS JCH[R]~))
( c o ) ~ ( P P ~ ~ ) ~
(R = Me, Ph), which c a n be protonated a t n i t r o g e n (R= Ne)
t o g i v e ac a t i o n i c carbene complex, Base and acetaldehyde with I
I
[OSH(CO)~(TMC) ( P P ~ ~ ) ~ ] ' g i v e s trans-[~sll(C0) 2 ( h l I C ~ [ ~ ~ e
]cH[M~] b )
(Pph3) 2]+.I
-
II
The a c t i o n of s i l v e r p e r c h l o r a t e a d carbon monoxide on. I
- -
IO S H C ~ (CO) (CIWZO) ( P P L ~ ) ~ produces [OSR(CO) 2 ( ~(PPh3) ~ 2 ] C ~
(XI
~ = ~ ) C H ( O M ~ ) C H ( M ~ ) , C H ( O : . ~ ~ ) C ( M ~ ) ~ , C H = C ( P ~ ) )from
which can be obtained1- -
OSH(C=NXY~)
( c o ) , ( P P ~ ~ ) , (W
= C H ( ~ ? ~ ~ ) C H ( M ~ ) , C H ( O : ~ ~ ) C ( M ~ ) ~ ) by r e v e r s i b l e-
deprotonation a t t h e ligand. Nethyl i o d i d e and O S H ( C = N X Y O ) ( C O ) ~ ( P P ~ ~ ) ~ r e a c t t o g i v e [ O S H ( C O ) ~ ( & J [ T ~ [ M ~ ] xyb) ( P P ~ ~ ) ~ ] + which do n o t deprotonate
a t t h e metal. O S H C ~ (CO) ( & M C ~ [ O M ~ J C [I-ie
j2b)
( P P ~ ~ ) ~ r e a c t s w i t h p e r c h l o r i c1
a c i d a f f o r d i n g O S C ~ ( O C ~ O ~ ) (CO)
(&HHcI![o:.!~Jc
[ ~ e ] ~ 6 ) ( p p h 3 ) which has 'I8 1
been used t o prepare [ O S C ~
( c o ) ~ ( ~ I I I c H [ ~ , I ~ ] c [ M ~ ] ~ ~ )
( P P ~ ~ ) ~ ] ' ,Infrared
and
1H
n.m.r.spectroscopy, conductivity and elemental
analysis have been used in formulation
andstructural assignment,
