- Email: [email protected]
Low oxidation state ruthenium chemistry
95
Journal of Organometallic Chemistry. 125 (1977) 95-103 0 Ekevier Sequoia S-A_. Lausanne - Printed in The Netherlands
LOW OXIDATION STATE RUTHENIUM CHEMISTRY HI *a THE REACTIONS OF AMINES WITH [ Ru(CO)sCl, 12AND RELATED COMPLEXES l*, M. PIZZOTIT,
S. CENINI C.N.R
F. PORTA
and G. La MONICA
Center. Zstituto di Chimica Genemle.
(Received June 28th,
Ea
Venezinn 21.20133
Milan0 (Ztaly)
1976)
Summarv Carbamoyl complexes of ruthenium(II), Ru(CO)~(RNH~)~CI(CONHR), have been isolated from the reactions of [ Ru(CO)~CI& with the amines RNHl (R = But, Bun, p-Me&&, p-MeOC&). By reaction of the carbamoyl complex (R = p-Me&&) with triphenylphosphine and hydrochloric acid the derivatives Ru(CO),(PPh&Cl(CONHR) and [Ru(CO)~(RNH~)~CI]+CT have been obtained. The complex Ru(PPh&C& did not give fully characterizable products in reactions with aromatic amines and carbon monoxide, but reacted with hydraxines and CO to give the complexes [Ru(PPh,)L(NH,-NH,)Cl,], (L = PPh3, CO) and Ru(PPh3)2L(PhNH-NH2)Clt (L = PhNH--NH,, CO).
Introduction
.
During our studies on the reactions of organic azides RN3 with carhonyl complexes of transition metals in low oxidation states, we prepared isocyanate derivatives by treatment of RN3 with coordinated carbon monoxide [l] (eq. la), a reaction discovered by Collman [2]: L,MCO
+ RN, + L,M(RNCO)
LJQRNCO)
+ Ns
(la)
+ HX + [L,,M(CONHR)r(X-)
(lb)
Protonation of the isocyanate complexes with mineral acids readily gave carbamoyl derivatives [l] (eq. lb). It is well known that carbamoyl complexes can be obtained by nucleophilic attack of aliphatic amines on coordinated car. -. -_
l
Forputlf~~li ; l‘&&&+gap
_+_&.&&&&_
_ _.
J
,
96
bon monoxide 131and the reaction of COC& with primary amines is the commonest route to organic isocyanates [4] (eq. 2): COClr + 3 RNHr
--RNH2
- HS
RmCwl
-RNH2_RNC0
(2)
Moreover a carbamoyl palladium complex has been suggested 133 as an intermediate during the reaction of amines with CO in the presence of palladium(H) chloride to give isocyauates [ 51. We thus undertook a study of the reactions of amines with a dichlorocarbonyl compiex, [Ru(CO),Cl,b, with’ the objective of producing chiorocarbamoyl complexes, which would give isocyanate derivatives by loss of HCl. Cblorocarbamoyl complexes of palladium and platinum have been recently reported [3b]. We have also studied the reactions of Ru(PPh&Ch with amines, and the reactions of the products with carbon monoxide. Results and discussion Reactions of [Ru(COJ3C12 jz with amines [~u(CO),Cl,]~ reacts with primary amines giving chlorocarbamoyl according to eq_ 3 (Table 1): Ru(CO)~(RNH&CI(CONHR)
IRuKX%CM~ + 8 RM-L -2 (R = But, I; Bun, II;p-Me&&,
III;p-MeOC&,
IV)
complexes
+ 2 RNH,
* HX (3)
Secondary amines did not give readily characterizable products. These reactions usually involve aliphatic amines and cationic carbonyl complexes [3] and it was of interest that aromatic amines also react, although under slightly more drastic conditions (at reflux) than those for the aliphatic amines (room temperature). A cationic ruthenium-carbonyl complex is probably involved as an intermediate even in reaction 3, aud_this point is considered below. In all eases the reaction also gives the salts RNH, - H2L Even when reaction 3 (R = p-MeC&&) was carried out in THF at 100°C and under CO pressure (20 atm), compound III was the only product isolated. When we attempted the reactions with the bromo Fo_mplex, [Ru(CO),Br,& in bromoform as &vent, rates were lower and the products more difficult to purify- Only compound V; [Ru(CO)2(p-MeC,I-I.NHz)Br(CONHC~~Me-p)~, gave acceptable elemental analyses. This compound is possibIy dimeric with bridging bromines (x = 2), having only five ligauds per metal atom. The observed molwt. is distinctly higher than that required for a monomer (Table l), but not satisfactory for a dimeric formulation. However the mol_wt.‘s were not very satisfactory even for the 6-coordinated derivatives, being slightly higber in some cases . than required; a fact for.which we have no-explanation. Compounds I and III react with JriphenyIpbospbine in benzene to give .tbe corresponding_ 1 carbamoyl derivativ_eswithtriphenylphosphine hgands (eq_ .4): . _ ~_ -- :.
Ru(CO),(RNH,),Cl(CONI+R) _~....
+-2_PPh, + Ru(CO)&?P&3l(C&iRj :
_
However onIy compound VI (R~.?&Me&) -_ .
.. -
a&&
’ -1
+ 2 R@H,
_--. :_ : (4) ’ __ >-:_:->_:A ; .+&;;~ :._____!. F be &++oMt&d (-XX-: - I’. -_z-..~;.“-> 1._:=-,-
I
“Vu.
_--_-_.._-.__
IBu(CO)[email protected])NH2)2ClJ’CI_.-I^_”
... I.____
_
..-.. .,.
._
.
.
.
.
.
whlta _.”
.___
white
RU(C~)~(PP~J)~CI(CONHC~H~M~.~)
“l.
-_.__I.-.____
-
154
pIb r230 yellow
~~~~CO)~@:MOC~H~NH~)D~CONHC~~CIMO~)J,
Y
___..
..-.__
43.03 (43.34) .
.
.._.
3,47 (3,SS)
4.394,54 (4.45)
4.08 (3,56)
4021 (4,41)
4.594.46 (4.78)
6.90 (7,29)
7.50 (7.29)
_“-.---...-_-..-.___.__..._“-.___-I-
63.46-66.li (64,87)
42.35' (42,67)
47.91 (45.95)
149-44
white
RU(C0)[email protected])2Cl(CONHC6H~OMc.p)
1y..
a,7 (41.0)
40.47 (41.04)
52.90-53.96 (53.23)
149
152
155-70
whita
white
..__.._____._.__--_^_-.l_l--_--
Malunll Analysaslfound (calcd.) (%) polrlt --H C (W ._______.____., _____.__-_...--
Whit0
~u(CO)2(Bu”NH2)2Cl(CONHBun)
Ru(bO)2(DutNH2)2CI(CONHBut)
_____“__..__
Colour
FOR CARBAMOYL COMPLEXES OF RUTHENIUM _--_-__ _--...__ _.^__...__.._-,..--
J11, R~~(~O)[email protected]~C~H~NH~)~C~(CONHC~H~M~.P)
11”
,,:I i:
ANAtiYnOAL DATA :, s ‘ ‘No; Oombound
5072 (5,96)
1.78-1.65 (1,64)
5.92 (6,87)
7,0a (7,14)
7,66-7.91 (7,76)
9,oa Kh50)
9,60 (9,56)
N _-.__ -..-_-__
15.13 (15.10)
4.5-4.9 (4.17)
16.88 (16.70)
7.12 (6.54)
8,64 WO)
8.52 (6,lO)
ClorBr
6,51 (5,64)
8838 (8,ft6)
0
822 (Sal)
650 (478)
414 (589)
503 (541)
515 (439)
557 (439)
Mol.wt, In CHCIJ
,
98
perimental), and these derivatives appear to be rather unstable, especially in solution. When reaction 4 was conducted in chloroform only the white c&Ru(CO)~(PPh&Cl, was isolated_ Like I-V, compound VI is a non-conductor in nitrobenzene. The presence of the carbamoyl ligand in these compounds was confirmed by oxygen analyses (compounds III and VI) and by reaction of compound III with hydrochloric acid in a non polar solvent, such as benzene, in which the product is insoluble (eq. 5) (cf- ref. 3) (Table 1): Ru(CO),(RNH,),CI(CONHR) om
+ 2 HCI --, [ Ru(CO),( RNHt)#l]+
-
Cl- + RNHz - HCI (5)
(VD:R=p-MeC&,)
The IR data for compound VII (Table 2) are in accordance with its formulation; in particular three v(C=O) bands were present in the carbonyl stretching region. The ‘H NMR data of compound VII are not reported because this derivative is uns*IabIein solution, nucleophilic attack by the anion giving a non ionic product which has not been fully investigated. Our formulation of VII as an ionic compound is based only on the 6-coordination of this cation. Compound VII is probably the cationic intermediate formed during reaction 1. Compounds I-VI presumably should produce isocyanate complexes of formula Ru(CO)&(RNCO) by loss of HCl. We found that reaction did take place with strong organic or inorganic bases but the products could not be characterized. Ruthenium-isocyanate complexes having L = PPhS and R = Ar-$Z- have 0 been made by another route [S], but their stability was attributed to the formation of a metallacycle involving the X=0 group of the aroyl isocyanate ligand. In their IR spectra compounds I-VI show two v(C=O) bands of equal intensity, indicative of a cis-arrangement of the carbonyl groups (in some preparations, compounds III, IV and V also gave a very weak band at higher frequencies).
TABLE2 OF RUTHENIUM
SPECTROSCOPICDATAFORCARBAMOYLCOMPLEXES No_
IRabaorptianb~~ia~ol(cm-')
'IiNMR_spectrainCDCl3
V(NH)
v(NHd
v
v +6
r
r
T
I II
3440 3360
3265-3240 3280-3230
2035-1960
1605-1580 159+155G
f-"
it-1
$t.68--8.71e
III IV V VI VII
3435 3420 3430 3330 -
3220-3120 3220-3110 3210-3120 3230-3170
2065-1985 2060-1980 206Wl980 2060-1970 213W2080 2060
162(t-1605-1590 1615-1606-1686 1625--161X+1680 169~lp80 . 1605-1675
6.7 5
4.35 4.3= 4.92 4-7 -
-
7.66-7.78 6.27-6.34c 7.74 -
99
Three bands were observed for compounds I-V in the 3450-3100 cm-’ region. The absorption at higher frequency is attributed to v(NH) of the carbamoyl group, since the two vibrations at lower frequencies are absent in compound VI, in which the amine has been replaced by triphenylphosphine. In the 1600 cm-’ region more and broad absorptions were observed, probably due to v(>C=O) of the carbamoyl group and to &NH) of the amines and RNHCOligands. The ‘H NMR spectra (Table 2) in most cases showed broad signals due to r(NH,) and 7(NH), these signals generally disappeared on treatment with D20. Compounds I, III and IV also show two distinct signals due to the paru substituent of the aromatic amines or to the Bu’ groups; these signals were approximately in the expected 2 : 1 ratio.
Reactions of Ru(PPh3)&12 with hydrazines and carbon monoxide Ru(PPh3),Cl, reacts with pyridine to give Ru(amine),(PPh&&
[7]. It also readily reacted in benzene with aromatic amines, but the violet products isolated from these reactions did not give satisfactory elemental analyses. By carbonylation of these materials, at atmospheric pressure, we isolated products which analysed correctly as Ru(CO)(PPh,)(RNH,),C1, (R = p-MeC,H,, p-MeOC,H,) (see experimental). However the IR spectra of these compounds showed a broad v(C=O) band below 2000 cm-‘, possibly due to the presence of other isomers. Well defined products have been isolated from the reactions of Ru(PPh&& with hydrazines (eq. 6) (Table 3): Ru(PPh&C12 + RNH-NH* (VIII): (IX):
R= Ph; R=H;
n = 2; n=l;
+ [ Ru( RNH-NH2),(PPh3)2Cll]m
(6)
m = 1 m=2
Compound IX is probably dimeric with bridging hydrazine, but the phenylhydrazinc derivative VIII adopts a monomeric structure because of the steric effect of the phenyl substituent. Such a proposal was made for the ruthenium complexes [e-g_ compound IX] isolated from the reaction of RuCls(Ph& with hydrazines 181. Support for these formulations came from the reactions of these compounds with carbon monoxide in which one molecule of PhNH-NH2 was displaced from compound VIII, and one phosphine replaced by CO in compound IX (es- 7): Ru(PhNH-NH2)2(PPh3)2Clz
+ CO + Ru(PhNH-NH2)(CO)(PPhS),C12
+ PhNH-NH? (7)
(Jo
ERu(NH,-rNH,)(PPh,),C1,],
+ CO --, [Ru(NH,-NH,)(CO)(PPh,)Cl,],
+ PPhS
The IR data for com&uxis VIII-XI (Table.4) agree with our formulations, and the v[Ru-Cl) bands suggest a frrxtzsconfiguration of chlorines. In no case did we observe a z-eSct& beeee& CO and the coordinated amine or hydrazine.
TABLE
9
.--_.
H
.
4,49 (4,66)
4,70 (4,67)
482 (6,OB)
._._____” -.__._-
_-____
8.06 (8,112)
9.41 (0.77)
7.26 (7,76)
6821 (6~38) ____ _._.-_.___I__
3,82 (9096)
9.40 (985)
6,06 (6,14)
N ’ Cl -__ ~r._l__..----_I-..-I-
M solvent, c Benzene u ro!vcnt.
4&19 935 (4&l 6) (9,9b) -.__..___^._ _...____,__.__._ ._-.._-
prle*ysuow
62,24 (62.02)
6&99 (59.94)
yellow. orange yellow
02.77 (69.10)
aolutlon, b WC13
.____-_____._
12
C
._... l_l-II.“____-__--.~-_---~
(%)
. . ..- -..___-
Analyses found (c&d.)
brown
. .. ___.- _-.-_
In nltrobenaene
tRu(CO)(PPhj)(NH2-NH2)Cl2
Xl
f All aompounde ue non conductors
Ru(CO)(PPh3)2(PhNH-NH2,62
X
IRu(PPha)z(NH2-NH2)C11)1
/ IX ‘,
,’
R~(PP~~)~(P~NH--~JHz)~CI~
VIII
--“---.__
Colour
FOR HYDRAZINF, DERIVATIVES OF RUTHENIUM0 -_____“_.--__--_._ ___-_.. --...-
Compound
DATA
No.
ANALYTICAL
978 (SSS)
894 c (992)
1140 (1466)
760 (91.2)
Mol. wt. b
_.__
H
101 TABLE
4
IR ABSORPTION
BANDS
IN NUJOL
NO.
V
VIII
328O&h).326Om.317Ovw 329OW0.328Om. 32OOvw.316Ovw 3270m D
IX X XI
a6evenlbandsintbe33~3100
Experimental
DERIVATIVES
OF RUTHENIUhf
tic01
v
1940 1960
320 320 330 330
cm-lregion.
-
All reactions were carried out under nitrogen. Reaction mixtures were worked up in the air, unless otherwise stated. Solvents were dry and purified. The starting complexes [Ru(CO)~CI,]~ [?I, [Ru(COj,Br,], [lo] and Ru(PPh,),Cl, [ll] were prepared by published procedures. IR spectra were obtained using a Perkin-Elmer 457 instrument; ‘H NMR spectra were recorded on a Varian 60 spectrometer with Me,,Si as internal standard. Elemental analyses were carried out in the analytical laboratory of Milan University, except for oxygen analyses which were carried out by Pascher’s Analytical Laboratories, Bonn. Ru(CO)~(Bu’NH2)2Cl(CONHBu’) (I) To a suspension of [Ru(CO)&lJ2 (0.2 g) in chloroform (15 ml) was added Bu’NH, (0.5 ml)_ A clear solution was immediately formed. After few minutes a white product precipitated, and after 1 h this was filtered off and shown to be ButNH2 - HCI by comparison of its IR spectrum with that of an authentic sample. The chloroform solution was evaporated almost to dryness and n-hexane added to give a white precipitate. This was filtered off, washed repeatedly with water (co. 100 ml) to remove B&NH, - HCl, then with n-hexane, and was dried in vacua (yield ca. 60%). The compound can be crystallized from chloroform/n-hexane in the presence of free Bu’NH,. Ru(CO)~(Bu”NH~,Cl(CONHBu”) (I..) This compound was prepared as described for I but with a 3 h reaction time. Evaporation to dryness of the chloroform solution and prolonged scratching of the oily residue in presence of n-hexane gave a white powder, This was filtered off, washed repeatedly with water and n-hexane, and &ied in vacua. Ru(CO)Jp4UeCJidVH&!l(CONHC&Me-p) (HI) (a) To a suspension of [Ru(CO),C~,]~ (0.2 g) in chloroform (20 ml) was added p-MeC&NI& (0.6 g). The solution was refluxed for 2 h during which a little white precip$at.e form,& (and was shown to bep-MeC&LJUH~ HCL by IR spectroscopy). The solution was evaporated almost to dryness, and addition of n-hexane followed ,by r+ratching gave a tihite powder. This was filtered off, washed reIJ=@dIY_?Qt.Ir .= water tq remove p-MeC&N_HI -- HCl and then with ethyl ether and fiGBy ‘dried in vacua (yield ca. 70%): l
103 TABLE
4
IR ABSORPTION
BANDS
NO.
V
VIII IX X XI
3280&h). 329O(sh). 3270m a
IN NUJOL
3260~. 3170~~ 3280m. 3200~~.
a Several bands in tbe 33W31OCl
Experimental
FOR HYDRAZINE
3160~
DERIVATIVES tic01
v
1940
320 320 330 330
1960 cm-’
OF RUTHENIUM
region.
-
AlI reactions were carried out under nitrogen. Reaction mixtures were worked up in the air, unless otherwise stated. Solvents were dry and purified. The starting complexes [Ru(CO)~CIJ~ [q], [Ru(COj,Br,], [lo] and Ru(PPh,),C& [ll] were prepared by published procedures. IR spectra were obtained using a Perkin-Ehner 457 instrument; ‘H NMR spectra were recorded on a Varian 60 spectrometer with Me& as i.nternaI standard. Elemental analyses were carried out in the analytical laboratory of Milan University, except for oxygen analyses which were carried out by Pascher’s Analytical Laboratories, Bonn. Ru(CO)2(Bu’NH2)2Cl(CONHBu’) Bu’NH, (0.5 ml)_ A clear solution was immediately formed. After few minutes a white product precipitated, and after 1 h this was filtered off and shown to be ButNH2 - HCI by comparison of its IR spectrum with that of an authentic sample. The chloroform solution was evaporated almost to dryness and n-hexane added to give a white precipitate. This was fiRered off, washed repeatedly with water (ca. 100 ml) to remove Bu’NH, - HCl, then with n-hexane, and was dried in vacua (yield ca. 60%). The compound can be crystalhzed from chloroform/n-hexane in the presence of free Bu’NH,. Ru(CO)2(Bu”NH2)2Cl(CONHBu”) (I..) This compound was prepared as described for I but with a 3 h reaction time. Evaporation to dryness of the chloroform solution and prolonged scratching of the oily residue in presence of n-hexane gave a white powder, This was filtered off, washed repeatedly with water and n-hexane, and dried in vacua. Ru(CO)~(p-A4eCJidVH2)&l(CONHC&Me-p) (HI) (a) To a suspension of [Ru(CO),CIJz (0.2 g) in chloroform (20 ml) was added p-Me&&NH, (0.6 g). The solution was retluxed for 2 h during which a little white precipitate fOnn,ea
and my
.&a
in tititi
(y@H
ca ,oS)_
Ru(CO)(PPh,),(PhNH-NH&l,
(X)
Compound VIII (0.16 g) was added to benzene (20 ml) while CO was bubbled through. The initial brown solution becarne yellow. After two days the solution was evaporated to small volume, and on addition of n-hexane the yellow product precipitated. It was filtered off, washed with n-hexane and dried in vacua. [Ru(CO)(PPh,)(NH,-NH&&J,
(XI)
Compound IX (0.1 g) was suspendedin chloroform (25 ml) while CO was bubbled through. After 12 h the lemon-yellow solution was evaporatedto small volume, and addition of n-hexane gave a pale-yellow product precipitated,which was filtered off, washed with n-hexane, and dried in vacua. Reactions
of Ru(PPh,)&I,
with aromatic
amines and carbon monoxide
Ru(PPh&Clr (0.25 g) and p-MeC6H4NH2 (0.14 g) were added to benzene (20 ml). After 6 h the red-violet solution was evaporated to small volume and n-hexane was added- The red-violet precipitate (O-1 g) was filtered off, washed with n-hexane and some of it was dissolved in benzene (15 ml) while CO was bubbled through. After 5 h the solution was evaporated to small volume and addition of n-hexane gave a grey precipitate.This was filtered off, washed with
n-hexane, and dried in vacua. It (m.p. 140°C) arialysedas Ru(CO)(PPha) @-MeC6H4NH2)&12, found: C, 58.70; H, 4.48; N, 3.93; Cl, 9.90; mol. wt., ‘714 in CHC13.Calcd.: C, 58.50; H, 4.88; N, 4.13; Cl, 10.49%; mol. wt., 676. v(eO) 1990(br) cm-‘, nujol mull. Similarresultswere obtained when p-MeOCsHeNH2 was used. Acknowledgements
We thank the Italian C.N.R. for financialsupport, and Dr. P. Fantucci for the
‘H NMR spectra.
References 1 S. Cenini and G. Jk Monica. Ino% Chbn Acta Rev.. 18 (1976) 279. 2 J.P. Collm8n. hf. Kubota. F.D. Vutine. J.Y. Sun and J.W. Kanp. J. Amer. Chem. Sot.. SO (1968) Act Chem. Rcr. 5 (1972) 335: 3 R.J. Anwlid. (b) W_ Beck and B. Purucker. J_ OrgrnomctaL Chem.. 112 (1976) 361. 4 S. Ozald, Chem. Rev., 72 (1972) 457. 5 E.W. Stem and M.L. Spector. J. Grg. Chcm.. 31<1966) 696. 6 S. Ceaini. A¶.Pizzotti. F. Porta and G. Ia Monica. J. Orgauometal. Chem.. 88 (1975) 237. 7 J.D. Gilbert red G. Wilkinson. J. Chem. Sot. A. (1969~1749. 6 J. Cbatt, G.J. Lei& and R.J. Paske. J. Cbem. Sot. A. <1969) 854. 9 A. Mantovard and S. Cudni. Inor& SYU.. 16 (1976) 51. E. Benedettiaad P. Pino. Cbim. Ind.
6430.
Journal of Organometallic Chemistry. 125 (1977) 95-103 0 Ekevier Sequoia S-A_. Lausanne - Printed in The Netherlands
LOW OXIDATION STATE RUTHENIUM CHEMISTRY HI *a THE REACTIONS OF AMINES WITH [ Ru(CO)sCl, 12AND RELATED COMPLEXES l*, M. PIZZOTIT,
S. CENINI C.N.R
F. PORTA
and G. La MONICA
Center. Zstituto di Chimica Genemle.
(Received June 28th,
Ea
Venezinn 21.20133
Milan0 (Ztaly)
1976)
Summarv Carbamoyl complexes of ruthenium(II), Ru(CO)~(RNH~)~CI(CONHR), have been isolated from the reactions of [ Ru(CO)~CI& with the amines RNHl (R = But, Bun, p-Me&&, p-MeOC&). By reaction of the carbamoyl complex (R = p-Me&&) with triphenylphosphine and hydrochloric acid the derivatives Ru(CO),(PPh&Cl(CONHR) and [Ru(CO)~(RNH~)~CI]+CT have been obtained. The complex Ru(PPh&C& did not give fully characterizable products in reactions with aromatic amines and carbon monoxide, but reacted with hydraxines and CO to give the complexes [Ru(PPh,)L(NH,-NH,)Cl,], (L = PPh3, CO) and Ru(PPh3)2L(PhNH-NH2)Clt (L = PhNH--NH,, CO).
Introduction
.
During our studies on the reactions of organic azides RN3 with carhonyl complexes of transition metals in low oxidation states, we prepared isocyanate derivatives by treatment of RN3 with coordinated carbon monoxide [l] (eq. la), a reaction discovered by Collman [2]: L,MCO
+ RN, + L,M(RNCO)
LJQRNCO)
+ Ns
(la)
+ HX + [L,,M(CONHR)r(X-)
(lb)
Protonation of the isocyanate complexes with mineral acids readily gave carbamoyl derivatives [l] (eq. lb). It is well known that carbamoyl complexes can be obtained by nucleophilic attack of aliphatic amines on coordinated car. -. -_
l
Forputlf~~li ; l‘&&&+gap
_+_&.&&&&_
_ _.
J
,
96
bon monoxide 131and the reaction of COC& with primary amines is the commonest route to organic isocyanates [4] (eq. 2): COClr + 3 RNHr
--RNH2
- HS
RmCwl
-RNH2_RNC0
(2)
Moreover a carbamoyl palladium complex has been suggested 133 as an intermediate during the reaction of amines with CO in the presence of palladium(H) chloride to give isocyauates [ 51. We thus undertook a study of the reactions of amines with a dichlorocarbonyl compiex, [Ru(CO),Cl,b, with’ the objective of producing chiorocarbamoyl complexes, which would give isocyanate derivatives by loss of HCl. Cblorocarbamoyl complexes of palladium and platinum have been recently reported [3b]. We have also studied the reactions of Ru(PPh&Ch with amines, and the reactions of the products with carbon monoxide. Results and discussion Reactions of [Ru(COJ3C12 jz with amines [~u(CO),Cl,]~ reacts with primary amines giving chlorocarbamoyl according to eq_ 3 (Table 1): Ru(CO)~(RNH&CI(CONHR)
IRuKX%CM~ + 8 RM-L -2 (R = But, I; Bun, II;p-Me&&,
III;p-MeOC&,
IV)
complexes
+ 2 RNH,
* HX (3)
Secondary amines did not give readily characterizable products. These reactions usually involve aliphatic amines and cationic carbonyl complexes [3] and it was of interest that aromatic amines also react, although under slightly more drastic conditions (at reflux) than those for the aliphatic amines (room temperature). A cationic ruthenium-carbonyl complex is probably involved as an intermediate even in reaction 3, aud_this point is considered below. In all eases the reaction also gives the salts RNH, - H2L Even when reaction 3 (R = p-MeC&&) was carried out in THF at 100°C and under CO pressure (20 atm), compound III was the only product isolated. When we attempted the reactions with the bromo Fo_mplex, [Ru(CO),Br,& in bromoform as &vent, rates were lower and the products more difficult to purify- Only compound V; [Ru(CO)2(p-MeC,I-I.NHz)Br(CONHC~~Me-p)~, gave acceptable elemental analyses. This compound is possibIy dimeric with bridging bromines (x = 2), having only five ligauds per metal atom. The observed molwt. is distinctly higher than that required for a monomer (Table l), but not satisfactory for a dimeric formulation. However the mol_wt.‘s were not very satisfactory even for the 6-coordinated derivatives, being slightly higber in some cases . than required; a fact for.which we have no-explanation. Compounds I and III react with JriphenyIpbospbine in benzene to give .tbe corresponding_ 1 carbamoyl derivativ_eswithtriphenylphosphine hgands (eq_ .4): . _ ~_ -- :.
Ru(CO),(RNH,),Cl(CONI+R) _~....
+-2_PPh, + Ru(CO)&?P&3l(C&iRj :
_
However onIy compound VI (R~.?&Me&) -_ .
.. -
a&&
’ -1
+ 2 R@H,
_--. :_ : (4) ’ __ >-:_:->_:A ; .+&;;~ :._____!. F be &++oMt&d (-XX-: - I’. -_z-..~;.“-> 1._:=-,-
I
“Vu.
_--_-_.._-.__
IBu(CO)[email protected])NH2)2ClJ’CI_.-I^_”
... I.____
_
..-.. .,.
._
.
.
.
.
.
whlta _.”
.___
white
RU(C~)~(PP~J)~CI(CONHC~H~M~.~)
“l.
-_.__I.-.____
-
154
pIb r230 yellow
~~~~CO)~@:MOC~H~NH~)D~CONHC~~CIMO~)J,
Y
___..
..-.__
43.03 (43.34) .
.
.._.
3,47 (3,SS)
4.394,54 (4.45)
4.08 (3,56)
4021 (4,41)
4.594.46 (4.78)
6.90 (7,29)
7.50 (7.29)
_“-.---...-_-..-.___.__..._“-.___-I-
63.46-66.li (64,87)
42.35' (42,67)
47.91 (45.95)
149-44
white
RU(C0)[email protected])2Cl(CONHC6H~OMc.p)
1y..
a,7 (41.0)
40.47 (41.04)
52.90-53.96 (53.23)
149
152
155-70
whita
white
..__.._____._.__--_^_-.l_l--_--
Malunll Analysaslfound (calcd.) (%) polrlt --H C (W ._______.____., _____.__-_...--
Whit0
~u(CO)2(Bu”NH2)2Cl(CONHBun)
Ru(bO)2(DutNH2)2CI(CONHBut)
_____“__..__
Colour
FOR CARBAMOYL COMPLEXES OF RUTHENIUM _--_-__ _--...__ _.^__...__.._-,..--
J11, R~~(~O)[email protected]~C~H~NH~)~C~(CONHC~H~M~.P)
11”
,,:I i:
ANAtiYnOAL DATA :, s ‘ ‘No; Oombound
5072 (5,96)
1.78-1.65 (1,64)
5.92 (6,87)
7,0a (7,14)
7,66-7.91 (7,76)
9,oa Kh50)
9,60 (9,56)
N _-.__ -..-_-__
15.13 (15.10)
4.5-4.9 (4.17)
16.88 (16.70)
7.12 (6.54)
8,64 WO)
8.52 (6,lO)
ClorBr
6,51 (5,64)
8838 (8,ft6)
0
822 (Sal)
650 (478)
414 (589)
503 (541)
515 (439)
557 (439)
Mol.wt, In CHCIJ
,
98
perimental), and these derivatives appear to be rather unstable, especially in solution. When reaction 4 was conducted in chloroform only the white c&Ru(CO)~(PPh&Cl, was isolated_ Like I-V, compound VI is a non-conductor in nitrobenzene. The presence of the carbamoyl ligand in these compounds was confirmed by oxygen analyses (compounds III and VI) and by reaction of compound III with hydrochloric acid in a non polar solvent, such as benzene, in which the product is insoluble (eq. 5) (cf- ref. 3) (Table 1): Ru(CO),(RNH,),CI(CONHR) om
+ 2 HCI --, [ Ru(CO),( RNHt)#l]+
-
Cl- + RNHz - HCI (5)
(VD:R=p-MeC&,)
The IR data for compound VII (Table 2) are in accordance with its formulation; in particular three v(C=O) bands were present in the carbonyl stretching region. The ‘H NMR data of compound VII are not reported because this derivative is uns*IabIein solution, nucleophilic attack by the anion giving a non ionic product which has not been fully investigated. Our formulation of VII as an ionic compound is based only on the 6-coordination of this cation. Compound VII is probably the cationic intermediate formed during reaction 1. Compounds I-VI presumably should produce isocyanate complexes of formula Ru(CO)&(RNCO) by loss of HCl. We found that reaction did take place with strong organic or inorganic bases but the products could not be characterized. Ruthenium-isocyanate complexes having L = PPhS and R = Ar-$Z- have 0 been made by another route [S], but their stability was attributed to the formation of a metallacycle involving the X=0 group of the aroyl isocyanate ligand. In their IR spectra compounds I-VI show two v(C=O) bands of equal intensity, indicative of a cis-arrangement of the carbonyl groups (in some preparations, compounds III, IV and V also gave a very weak band at higher frequencies).
TABLE2 OF RUTHENIUM
SPECTROSCOPICDATAFORCARBAMOYLCOMPLEXES No_
IRabaorptianb~~ia~ol(cm-')
'IiNMR_spectrainCDCl3
V(NH)
v(NHd
v
v
r
r
T
I II
3440 3360
3265-3240 3280-3230
2035-1960
1605-1580 159+155G
f-"
it-1
$t.68--8.71e
III IV V VI VII
3435 3420 3430 3330 -
3220-3120 3220-3110 3210-3120 3230-3170
2065-1985 2060-1980 206Wl980 2060-1970 213W2080 2060
162(t-1605-1590 1615-1606-1686 1625--161X+1680 169~lp80 . 1605-1675
6.7 5
4.35 4.3= 4.92 4-7 -
-
7.66-7.78 6.27-6.34c 7.74 -
99
Three bands were observed for compounds I-V in the 3450-3100 cm-’ region. The absorption at higher frequency is attributed to v(NH) of the carbamoyl group, since the two vibrations at lower frequencies are absent in compound VI, in which the amine has been replaced by triphenylphosphine. In the 1600 cm-’ region more and broad absorptions were observed, probably due to v(>C=O) of the carbamoyl group and to &NH) of the amines and RNHCOligands. The ‘H NMR spectra (Table 2) in most cases showed broad signals due to r(NH,) and 7(NH), these signals generally disappeared on treatment with D20. Compounds I, III and IV also show two distinct signals due to the paru substituent of the aromatic amines or to the Bu’ groups; these signals were approximately in the expected 2 : 1 ratio.
Reactions of Ru(PPh3)&12 with hydrazines and carbon monoxide Ru(PPh3),Cl, reacts with pyridine to give Ru(amine),(PPh&&
[7]. It also readily reacted in benzene with aromatic amines, but the violet products isolated from these reactions did not give satisfactory elemental analyses. By carbonylation of these materials, at atmospheric pressure, we isolated products which analysed correctly as Ru(CO)(PPh,)(RNH,),C1, (R = p-MeC,H,, p-MeOC,H,) (see experimental). However the IR spectra of these compounds showed a broad v(C=O) band below 2000 cm-‘, possibly due to the presence of other isomers. Well defined products have been isolated from the reactions of Ru(PPh&& with hydrazines (eq. 6) (Table 3): Ru(PPh&C12 + RNH-NH* (VIII): (IX):
R= Ph; R=H;
n = 2; n=l;
+ [ Ru( RNH-NH2),(PPh3)2Cll]m
(6)
m = 1 m=2
Compound IX is probably dimeric with bridging hydrazine, but the phenylhydrazinc derivative VIII adopts a monomeric structure because of the steric effect of the phenyl substituent. Such a proposal was made for the ruthenium complexes [e-g_ compound IX] isolated from the reaction of RuCls(Ph& with hydrazines 181. Support for these formulations came from the reactions of these compounds with carbon monoxide in which one molecule of PhNH-NH2 was displaced from compound VIII, and one phosphine replaced by CO in compound IX (es- 7): Ru(PhNH-NH2)2(PPh3)2Clz
+ CO + Ru(PhNH-NH2)(CO)(PPhS),C12
+ PhNH-NH? (7)
(Jo
ERu(NH,-rNH,)(PPh,),C1,],
+ CO --, [Ru(NH,-NH,)(CO)(PPh,)Cl,],
+ PPhS
The IR data for com&uxis VIII-XI (Table.4) agree with our formulations, and the v[Ru-Cl) bands suggest a frrxtzsconfiguration of chlorines. In no case did we observe a z-eSct& beeee& CO and the coordinated amine or hydrazine.
TABLE
9
.--_.
H
.
4,49 (4,66)
4,70 (4,67)
482 (6,OB)
._._____” -.__._-
_-____
8.06 (8,112)
9.41 (0.77)
7.26 (7,76)
6821 (6~38) ____ _._.-_.___I__
3,82 (9096)
9.40 (985)
6,06 (6,14)
N ’ Cl -__ ~r._l__..----_I-..-I-
M solvent, c Benzene u ro!vcnt.
4&19 935 (4&l 6) (9,9b) -.__..___^._ _...____,__.__._ ._-.._-
prle*ysuow
62,24 (62.02)
6&99 (59.94)
yellow. orange yellow
02.77 (69.10)
aolutlon, b WC13
.____-_____._
12
C
._... l_l-II.“____-__--.~-_---~
(%)
. . ..- -..___-
Analyses found (c&d.)
brown
. .. ___.- _-.-_
In nltrobenaene
tRu(CO)(PPhj)(NH2-NH2)Cl2
Xl
f All aompounde ue non conductors
Ru(CO)(PPh3)2(PhNH-NH2,62
X
IRu(PPha)z(NH2-NH2)C11)1
/ IX ‘,
,’
R~(PP~~)~(P~NH--~JHz)~CI~
VIII
--“---.__
Colour
FOR HYDRAZINF, DERIVATIVES OF RUTHENIUM0 -_____“_.--__--_._ ___-_.. --...-
Compound
DATA
No.
ANALYTICAL
978 (SSS)
894 c (992)
1140 (1466)
760 (91.2)
Mol. wt. b
_.__
H
101 TABLE
4
IR ABSORPTION
BANDS
IN NUJOL
NO.
V
VIII
328O&h).326Om.317Ovw 329OW0.328Om. 32OOvw.316Ovw 3270m D
IX X XI
a6evenlbandsintbe33~3100
Experimental
DERIVATIVES
OF RUTHENIUhf
tic01
v
1940 1960
320 320 330 330
cm-lregion.
-
All reactions were carried out under nitrogen. Reaction mixtures were worked up in the air, unless otherwise stated. Solvents were dry and purified. The starting complexes [Ru(CO)~CI,]~ [?I, [Ru(COj,Br,], [lo] and Ru(PPh,),Cl, [ll] were prepared by published procedures. IR spectra were obtained using a Perkin-Elmer 457 instrument; ‘H NMR spectra were recorded on a Varian 60 spectrometer with Me,,Si as internal standard. Elemental analyses were carried out in the analytical laboratory of Milan University, except for oxygen analyses which were carried out by Pascher’s Analytical Laboratories, Bonn. Ru(CO)~(Bu’NH2)2Cl(CONHBu’) (I) To a suspension of [Ru(CO)&lJ2 (0.2 g) in chloroform (15 ml) was added Bu’NH, (0.5 ml)_ A clear solution was immediately formed. After few minutes a white product precipitated, and after 1 h this was filtered off and shown to be ButNH2 - HCI by comparison of its IR spectrum with that of an authentic sample. The chloroform solution was evaporated almost to dryness and n-hexane added to give a white precipitate. This was filtered off, washed repeatedly with water (co. 100 ml) to remove B&NH, - HCl, then with n-hexane, and was dried in vacua (yield ca. 60%). The compound can be crystallized from chloroform/n-hexane in the presence of free Bu’NH,. Ru(CO)~(Bu”NH~,Cl(CONHBu”) (I..) This compound was prepared as described for I but with a 3 h reaction time. Evaporation to dryness of the chloroform solution and prolonged scratching of the oily residue in presence of n-hexane gave a white powder, This was filtered off, washed repeatedly with water and n-hexane, and &ied in vacua. Ru(CO)Jp4UeCJidVH&!l(CONHC&Me-p) (HI) (a) To a suspension of [Ru(CO),C~,]~ (0.2 g) in chloroform (20 ml) was added p-MeC&NI& (0.6 g). The solution was refluxed for 2 h during which a little white precip$at.e form,& (and was shown to bep-MeC&LJUH~ HCL by IR spectroscopy). The solution was evaporated almost to dryness, and addition of n-hexane followed ,by r+ratching gave a tihite powder. This was filtered off, washed reIJ=@dIY_?Qt.Ir .= water tq remove p-MeC&N_HI -- HCl and then with ethyl ether and fiGBy ‘dried in vacua (yield ca. 70%): l
103 TABLE
4
IR ABSORPTION
BANDS
NO.
V
VIII IX X XI
3280&h). 329O(sh). 3270m a
IN NUJOL
3260~. 3170~~ 3280m. 3200~~.
a Several bands in tbe 33W31OCl
Experimental
FOR HYDRAZINE
3160~
DERIVATIVES tic01
v
1940
320 320 330 330
1960 cm-’
OF RUTHENIUM
region.
-
AlI reactions were carried out under nitrogen. Reaction mixtures were worked up in the air, unless otherwise stated. Solvents were dry and purified. The starting complexes [Ru(CO)~CIJ~ [q], [Ru(COj,Br,], [lo] and Ru(PPh,),C& [ll] were prepared by published procedures. IR spectra were obtained using a Perkin-Ehner 457 instrument; ‘H NMR spectra were recorded on a Varian 60 spectrometer with Me& as i.nternaI standard. Elemental analyses were carried out in the analytical laboratory of Milan University, except for oxygen analyses which were carried out by Pascher’s Analytical Laboratories, Bonn. Ru(CO)2(Bu’NH2)2Cl(CONHBu’) Bu’NH, (0.5 ml)_ A clear solution was immediately formed. After few minutes a white product precipitated, and after 1 h this was filtered off and shown to be ButNH2 - HCI by comparison of its IR spectrum with that of an authentic sample. The chloroform solution was evaporated almost to dryness and n-hexane added to give a white precipitate. This was fiRered off, washed repeatedly with water (ca. 100 ml) to remove Bu’NH, - HCl, then with n-hexane, and was dried in vacua (yield ca. 60%). The compound can be crystalhzed from chloroform/n-hexane in the presence of free Bu’NH,. Ru(CO)2(Bu”NH2)2Cl(CONHBu”) (I..) This compound was prepared as described for I but with a 3 h reaction time. Evaporation to dryness of the chloroform solution and prolonged scratching of the oily residue in presence of n-hexane gave a white powder, This was filtered off, washed repeatedly with water and n-hexane, and dried in vacua. Ru(CO)~(p-A4eCJidVH2)&l(CONHC&Me-p) (HI) (a) To a suspension of [Ru(CO),CIJz (0.2 g) in chloroform (20 ml) was added p-Me&&NH, (0.6 g). The solution was retluxed for 2 h during which a little white precipitate fOnn,ea
and my
.&a
in tititi
(y@H
ca ,oS)_
Ru(CO)(PPh,),(PhNH-NH&l,
(X)
Compound VIII (0.16 g) was added to benzene (20 ml) while CO was bubbled through. The initial brown solution becarne yellow. After two days the solution was evaporated to small volume, and on addition of n-hexane the yellow product precipitated. It was filtered off, washed with n-hexane and dried in vacua. [Ru(CO)(PPh,)(NH,-NH&&J,
(XI)
Compound IX (0.1 g) was suspendedin chloroform (25 ml) while CO was bubbled through. After 12 h the lemon-yellow solution was evaporatedto small volume, and addition of n-hexane gave a pale-yellow product precipitated,which was filtered off, washed with n-hexane, and dried in vacua. Reactions
of Ru(PPh,)&I,
with aromatic
amines and carbon monoxide
Ru(PPh&Clr (0.25 g) and p-MeC6H4NH2 (0.14 g) were added to benzene (20 ml). After 6 h the red-violet solution was evaporated to small volume and n-hexane was added- The red-violet precipitate (O-1 g) was filtered off, washed with n-hexane and some of it was dissolved in benzene (15 ml) while CO was bubbled through. After 5 h the solution was evaporated to small volume and addition of n-hexane gave a grey precipitate.This was filtered off, washed with
n-hexane, and dried in vacua. It (m.p. 140°C) arialysedas Ru(CO)(PPha) @-MeC6H4NH2)&12, found: C, 58.70; H, 4.48; N, 3.93; Cl, 9.90; mol. wt., ‘714 in CHC13.Calcd.: C, 58.50; H, 4.88; N, 4.13; Cl, 10.49%; mol. wt., 676. v(eO) 1990(br) cm-‘, nujol mull. Similarresultswere obtained when p-MeOCsHeNH2 was used. Acknowledgements
We thank the Italian C.N.R. for financialsupport, and Dr. P. Fantucci for the
‘H NMR spectra.
References 1 S. Cenini and G. Jk Monica. Ino% Chbn Acta Rev.. 18 (1976) 279. 2 J.P. Collm8n. hf. Kubota. F.D. Vutine. J.Y. Sun and J.W. Kanp. J. Amer. Chem. Sot.. SO (1968) Act Chem. Rcr. 5 (1972) 335: 3 R.J. Anwlid. (b) W_ Beck and B. Purucker. J_ OrgrnomctaL Chem.. 112 (1976) 361. 4 S. Ozald, Chem. Rev., 72 (1972) 457. 5 E.W. Stem and M.L. Spector. J. Grg. Chcm.. 31<1966) 696. 6 S. Ceaini. A¶.Pizzotti. F. Porta and G. Ia Monica. J. Orgauometal. Chem.. 88 (1975) 237. 7 J.D. Gilbert red G. Wilkinson. J. Chem. Sot. A. (1969~1749. 6 J. Cbatt, G.J. Lei& and R.J. Paske. J. Cbem. Sot. A. <1969) 854. 9 A. Mantovard and S. Cudni. Inor& SYU.. 16 (1976) 51. E. Benedettiaad P. Pino. Cbim. Ind.
6430.