A new hydrido complex of Ir(I) with triphenylphosphite

INORG.

NUCL.

A NEW

CHEM.

LETTERS

Vo|.

5,

pp.

767-769, 1 9 6 9 .

Pergamon Pre*s.

Prlnt.d

In

Greet

HYDRIDO COMPLEX OF Ir(1) WITH TRIPHENYLPHOSPHITE D. Giusto ( R e t r i e d 21 M ~ 1969; In ~ v l s ~ ~

~ Jun* 1969)

CoN.Ro Centro dei Composti di Coordinazione~ Istituto di Chimi ca Generale d e l l T U n i v e r s i t ~ Via Venezian 21, 20133 Milan~

Many complexes of transition metals such as Co (1,3,4), Rh(l,2,4),

Ir (i~2), Fe (3)~ Os (1,2), Re (5) have been prepa-

red very recently,

showing an increasing interest to the phos-

phite esters as ligands, although some platinum(O) have

been

prepared more then ten years ago (6). This work reports the preparation of HIr[P(OPh)3]4~

closely related to the Cobalt

(1,3~4) and Rhodium (1,4) derivatives, and very similar to the known HIr(PF3)4 (7)° It is obtained by reaction of H3Ir(PPh3)3 with P(OPh)3 as a white crystalline compound (MOP.=127°), stable to (Calc. for HIr~P(OPh)3]4:

the

air°

C, 60.21; H, 4.25; O, 13.4; M.W.1435o

Found: C~ 60.15; H~ 4°24; O, 12.98; M.W. 1475). The reaction was carried out treating i gr of H31r(PPh3)3 with 2 cc of

triphenylphosphite in a test tube at iO0 ° (oil bath)

for I hr~ (until there i~ no more gas developing from the reaction) o The mixture was then treated with 25 cc of n-hexane and very quickly filtered. By standing overnight~ a white crystalline precipitate is formed, then recrystallised from chloroform and ethanol (gr O.360~ yield ~ 2 5 % ) o Both its infrared spectrum~ recorded

on a Perkin-Elmer 621

spectrometer in chloroform solution at room temperature and -I showing a band of medium intensity at 2055 cm , and N.M.R. spectrum, recorded on a Pe~kin-Elmer RIO spectrometer at 60 Mc in chloroform solution at room temperature and showing an absorption centered at 23

~ confirm the presence of a hydri-

767

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COMPLEX OF I,(I)

768

Vol. 5, No. 9

dic hydrogen atom (the relative intensities of the signals due to the aromatic and hydridic hydrogen atoms are very close to 60;i). The absorptions at 23

in the N.M.R. spectrum is ~ l i t

into a quintuplet with coupling constant J = 25 e.p.s. Some suggestions about the stereochemistry of this compound can be drawn by the N.M.R. spectrum. In agreement with a pentacoordination,

the compound can assume three different configu-

rations: (a) square pyramidal (C4v symmetry); (b) trigonal bipyramidal symmetry); 2v (c) trigonal bipyramidal

(hydridic hydrogen in equatorial pos!

tion, C

(hydridic hydrogen in axical position,

C

symmetry). SV The apparent magnetic equivalence of the ~ I nuclei leads to consider the structure (a) the only consistent with the N.M.R. spectrum. Unless, as for the related Cobalt and Rhodium complexes (4), it would be considered a tetrahedral configuration of the phosphorus atoms of the ligands with an intra or intramolecular rearrangement of the hydridic hydrogen in solution. A similar behavior has been also suggested for the Rhenium hydrido complexes, such as H 5 R e [ P ( P h ) ~ 8

and HTRe[P(Ph)s]2

(8,9). An X-ray analysis of this compound, now in progress, will give more detailed information. Acknowledgment - The author thanks Mrs. M. Bonf& for molecular weight determination and Dr. G. Bonora for N.M.R. spectrum recording°

References i. J.J. LEVISON, S.D. ROBINSON - Progr. Coord. Chem. Ed. M. Cais p. 319 (1968) 2. S.D. ROBINSON - Chem. Comm. 521 (1968) 3. W. KRUSE, R.H. ATALLA - Chem. Comm. 921 (1968)

Vol. 5, No. 9

COMPLEX OF Jr(l)

4. J.J. LEVISON,

S.D. R O B I N S O N

5. M. FRENI - P r i v a t e 6. L. M A L A T E S T A ,

7. T. K R U C K - Angew. 8. Lo M A L A T E S T A ~

9o J.CHATT,

M.

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(1968)

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