TRIPHENYLARSINE COMPLEXES O F COBALT(I1) 239
Vol. 1, No. 2, May 1962
CONTRIBUTION FROM THE DEPARTMENT O F CHEMISTRY, MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE 39, MASSACHUSETTS
Triphenylarsine and Triphenylarsine Oxide Complexes of Cobalt(I1) BY D. M. L. GOODGAME, M. GOODGAME, AND F. A. COTTON'
Received October 9, 1961 This paper reports spectral, magnetic, and X-ray powder data for several cobalt( 11) complexes of triphenylarsine J. In addition oxide, and the preparation and characterization of the triphenylarsine complex, [Co(( CSH~)~AS)ZIY to the compounds [eo((C&)3As0)&12], [co(( C6H6)3AsO)~Br2], and [co(( C & ~ ) ~ A S O c) ~l o] (4 ) ~previously re[Co((CSH~)~ASO)~]IZ, and [Co((C6H6)3ported by Phillips and Tyree, the new compounds [Co(( CSH~)~ASO)ZI~], AsO)$(NCS)2]also were studied. The results are discussed in terms of ligand field theory. Points of particular ) ~which ] I ~ , the neutral ligand has displaced an anionic ligand, interest are the formation of [eo(( C ~ H ~ ) ~ A S O in the evidence that in the thiocyanate complex the thiocyanate ions are N-bonded, and the properties of [Co(( C6H6)3A~)212], which is the only triphenylarsine complex which could be isolated, although several analogous triphenylphosphine complexes of Co(11) are known.
Introduction The coordination compounds of triphenylphosphine oxide with a number of transition metals have been examined in some The information on complexes of triphenylarsine oxide is more limited, however. There have been a few isolated examples of complexes containing arsine oxides in the earlier literature12-14; more recently, Phillips and Tyree16 have made a general survey of the coordination chemistry of triphenylarsine oxide, reporting complexes with salts of eight transition metals and two non-transition metals, and previous papers from this Laboratory have reported in detail on the molecular and electronic structures of complexes of Cu(I1) halides,1° Ni(11) halides,lB and Mn(I1) halides.ll In this paper we are reporting a similar detailed study of some Co (11) complexes of triphenylarsine oxide. In addition, we have attempted to prepare triphenylarsine complexes of Co(I1) analogous to
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(1) Alfred P. Sloan Foundation Fellow. (2) R. H . Pickard and J. Kenyon, J . Chem. Soc., 262 (1906). (3) J. C. Sheldon and S. Y . Tyree, J . Am. Chem. SOC.,80, 4775 (1958). (4) K. Issleib and B. Mitscherling, 2. anorg. u. allgem. Chem., 304, 73 (1960). ( 5 ) F. A. Cotton and E. Bannister, J . Chem. Soc., 1873 (1960). (6) E. Bannister and F. A. Cotton, ibid., 1878 (1960). (7) E. Bannister and F. A. Cotton, ibid., 2276 (1960). (8) F. A. Cotton, R. D. Barnes, and E. Bannister ibid., 2199 (1960). (9) F. A. Cotton and D. M. L. Goodgame, J . Am. Chem. Soc., 82, 5771 (1960). (10) D. M. L. Goodgame and F. A. Cotton, J . Chem. Soc., 2298 (1961). (11) D. M. L. Goodgame and F. A. Cotton, ibid., 3735 (1961). (12) A. Partheil, e l al., Archiw. Pharm., 287, 136 (1899). (13) R. S. Nyholm, J . Chem. Sod., 1767 (1951). (14) H. A. Goodwin and F. Lions, J . A m , Chem. Soc., 81, 311 (1959). (15) D. J. Phillips and S. Y. Tyree, ibid., 88, 1806 (1961). (16) D. M. L. Goodgame and F. A. Cotton, Ibid., 82, 5774 (1960).
those formed by triphenylphosphine.
17118
Experimental Preparation of Compounds. Diiodobis( triphenylarsine)cobalt(II).-A hot solution of triphenyl arsine (4 08 g., 0.0133 mole) in nitromethane (20 ml.) was mixed with one of hexaaquo cobalt(I1) iodide (2.81 g., 0.0067 mole) in the same solvent ( 5 ml.). The deep.green solution obtained yielded brown crystals on cooling. These were filtered, washed with a small quantity of diethyl ether, and dried in vacuo over sulfuric acid; yield, 2.07 g. (33%), m.p. 200". Anal. Calcd. for C ~ ~ H ~ O A S ~ C, C O46.73; I Z : H, 3.27; As, 16.19; I, 27.44. Found: C, 46.64; H, 3.23; As, 15.92; I, 27.43. The compound forms green solutions in cold chloroform, acetone, or acetonitrile, but a blue solution is formed with cold ethyl acetate. I t is insoluble in cyclohexane, carbon tetrachloride, and chlorobenzene, and decomposed by methylene chloride or dioxane. Dihalobis(triphenylarsine oxide)cobalt(II) Compounds. -khese were all prepared by essentially the same method. A solution of triphenylarsine oxide (0.01 mole) in absolute ethanol ( N 6 ml.) was mixed with a solution of the cobalt salt (0.005 mole) in absolute ethanol (- 5 ml.). For the chloro and bromo compounds the products separated immediately as blue crystals. For the thiocyanato compound the product separated from hot solution as a blue oil which subsequently was crystallized by cooling the mixture for 2 hr. in a refrigerator followed by warming and stirring. In preparing the iodo compound, as the CoI2 solution was added to the (C&&AsO solution a bright blue solid formed immediately but on completion of the addition of the COIZ the color of the solid tended to blue-green. The mixture was heated to boiling and then allowed to cool with stirring for an hour when the solid was entirely blue-green The crystals of all complexes were filtered, washed once with cold absolute ethanol, and dried i n vacuo over sulfuric acid The yields, colors, melting points, and analyses of these compounds are given in Table I. (17) P. A. Cotton, 0. D. Faut, D. M. L. Goodgame, and R. H . Holm, ibid., 38, 1780 (1961) (18) F. A. Cotton, D. M. L. Goodgame, M. Goodgame, and A Sacco, i b t d . , 83, 4157 (1961).
240 D. M. L. GOODGAME, M. GOODGAME, AND F. A. COTTON
PROPERTIES AND
TABLE I ANALYTICAL DATAFOR cO( ( C ~ H ~ ) ~ . ~ S OCOMPOUNDS )Z&
-__~
M.P.
Found
Calcd.
Found
Analyses---CI, Br, I, or N Calcd. Found Calcd.
232 214 205 201
55.6 49.9 45.6 55.6
55.84 50.09 45.17
3.91 3.52 3.18 3.96
3.91 3.50 3.16 3.69
Sield, Compound
Color
cO((C,jHs)&O)zC12 Co(
