The dihydrate heated in V U C Z L Ofor 6 h r . at 58" yielded the aiihydrous compound, a purple crystalline material. Anal. Calcd. for Co(CbH.102)?: Co, 22.94; C, 46.71; II, 3.48. Found: C0,22.8; C,46.89; 1-1,5.56. Bis-( salicylaldehyde)-Co( II).-The procedure of Tyson and hdams'8 led t o a n orange crystalline product, t h e dihydrate. Anal. Calcd. for C O ( C ~ H S O ~ ) ~ . ~ HCo, * O :17.48; C, 49.85; H , 4.18. Found: Co, 17.2; C , 49.97; H , 4.48. By heating the dihydrate i n vacuo for 12 h r . a t B o , t h e brown crystalline anhydrous compound was obtained. Anal. Calcd. for C O ( C , H S O ~ ) ~C:o , 19.57; C, 55.81; IH,3.3.5. Found: Co, 19.6; C, 55.71; H, 3.61. Bis-(benzoy1acetonato)-Co(I1) .-The compound was reported previously by Musante.'Q T h e orange-brown product was obtained by direct reaction of an aqueous solution ( i f Co(I1) acetate with an ethanolic solution of benzoylacetone; it was recrystallized twice from methanol-water t o give yellowish crystals which readily lost water on standing. These crystals were completely dehydrated to the dark brown anhydrous compound by heating i n vacuo a t 80" for 24 hr. A n a l . Calcd. for Co(CloHgO:!)2: Co, 15.46; C , 63.00; H, 4.76. Found: Co, 15.5; C, 62.95; H , 4.72. Bis-(ethylbenzoy1acetato)-Co(II).-Cobalt( 11) acetate tetrahydrate (12.5 g . ) was dissolved in 100 ml. of 50% ethanol t o which was then added 19.1 g. of ethylbenzoylacetate. 3 .V ammonia was added slowly until the solution was slightly basic. X yellowish product precipitated which was filtered off, washed well with water and ethanol and air-dried giving a light yellow powder. Anal. Calcd. for C O ( C I ~ H ~ ~ O ~ ) ~Co, . ~ H12.35; ~ O : C, 35.35; H , 5.49. Found: Co, 12.3; C , 55.31; H , 5.58. Heating i n vacuo at 80" for 4 hr. produced the violetbrown anhydrous cornpound. Anal. Calcd. for Co(C1lH11O3)2: Co, 13.35; C, 59.87; H , 5.02. Found: C o , 13.1; C, 59.75; H , 4 . 9 3 . Bis-(guaiaco1ato)-Co(II).-The compound has been mentioned previously by hiellor and Craig." 6.2 g. of cobaltous acetate tetrahydrate was dissolved in 100 ml. of 50% ethanol. T o this solution was added 6.2 g . of guaiacol (o-methoxyphenol) in 100 ml. of ethanol and 6 N NH3 was added slowly with stirring as a granular precipitate formed. The purple product was filtered off, washed well with water and ethanol and dried i n vacuo. Anal. Calcd. for C O ( C ~ H ~ O ?Co, ) ~ : 19.31; C, 55.10; H , 4 . 6 2 . Foucd: Co, 19.2; C,54.96; H,4.81. Bis-(hexafluoroacety1acetonato)-Co(I1) Hydrate.-The compound was obtained by direct reaction of an aqueous
solution of cobaltous acetate with ail ethanolic solution of hexafluoroacetylacetone. The orange crystalline product was twice recrJ-stallized from ethanol-water . Anal. Calcd. for C O ( C ~ N F ~ O ~ ) ~ . . ~ : ' Co, ~ H ~ 11.36; O: C , 23.18; H, 1.36. Found: C n , 11.1; C , 23.10; H , 1.78. The hydrate could nnt he dch)drated by heating i n v a c u o a t 100" for 24 hr. Bis-(trifluoroacety1acetonato)-Co(II).-The hydrate was obtained bv a direct reaction similar to t h a t used t o prepare the hydrate nf the hexafluoro compound. Anal. Calcd. for Co(C5H4F302)?.5/2 H20: Co, 14.37; C, 29.28; H , 3.19. Found: Co, 14.0; C, 29.48; H, 3.46. The anhydrous compound was obtained from the h y drate as previously described.16 Bis-(tropo1onato)-Co(II).-Tropolone was prepared according t o the method of Doering and Knox.*l The crude product was sublimed, m.p. 48-49", lit. 49'; 1.06. g. of cobaltous acetate tetrahydrate was dissolved in 20 ml. of water and added slowly to a solution of 1.04 g . of tropolone in 30 ml. of 5OYo ethanol. X blood red precipitate formed which was filtered off, washed carefully with water, a small amount of 50% ethanol, ether and air-dried. Anal. Found: C, 52.97; H , 3.69; corresponding closelJto the monohydrate. Calcd. for Co(CiHSO:!)T.H20: C, 52.68; H , 3.79. This product was dried i n vacuo a t 58" for three day5 to give the deep red anhydrous compound. Anal. Calcd. for C O ( C ~ H S O P )C~,: 55.81; H , 3.25. Found: C, 55.i7; H , 3.59. Co(I1) Kojate.-The compound was reported previously by Wiley, et aZ.22; 4.4g. of cobaltous acetate tetrahydrate was dissolved in 25 ml. of water and t o this solution was added 5 g. of sublimed kojic acid in 40 ml. of SOTGethanol. Xn orange precipitate slowly appeared. The solution was allowed t o stand for 24 hr.; the orange product was filtered and washed thoroughly with water, ethanol and ether. A light orange powder resulted, insoluble in common noncoordinating solvents. Anal. Found: C , 41.49; H , 3.29; Co, 16.5; agreeing best with C O ( C ~ H ~ O ~ ) ~ . for ~ / ~which, H : O calcd.: C, 41.16; H, 3.17; Co, 16.76. T h e water could not be removed by lieating i n m c u o a t 100' for 24 h r .
(18) G. N. Tyson ana S. C. Adams, THISJOURNAL, 62, 1228 (1940). (19) C. Musante. Gum. c h i m . itul., 76, 123 (1946). (20) D. P. hlellor and D. P. Craig, J . Pvoc. R o y . SOL.,N . S. W a l e s , 74, 49.5 (1940)
(21) W. yon E. Doering and L. H. Knox, THISJ O U R N A L , 73, 828 (1951). (22) J. W. Wiley, G. iY.Tyson a n d J. S. Steller, ibid., 64, 963 (1942).
[CONTRIBUTIOS FROM
THE
Acknowledgments.--\Ye are grateful to the National Science Foundation and the U. S. Atomic Energy Commission (Contract AT(30-1)-1956) for financial support and to the General Electric Cornpany for a Charles Coffin Fellowship to R. H. H.
DEPARTMENT OF CHEMISTRY, MASSACHUSETTS INSTITUTEOF TECHNOLOGY, CAMBRIDGE 39, lhf ASSACHUSETTS]
Magnetic Evidence Indicative of Structures and Structural Changes in Complexes of Cobalt(I1) B Y F.A. COTTON AND R.H.HOLX RECEIVED DECEMBER 4, 1959 It is observed t h a t the literature now contains d a t a and generalizations relating to the magnetic properties of a number of basic kinds of cobaltous complexes. It is shown t h a t in this contest magnetic d a t a reported for bis-(p-toluidine)-cobalt(I1) thiocyanate as a solid and in several solvents and for several isonitrile complexes of Co(l1) can be used to infer certain features of stereochemistry and changes in stereochemistry of these substances.
Recent studies in this Laboratory have established that the magnetic behavior of tetrahedral cobaltous complexes is in good accord with the genligand pattern to be expected theory and, furthermore, semi-quantitative correli-
tions have been established between magnetic moments of such complexes and the positions of the ligands in the spectrochemical series.'.' I t has (1) R. H. Holm a n d F. A . Cotton, J Chern. P h y s . , 31, 788 ( l 9 5 9 ) , (2) K . H. H , , I a~n d F., j , Cutton, ihi(i , 3 2 , i n i,resi.
F..I. COTTOR.IND R.H. H m v
"IS I
STRUCTURES AND hf AGXETIC MOMENTS Corn poi1 n d
OF
T'ol. s2
TABLE I REPRESENTATIVE ~IEXACO6RDINATEDCOMPLEXES OF CCJ(11) Structure-
hlagnetic moment, B.hI.ns h
COCl2 CdIz structure with c o x 6 octahedra' 5.29 ( e = +38)5 CoBr2 CdIz structure with Cox6 octahedra' 5 . 2 ( e = -6)' COIZ CdIz structure with COS6 octahedra' 5.0 (8 = +5)7 coo NaCl structure; Co(I1j is 6-coordinated* 4 . 9 2 (0 = -2SOj8 4.s5(0 = -1)9 Co(0H)z CdI2 structure with C o ( 0 H ) s units' CoClz.6HzO Contains trans- [ C O ( H Z O ) ~ unitslo C~~] 4.94C1' (SH~)zCo(HzO)e(S04)z Slightly tetragonal Co(H20)6~ n i t s ' ~ - ~ 4 5 , 1 z d (e = --27)15 CO(H 2 0 ) 6 ( C104)2.6H20 C o ( H 2 0 ) ~ ions +~ 4,9311 trans-CoS,Clz units as in S i complex17 4. COClZ(PY)(" CO(OCOCII3)2.4HzO Tetragonal Coo6 units as in Ni salt19 5 . 16',' KCo!II) [Co(III)(CN)sl Contains octahedral Co(II)?i6 unitsz0 5 30'20 K2Co(II)I F ~ ( I I ) ( C N ) . S ] Contains octahedral Co(II)?;6 units20 1.WC% trans-CoS4C12units as in Ni complex21 CO[SC(NHz)z]4Clz 4.go".' References indicated. * 0 is Weiss constant in the expression p(B.M.) = 2.8-ld/xy(T--8/. Calculated from susceptibility a t room temperature only. Calculated from xv a t 300" a i d e. e py = pyridine. Measurenient made h y present authors.
'
also been found that a number of planar, quadrico- like the spin-free planar species, have moments in ordinate, spin-free Co(I1) complexes all have mo- the range 4.8-5.3 B.M., there being no evident ments in the range 4.S-5.2 R.,1-I.,3 and this has been correlation between the room temperature nioexplained on the basis that in complexes of this ments and the relative strengths of the ligand fields. type the ground electronic state of the Co(I1) ion Spin-paired complexes of both planar and octahas intrinsic orbital degeneracy thus giving a sub- hedral types have been discussed already by Figgis stantial orbital contribution to the moment which and N y h ~ l mwho , ~ ~concluded from a survey of data is largely independent of the strength of the ligand available in the literature that for spin-paired field. square complexes the moments often had very high To complete the necessary basis for interpretation orbital contributions and ranged from 2.1 to 2.9 of some new results to be reported here and others B.M., while for spin-paired octahedral complexes, already in the literature, we must also consider the orbital contributions were generally low, moments magnitudes of the moments to be expected in three falling in the range 1.7-2.0 B.M. other types of Co(I1) Complexes, vzz., (1) spin-4 substance to which the magnetic criteria outpaired squai e, quadricoordinate species, (2) spin- lined above may be applied is bis-(p-toluidine) copaired octahedral species and (3) spin-free octahe- balt(I1) thiocyanate. I n the solid state this comdral species. For the last of these, data available pound is pink, insoluble in most common solvents, in the literature together with a few observations and the cobalt ion has a moment of 4.93 B.M. This of our own afford satisfactory evidence. Such data moment is quite incompatible with the existence of for complexes whose structures are known are col- tetrahedral monomeric molecules in the crystal, for lected in Table I. Additional data for other hexa- which a moment in the range 4.5-4.6 B.M. might be coordinated complexes of this type are available expected on the basis of the results given in refs. 1 e l s e ~ - h e r e . ~I t~will - ~ ~be seen that these complexes, and 2. The pink color is indicative of octahedrally coordinated Co(I1) and the reflectance spectrum (3) F. A . Cotton and R. H. Holm, THISJ O U R N A L , 82, 2979 (19GO). (4) A. F. Wells, "Structural Inorganic Chemistry," Oxford Univ. reveals a weak band a t 470 mp, typical of octahePress, N e w York, N . Ti., 1030. dral Co(I1). Moreover the infrared spectrum has a ( 5 ) C. S t a r r . I?. Bitter and A. R. K a u l m a n n , P h y s . Rea., 58, 977 band at 2145 cm.-l which is believed to be diagnos(1940). tic of bridging-SCN-group~.~~ Hence the struc(6) W. J. D e H a a s and B. H. Schultz, Physicc, 6 , 481 (1939). (7) U '. Klemm and W. S c h u t h , %. anorg. ailgem. Chem., 210, 33 ture is very probably polymeric octahedral, similar (1933). to the structures known to exist in Cd[SC(NH(8) C . Henry LeBlanchetais, J . P h y s . R a d i u m , 12, 765 (1951). CH~)~]~(NCS ruLi(NH3)2(NCS)227 )Z,~~ and MII(py)2(9) J. T . Richardson a n d I-. W. Vernon, J. P h y s . Chem., 62, 1153 * example. I n solu(r';CS)2 (MI1 = Ni, C O ) , ~for (1958). ( I O ) hlizuno. Ukei a n d Sugawara, J . P h y s . SOC. J a p a n . 14, 383 tion in dimethylformamide the moment was found (151.59); E . V. Stroganov, I. 1. Kozhina a n d S. N. Andreev, Chem. to be 4.8s B.M. The difference between this and AbJtr., 52, 17880f (1958). 4.93 B . X . is within the sum of the experimental (11) R. S. Nyholm, Q u n r t . Reus., 7 , 402 (1953). uncertainties in both figures, but the observed deep ( I ? ) W.Hoffman, Z . Krisf., 75, 158 (1930). (13) W. Hoffman, i b r d . , 76, 279 (1931). blue color of the solution suggests that it must now (14) F. Halla and E. Mehl, 2 . onorg. allgem. Chem., 199, 379 (1931). (1.5) 13. N. Figgis a n d R. S. Nyholm, J . Chem. ~ o c . ,338 (1959).
(16) A . Sacco a n d M. Freni, Gaez. chim. d d . , 89, 1800 (1959). (17) M. A . Porai-Koshits a n d A. S. Antsishkina, A k a d . ivauk. S S.S.R., 29, 19 (1955). (18) J . A . Friend ana D. P. Mellor, J . Proc. Roy. SOL.A'. S. Wales, 81, 154 (1947). (19) J . N. v a n Niekirk a n d F. R . L. Schoening, Acta Cryst., 6 , 609 ( 1 !J 5 3 ) . (20) J. Richardson and N . Elliott, THISJ O U R N A L , 62, 3182 (1940). (21) L. Cavalca, hl. Kardelli and A. Hralbanti, Gaez. c h i m . ifal , 86, 942 (19>01.
(22) G. Foen, " Constantes selectionnCes diamagnetisme e t pararnagnrtisme," Masson a n d Cie, Paris, 1957. (23) S. C. Base a n d A . M i t r a . I n d . J . P h y s i r s , 26, 393 (1952). 124) B. .'IP Figgis and R.S. S y h o l u i , J . C h e w S o r . , 1 2 (1954). (25) J. C h a t t , L. A. Duncanson, F. A. H a r t and P. (>. Owston, N n l u r e , 181, 43 (1958). (26) L. Cavalca, M . Nardelli and G. F a v a , Proc. C h c m . So
