572
JOHN
T. DONOGHUE AND RUSSELL S. DRAGO
Inorganic Chemistry CONTRIBUTION FROM WM.A. NOYESCHEMISTRY LABORATORY, UKIVERSITY OF ILLINOIS, URBANA, ILLISOIS
Non-aqueous Coordination Phenomena-Complexes of Hexamethylphosphoramide. 11. Pseudo-tetrahedral Complexes of Nickel(I1) and Cobalt(I1) BY JOHK T. DOh-OGHUEl
AND
RUSSELL
S. DRAG0
Received Nottembe~1 , 1962 In part I,2we reported tetrahedral cations formed by Xi(1i) and Co(I1) with the ligand hexamethylphosphoramide, O P [h-(CHa)~]3 (HMPA). In this paper we report adducts of Co(I1) and S i ( 1 I ) halides and nitrates with this ligand, in which the anions from the original metal salts remain coordinated in the complexes The compounds reported are treated in three general classes: CoXz.2HMPX (X = halide), r\'iXz.2HMPA, and M(hTOa)2.2HhIPA( M = Co, h-i, Cu) The preparations of these compounds are outlined. Conductivity, spectral, magnetic, and other data are interpreted to infer the structures of these compounds From the data presented, i t can be concluded t h a t most of these compounds contain Co(I1) and Ki(I1) in tetrahedral environments
Introduction
described above: Co [ ( C ~ H ~ ) ~ P ]Co ~X [(c6H6)3hs]dZ, and [ C O ( C ~ H , ~ ) ~ P )Complexes ~ X ~ ] . ~ involving phosz, I n an earlier article, the unusual coordinating propphine oxide and arsine oxide ligands coordinated to coerties of hexamethylphosphoramide, OP [ N ( C H B ) Z ] ~ balt(I1) and nickel(I1) also have been investigated.6 (HMPA), were introduced. Coordination of this Tetrahedral cobalt(I1) complexes of the type CoLzXz ligand to Ni(I1) resulted in the isolation of the first (where L = (C6Hj)sAsO or (C6H6)3P0and X = halide) tetrahedral cationic complex of this ion as the perare reported. The nickel complexes [ N ~ ( C C H ~ ) ~ P O ) ~ chlorate salt. The spectral and magnetic characterX 2 ] and [Ni(C6H6)&OXz] are reported to contain istics of Ni(HMPA)4+? are very similar to those of tetrahedral nickel(I1). NiC14-2. Data presented in this first article also inI n contrast to the above type complex, i t was found7 dicated that HMPA and chloride ion occupy nearby that nickel(I1) chloride and cobalt(I1) chloride formed positions in the spectrochemical series. It was therecomplexes with dimethyl sulfoxide of the type: (Nifore of interest to prepare complexes of this ligand with [(CH3)zSO]6] KiCI4 and { Co [(CH&SO]G][CoC14]. In various nickel halides and to compare these products view of the above described variations in structure, it with other reported nickel complexes. Complexes of was of interest to determine the formulation of the the cobalt halides and nitrate as well as nickel nitrate HMPX complexes formed with these metal halides. also were investigated. It is felt that more data of this type must be accumuExperimental lated to enable generalizations to be made concerning CoXz.2HMPA Compounds (X = C1, Br, I, NCS).-Five g. of the essential factors leading to the different kinds of anhydrous CoXz was dissolved in 20 ml. of A.R. acetone and complexes which result. The variations in structures excess HMPA added. T h e mixture was allowed to stir for 2 hr. reported for some of these metal complexes will be rePrecipitation was accomplished by adding a 10: 1 volume excess viewed briefly. In 1958, Venanzi reported3the pseudoof lory boiling (30-60") petroleum ether. The solids were filtered, tetrahedral (i.e.] C2") complex NiC12.2(C6H5)3P. I t washed fifteen times with petroleum ether, and dried in vacuo over H2S04; yields ranged from 50-80%. also was reported that the bromo and iodo derivatives Anal. Calcd. for CoCla.2HMPA: C , 29.52; H, 7.46; AT, were most probably tetrahedral, while a thiocyanate 17.22. Found: C, 29.73; H, 7.51; N , 16.91. Calcd. for derivative was found t o be trans-planar. Similar comCoBry.2HMPA: C, 24.97; H, 6.30; S,14.56. Found: C, plexes were prepared for the ligands (p-anisyl)3P, (p28.30; H, 6.28; N, 14.34. Calcd. for Co(SCS)2.2HMPA: tolyl)3P, and ( C ~ H & P ( ~ - C ~ H S )Complexes .*" formed C, 31.51; H, 6.81; S,21.01. Found: C, 31.69; H, 6.69; with nickel(I1) halides by the ligands (n-CdHg)zP- N , 20.73. Calcd. for Co12*2HMPL4: C, 21.47; H,5.42; S, 12.52. Found: C , 21.61; H, 5.64; S,12.74. C6H64b and some aliphatic phosphines5 resulted in Molecular weights for the dichloro derivative in benzene and trans-planar complexes. These complexes studied by toluene were found to be 477 and 498. The calculated value for Venanzi generally are acknowledged to be the first a monomer is 488. genuinely demonstrated tetrahedral complexes of NiX2.ZHMPA (X = C1, Br, I).-Five g . of anhydrous nickel halide was dissolved in excess HMPA by heating to greater thati nickel(I1). 100'. The temperature was maintained for 1 h r . to expel water Cotton and co-workers have described several tetrafrom the reactants. The reaction mixture then W:LS p o t i r d hedral complexes of cobalt( I I) halides similar to those into 150 nil. of low petroleum ether and alloucd to cool. Tllc (1) Universal Match Foundation Fellow. Abstracted in part from t h e Ph.D. Thesis of John T. Donoghue. (2) J. T. Donoghue a n d R. S. Drago, Inovg. Chrvz., 1, 866 (1962). (3) L. M. Venanzi. J . C h e m Soc., 719 (1958). (4) (a) M. C. Browning, R. F. B. Daries, D. J. Morgan, E. Sutton, and L. M. Venanzi, ibid., 4816 (1961); (b) C. R. Coussmaker, M. H. Hutchinson, J. R. Mellor, L. E. Sutton, and L. M. Venanzi, ibid., 2075 (1961). ( 5 ) G. Giacometti and A. Turco. J . Inoig. Sucl. Chem., 16, 247 (1960); A, Turco, V. Scatturin, a n d G. Giacometti, A7nluve, 183, 601 (1959).
crystals were collected, washed fifteen times with petroleum ether, and dried in z1acuo over H,SO, for 48 hr; yields varied from 70-90'i;. (C) I>.hl. 1,. Goodgame, R.1 Goodgame, and F. A. Cotton. I i z o ~ g .Chein., 1, 239 (1962), contains most of t h e references t o this work. (7) D. W. X e e k , D. K. Straub, and R . S. Drago, J . Ant. Cheiiz. S a c . , 82, 6013 (1960), and references contained therein.
I
I
1000-
;
',
# ! \ 800-
I
I
t
I
I
ELECTRONIC ABSORPTION SPECTRA OF C o X 2 ' 2 H M P A COMPOUNOS IN CHsNOz SOLUTION A X=CI B x=Br
c x=r
D X=NCS
\ 1
\ 1
Anal. Calcd. for NiC12.2HMPX: C, 29.53; H, 7.45; N, 17.22. Found: C, 29.44; H, 7.49; N, 17.07. Calcd. for NiBrz.2HMPA: C, 24.98; H , 6.30; N, 14.57. Found: C, 24.71; H, 6.57; N , 14.33. Calcd. for NiI292HMPA: C, 21.49; H , 5.43; N, 12.53. Found: C, 21.68; H , 5.64; N, 12.16. Nitrato Complexes.-These compounds were prepared by dehydrating the hydrated nitrate with 2,2-dimethoxypropane as previously described.2 An excess of ligand then was added and the mixture allowed to stir. Precipitation was accomplished by adding a 10: 1 excess of low petroleum ether; yields were 90% or better. Anal. Calcd. for Co(N03)z.BHMPA: C, 26.62; H, 6.72; hT, 20.70. Found: C, 26.95; H , 6.79; N, 20.56. Calcd. for Ni(NOs)z.2HMPA: C, 26.63; H , 6.72; N, 20.70. Found: C, 26.92; H , 6.77; N, 20.33. Calcd. for Cu(NO3)2.2HMPA: C, 26.40; H, 6.66; N, 20.53. Found: C, 26.24; H, 6.68; N, 20.28.
ELECTRONIC ABSORPTION SPECTRA OF Ni XZ'2HMPA COMPOUNDS I N CHaNOa
Conductance Measurements.-Measurements of the conductivities of nitromethane solutions of these complexes were obtained as previously described.% The results are indicated in Table I . Spectral Measurements.-Electronic spectra of nitromethane
TABLE I Concn
,
Temp.,
Compound
M
OC.
Axmolar
CoClz.2HMPA CoBrz .2HMPA CoIz.2HMPA CO(NCS)z .2HMPA Co(NOZ)z.SHMPA NiClz. 2HMPA NiBrz-ZHMPA NiI2.2HRIIPA Ni( NO& 2HMPA
0 . 001
27,o 26.0 27.0 27.0 27.0 25.4 25.4 25.4 28.0
I .41 1.44 1.15 1.84 1.15 1.32 1.03 2.12 3.10
,0005 ,0003 ,001 ,0020 ,001 ,0005 ,0005 ,0005
574
JOHN
T. DONOGHUE ANDIRUSSELL S. DRAGO
TABLE I1 SPECTRAL DATAFOR CoX2.2HMPA, KiX2.2HMPA, A N D CU(NOs)z.BHMPA va
Medium
Amax, m,u
CoCli . 2 H M P h
Solid, reflectance
CoCli. BHMPX
0.002 AI in CHaNOz
432 475 498 600 (sh) 656 515 (sh) 590 (sh) 605 (sh) 650 (545) 407 440 480 (sh) 510 590 (sh) 640 655 690 590 (sh) 620 (400)$ 647 (450) 67%(440) 415 460 520 570-700 630 (sh) 655 (404) 725 (330) 760 (sh) 805 (120) 490 565 (sh) 585 630 650 (sh) 565 (sh) 605 (980) 616 (960) 622 (950) 630 (sh) 540-600
Compound
CoBr2.2HMPA4
Solid, reflectance
0 , 0 0 2 31 iii CHsX'O2
Solid, reflectance
5
x
10-4 AI in CH3N02
CO(NCS)2.2HMPX
Solid, reflectance
CO(S C S ) 2 '2HMPA
0 , 0 0 1 M in
CHan'Oz
CO(SOj)?* P H M P I CO(S 0 s ) Z .2HMPX NiC1,. 2HMPA
KiC12.2HMPA
S i B r 2 .2HMPX
SiBr2.2HMPA
Xi12. 2HMPA
Solid, reflcctance 0.001M in CHsSOz Solid, reflectance
0,005 M in CH3NO; Solid, reflectance
402 436
Solid, reflectance
1450 (43) 1700 (42) 1850 (42)
14-30 (55)" 1700 (53) 2000 (42)
1580 (79) 1620 ( 8 2 ) 1800 (74)
1150 (12) 1410 (sh) 1590 ( S h )
1230 (14) 1300 (sh) 1600 (sh)
442
NiIp.PHMPA
0. 01 ALLin acetoneb
TABLE I1 (Continued) Compound
Medium
460 510 535 640 700 420 (>1200) 1190(29) 585 (215)
va
Y2
Amax, mp
Amax, mp
Cu( K O ~ ) Z * Z H M P ASolid, reflect-
700
378 (110) 750 (55) -440 >'io0
