Anionopentaaminecobalt(II1) Complexes J. P. Collman, R. R. Gagne, C. A. Reed, W. T. Robinson, and G. A. Rodley, Proc. Natl. Acad. Sci. U.S.A.,71, 1326 (1974). K. Watters and R. G. Wilkins, Inorg. Chem., 13, 752 (1974), and references therein. D. W. Gruenwedel, Inorg. Chem., 7, 495 (1968). A. Zuberbuhler, T. Kaden, and F. Koechlin, Helu. Chim. Acta, 54, 1502 (1971).
L. G. Stadther, R. Prados, and R. B. Martin, Inorg. Chem., 12, 1814 (1973).
R. F. Bogucki, G. McLendon, and A. E. Martell, J. Am. Chem. SOC.,
98, 3202 (1976). F. L. Pyman, J . Chem. SOC.,190 (1916).
H. Schubert and W. D. Rudorf, Angew. Chem., 78, 715 (1966). R. G. Jones, J . Am. Chem. SOC.,71, 383 (1949). P. E. Iverson and H. Lund, Acta Chem. Stand., 20, 2649 (1966). F. J. C. Rossotti and H. Rossotti, J. Chem. Educ., 42, 375 (1965).
Inorganic Chemistry, Vol. 17, No. 8, 1978 2197 F. J. Welcher, “The Analytical Uses of Ethylenediaminetetraacetic Acid”, Van Nostrand, Princeton, N.J., 1958. W. R. Harris, R. J. Motekaitis, and A. E. Martell, Inorg. Chem., 14, 974 (1975).
R. M. Smith and A. E. Martell, “Critical Stability Constants: Amine”, Vol. 2, Plenum Press, New York, N.Y., 1975. A. G. Loomis, “International Critical Tables of Numerical Data, Physics, Chemistry and Technology”, Vol. 111, E. W. Washburn et al., Ed., McGraw-Hill, New York, N.Y., 1928, p 257. W. J. Eilbeck, F. Holmes, and T. W. Thomas, J . Chem. Sot. A , 113 (1969).
D. H. Huchital and A. E. Martell, J . Chem. SOC.,Chem. Commun., 868 (1973). D. H. Huchital and A. E. Martell, Inorg. Chem., 13, 2966 (1974). G. McLendon and A. E. Martell, J . Chem. SOC.,Chem. Commun., 223 (1975).
Contribution from the Department of Chemistry, University of Canterbury, Christchurch, New Zealand
Anionopentaaminecobalt(111) Complexes with Polyamine Ligands. 11. Synthesis, Characterization, and Reaction Kinetics of Some cis-Chlorobis(1,3-diaminopropane)(alkylamine)cobalt(111) Complexes BARBARA M. OULAGHAN and DONALD A. HOUSE* Received November 11, I977 The c i ~ - C o C l ( t m d ) ~ ( Acation ) ~ + (A = “3, Me”,, Et”,, n-PrNH2, n-BuNH2, i-BuNHz, and BzNH2) is produced when trans-[CoClZ(tmd),] (C104), dissolved in dimethylacetamide (DMA), is reacted with aqueous, alcoholic, or DMA solutions of the amine. Tetrachlorozincate(I1) and perchlorate salts have been isolated and characterized by analysis and I3CN M R spectra. The cis configuration has been established by resolution of the complexes with A = Me“, and BzNH,. Rates of both acid and base hydrolysis are about 100 times faster than their bis(ethy1enediamine) analogues due to a decrease of about 10 kJ mol-’ in the activation energies. The activation parameters for both reactions show the same trends with variation in A. Second-order rate constants for the Hg2+-assistedaquation and Fez+ reduction of this series of complexes have also been measured.
Introduction Considerable reaction rate data have been accumulated for cis-CoCl(en)2(A)2+complexes, where A is an aliphatic primary or aromatic heterocyclic tertiary amine.’g2 However, the influence of the diamine on the kinetic parameters has not been investigated to any great extent.’ In this paper, we describe the synthesis of some c i s - C ~ C l ( t r n d ) ~ ( A )(A ~ + = aliphatic primary amine) c o m p l e x e ~ . ~We are thus able to study the influence of the six-membered chelate rings on the rates of acid and base hydrolysis for these chloropentaaminecobalt(II1) systems. In addition, these complexes allow a comparison of the visible absorption and chiroptical parameters with their bis(ethy1enediamine) analogues. Experimental Section The commercially available amines were used without further purification. Ammonia was used as an aqueous solution ( p = 0.880), methylamine as a 40% aqueous solution, ethylamine as a 33% alcoholic solution, and the other amines as pure liquids. All other chemicals were A R or the best Reagent Grade available. Caution! Although we have experienced no difficulties with the perchlorate salts of the complexes mentioned herein, these complexes should be treated as potentially explosive and handled with care.
trans-Dichlorobis(1,3-diaminopropane)cobalt(III) Perchlorate: trans-[C~Cl~(tmd)~]ClO~. A solution of 1,3-diaminopropane (62 g) in water (200 mL) was quickly added (over 1-2 min) to a solution of CoC12.6H20 (100 g) in water (200 mL) which was stirred with a good stream of oxygen gas. A green precipitate formed but this slowly dissolved as the reaction proceeded and a dark brown solution was obtained after 1 h of oxygenation. Hydrochloric acid (1 50 mL, 12 M) and perchloric acid (50 mL, 72%) were separately added, and the solution was warmed on a steam bath for 10 min. Green crystals of the desired product deposited from the hot solution which was
0020-1669/78/1317-2197$01.00/0
rapidly cooled to r w m temperature in ice before filtration. The product (60 g, 62%) was washed with 2-propanol and then ether and air-dried. In certain cases, the mother liquor slowly deposited a mixture of green and red crystals, but the nature of this latter product has not yet been established. cis-Chlorobis(1,3-diaminopropane)(amine)cobalt(III) Salts, cis[CoCl(tmd),(amine)]ZnC14.t r ~ n s - [ C o C l ~ ( t m d ) ~ ] C(1100g) ~ was stirred into 40 mL of DMA to give a green solution. Amine, 1.5 times the theoretical amount, was added as quickly as possible. (The green starting material seems to recrystallize from the initial green solution after about 5 min at room temperature.) The color changed to violet and this color change was accelerated by heating. (Heating should not be excessive as most of the amines are low boiling liquids.) After overnight stirring at room temperature (17-20 h) the solution was filtered from a small amount of unreacted starting material and HCl ( 5 mL, 12 M), ZnClz (15 g), and 2-propanol (80 mL) were successively added. The purple-red ZnC14,- salt (often contaminated with green starting material) usually crystallized within 30 min and was collected by filtration (8-12 g). One recrystallization from the minimum volume of 60 OC 0.1 M HCI (50-100 mL), with HCl (10 mL, 12 M) and ZnCl, (15 g) added after filtration of small traces of undissolved solid, gave 4.5-5 g of pure cis-[C~Cl(tmd)~(amine)]ZnCl~. Tetrachlorozincate(I1) salts for amine = MeNHz, EtNHz, n-PrNHz, n-BuNH,, and i-BuNHzwere anhydrous while those of amine = N H 3 and BzNH2 crystallized as monohydrates. With amine = i-PrNH,, sec-BuNH2, and 3,5-dimethylpyridine, the reaction did not appear to take place, while with amine = cyclohexylamine, a favorable color change took place, but only unreacted starting material was recovered in the workup. ~is-[CoCl(tmd)~(amine)](ClO~)~. The appropriate tetrachlorozincate(I1) salt (2 g) was dissolved in 20-40 mL of warm 0.1 M HCl. HC104 ( 5 mL, 72%) and NaC1O4.H20 (3 g) were added, and the solution was allowed to cool slowly to room temperature and then in ice. About 1-1.3 g (60-70%) of the diperchlorate salts was collected by filtration and washed with 2-propanol and then ether and air-dried.
0 1978 American Chemical Society
Barbara M. Oulaghan and Donald A. House
2198 Inorganic Chemistry, Vol. 17, No. 8, 1978
Table I. I3C NMR Spectral Data (DMF or H,O) for Some cisCoCl(tmd),(A)Z' Complexesa Me",
"3
Assignmentb Aromatic C
DMF
H,O
C(1) C(2) C(3)
(34) W )
39.22
C(A)
26.09
39.56 39.37 39.06 38.79 38.58 26.18 25.89 25.50 24.72
Et", DMF
n-PrNH, DMF
DMF
H,O
28.84
28.91
39.13(?) 16.52
45.53 24.89 11.27
39.05 38.70 38.43
39.27 38.98 38.37
39.13(?) 38.92 38.78 38.52
25.82 25.27
25.82 25.49
25.96 25.42
n-BuNH, i-Bu", DMF DMF
BzNH, DMF 139.01 129.63 129.10 128.30 47.50
HZ0 137.59 130.01 129.50 129.30 47.45
30.29 51.09 20.30
39.00 38.77 38.36
43.49 33.85 20.29 13.78 39.02 38.82 38.38
39.17 38.51
38.99 38.91 38.59
39.28 39.13 38.64 38.31
25.81 25.27
25.82 25.31
25.93 25.40
25.84 25.48
25.82 25.48
a A t -25 'C, ppm relative to dioxane = 67.4 ppm. bAssignments in the order NH,CH,(l)-CH,(2)-CH,(3)-CH3(4) andNH,CH,(B)CH,(A)-CH, (B)-NH, for the aliphatic carbon atoms. Doubtful assignments are indicated (?). Table 11. Analytical Data and Visible Absorption Spectral Parameters for Some cis-[CoCl(tmd),(A)] Y Salts
YZ-
A 3 "
Me", Et", n-PrNH, n-BuNH, i-BuNH, BzNH,
a In
Formula Ionic C1Non-CI0,- Clwt Calcd Found Calcd Found
ZnCI,.H, 0 (c104)~ ZnCI, (ClO,),*H,O ZnC1, (CIO,),~H,O ZnC14 (C10,L ZnC1, (C104)2 ZnCI, (ClO,),~'/~H,O ZnCl,.H,O
486.6 459.5 48 1.4 490.5 495.4 505 509.4 501 523.4 515 523.4 524 574.6
(C10,)Z
548.5
1.0 M HC10,.
In 0.1 M HCIO,.
29.2
24.7
29.3
24.6
Amax, nm (e,
Amin, nm (e,
Amax, nm (e,
Amin, nm (e,
M-' cm-')
M-' cm-')
M-' cm-')
M-' cm-')
36.4 7.7
37.8 7.8
548 (47.6)a2C 548 (47.9)b
425 (15.2) 425 (16.0)
370 (64.1) 370 (64.6)
338 (36.9) 338 (36.1)
7.24 35.8 7.03 34.9 7.08 33.9 6.89 33.9 6.77 30.9
7.27 35.1 6.90 34.5 6.91 33.7 6.91 33.0 6.77 31.3
540 (51.2)b
427 (13.0)
370 (63.7)
336 (33.2)
540 (54.4)b
430 (14.9)
373 (66.0)
338 (36.2)
540 (53.4)b
430 (12.6)
372 (63.6)
338 (31.9)
532 (55.4)b
430 (13.7)
372 (65.3)
338 (35.8)
532 (55.2)b 535 (61.0)a 535 (59.0)b 6.43 534 (61.2)b
428 (12.5) 432 (14.9) 432 (14.4) 432 (14.9)
372 (66.1) 370 sh (84.5) 370 sh (81.8) 365 sh (86.1)
338 (34.6)
6.47
There is a pronounced shoulder at -480 nm on the low-wavelength side of this band.
The salts are readily soluble in dimethylformamide. Anhydrous salts were obtained for A = NH3, n-PrNH2, n-BuNH2, and BzNH2 while the others were hemi- (A = i-BuNH2)or monohydrates (A = MeNH2, Et",). Resolution of cis-[C~Cl(trnd)~(BzNH~)]ZnCI~. The racemic salt (5 g) was dissolved in 80 mL of warm 0.01 M HC1 and 3 g of solid NH4-(+)-BCS3was stirred in. A purple precipitate deposited over several days and was collected in crops. After 2.0 g (four crops) of the less soluble diastereoisomeride had been collected, HC1 (10 mL, 12 M) and ZnC12 (10 g) were added to give a ZnC1:- salt (crop 5). The CD spectrum of the products was recorded in 0.1 M HC10, and the data are, in order, crop number, weight (g), At (470 nm, M-' cm-'): 1, 0.13, +0.098; 2, 0.61, +0.104;3, 1.27, +0.114; 4,0.044, +0.122; 5,0.82, just negative. Crops 1-4 were combined and dissolved in 20 mL of 12 M HCI. Solid ZnC1, (10 g) was stirred in and the (+)5s9-ZnC1z- salt deposited (0.78 8). Chiroptical properties are [MI5g9 = +12, = +76, = 0, and = +20 (sh) deg mol-' m-l. Ae(568) = -0.102, Ae(528) = 0, Ae(468) = +0.168, Ae(360) = 0, At(350) = -0.007, and At(340) = 0 M-' cm-'. Treatment of the (+)-chloro complex with excess Hg2+ rapidly with the following produces (+)5s9-Co(tmd)2(BzNH2)(OH2)3+ chiroptical parameters: [MI589 = +5, [MI515 = +93, [MI460 = 0 , [MIM2= -13, = 0 deg mol-' m-I. At(550) = 4.123, At(515) = 0, At(468) = +0.228, Ae(368) = 0, At(355) = -0.013, At(340) = 0 M-' cm-I. Resolution of ~is-[CoCl(trnd)~(MeNH~)](ClO~)~-H~O. The racemic salt (2 g) was dissolved in 40 mL of 60 O C aqueous 0.1 M tartaric acid and 2 g of solid Na-(+)-AsOT3 was stirred in. Crops of the less soluble diastereoisomeride were collected after 3 and 20 h at room temperature. Circular dichroism parameters for samples dissolved in 3 M HC104 are the following: crop 1 Ac(570) = +0.066, At(530)
= 0, At(485) = -0.091, Ae(425) = 0; crop 2 (same wavelengths) At
= +0.057, 0, -0.090, 0, respectively. Kinetic Data. Rates of acid hydrolysis (1.0 M HCI0.J were measured by CI- titration and by ~pectrophotornetry,~~~ while base hydrolysis rates (0.1 M NaC1) were measured using a ~ H - S t a t . ' - ~ Appropriate rate constants were calculated from the extent of reaction vs. time data using the previously described equation^.^-^^ Mercury(I1)-assisted aquation rate constants (p = 1.0 M, 298 K) were obtained using a hand-powered double syringe stopped-flow system coupled to a 5.0-cm flow-through spectrophotometer cell. Pseudo-first-order rate constants were calculated using the half-life method as the [Hgz'] was always >10 times the complex ion concentration. Second-order rate constants for the iron(I1) reduction reactions were obtained spectrophotometrically by use of the repetitive scan technique or at 535 nm. The complex, as the tetrachlorozincate salt, was added to 5 mL of NaC104 (0.6 M in 0.1 M HC104) to form a ca. M solution. Standardized (KMn04) FeSO, (5 mL, 0.7 M in 0.1 M HC104) was added and the solutions were mixed before transferring to a 5.0-cm jacketed spectrophotometer cell. Reactions were followed for at least 7 half-lives. Spectral Measurements. Visible absorption spectra (three determinations, 320-650 nm) were recorded in 0.1 M HC104 using matched 5.00-cm cells, while IR spectra were run in Nujol mulls. I3C N M R spectra (in DMF) and CD spectra (in 0.1 M HC104) were obtained as previously described.9b
Results and Discussion Characterization of the Complexes. Seven cis- [CoCl(tmd)2(A)][ZnCl?- or 2C10
