Jan. 20, 1964 [CONTRIBUTION FROM
CU(I1) THE
AND
Ni(I1) COMPLEXES WITH 1,3-PROP.4NEDILU1INE
CHEMISTRY DEPARTMENT, VICTORIA UXIVERSITY
OF
223
WELLIKGTON, WELLINGTON, NEW ZEALAND]
Transition Metal Complexes with Aliphatic Schiff Bases. V. Copper(I1) and Nickel(I1) Complexes of 1,3-Propanediamine and Their Reactions with Acetone BY D. A. HOUSEAND N. F. CURTIS RECEIVED JULY23, 1963 The preparation of S i ( t m d ) 3 (ClOa):! ( I ) , Ni(tmd)2(py)z(C1O4)2.2H10(11), Xi(tmd)~C12,2H20( I I I ) , Cu(tmd)zand Cu(trnd)rCln H L O (V)(trnd = 1,3-propanediamine, py = pyridine) IS described Reaction of the perchlorate salts with acetone gives initially Schiff base complexes containing two coordinated S - i s o propylidine groups Further reaction of acetone with I or IV gives complexes containing a cyclic quadridentate ligand coordinated by two secondary amine and two azomethine donor groups The absorption spectra and diamagnetism of the nickel( 11) Schiff base complexes indicate square-planar structures (c104)3(IV),
Previous papers in this series 1-4 have described the compounds prepared by condensing aliphatic ketones with 1,2-diamine~'-~J and trieth~lenetetramine~ complexes of copper(I1) and nickel(I1). This paper describes the compounds formed by the reaction of acetone with 1,3-propanediamine (trimethylenediamine = tmd) copper (II) and nickel(1 I) perchlorates. There has been relatively little recent work on the synthesis of copper(I1) and nickel(I1) complexes using 1,3-propanediamine as a ligand. The nickel(I1) complexes Xi (tmd)sPtC14, Ni (tmd)2iSCN)2,Ni(tmd)2S04, and Ni(tmd)z(C4H402N)2have been prepared by T s c h ~ g a e f f and ~ , ~ the copper(I1) complexes Cu(tmd)2jC104)2and Cu(tmd)2(0.S02.C10H7)2 by Pfeiffer and his co-workers.Y Both the monohydrate and the anhydrous Cu(tmd)nS04have also been prepared. The complexes S i (tmd) (C104)2, Ni (tmd)3C12.2H20, Ni(tmd)z(py)2(C104)2.2H20, Cu(tmd)z(ClO&, Cu(tmd) (C104)2.CH30H, and Cu (tmd)zC12.Hz0 are described in this paper. The nickel salts are blue-violet in color, as compared to the mauve of their ethylenediamine analogs, and dissolve in water or methanol to give blue solutions characteristic of nickel(I1) bis-diamine salts. The log K1 value for the r\;i(trnd)32+ion is 1.23, whereas the corresponding value for the Ni(en)32+ion is 4.42 and the extensive dissociation of the tris-( 1,3-propanediamine) complexes in solution is reflected in these figures.I0 Bis-( 1,3-propanediamine)-copper(II) perchlorate was prepared essentially by the method of Pfeiffer8 and a methanolate, Cu(tmd)2(C104)2.CH30H, was obtained by recrystallization of this material from methanol. The infrared spectra of the hydrates show strong water bands in the 35i)O cm.-' region and a weaker band a t about 1630 cm.-'. A411compounds show bands characteristic of coordinated primary amine groups between 3225 and SXOO c m - ' , a t 3260 cm.-', and also a t about 1590 cn1.-1. N-Isopropylidene Complexes.-LVhen a solution of tris-( 1,3-propanediamine)-nickel(II)perchlorate in dry acetone is boiled for a few minutes and allowed to cool, a bright yellow crystalline compound is precipitated. Bis- (1 ,3-propanediamine)-copper(I1)perchlorate yields a purple crystalline compound under the same conditions. These compounds are insoluble in cold water, and in warm water are decomposed to give acetone and the metal diamine complex. They are also insoluble in methanol, ethanol, and acetone but dissolve in dimethChem .Soc , 4409 (1960) ( 2 ) M >I Blight and N.F Curtis, r b i d . , 1204 (1962) ( 3 ) R.1 M Blight and N.F Curtis, ibid , 3016 (1962) (-1) I) A House and h' F Curtis, J A m Ckvm S O C84, , 3248 (1962). (.i) N F.Curtis and I ) .4 House, r h e i n l i i d . (Imndonl, 1708 (1961). 16) 1.. Tschugaeff. B e y , 39, 3190 (1906). (71 I, 'Tschugaeff, J . p a k t I'hrin , [ i i l 76, 88 (1007) (81 P Pieiller. E Schrnitz. and A . Bohm, Z asovg ('hem , 270, 287 11952) 19) I . H Amundsen and I. 4 Malentacchi. J A m C h e m , 5 0 6 , 67, 493 (1945) (10) I Poulsen and J BJerrum, A c t a C h e m Scaitrf , 9 , 1407 (1955)
ylformamide t o give unstable solutions. Analytical data indicate that two acetone molecules have condensed to the primary amine groups of the coordinated ligand and, in the case of nickel, one 1,3-propanediamine molecule is eliminated from the coordination sphere to give a square-plana1 , diamagnetic complex. MCsH1oN4zT
+ 2C3H60 +M C I I H I E N ~ ' ++ 2Hz0 M
=
S i or Cu
The infrared spectra show bands due to -NH2 at 3300, 3160, and 1598 cm.-l also present in the starting material, and a new band a t 1665 cm.-' assigned t o the -C=Nsystem. Because these compounds are readily hydrolyzed by water to give acetone only, we have assigned them simple N-isopropylidene structures I and I1 with possible configurations A, 8, and C CH3\
/CH3 C
CH3'
c'C&
Anion = C I 0 4 I , M = Si 11, M = Cu A , isopropylidene groups on S1 and N3 B, isopropylidene groups on S 1 and I\i2 C, isopropylidene groups on S1 and 5 4
Because of the unstable nature of the ligand, it is difficult t o decide which of the three configurations A, B, or C is the most likely. X model of the complex with structure B shows considerable overlap of the -CH3 groups in the adjacent isopropylidene systems and considerable distortion from the plane would result if this configuration were adopted. Of A and C , X is favored, as compounds containing two imine linkages have been shown by X-ray methods to prefer the trans position unless forced into a czs Tosition by the nature of the ligand." The structures of I and I1 differ from those containing two acetone residues I11 and IV previously described'-5 in that a bridged quadridentate ligand is not formed.
(1) N F Curtis, J
CHsNC CH3 111, M = Xi IV, M = Cu Anion = CIOI-
\., M Anion
= =
S i CIOI-
(11) A . 1% XIartell and X f . Calvin, "Chemistry of the SIetal Chelate Compounds," Prentice-Hall. Inc , Englewood Cliffs, N J , l%:?, p p 271 276
D. A. HOUSEAND N. F. CURTIS
224
Vol. 86
Compounds 111 and I V are stable in water and on hyacid for about 5 min. and obvious decomposition occurs drolysis with 2 M acid give mesityl oxide as the only within 1 min. on addition of ammoniacal dimethylglycarbonyl product, thus indicating a C6 bridge in the oxime solution. Boiling 2 M sodium hydroxide solucomplex.5 Compounds I and 11, however, show no tion gives a precipitate of nickel(I1) hydroxide and evidence for C6 bridges; indeed, their stability is simiyellow ammonium sulfide forms black nickel(I1) sulfide lar to that of other simple aliphatic Schiff base comafter 15 min. a t room temperature The copper complexes.'"-'* -An analogy with compound I occurs in plex shows similar reactivity with acids, bases, and the nickel(I1)-ethylenediamine-acetone system, as the yellow ammonium sulfide solution, but gives no reaction compound V,with one X-isopropylidene group, can be with a-benzoinoxime or salicylaldoxime reagents. The formed'.5and this is slowly hydrolyzed by water to give complexes VIII and I X are unreactive toward all the acetone and 111. The compound I1 is the first copperabove reagents. This increased reactivity may be (11) complex in this series with an N-isopropylidene due t o the increased strain involved with four sixgroup in the ligand. membered rings surrounding the central metal ion. Previous work in the ethylenediamine series has Visible and Ultraviolet Spectra (Table I).-The shown that the production of the cyclic complex VI1 is visible and ultraviolet spectra of VI are similar to those diamine catalyzed'j and by using Ni(en)2(py)2(C104)2. of the ethylenediamine analog VIII, but the copper x H 2 0 only 111 is formed. However on treating Nicomplex VI1 has its absorption maxima shifted to higher (tmd)z(py)2(C104)2.2Hs0 with acetone in a sealed tube wave lengths compared to those of I X . This shift is only compound I could be obtained. large enough for a shoulder a t 212 mp t o be observed. Cyclic Complexes.-When the metal 1,3-propanediTABLE I amine perchlorate complexes are allowed to stand in VISIBLE A N D ULTRAVIOLET SPECTRA IN AQUEOUSSOLUTIOX dry acetone a t room temperature for about 4 days, a Nickel compounds Copper compounds different type of complex is formed. In the case of -absorption maxima----a bsorption maxima--nickel, the new perchlorate salt forms as large orangecm cm -' colored crystals as the reaction proceeds, but the new rnp X 10-3 c mp X lo3 e copper salt is more soluble in the acetone solution. I t VI1 590 16 9 280 1-1 436 22 8 100 is, however, readily isolated as maroon-colored crystals 286 35 0 6100 277" 35 1 2,460 from the reaction mixture. These compounds are 47 2 7000 212" 43 5 15,200 230" water soluble and moderately stable to hydrolysis. De222 45 0 16,300 composition with 2 M acid and steam distillation of the YIIIl 436 22 8 104 1x3 505 19 e 126 hydrolyzed solution gives mesityl oxide as the only car282 35 4 5,400 260 38 4 5400 bonyl product (isolated as the 2,4-dinitrophenylhydra7,900 238" 42 0 zine derivative and characterized by the X-ray powder 213 47 0 17,300 pattern) i n d i c a t i q C6 bridging units in the complex. a This peak is present as a shoulder on the adjacent, more inThe infrared spectrum shows the -NH2 bands a t 3290, tense, peak. 3340, and 15% cm.-', present in the starting amine The low intensity band in the visible region is due to complexes, to be absent, and a new band due to the C -h,T- system appears a t 1660 cm.-'. There is the Laporte forbidden d--d transition. For VI and VIII the band a t 436 mp ( 6 100) is characteristic of the also a strong band a t about 3230 a n - - ' due to the cosingle band of square-planar nickel(I1) complexesI6 and ordinated -SH group.: Thus these compounds are the one broad asymmetric band observed in the visible assigned cyclic structures V I and VII, analogous to the region of VI1 and I X is characteristic of copper(I1) corresponding compounds prepared from the metal complexes. For VI and VIII, the band a t about 28@) ethylenediamine perchlorates, VIII' and I X . The mp is, from its intensity, an "allowed transition" and position of the double bonds relative to the central is probably associated with the a-electrons of the azometal ion is uncertain and they could be either in the methine group conjugated by n-bonding using the trans (as shown) or cis configurations. LITith the cond , , yz orbitals of the central nickel atom, as it disappears figuration shown, VI is 1,5,9,13-tetraza-2,4,4,10,12,12on reduction-" (ie.,removal of the azomethine system). hexamethylcyclohexadeca- 1,9-diene nickel(I1) perchloBands in the 210-230 mp region with high intensity rate and VI1 is the corresponding copper(I1) salt. VI is ( e 16,000) are thought t o arise from a charge-transfer diamagnetic, supporting the square-planar structure. transition. The ultraviolet region of the copper(I1) complexes VI1 and 1X shows a band at about 270 m p which is unchanged on reduction and has therefore been assigned to a charge-transfer transition while the intense absorption in the region of 200 mp in IX is absent in the reduced ~ o r n p l e x -and ' ~ is thus assigned t o the n-electron transition. Similarly the 212 mp band in VI1 is atC H d c: '\CH3 tributed to a n-electron transition. Further details of the spectra for these and the reduced complexes will VI, M = Si, x = 3 be published later. YII, M = c u , x = 3 -1
'cHd
V111,l M 1 s , 3 M
= =
Si, x CU, x
= 2 = 2
These cyclic complexes, although much more stable than those containing N-isopropylidene groups, are less resistant to chemical attack than their ethylenediamine analogs. For example, an aqueous solution of the nickel complex is hydrolyzed by boiling 2 M perchloric (12) (14) 04) (12)
1; Hoyer, .Volui.zeirs, 46, 14 (1959) G . 1. Eichhorn and J . C Bailar, J A m Chem Soc., 7 5 , 290n (1953). G 1. Eichhorn and N , D SIarchand, ibid , 78, 2688 (ISs5S) 13 K J Powell. Thesis, University of New Zealand. 1461.
Experimental Tris-(1,J-propanediamine)-nickel(I1)Perchlorate, Si(trnd)a(ClO~)s.--Sickel(II) perchlorate hexahydrate (36.5 g., 0.1 mole) was dissolved in alcohol (150 ml.) and this solution added dropwise with stirring t o a warm solution of 1,3-propanedianiine (22.2 g . , 0.3 mole) in alcohol (150 ml.). Heat was liberated and the solution turned blue. On cooling and stirring, niauve crystals were readily obtained and, after filtration, the product (40 g . , 84%) was dried a t 110'. (16) C K J#rgensen, "Absorption Spectra and Chemical Bonding in Complexes," Pergamon Press, New York, N . Y . , 1962, p. 286 ( 1 7 ) N. F Curtis, J . Chem Soc., in press.
Jan. 20, 1964
C U ( I 1 ) AND
h:i(II)
C O M P L E X E S WITH 1 , 3 - P R O P A N E D I A M I N E
Anal. Calcd. for ~ i C & o ~ 6 ( C 1 0 4 ) 2 : C, 22.5; H, 6.3; N, 17.5; S i , 12.2. Found: C, 22.6; H, 6.8; S, 17.4; S i , 12.0. Tris-( 1,3-propanediamine)-nickel( 11) Chloride Dihydrate, S i (tmd)XC12 ~2H20.-Kickel(II) chloride hexahydrate (24 g., 0.1 mole) was dissolved in ethanol (100 ml.) and 1,3-propanediamine (23 g., 0.3 mole) diluted with an equal volume of ethanol was slowly added. A blue-violet solution was obtained and on cooling in ice the dihydrate (27 g., 70Yc) was deposited. X sample was prepared for analysis by recrystallization from isopropyl alcoholwater solution. Anal. Calcd. for KiC9H3&~CI2.2H20: C, 27.9; H, 8.9; S , 21.6; S i , 15.1; CI, 18.3. Found: C , 28.2; 11, 9.1; S, 21.1; Xi, 15.5; CI, 18.4. Bis-( 1,3-propanediamine)-bis-(pyridine)-nickel(11) Perchlorate Dihydrate, Xi( tmd)2(py)d C104)2 ~2H20.-?hckel( 11) perchlorate hexahydrate (9.1 g . , 0.025 mole) was dissolved in alcohol (30 ml.) and 1,3-propanediamine (3.7 g., 0.05 mole) added with stirring. The solution was heated t o boiling and filtered while hot. Pyridine ( 9 g . , 0.1 mole) was added t o the warm blue filtrate and mauve crystals of the product formed on cooling. Ether (10 m l . ) was added t o complete crystallization. The product (11 g., 8557) was recrystallized from water-ethanol solution containing a few drops of pyridine. Anal. Calcd. for SiClsH30?\Ts(C101)2.2H20: C, 32.0; H, 5 . 7 ; S i , 9.8. Found: C , 31.8; H , 5.5; Ni, 9.9. Bis-( N-isopropylidene-l,3-propanediamine )-nickel(11)Perchlorate ( I ).-(a) Tris-( 1,3-propanediamine)-nickel( 11) perchlorate ( 8 9 . ) was added t o dry acetone (100 ml.) and the solution heated t o boiling. T h e mauve hexaammine salt dissolved and after 2 min. the solution turned yellow and yellow crystals of the product were precipitated. Boiling was continued for a further 5 min. and the solution cooled and filtered. The yellow crystalline product was washed well with acetone and dried a t 100'; yield almost quantitative. T h e salt is decomposed by warm water and was not recrystallized. ( b ) Bis - ( 1,3 - propanediamine)-bis-(pyridine)nickel(II) perchlorate dihydrate ( 8 8.) was placed in a Carius tube and 50 ml. of acetone added. After 10 min. heating at loo", the walls of the tube were covered with yellow crystals, and after 12 hr., the product was filtered, washed well with acetone, and air dried; yield almost quantitative. Anal. Calcd. for KiC12H28S1(C10~)~: C, 28.9; H , 5.8; S , 11.5, S i , 12.0. Found ( a ) : C , 29.0; H , 5.8; S , 11.6; S i , 12.0. ( b ) : C, 29.2; H , 6.0; S, 11.8; S i , 12.0. 1,5,9,13-Tetraza-2,4,4,10,12,12-hexamethylcyclohexadeca-l,9dienenickel(I1) Perchlorate (VI) .-Tris-( 1,3-propanediamine)nickel(I1) perchlorate (10 9.) was dissolved in dry acetone (200 ml.) and the mauve solution allowed t o stand a t room temperature in a stoppered flask. T h e solution slowly turned yellowbrown and deposited a small quantity of green powder (probably nickel(I1) hydroxide). After 4 days, orange crystals of the cyclic complex 1.1 were formed on the walls of the flask. The reaction was stopped after 10 days by decanting the reactant solution from the crystals and washing them twice with hot alcohol to remove acetone polymers. T h e crystalline product was recrystallized from hot water. A further quantity of the product was isolated from the acetone solution. The deep orange solution was diluted with an equal volume of water, brought to boiling, and filtered from the insoluble material. Decolorizing charcoal was added t o the filtrate and the solution boiled until all the acetone had vaporized. After filtration and cooling, orange crystals of the product were formed. The total yield of recrystallized material was 5 g . , 40%. Anal. Calcd. for NiC18Hda(CI04)2: C, 38.3; H , 6.4; N , 9.9; Xi, 10.4. Found: C, 38.6; H , 6.7; 9,9.9; Xi, 10.4. Bis-( 1,3-propanediamine)-copper( 11) Perchlorate,8 Cu(tmd)2(ClOa)*.-Cnpper( 11) perchlorate heptahpdrate (32.4 g . ) was dissolved in alcohol (150 ml.) and slowly added t o a stirred solution
225
of 1,3-propanediamine (15 9.) dissolved in alcohol (100 ml.). A vigorous reaction took place and the solution turned bright blue with the liberation of much heat. As the mixture cooled, blue crystals of the product were readily formed. T o complete crystallization, ether (20 ml.) was added t o the cool solution. The product was washed with 50-50 alcohol-ether solution and dried a t 40'; yield 34 g., 957,. Some of the blue anhydrous perchlorate was placed in an extraction thimble and extracted with refluxing methanol into hot isopropyl alcohol. A blue, crystalline perchlorate methanolate was obtained in the extracting flask. The methanol is only slowly removed by heating a t 100". Anal. Calcd. for C U C ~ H H S ~ C I ~C, O ~19.0; : H , 5.5; Cu, 14.4. Found: C, 19.1; H, 5.7; Cu, 14.4. Bis-(l,3-propanediarnine)-copper(II) Chloride Monohydrate, Cu(tmd)~CI2;H20.-Anhydrous copper(I1) chloride (13.4 g., 0.1 mole) was dissolved in ethanol (90 m l . ) and water (10 ml.) and this solution added t o 1,3-propanediamine (15 g . , 0.201 mole) in ethanol (20 ml.). A bright blue solution was obtained, and on the addition of ether and cooling in ice, blue crystals of the monohydrate (28 g., 93'3) crystallized. X sample for analysis was prepared by crystallization from water-methanol-isopropyl alcohol solution. A n a l . Calcd. for C ~ I C E " O K ~ C ~ Z . HC, ~ O23.9; : H , 7.4; K , 18.6; C1, 23.6; Cu, 21.1. Found: C, 23.8; H , 7.9; S , 18.6; CI, 23.6; Cu, 20.9. Bis-( N-isopropylidene-l,3-propanediamine)-copper( 11) Perchlorate (II).-Bis-( 1,3-propanediamine)-copper(11) perchlorate (8 9.) was treated as in procedure ( a ) for the nickel complex I . Purple crystals of the product were obtained in an almost quantitative yield. The product was not recrystallized. Anal. Calcd. for C U C I & Z ~ ? \ T ~ C ~c, ~ O 29.3; ~: H, 5 . 7 ; N , 11.8; Cu, 12.9. Found: C, 29.1; H , 5 . 7 ; S, 11.5; Cu, 13.1.
1,5,9,13-Tetraza-2,4,4,10,12,12-hexamethylcyclohexadeca 1,9-dienecopper(II) Perchlorate (VII).-Bis-( 1,3-propanediamine)-copper(11) perchlorate (10 g . ) was dissolved in dry acetone (200 ml.) and allowed to stand at room temperature in a stoppered flask. T h e solution turned purple-brown after 1 day and after 5 days was diluted with an equal volume of water, brought t o boiling, and filtered from the insoluble material. The acetone was removed by boiling and, after two treatments with decolorizing charcoal, a blue solution with a reddish tinge was obtained. This was concentrated on a water bath and, o n cooling, maroon crystals of the product were formed. The product (1.1 g . ) was recrystallized from water, washed with alcohol, and dried a t 40'. Some 5 g . of unchanged starting material was recovered from the mother liquor; the yield based on bis-( 1,3-propanediarnine)-copper(11) perchlorate used is 15%. Anal. Calcd. for C U C I ~ H ~ ~ N ~ ( C IC, O ~37.9; )~: H, 6.4; N, 9.8; Cu, 11.1. Found: C, 38.1; H, 6.6; S , 10.2; Cu, 11.2. Analysis.-Methods used were similar to those described pre~iously.~ Spectra.-The visible and ultraviolet spectra were determined in aqueous solution using a Hilger and Watts H700 Uvispek spectrophotometer. The infrared spectra were determined in mulls, a Perkin-Elmer Model 221 infrared Spectrophotometer being used. Magnetic Susceptibilities.-The magnetic susceptibilities of I and VI were measured for the solid by the Gouy method. Both compounds were diamagnetic a t 18".
Acknowledgments.-The authors thank Mr. R. Woods of this department for the infrared spectral determinations and Dr. A. D. Campbell of the Otago University for the C and H analyses.
