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Dipole moments of some metal complexes of five new monothio-β-diketones
.L inorg, nuel. Chem. Vol. 43, pp. 1803-1806, 1981 Printed in Great Britain.
0022-1902/81[081803~4502.0010 Pergamon Press Ltd.
DIPOLE MOMENTS OF SOME METAL COMPLEXES OF FIVE NEW MONOTHIO-fl-DIKETONES MANORANJAN DAS School of Chemistry, University of New South Wales, Kensington, N.S.W., 2033, Australia
(Received 9 April 1980; received for publication 14 November 1980) Abstract--Dipole moments have been determined for Co(IlI), Ni(II), Pd(II), Pt(II), Cu(II) and Zn(II) complexes of the fluorinated monothio-fl-diketonesRC(SH)=CHCOCF3 [R = 5'-methyl-2'-thienyl,5'-chloro-2'-thienyl,4'-isopropylphenyl, 4'-tert-butylphenyl and Y-fluoro-4'-methoxyphenyl]from static-polarization measurements. The moments clearly indicate cis-square-planar configurationsfor the nickel, palladium and platinum complexes. The zinc complexes have tetrahedral structure and copper complexes have distorted cis-square-planar structure. The cobalt complexes perhaps have [acial-octahedral structure. The values of dipole moment for the complexes varies with R: 5'-methyl-2'-thienyl> Y-fluoro-4'-methoxyphenyl> 4'-isopropylphenyl~ 4'-tert-butylphenyl> 5'-chloro-2'thienyl. (CF3COOC2Hs), catalyzed by sodium methoxide[6]. 1,1,1Trifiuoro-4-(5'-methyl-2'-thienyl)butane-2,4-dione (II; R= CH3C4H2S), m.p. 59°C (Found: C, 45.48; H, 2.76; S, 13.36%. CgH7F302Srequires C, 45.78; H, 2.99; S, 13.58%).4-(5'-Chloro-2'thienyl)-l,l,l-trifluorobutane-2,4-dione (II; R=CIC4H2S), m.p. 37°C (Found: C, 37.63, H, 1.71; S, 12.64%.CsH4CIF302Srequires C, 37.45; H, 1.57; S, 12.50%). l,l,l-Trifluoro-4-(4'-isopropylphenyl)butane-2,4-dione(II; R=4'-(CH3)2CHC6H4), b.p. 273°C (Found: C, 61.02; H, 4.97%. CI3HI3F302requires C, 60.44; H, 5.07%). 4-(4'-tert-Butylphenyl)-l,l,l-trifluorobutane-2,4-dione(II; R=4'-(CH~hCC6H4), m.p. 65°C (Found: C, 61.85; H, 5.47%. C~4HjsF302 requires C, 61.73; H, 5.55%). 1,1,1-Trifluoro-4-(Yfluoro-4'-methoxyphenyl)butane-2,4-dione[l l] (II; R=Y-fluoro4'-methoxyphenyl-,m.p. 83°C Anal Calc for C,HsF403; C, 50.00; H, 3.05%. Found: C, 50.13; H, 2.88%.
INTRODUCTION
Recently we have reported[l-6] the dipole moments of some square-planar, octahedral and tetrahedral complexes of large numbers of fluorinated monothio-~diketones (I). The effect of substituents, both electrophilic and nucleophilic, in the phenyl ring of CsH6C(SH)=CHCOCF3 on the dipole moment of their metal complexes were extensively investigated in these studies. The determination of dipole moments of these complexes were possible because of their solubilities in
R CH CF3 ~C~/- "-C/
R CH~, CF3 ~C,/" ~.C~
il
S
il
-.
'"
0
I
H
S~H,.-O
(b) Preparation of monothio-~-diketones The monothio-fl-diketoneswere prepared by the action of dry H2S gas on an alcoholic solution of the/3-diketones, catalyzed by HC1gas [6, 121.l,l,l-Trifluoro-4-mercapto-4-(5'-methyl-2'-thienyl)but-3-en-2-one (I; R = CH3C4H2S) was obtained as red crystal, m.p. 55.5°C (Found: C, 42.67; H, 2.74; S, 24.99. CgH7F~OS2 requires C 42.87; H, 2.80; S, 25.43%). The other four compounds were obtained as red liquids. They were not purified via the lead complex. The impure crude ligands were used for the preparation of metal complexes.
(1)
R""rr/ I"[ 0
C H2 ~ . c j C Fa [[
0
"-,
x
R CH ~c~/" I II
CF3
OxH..0 (ll)
(c) Preparation of metal complexes Ni(II). Nickel acetate tetrahydrate (1 g, 4 mmol) in hot ethanol (70ml) was added to a solution of the monothio-fl-diketone (8 mmol) in ethanol (30 ml). The mixture was cooled in ice and the resulting brown precipitate filtered off. It was recrystallized from 100ml petroleum ether (b.p. 40--60°C). When R= CH3C41-I2S,the crude product was recrystallized from 150ml 4:1 acetone-benzene mixture; when R = CIC4H2S, it was recrystallized from 150 ml 1: 1 acetone-petroleum ether; and 200 ml of a 3:1 mixture was used when R = Y-fluoro-4'-methoxyphenyl. Pd(II) A filtered solution of potassium tetrachloropalladate(II) (1.5 g, 4.6 mmol) in water (60 ml) was added to a solution of the monothio-/~-diketone(9.2 mmol) in acetone (60 ml). The resulting orange precipitate was filtered off and recrystallized from acetone. When R = CH3C4H2S,the crude product was recrystallized from 200 ml 1: 1 acetone-benzene mixture and from 250 ml of a 4:1 mixture when R = CIC4H2S. Pt(lI). A filtered solution of potassium tetrachloroplatinate(II) (1.5 g, 3.6 mmol) in water (60 ml) was added to a solution of the monothio-/3-diketone(7.2 mmol) in acetone (60 ml). The mixture EXPERIMENTAL was refiuxed for 15 min and cooled in ice. The filtered red precipitate was recrystallized from acetone. When R=subs(a) Preparation of ~-diketones The following/3-diketones were prepared by Claisen conden- tituted thienyl, the crude products were recrystallized from 2:1 sation of methyl ketone (RCOCH3) and ethyl trifluoroacetate acetone-water mixture. organic solvents. They are monomeric in solution. In contrast, the complexes of fluorinated /~-diketones (II) are generally polymeric, solvated and insoluble in organic solvents. Because of these unfavourable properties the dipole moments of very few metal complexes of fluorinated /Ldiketones were reported[7]. Some Cu(II) complexes of RCOCH2COCF3 are soluble in benzene, and their dipole moments were determined[8-10]. The dipole moments of some metal complexes of 1,1,l-trifluoro-4-mercaptohl-(2'-thienyl)but-3-en-2-one (I; R=2'-thienyl) were previously reported by us[l,3]). Now we have prepared two new monothio-/3-diketones with R as substituted 2'-thienyl. The dipole moments of the metal complexes of these two ligands along with those of three new monothio-B-diketones with R as substituted phenyl groups are presented in this report.
INCroe 43,no, 8--F
1803
29.68
Orange Red Brown
PdL 2
PtL 2
CoL 3
49.44 43.50 43.14 39.58
34.83
Red Brown Brown Orange
Red Brown Yellow Brown
I~L 2
CoL3
3 ' - F l u o r o - 4 ' -methoxyphenyl NiL 2 PdL2
PtL 2
CuL2 ZnL2
CoL3
44.40
42.06 42.77
54.25
53.26
Orange
4'-te~t-Butylphenyl
52.96
2.22
2.12 2.20
1.73
1.98
2.09
4.46
3.67
4.03
4.42
4.06
3.90
51.17
PdL2
ZnL2
3.34
3.50
4.07
1.15
0.91
0.91
0.83
2.21
1.96
1.96
2.04
1.79
1.95
Found H
41.90
Brown
Yellow
PtL 2
51.19
47.59
Brown
Red
PdL 2
NiL 2
Brown
Orange
NiL 2
32.54
25.76
39.70 31.74
NiL 2
Brown
CoL 3
37.89
37.79
30.72
35.32
38.31
C
Brown
Brown Yellow
ZnL 2
Red
PZL2
CuL 2
Brown Orange
PdL 2
Colour
NiL 2
Compound
CoL3
4'-Isopropylphenyl
5'-Chloro-2'-thienyl
5 '-Methyl-2' -thienyl
R (%)
10.47
10.00 10.39
8.33
9.61
10.34
10.21
8.60
9.20
10.39
10.55
10.08
8.74
9.70
10.34
21.95
17.00
19.70
21.68
23.83
22.31
22.60
18.02
20.8
23.2
S
6.50
10.33
25.48
15.85
9.49
6.30
24.92
15.S0
9.20
6.53
25.83
16.02
9.60
6.58
16.27
9.70
7.19
11.41
27.51
17.39
10.41
M
Table 1. Analytical data for the complexes of RC(SH)=CHCOCF3
44.22
42.47 42.35
35.06
39.74
42.81
54.77
43.66
49.39
53.10
53.30
51.02
42.11
47.83
51.60
33.01
26.02
29.59
31.93
39.90
38.08
38.20
31.00
35.52
38.53
2.36
2.27 2.26
1.87
2.12
2.29
4.60
3.67
4.14
4.46
4.13
3.95
3.26
3.70
4.00
1.04
0.82
0.9_3
1.00
2.23
2.13
2.14
1.73
1.99
2.16
Calculated C H (%)
10.73
10.32 10.27
8.51
9.65
10.40
10.45
8.33
9.20
10.13
10,94
10.48
8.65
9.82
10.59
22.02
17.37
19.73
21.30
23.68
22.58
22.65
18.38
21.06
22.85
S
6.57
10.22
25.89
16.01
9.51
6.40
25.35
15.63
9.27
6.70
26.30
16.35
9.70
6.75
16.38
9.75
7.25
ii .23
27.97
17.48
10.46
M
Z
z
> Z O
oo
Dipole moments of some metal complexes of five new monothio-//-diketones Cu(II). Copper acetate monohydrate (1 g, 5mmol) in hot ethanol (70ml) was added to a solution of the monothio-fldiketone (10 retool) in ethanol (30 ml). The mixture was cooled in ice. The filtered brown precipitate was recrystallized from 250 ml 1 : I acetone-petroleum ether mixture. Zn(II). Zinc acetate dihydrate (1 g, 4.5 retool) in hot ethanol (70ml) was added to a solution of the monothio-//-diketone (9 retool) in ethanol (30 ml). The addition of 100 ml water to the cooled mixture precipitated the yellow complex which was recrystallized. When R = CH3C4H2S, it was recrystallized from 250ml 4:1 petroleum ether-benzene mixture and from 175 ml 6:1 petroleum ether-acetone mixture when R=Y-fluoro-4'methoxyphenyl. When R = 4'-isopropylphenyl, the addition of water to the cooled reaction mixture separated the product in colloidal form which was extracted with 150 ml petroleum ether. The extract, after drying over anhydrous sodium sulphate, was concentrated to 50 ml and left in the refrigerator for 24 hr. The solid product was filtered and dried. Co(Ill). Co(II) acetate tetrahydrate (lg, 4retool) in ethanol (150ml) was added to a solution of the monothio-fl-diketone (12mmol) in ethanol (50ml). The deep brown solution was filtered and air passed through the solution for about 3 hr. The brown deposit was filtered and washed with ethanol. When R = 4'-(CH3)3CC6H4, the product was recrystallized from 80 ml petroleum ether. Analytical data for the complexes are shown in Table 1.
1805
The appreciable large values of dipole moments indicate cis-square-planar configurations for the complexes of nickel, palladium and platinum. For a given ligand the dipole moments decrease in the order: P t > P d > N i , although the variation is within 0.4 D. This is the order of decreasing b class character[16]. X-Ray structure determination has confirmed the cis configuration for nickel[17-20], palladium[21], and platinum[21] complexes of some monothio-fl-diketones. Preferential formation of cis structure in the square-planar transition metal complexes of sulphur containing ligands probably due to d,~-d,~ bonding between the metal and suplhur atoms [22]. The dipole moments of copper complexes are about 0.7--0.9 D lower than the mean values for the nickel, palladium and platinum complexes of the same ligand. This difference has been attributed to significant distortion from the c/s-square-planar towards the tetrahedral configuration. Further lower values for zinc complexes are due to their tetrahedral structure[23]. The relatively high values obtained for the dipole moments of tris(monothio-B-diketonato)Co(III) complexes indicate the facial-octahedral(III) rather than meridional-octahedral (IV) configuration. It is interesting to note that three sulphur atoms are at right angles to the
(d) Determination of dipole moments Dielectric constants were measured at 25°C with an WTW Dipolemeter Type DM 01 with Type DFL-1 cell. Refractive indices were obtained at 25°C with an Abbe 60 Refractometer. The detailed procedure of the calculation of dipole moments was described in our earlier report[6]. RESULTS AND DISCUSSION Dipole moments of the metal complexes of the monothio-B-diketones were determined from static-polarization measurements. The values are given in Table 2 together with the moments previously reported for the related metal complexes. Later values are shown for the purpose of comparison. Metal complexes often have an appreciable value for atomic polarization[13-15]. Dipole moments determined by the static-polarization method include the contribution due to this effect and no corrections were applied. Our earlier results[l,3] indicate that the average values for atomic polarization are 0.32, 0.85 and 0.49 D for square-planar, octahedral and tetrahedral complexes, respectively.
(tit)
(IV)
metal in the facial structure and thus in correct position for d,, - d~ bonding with the metal atom. X-ray studies of the trischelates of cobalt[24] and iron[25] of some monothio-/3-diketones conlirmed their facial structures. Holm et al. had postulated the facial configuration on the basis of PMR studies on some tris(monothio-~diketonato)Co(III) [26]. With R as substituted thienyl ring the dipole moment of the complexes varies as 5'-methyl-2'-thienyl>2'-
Table 2. Dipole moments of the metal complexes of RC(SH)=CHCOCF3 R
NiL 2
PdL 2
PtL 2
CuL 2
ZnL 2
CoL 3
5'-Chloro-2'-thienyl
4.12
4.25
4.32
*
*
5.20
5'-Hethyl-2'-thienyl
6.90
7.20
7.31
6.21
4.63
8.67
2'-Th£enyl
5.74 a
5.88 a
6.09 a
4.96 a
5. 57b
7.14a
4'-Isopropylphonyl
5.80
5.98
"6.38
*
3.77
7.29
4'-~e~t-Butylphenyl
5.84
5.91
6.51
*
*
7.36
3'-Fluoro°4'-methogyphenyl
6.24
6.48
6.62
5.70
4.89
7.62
Phenyl
4.92 a
5.02 a
5.35 a
4-39a
3.07b
6.54a
4'-Methylphenyl
5.84 a
5.91 a
6.16 a
5.I 2a
3.65b
7.36a
"Compound could n o t be i s o l a t e d ,
aData from r e £ . 1.
bData from r e f .
3.
1806
MANORANJAN
thienyl > 5'-chloro-2'-thienyl. Such variations were also observed when R is a para substituted phenyl ring: 4'-methylphenyl > phenyi > 4'-chlorophenyl. The differences of dipole moments of the metal complexes are very small with R as 4'-isopropylphenyl and 4'-tertbutylphenyl groups, and are similar to those with 4'methylphenyl. This indicates that there are very little differences in the nucleophilic ( + I effect) properties between CH3, (CH3)2CH and (CH3)3C groups. The effect of substituents on the dipole moments arise from similar causes to those tabulated in Ref. (5). The complexes with R = substituted thienyl are less soluble in benzene than those with R = substituted phenyl groups. Again, the complexes with R as 5'-chloro2'-thienyl are more soluble than those with R = Y-methyl2'-thienyl.
REFERENCES
1. M. Das, S. E. Livingstone, S. W. Filipczuk, J. W. Hayes and D. V. Radford, J. Chem. Soc. Dalton Trans. 1409(1974). 2. M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 452 0975). 3. S. W. Filipczuk, J. W. Hayes, D. V. Radford, M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 886 (1975). 4. M. Das, S. E. Livingstone, J. H. Mayfield, D. S. Moore and N. Saha, Austral J. Chem. 29, 767 (1976).' 5. M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 662 (1977). 6. M. Das, Inorg. Chim. Acta 36, 79 (1979). 7. K. C. Joshi and V. N. Pathak, Coord. Chem. Rev. 22, 37 (1977).
DAS
8. P. J. McCarthy and A. E. Martell, 3. Am. Chem. Soc. 78, 2106 (1956). 9. R. H. Holm and F. A. Cotton, J. Inorg. NucL Chem. 15, 63 (1%0). 10. M. Das and S. E. Livingstone, Inorg. Chim. Acta 14, 267 (1975). 11. K. C. Joshi, V. N. Pathak and S. Bhargava, J. Indian Chem. Soc. 55, 759 (1978). 12. M. Das, Transition Met. Chem. 5, 17 (1980). 13. A. E. Finn, G. C. Hampson and L. E. Sutton, J. Chem. Soc. 1254 (1938). 14. J. E. Coop and L. E. Sutton, J. Chem. Soc. 1269(1938). 15. J. McQueen and J. W. Smith, J, Chem. Soc. 1821 (1956). 16. S. Ahrland, J. Chatt and N. R. Davies, Quart. Rev. 12, 265 (1958). 17. L. Kutschabsky and L. Beyer, Z. Chem. It, 30 (1971). 18. J. Sider, P. Thomas, E. Uhlmann and E. Horne, Z. Anorg. Allgem. Chem. 380, 160 (1971). 19. O. Siiman, D. Titus, C. Cowman, J. Fresco and H. Gray, J. Am. Chem. Soc. 96, 2353 (1974). 20. D. C. Craig,M. Das, S. E. Livingstoneand N. C. Stephenson, Cryst. Struct.Commun. 3, 283 (1974). 21. E. A. Shugam, L. H. Shkol'nikova and S. E. Livingstone, Zhur. Strukt.Khim. 8, 555 (1967). 22. D. P. Craig, A. Maccoll, R. S. Nyholm, L. E. Orgel and L. E. Sutton, J. Chem. $oc. 332 (1954). 23. B. F. Hoskins and C. D. Pannan, Inorg.NucL Chem. Lett.II, 405 (1975). 24. J. Ollis, M. Das, V. J. James, S. E. Livingstone and K. Nimgirawath, Cryst. Struct. Commun. 5, 679 (1976). 25. B. F. Hoskins and C. D. Pannon, lnorg. NucL Chem. Lett. 11, 409 (1975). 26. R. H. Holm, D. H. Gerlach, J. G. Gordon and M. G. McNamee, J. Am. Chem. Soc. 90, 4184 (1%8).
0022-1902/81[081803~4502.0010 Pergamon Press Ltd.
DIPOLE MOMENTS OF SOME METAL COMPLEXES OF FIVE NEW MONOTHIO-fl-DIKETONES MANORANJAN DAS School of Chemistry, University of New South Wales, Kensington, N.S.W., 2033, Australia
(Received 9 April 1980; received for publication 14 November 1980) Abstract--Dipole moments have been determined for Co(IlI), Ni(II), Pd(II), Pt(II), Cu(II) and Zn(II) complexes of the fluorinated monothio-fl-diketonesRC(SH)=CHCOCF3 [R = 5'-methyl-2'-thienyl,5'-chloro-2'-thienyl,4'-isopropylphenyl, 4'-tert-butylphenyl and Y-fluoro-4'-methoxyphenyl]from static-polarization measurements. The moments clearly indicate cis-square-planar configurationsfor the nickel, palladium and platinum complexes. The zinc complexes have tetrahedral structure and copper complexes have distorted cis-square-planar structure. The cobalt complexes perhaps have [acial-octahedral structure. The values of dipole moment for the complexes varies with R: 5'-methyl-2'-thienyl> Y-fluoro-4'-methoxyphenyl> 4'-isopropylphenyl~ 4'-tert-butylphenyl> 5'-chloro-2'thienyl. (CF3COOC2Hs), catalyzed by sodium methoxide[6]. 1,1,1Trifiuoro-4-(5'-methyl-2'-thienyl)butane-2,4-dione (II; R= CH3C4H2S), m.p. 59°C (Found: C, 45.48; H, 2.76; S, 13.36%. CgH7F302Srequires C, 45.78; H, 2.99; S, 13.58%).4-(5'-Chloro-2'thienyl)-l,l,l-trifluorobutane-2,4-dione (II; R=CIC4H2S), m.p. 37°C (Found: C, 37.63, H, 1.71; S, 12.64%.CsH4CIF302Srequires C, 37.45; H, 1.57; S, 12.50%). l,l,l-Trifluoro-4-(4'-isopropylphenyl)butane-2,4-dione(II; R=4'-(CH3)2CHC6H4), b.p. 273°C (Found: C, 61.02; H, 4.97%. CI3HI3F302requires C, 60.44; H, 5.07%). 4-(4'-tert-Butylphenyl)-l,l,l-trifluorobutane-2,4-dione(II; R=4'-(CH~hCC6H4), m.p. 65°C (Found: C, 61.85; H, 5.47%. C~4HjsF302 requires C, 61.73; H, 5.55%). 1,1,1-Trifluoro-4-(Yfluoro-4'-methoxyphenyl)butane-2,4-dione[l l] (II; R=Y-fluoro4'-methoxyphenyl-,m.p. 83°C Anal Calc for C,HsF403; C, 50.00; H, 3.05%. Found: C, 50.13; H, 2.88%.
INTRODUCTION
Recently we have reported[l-6] the dipole moments of some square-planar, octahedral and tetrahedral complexes of large numbers of fluorinated monothio-~diketones (I). The effect of substituents, both electrophilic and nucleophilic, in the phenyl ring of CsH6C(SH)=CHCOCF3 on the dipole moment of their metal complexes were extensively investigated in these studies. The determination of dipole moments of these complexes were possible because of their solubilities in
R CH CF3 ~C~/- "-C/
R CH~, CF3 ~C,/" ~.C~
il
S
il
-.
'"
0
I
H
S~H,.-O
(b) Preparation of monothio-~-diketones The monothio-fl-diketoneswere prepared by the action of dry H2S gas on an alcoholic solution of the/3-diketones, catalyzed by HC1gas [6, 121.l,l,l-Trifluoro-4-mercapto-4-(5'-methyl-2'-thienyl)but-3-en-2-one (I; R = CH3C4H2S) was obtained as red crystal, m.p. 55.5°C (Found: C, 42.67; H, 2.74; S, 24.99. CgH7F~OS2 requires C 42.87; H, 2.80; S, 25.43%). The other four compounds were obtained as red liquids. They were not purified via the lead complex. The impure crude ligands were used for the preparation of metal complexes.
(1)
R""rr/ I"[ 0
C H2 ~ . c j C Fa [[
0
"-,
x
R CH ~c~/" I II
CF3
OxH..0 (ll)
(c) Preparation of metal complexes Ni(II). Nickel acetate tetrahydrate (1 g, 4 mmol) in hot ethanol (70ml) was added to a solution of the monothio-fl-diketone (8 mmol) in ethanol (30 ml). The mixture was cooled in ice and the resulting brown precipitate filtered off. It was recrystallized from 100ml petroleum ether (b.p. 40--60°C). When R= CH3C41-I2S,the crude product was recrystallized from 150ml 4:1 acetone-benzene mixture; when R = CIC4H2S, it was recrystallized from 150 ml 1: 1 acetone-petroleum ether; and 200 ml of a 3:1 mixture was used when R = Y-fluoro-4'-methoxyphenyl. Pd(II) A filtered solution of potassium tetrachloropalladate(II) (1.5 g, 4.6 mmol) in water (60 ml) was added to a solution of the monothio-/~-diketone(9.2 mmol) in acetone (60 ml). The resulting orange precipitate was filtered off and recrystallized from acetone. When R = CH3C4H2S,the crude product was recrystallized from 200 ml 1: 1 acetone-benzene mixture and from 250 ml of a 4:1 mixture when R = CIC4H2S. Pt(lI). A filtered solution of potassium tetrachloroplatinate(II) (1.5 g, 3.6 mmol) in water (60 ml) was added to a solution of the monothio-/3-diketone(7.2 mmol) in acetone (60 ml). The mixture EXPERIMENTAL was refiuxed for 15 min and cooled in ice. The filtered red precipitate was recrystallized from acetone. When R=subs(a) Preparation of ~-diketones The following/3-diketones were prepared by Claisen conden- tituted thienyl, the crude products were recrystallized from 2:1 sation of methyl ketone (RCOCH3) and ethyl trifluoroacetate acetone-water mixture. organic solvents. They are monomeric in solution. In contrast, the complexes of fluorinated /~-diketones (II) are generally polymeric, solvated and insoluble in organic solvents. Because of these unfavourable properties the dipole moments of very few metal complexes of fluorinated /Ldiketones were reported[7]. Some Cu(II) complexes of RCOCH2COCF3 are soluble in benzene, and their dipole moments were determined[8-10]. The dipole moments of some metal complexes of 1,1,l-trifluoro-4-mercaptohl-(2'-thienyl)but-3-en-2-one (I; R=2'-thienyl) were previously reported by us[l,3]). Now we have prepared two new monothio-/3-diketones with R as substituted 2'-thienyl. The dipole moments of the metal complexes of these two ligands along with those of three new monothio-B-diketones with R as substituted phenyl groups are presented in this report.
INCroe 43,no, 8--F
1803
29.68
Orange Red Brown
PdL 2
PtL 2
CoL 3
49.44 43.50 43.14 39.58
34.83
Red Brown Brown Orange
Red Brown Yellow Brown
I~L 2
CoL3
3 ' - F l u o r o - 4 ' -methoxyphenyl NiL 2 PdL2
PtL 2
CuL2 ZnL2
CoL3
44.40
42.06 42.77
54.25
53.26
Orange
4'-te~t-Butylphenyl
52.96
2.22
2.12 2.20
1.73
1.98
2.09
4.46
3.67
4.03
4.42
4.06
3.90
51.17
PdL2
ZnL2
3.34
3.50
4.07
1.15
0.91
0.91
0.83
2.21
1.96
1.96
2.04
1.79
1.95
Found H
41.90
Brown
Yellow
PtL 2
51.19
47.59
Brown
Red
PdL 2
NiL 2
Brown
Orange
NiL 2
32.54
25.76
39.70 31.74
NiL 2
Brown
CoL 3
37.89
37.79
30.72
35.32
38.31
C
Brown
Brown Yellow
ZnL 2
Red
PZL2
CuL 2
Brown Orange
PdL 2
Colour
NiL 2
Compound
CoL3
4'-Isopropylphenyl
5'-Chloro-2'-thienyl
5 '-Methyl-2' -thienyl
R (%)
10.47
10.00 10.39
8.33
9.61
10.34
10.21
8.60
9.20
10.39
10.55
10.08
8.74
9.70
10.34
21.95
17.00
19.70
21.68
23.83
22.31
22.60
18.02
20.8
23.2
S
6.50
10.33
25.48
15.85
9.49
6.30
24.92
15.S0
9.20
6.53
25.83
16.02
9.60
6.58
16.27
9.70
7.19
11.41
27.51
17.39
10.41
M
Table 1. Analytical data for the complexes of RC(SH)=CHCOCF3
44.22
42.47 42.35
35.06
39.74
42.81
54.77
43.66
49.39
53.10
53.30
51.02
42.11
47.83
51.60
33.01
26.02
29.59
31.93
39.90
38.08
38.20
31.00
35.52
38.53
2.36
2.27 2.26
1.87
2.12
2.29
4.60
3.67
4.14
4.46
4.13
3.95
3.26
3.70
4.00
1.04
0.82
0.9_3
1.00
2.23
2.13
2.14
1.73
1.99
2.16
Calculated C H (%)
10.73
10.32 10.27
8.51
9.65
10.40
10.45
8.33
9.20
10.13
10,94
10.48
8.65
9.82
10.59
22.02
17.37
19.73
21.30
23.68
22.58
22.65
18.38
21.06
22.85
S
6.57
10.22
25.89
16.01
9.51
6.40
25.35
15.63
9.27
6.70
26.30
16.35
9.70
6.75
16.38
9.75
7.25
ii .23
27.97
17.48
10.46
M
Z
z
> Z O
oo
Dipole moments of some metal complexes of five new monothio-//-diketones Cu(II). Copper acetate monohydrate (1 g, 5mmol) in hot ethanol (70ml) was added to a solution of the monothio-fldiketone (10 retool) in ethanol (30 ml). The mixture was cooled in ice. The filtered brown precipitate was recrystallized from 250 ml 1 : I acetone-petroleum ether mixture. Zn(II). Zinc acetate dihydrate (1 g, 4.5 retool) in hot ethanol (70ml) was added to a solution of the monothio-//-diketone (9 retool) in ethanol (30 ml). The addition of 100 ml water to the cooled mixture precipitated the yellow complex which was recrystallized. When R = CH3C4H2S, it was recrystallized from 250ml 4:1 petroleum ether-benzene mixture and from 175 ml 6:1 petroleum ether-acetone mixture when R=Y-fluoro-4'methoxyphenyl. When R = 4'-isopropylphenyl, the addition of water to the cooled reaction mixture separated the product in colloidal form which was extracted with 150 ml petroleum ether. The extract, after drying over anhydrous sodium sulphate, was concentrated to 50 ml and left in the refrigerator for 24 hr. The solid product was filtered and dried. Co(Ill). Co(II) acetate tetrahydrate (lg, 4retool) in ethanol (150ml) was added to a solution of the monothio-fl-diketone (12mmol) in ethanol (50ml). The deep brown solution was filtered and air passed through the solution for about 3 hr. The brown deposit was filtered and washed with ethanol. When R = 4'-(CH3)3CC6H4, the product was recrystallized from 80 ml petroleum ether. Analytical data for the complexes are shown in Table 1.
1805
The appreciable large values of dipole moments indicate cis-square-planar configurations for the complexes of nickel, palladium and platinum. For a given ligand the dipole moments decrease in the order: P t > P d > N i , although the variation is within 0.4 D. This is the order of decreasing b class character[16]. X-Ray structure determination has confirmed the cis configuration for nickel[17-20], palladium[21], and platinum[21] complexes of some monothio-fl-diketones. Preferential formation of cis structure in the square-planar transition metal complexes of sulphur containing ligands probably due to d,~-d,~ bonding between the metal and suplhur atoms [22]. The dipole moments of copper complexes are about 0.7--0.9 D lower than the mean values for the nickel, palladium and platinum complexes of the same ligand. This difference has been attributed to significant distortion from the c/s-square-planar towards the tetrahedral configuration. Further lower values for zinc complexes are due to their tetrahedral structure[23]. The relatively high values obtained for the dipole moments of tris(monothio-B-diketonato)Co(III) complexes indicate the facial-octahedral(III) rather than meridional-octahedral (IV) configuration. It is interesting to note that three sulphur atoms are at right angles to the
(d) Determination of dipole moments Dielectric constants were measured at 25°C with an WTW Dipolemeter Type DM 01 with Type DFL-1 cell. Refractive indices were obtained at 25°C with an Abbe 60 Refractometer. The detailed procedure of the calculation of dipole moments was described in our earlier report[6]. RESULTS AND DISCUSSION Dipole moments of the metal complexes of the monothio-B-diketones were determined from static-polarization measurements. The values are given in Table 2 together with the moments previously reported for the related metal complexes. Later values are shown for the purpose of comparison. Metal complexes often have an appreciable value for atomic polarization[13-15]. Dipole moments determined by the static-polarization method include the contribution due to this effect and no corrections were applied. Our earlier results[l,3] indicate that the average values for atomic polarization are 0.32, 0.85 and 0.49 D for square-planar, octahedral and tetrahedral complexes, respectively.
(tit)
(IV)
metal in the facial structure and thus in correct position for d,, - d~ bonding with the metal atom. X-ray studies of the trischelates of cobalt[24] and iron[25] of some monothio-/3-diketones conlirmed their facial structures. Holm et al. had postulated the facial configuration on the basis of PMR studies on some tris(monothio-~diketonato)Co(III) [26]. With R as substituted thienyl ring the dipole moment of the complexes varies as 5'-methyl-2'-thienyl>2'-
Table 2. Dipole moments of the metal complexes of RC(SH)=CHCOCF3 R
NiL 2
PdL 2
PtL 2
CuL 2
ZnL 2
CoL 3
5'-Chloro-2'-thienyl
4.12
4.25
4.32
*
*
5.20
5'-Hethyl-2'-thienyl
6.90
7.20
7.31
6.21
4.63
8.67
2'-Th£enyl
5.74 a
5.88 a
6.09 a
4.96 a
5. 57b
7.14a
4'-Isopropylphonyl
5.80
5.98
"6.38
*
3.77
7.29
4'-~e~t-Butylphenyl
5.84
5.91
6.51
*
*
7.36
3'-Fluoro°4'-methogyphenyl
6.24
6.48
6.62
5.70
4.89
7.62
Phenyl
4.92 a
5.02 a
5.35 a
4-39a
3.07b
6.54a
4'-Methylphenyl
5.84 a
5.91 a
6.16 a
5.I 2a
3.65b
7.36a
"Compound could n o t be i s o l a t e d ,
aData from r e £ . 1.
bData from r e f .
3.
1806
MANORANJAN
thienyl > 5'-chloro-2'-thienyl. Such variations were also observed when R is a para substituted phenyl ring: 4'-methylphenyl > phenyi > 4'-chlorophenyl. The differences of dipole moments of the metal complexes are very small with R as 4'-isopropylphenyl and 4'-tertbutylphenyl groups, and are similar to those with 4'methylphenyl. This indicates that there are very little differences in the nucleophilic ( + I effect) properties between CH3, (CH3)2CH and (CH3)3C groups. The effect of substituents on the dipole moments arise from similar causes to those tabulated in Ref. (5). The complexes with R = substituted thienyl are less soluble in benzene than those with R = substituted phenyl groups. Again, the complexes with R as 5'-chloro2'-thienyl are more soluble than those with R = Y-methyl2'-thienyl.
REFERENCES
1. M. Das, S. E. Livingstone, S. W. Filipczuk, J. W. Hayes and D. V. Radford, J. Chem. Soc. Dalton Trans. 1409(1974). 2. M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 452 0975). 3. S. W. Filipczuk, J. W. Hayes, D. V. Radford, M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 886 (1975). 4. M. Das, S. E. Livingstone, J. H. Mayfield, D. S. Moore and N. Saha, Austral J. Chem. 29, 767 (1976).' 5. M. Das and S. E. Livingstone, J. Chem. Soc. Dalton Trans. 662 (1977). 6. M. Das, Inorg. Chim. Acta 36, 79 (1979). 7. K. C. Joshi and V. N. Pathak, Coord. Chem. Rev. 22, 37 (1977).
DAS
8. P. J. McCarthy and A. E. Martell, 3. Am. Chem. Soc. 78, 2106 (1956). 9. R. H. Holm and F. A. Cotton, J. Inorg. NucL Chem. 15, 63 (1%0). 10. M. Das and S. E. Livingstone, Inorg. Chim. Acta 14, 267 (1975). 11. K. C. Joshi, V. N. Pathak and S. Bhargava, J. Indian Chem. Soc. 55, 759 (1978). 12. M. Das, Transition Met. Chem. 5, 17 (1980). 13. A. E. Finn, G. C. Hampson and L. E. Sutton, J. Chem. Soc. 1254 (1938). 14. J. E. Coop and L. E. Sutton, J. Chem. Soc. 1269(1938). 15. J. McQueen and J. W. Smith, J, Chem. Soc. 1821 (1956). 16. S. Ahrland, J. Chatt and N. R. Davies, Quart. Rev. 12, 265 (1958). 17. L. Kutschabsky and L. Beyer, Z. Chem. It, 30 (1971). 18. J. Sider, P. Thomas, E. Uhlmann and E. Horne, Z. Anorg. Allgem. Chem. 380, 160 (1971). 19. O. Siiman, D. Titus, C. Cowman, J. Fresco and H. Gray, J. Am. Chem. Soc. 96, 2353 (1974). 20. D. C. Craig,M. Das, S. E. Livingstoneand N. C. Stephenson, Cryst. Struct.Commun. 3, 283 (1974). 21. E. A. Shugam, L. H. Shkol'nikova and S. E. Livingstone, Zhur. Strukt.Khim. 8, 555 (1967). 22. D. P. Craig, A. Maccoll, R. S. Nyholm, L. E. Orgel and L. E. Sutton, J. Chem. $oc. 332 (1954). 23. B. F. Hoskins and C. D. Pannan, Inorg.NucL Chem. Lett.II, 405 (1975). 24. J. Ollis, M. Das, V. J. James, S. E. Livingstone and K. Nimgirawath, Cryst. Struct. Commun. 5, 679 (1976). 25. B. F. Hoskins and C. D. Pannon, lnorg. NucL Chem. Lett. 11, 409 (1975). 26. R. H. Holm, D. H. Gerlach, J. G. Gordon and M. G. McNamee, J. Am. Chem. Soc. 90, 4184 (1%8).