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The formation constants of some bivalent ion complexes with 1-(substituted phenylazo)-2-naphthols in aqueous acetone
Notes
1091
decreased considerably and is observed at 665 and 685 cm -J in nickel and cuprous complexes respectively: indicating bonding through sulphur. The C - N stretching frequency at 1393 cm -~ for the free ligand [8] is slightly increased to 1410-1420 cm -3 in the complexes. Generally, the deformation and rocking frequencies of NH~ at 1030, 1306 and 1648 cm -~ do not show any regular variation in the complexes. The nickel complex, NiCI2. ITAM, may achieve six coordination by chlorine bridging and axial sulphur bonding as shown below: Ni
I
I
S=C--
/Ni~
/Ni CI
Ni ~CI /
~
S~C--
These bridging chlorides may account for the superexchange phenomenon giving low magnetic moment. The insolubility of the complex in most of the organic solvents is consistent with a polymeric nature.
Department of Inorganic and Physical Chemistry Indian Institute of Science Bangalore- 12 India
.I. inor~,,, nucl. ( ' h e m . . 1972, Vol, 34, pp. 1091-1094.
Pergamon Press.
R. R. I Y E N G A R D. N. S A T H Y A N A R A Y A N A C. C. PATEL
Printed in Great Britain
The formation constants of some bivalent ion complexes with 1-(substituted phenylazo)-2-naphthols in aqueous acetone (Received 2 April 1971 ) THOUGH A large number of chromium (111), cobalt(Ill) and copper(ll) complexes with azo dyes capable for forming two annelated chelate rings with metal ions have been used as colouring materials, the formation of metal complexes of phenylazonaphthol and its simple derivatives has not been studied. In the present note are reported the stoichiometric formation constants (K) for the stepwise formation of metal complexes of l-phenylazo-2-naphthol (l), some of its 2'- and 4'-substituted derivatives (II-XIV), l-(2',4',6'-tribromophenylazo)-2-naphthol (XV), 1-(l'-naphthylazo)-2-naphthol tXVI) and 1-(2'-naphthylazo)-2-naphthol (XVII) with some bivalent ions using pH-titrations[l] in 3:1 acetone:water medium containing 0.100M KNO3 at 25°. The uranyl ion containing the metal in 6-+- oxidation state, nevertheless, is bivalent and was included in the present studies, but Be2+ was excluded because of its extensive hydrolysis in aqueous media. EXPERIMENTAL The different azo compounds (I-XVII) were prepared by diazotizing the respective substituted aromatic amine and coupling them with 2-naphthol in alkaline medium. The precipitated azo coral. H. Irving and lq. S. Rossotti, J. chem. Soc. 2904 (1954).
1092
Notes T ab le 1. T h e s t o i c h i o m e t r i c formation c o n s t a n t s (log K values) of bivalent ion complexes of
Metal
K
H+ Mn2+ Fe z+
K~" K~ Kt K2 K1 K2 KI K2 K~ K2 K1 K2 KI K2 Kt K2
Co 2+ Ni2+ Cu 2+ Zn 2+ Cd 2÷ UO22. P b 2+
Hg~+ Mg2+ Ca z+ Sr~÷ Ba~+
K1
K2 K~ K2 K1 K~ K1 K~
i
II
111
IV
12.82--.0.03 13-18±0.03 12.50..+0.03 13.20..+0.02 7-32--+0.04 7.84--+0.04 6.96--+0-04 7.76--+0.07 8.88±0.04 9.62-+0.04 11,24-+0-07 11.42-+0.07 8.06--+0.07 8.84--+0.08 10.90..+0.10 10.72..+0.09 8.76±0.04 9,82±0.04 8.57+0.05 9,32±0.04 7.44--+0,08 7.91..+0.06 7.02--+0.07 7.77--+0.06 9.73--+0.05 10.43..+0-04 9,36--+0.03 9.97--+0.05 8.74 - 0.08 9.34± 0.07 8.55--.+0,06 8-94± 0.08 11.07-+0.04 11,56±0.05 10.88-+0.05 11.32..+0,05 10.21..+0,06 10.76..+0.09 10.00-+0.06 10.34..+0.09 8.69--+0-04 9.24-+0.1M 8.41..+0.05 8.91..+0.04 7-14 ± 0.07 8.34-+0.08 6.82± 0.07 7.94 ± 0-08 7.96--+0.04 8.64±0.04 7.76--+0.04 8.37-+0.05 6.78___0.07 8.00-.+0.07 6.53--+0.06 7.54--+0.06 10.64..+0.07 11.04±0.04 10.42..+0.06 10-82..+0.06 9.84--+0.09 10.26..+0-08 9.66--+0-09 9.93--+0.09 8'44±0"06 9"03--+0'06 8"18..+0'05 8"72-+0"06 7"02--+0"09 8'04..+0'10 6"73±0"08 7"64----.0"10 7'46±0'06 7"94±0"07 7"26--0"05 7'74±0"06 6"42--+0'07 6'94±0-10 6"04--+0-07 7'16-----0"10 7.29±0"06 7"76--+0"06 7"02-+0"06 7"55--+0'06 7.02±0.07 7-58±0.06 6.76±0.06 7.39±0.07 6.76---+0-07 7.35--+0.07 6.42--+0.08 7.16..+0.07 6-44--+0.07 6.97--+0.08 6.26--+0.08 6.79--+0.07
V
VI
VII
VIII
8.21±0.02 11.83+_.0-03 11-87±0.03 12.04±0.04 4.19..+0.03 6.04+__0.03 6.29±0.03 6-68+0.04 5.32-+0.03 7.04-+0.04 7.13..+0,03 7.36--+0.04 4.69--+0.06 6.46--+0.08 6.54--+0.06 6.71..+0.07 5,02±0.04 7.76±0.05 7.84±0.04 7.97±0-05 4.32--+0.06 6-66+0.07 6.64--+0.07 6.79--+0.07 5.69--+0.04 8.64-+0.04 8.74--+0,04 8.97-+0.04 5.02± 0.07 7-96-+0.06 8-03-+ 0.06 8.25± 0.06 6.91..+0.05 10.20..+0.04 10.24-+0.05 10.32..+0-04 6-32--+0.07 9.36--+0.07 9.47--+0.07 9.62--+0.06 4.78--+0.05 7.36-+0.04 7.43--+0.04 7.76--+0.05 3.98± 0.07 6.47-+0.08 6.44 ± 0.08 6.60 ± 0.08 4.32--+0.04 7.00--+0.05 7.13-+0.04 7.30-+0.05 3.71..+0.06 5.98--+0.06 5.92--+0.06 6.17..+0.08 6.23--+0.04 9.66--+0-04 9.78-+0.04 9.92-+0.04 5.52--+0.07 8.84--+0.07 8.97--+0.07 9-11..+0.07 4'52--+0"04 7"20-+0"05 7'22--+0"05 7'46-+0"05 3'82±0"07 6"24--+0"08 6"13..+0"08 6"36-+0"08 3"98±0-05 6"68±0"05 6"74±0'05 6"88-+0'05 3"47-----0-08 5'92--.0"08 5'96-----0-08 6'01..+0"08 3"88--+0"07 6"42-+0"06 6'54--+0"06 6"73--+0'06 3.72±0.07 6.37±0.06 6.44-+0.06 6.53±0.06 3.54--+0.07 6.30--+0.08 6.34--+0.08 6.24--+0-08 3-38--+0.06 5.92--+0-08 5.94--+0.08 5.95-+0.08
R
I R=H X XI XII XIII XIV
R=Me R=OH R=OMe R=NO2 R = C1
1 R=H II llI IV V
R=Me R=OH R=OMe R=NO2
VI VII VIII IX
R=CI R=Br R=I R=SO3H
pounds were purified by r e p e a t e d crystallizations, their purities being a s c e r t a i n e d by their melting points. The metal solutions were prepared from the c o r r e s p o n d i n g nitrates (B.D.H. A n a l a R or M e r c k pro analysi) and standardized g r a v i m e t r i c a l l y [2]. KNOa was used to keep ionic c o n c e n t r a t i o n at 0.100M KNOa. All the titrations were done in 3:1 v/v a c e t o n e : w a t e r m e d i u m contining 0.100M K N O a at 25°C (___I°C) in the manner[3] described elsewhere. T h e following c onc e nt ra t i on sets were used for each m e t a l - l i g a n d sy stem: ( 1) 0.001M metal + 0.010M ligand, (2) 0.005M metal + 0.010M ligand, (3) 0.010M m e t a l + 0 . 0 1 0 M ligand, (4) 0.005M m e t a l + 0 . 0 2 0 M ligand, (5) 0.005M m e t a l + 0 . 0 3 0 M ligand, (6) 2. A. 1. Vogel, A Text Book of Quantitative Inorganic Analysis 3 rd Edn. Longma ns , L o n d o n (1962). 3. G u r C h a r a n Singh Manku, Austral. J. Chem. 24,92 5 ( 1971 ).
Notes
1093
I-i s u b s t i t u t e d p h e n y l ) a z o - 2 - n a p h t h o l s in 3 : 1 a c e t o n e : w a t e r m e d i u m at 25°C containing 0.100M KN O:~ IX 7.64+_0-02 3.92+--0.03 4.90+_0.04 4.08+_0-07 4.73+_0.05 3-99+_0-08 5.18+_0,05 4.62±0.07 6.50_+0-05 5.78+_0.06 4.52+_0.04 3.70_+0.06 4.00±0.05 3.18±0.07 6.28_+0.04 5.30_+0.06 4.20_+0-04 3-52±0-07 3.70_+0.06 2.96+_0.09 3.52+_0.07 3-29_+0.07 3.t8±0.08 3.00+_0,08
X
XI
XII
Xlll
13.11+_0.04 12.37±0.04 12.93±0.04 7.35+_0.05 7.24+_0.04 8.03±0.04 9.45+_0.04 11.96_+0-09 11.84+_0.08 8.35±0.09 11.25±0.15 11.03+-0.10 9.45+_0.04 9.04+_0.07 9.94+_0.04 8.26±0.08 8.24+--0.09 9.04±0.10 9-96+_0.05 9.95±0.06 10.55+_0.06 8.45±0.07 %16±0.09 9-75±0.09 11-35+_0.05 11.25±0-04 11-60+_0.04 9-97+_0-09 10,45+_0.09 10.73±0,09 8.95±0.04 8,66_+0.06 9.55+_0.04 7-42+_0.08 8,00_+0.07 8.83+_0,09 8.35+_0-04 8.16_+0.04 8.75-----0,04 7.03+_0-08 7,16+_0.09 7.43+_0,09 10.76±0-04 10,57+_0.05 11.28_+0,03 9.16+_0.09 9.85+_0.07 10.38_+0,07 8-55_+0.04 8.45_+0.06 9.20+_0.04 7.75+_0.10 7.83±0-09 8.45±0,07 7.76+_0.07 7.65_+0.05 8.19±0,05 6.36+_0.09 6.87±0.07 7.45_+0.06 7.26+_0.07 7.26_+0.08 7-96+_ff07 6.96+_0.07 6.98+_0.07 7.66±0.07 6.63+_0.08 6.60+_0.07 7-37+_0,08 6.42+_0.08 6.37+_0.07 6.97_+0-08
XIV
7.88+_0.02 11.67±0.04 4.07+_0.03 5.66+_0.05 4.42±0.04 6-75±0-04 5.81+-0.08 4.46±0.04 7.48+_0-05 3-31+_0.07 6.40+_0,08 4-97±0.04 8.26+_0.04 3.24±0-07 7.03+_0.07 6.04±0.06 9.77+_0.04 4.31+_0.09 7.51±0.08 4.03_+0.05 7.02_+0-04 2.92_+0.08 5.90±0.08 3.40+_0.05 6.51±0-05 5.36+_0.07 5.37±0.05 9.29+_0.04 3.79+_0.07 8.02+_0-08 3.80±0.08 6-83+_0.05 5.66_+0.09 3.17±0.06 6.24_+0.05 5.20_+0.09 3-07±0.07 6.03+_0.06 2-99±0.08 5.84_+0.06 2.75±0.08 5-72_+0.08 2.65+_0.09 5-53+_0.07
XV
XVI
XVII
11.20+_0,03 12.59+_0.04 12.62±0.04 6.02+_0.04 7.02+_0,04 7.27+_0.05 6.34±0.05 7.54+_0.06 7.80+_0.07 7.24+_0.05 5.33+_0,10 7.94+_0,05 6.01_+0-10 9,29+_0,05 7.84+_0.09 6.95+_0.04 5.05+_0.08 6.33+_0.04 4.74___0.08 8-79+_0.04 694+_0.08 6-54___0.05 4,94+_0.10 5-90±0,06 4.53+-0.11 5-72+-0.10 5,33_~0.09 5.20+_0.08 5,08+_0.10
8.05+_0.04 8.52±0.06 7-25+_0.07 7-86+_0.09 9.03+_0.05 9.57+_0.04 8.15+_0.07 8.75_+0.08 10,24+_0.04 10.76+_0.05 9.49+__0.09 9.93+_0.09 7.80_+0-05 8.24+_0.06 6-97+_0.07 7.35+_0-11 7.02+_0.04 7.80+_0.04 6.33±0.09 6-85±0-10 9.90_+0.06 10.44+_0.07 9.02±0.09 9.66+_0.09 7.32+_0.06 8.02±0.06 6.72+_0.09 6-95±0-09 6.70+_0-06 7-32+-0-07 6.02+_0.09 6.35+-0.12 6.44+_0.07 7.10+_0.07 6.03+_0.07 6-77+_0-07 5.85±0.10 6.42_+0-09 5-50+_0-10 6.02+_0.11
0"010M m e t a l + 0,020M ligand, (7)0.020M metal + 0 - 0 3 0 M ligand, (81 0.030M m e t a l + 0 . 0 5 0 M ligand. and (9) 0.050M metal + 0.050M ligand. CALCULATIONS
AND
RESUI.TS
The s t e p w i s e proton a s s o c i a t i o n c o n s t a n t s (Kt H and Ke H) for the ligands w e re d e t e r m i n e d from the c o r r e s p o n d i n g formation functions t~h(B) by the linear plots of the equations: hh log ]-~fih = log K f - - B fih - - 1
og ~
= log K~" -- B.
F r o m the titration curves, the formation functions f i ( L ) for the metal c o m p l e x e s were calculated using equations proposed by Irving and Rossotti[1] and were found to be coincident for all the above c o n c e n t r a t i o n sets showing the absence of any p o l y n u c l e a r or protonated complexes[4]. This is in confirmation with the o b s e r v a t i o n s of J o h n s o n et al. [5] who did not obtain any e vi de nc e for the formation of protonated cobaltazo dyes c o m p l e x e s , and conc l ude d that ionization of the reagent preceeds the c o m p l e x formation with metal ions. The respecti ve formation c ons t a nt s were then calculated from the linear equation: -- h K j L 1 --
~--~-fi LK2 = 1
12)
The results are given in T a b l e 1. DISCUSSION Fro m T ab le 1, it is o b s e r v e d that (1t Log K for the metal c o m p l e x e s for a metal ion with these ligands having p a r a substituents, 4. F. J. C. Rossotti and H. Rossotti, D e t e r m i n a t i o n o f S t a b i l i t y C o n s t a n t s , p. 62. M c G r a w - H i l l , N e w Y o r k (1 961 ). 5. A. J o h n s o n , M. S. Mort, R. H. Peters and M. J. Wada, Tex. 21,453 (1962).
1094
Notes
increase in the order SO3H < NO~ < CI ~< Br < I < OH < OMe < Me, which is similar to that observed for l-phenyl-3-methyl-4-(4'-substituted phenylazo)-pyrazolones[6]. In case of ortho substituents also, with the reversal of positions of Me and OMe, the above order holds. (2) In case of isomeric ligands containing OH and OMe substituents, log K for the metal complexes with ortho substituents are more than those for the para substituents, though log K1H are almost equal; and this may be due to the fact that the electron pair on oxygen atom of the ortho substituted ligand may be utilized in the formation of another chelate ring; of two similar ligands, one forming more annelated chelate rings forms more stable complexes [7]. (3) Log K for the trisubstituted derivative (XV) as well as for the naphthylazonaphthols (XVI) and (XVII) are less than that for the phenylazonaphthol (1), probably due to the steric hinderance. (4) In the case of most of these ligands, the stability sequence observed, i.e. Cu > UO~ z+ > Ni > Co > Zn > Pb > Cd > Hg > Mg > Ca > Sr > Ba, is similar to that observed for the bidentate azopyrazolones[6]. Further, (a) logK for most ligands are in the order Mn < Co < Ni < Cu > Zn, observed for many other ligands[8]; (b) in the same periodic group, log K increases with the decreasing size of the ions, viz. Zn > Cd > Hg and Mg > Ca > Sr > Ba; (c) log K for Cu and Ni complexes are more than those for the UO22+ and Zn complexes, probably due to the fact that the azo compounds are one O - and one N - donor ligands, the latter ions have considerable less affinity for N-donors. (5) In some cases, especially with OH and OMe as the substituents, it is observed that (a) log K for Fe ~÷ complexes are highest among all metals, and (b) log K for Co > Ni. According to the size of these ions, the order should be Fe < Co < Ni. These discrepancies may be due to the possible oxidations of Fe ~+ and Co s+ resulting in the formation of very stable complexes of the corresponding tervalent metal ions.
Department o f Chemistry Hans R a j College Delhi-7 India
GUR CHARAN SINGH MANKU RAMESH C H A N D E R C H A D H A NARESH K U M A R N A Y A R
Department o f Chemistry A.R.S.D. College, N e w Delhi-23 India
M A N M O H A N S I N G H SETHI
6. F. A. Snavely, W. C. Fernelius and B. P. Block, J. Am. chem. Soc. 79, 1028 (1957); F. A. Snavely, B. D. Krecker and C. G. Clark, J. Am. chem. Soc. 81, 2337 (1959); F. A. Snavely and B. D. Krecker, J. Am. chem. Soc. 81, 4199 ( 1959). 7. R. N. Hurd, G. De Lamater, G. C. McElkeny and J. P. McDermott, In Advances in the Chemistry o f Coordination Compounds (Edited by S. Kirschner), p. 355, MacMillan, New York (1961). 8. M. Calvin and N. C. Melchior, J. Am. chem. Soc. 70, 3270 (1948), K. Yamasaki and K. Jones, Nature 166, 998 (1950); B. E. Bryant, W. C. Fernelius and B. E. Douglas, Nature 170, 247 (1952); H. Irving and R. J. P. Williams, J. chem. Soc. 3192 (1953).
J. inorg, nucL Chem., 1972, Vol. 34, pp. 1094-1098.
Pergamon Press.
Printed in Great Britain
Thermal decomposition of commercial ferric sulphates (Received 7 April 1971 ) FERRIC sulphate is not as common as ferrous sulphate, owing probably to its limited industrial application. But it is beginning to find more industrial applications, particularly in the fields of catalysis and explosives. In connection with its use in explosives, a project was begun in this laboratory to develop a
1091
decreased considerably and is observed at 665 and 685 cm -J in nickel and cuprous complexes respectively: indicating bonding through sulphur. The C - N stretching frequency at 1393 cm -~ for the free ligand [8] is slightly increased to 1410-1420 cm -3 in the complexes. Generally, the deformation and rocking frequencies of NH~ at 1030, 1306 and 1648 cm -~ do not show any regular variation in the complexes. The nickel complex, NiCI2. ITAM, may achieve six coordination by chlorine bridging and axial sulphur bonding as shown below: Ni
I
I
S=C--
/Ni~
/Ni CI
Ni ~CI /
~
S~C--
These bridging chlorides may account for the superexchange phenomenon giving low magnetic moment. The insolubility of the complex in most of the organic solvents is consistent with a polymeric nature.
Department of Inorganic and Physical Chemistry Indian Institute of Science Bangalore- 12 India
.I. inor~,,, nucl. ( ' h e m . . 1972, Vol, 34, pp. 1091-1094.
Pergamon Press.
R. R. I Y E N G A R D. N. S A T H Y A N A R A Y A N A C. C. PATEL
Printed in Great Britain
The formation constants of some bivalent ion complexes with 1-(substituted phenylazo)-2-naphthols in aqueous acetone (Received 2 April 1971 ) THOUGH A large number of chromium (111), cobalt(Ill) and copper(ll) complexes with azo dyes capable for forming two annelated chelate rings with metal ions have been used as colouring materials, the formation of metal complexes of phenylazonaphthol and its simple derivatives has not been studied. In the present note are reported the stoichiometric formation constants (K) for the stepwise formation of metal complexes of l-phenylazo-2-naphthol (l), some of its 2'- and 4'-substituted derivatives (II-XIV), l-(2',4',6'-tribromophenylazo)-2-naphthol (XV), 1-(l'-naphthylazo)-2-naphthol tXVI) and 1-(2'-naphthylazo)-2-naphthol (XVII) with some bivalent ions using pH-titrations[l] in 3:1 acetone:water medium containing 0.100M KNO3 at 25°. The uranyl ion containing the metal in 6-+- oxidation state, nevertheless, is bivalent and was included in the present studies, but Be2+ was excluded because of its extensive hydrolysis in aqueous media. EXPERIMENTAL The different azo compounds (I-XVII) were prepared by diazotizing the respective substituted aromatic amine and coupling them with 2-naphthol in alkaline medium. The precipitated azo coral. H. Irving and lq. S. Rossotti, J. chem. Soc. 2904 (1954).
1092
Notes T ab le 1. T h e s t o i c h i o m e t r i c formation c o n s t a n t s (log K values) of bivalent ion complexes of
Metal
K
H+ Mn2+ Fe z+
K~" K~ Kt K2 K1 K2 KI K2 K~ K2 K1 K2 KI K2 Kt K2
Co 2+ Ni2+ Cu 2+ Zn 2+ Cd 2÷ UO22. P b 2+
Hg~+ Mg2+ Ca z+ Sr~÷ Ba~+
K1
K2 K~ K2 K1 K~ K1 K~
i
II
111
IV
12.82--.0.03 13-18±0.03 12.50..+0.03 13.20..+0.02 7-32--+0.04 7.84--+0.04 6.96--+0-04 7.76--+0.07 8.88±0.04 9.62-+0.04 11,24-+0-07 11.42-+0.07 8.06--+0.07 8.84--+0.08 10.90..+0.10 10.72..+0.09 8.76±0.04 9,82±0.04 8.57+0.05 9,32±0.04 7.44--+0,08 7.91..+0.06 7.02--+0.07 7.77--+0.06 9.73--+0.05 10.43..+0-04 9,36--+0.03 9.97--+0.05 8.74 - 0.08 9.34± 0.07 8.55--.+0,06 8-94± 0.08 11.07-+0.04 11,56±0.05 10.88-+0.05 11.32..+0,05 10.21..+0,06 10.76..+0.09 10.00-+0.06 10.34..+0.09 8.69--+0-04 9.24-+0.1M 8.41..+0.05 8.91..+0.04 7-14 ± 0.07 8.34-+0.08 6.82± 0.07 7.94 ± 0-08 7.96--+0.04 8.64±0.04 7.76--+0.04 8.37-+0.05 6.78___0.07 8.00-.+0.07 6.53--+0.06 7.54--+0.06 10.64..+0.07 11.04±0.04 10.42..+0.06 10-82..+0.06 9.84--+0.09 10.26..+0-08 9.66--+0-09 9.93--+0.09 8'44±0"06 9"03--+0'06 8"18..+0'05 8"72-+0"06 7"02--+0"09 8'04..+0'10 6"73±0"08 7"64----.0"10 7'46±0'06 7"94±0"07 7"26--0"05 7'74±0"06 6"42--+0'07 6'94±0-10 6"04--+0-07 7'16-----0"10 7.29±0"06 7"76--+0"06 7"02-+0"06 7"55--+0'06 7.02±0.07 7-58±0.06 6.76±0.06 7.39±0.07 6.76---+0-07 7.35--+0.07 6.42--+0.08 7.16..+0.07 6-44--+0.07 6.97--+0.08 6.26--+0.08 6.79--+0.07
V
VI
VII
VIII
8.21±0.02 11.83+_.0-03 11-87±0.03 12.04±0.04 4.19..+0.03 6.04+__0.03 6.29±0.03 6-68+0.04 5.32-+0.03 7.04-+0.04 7.13..+0,03 7.36--+0.04 4.69--+0.06 6.46--+0.08 6.54--+0.06 6.71..+0.07 5,02±0.04 7.76±0.05 7.84±0.04 7.97±0-05 4.32--+0.06 6-66+0.07 6.64--+0.07 6.79--+0.07 5.69--+0.04 8.64-+0.04 8.74--+0,04 8.97-+0.04 5.02± 0.07 7-96-+0.06 8-03-+ 0.06 8.25± 0.06 6.91..+0.05 10.20..+0.04 10.24-+0.05 10.32..+0-04 6-32--+0.07 9.36--+0.07 9.47--+0.07 9.62--+0.06 4.78--+0.05 7.36-+0.04 7.43--+0.04 7.76--+0.05 3.98± 0.07 6.47-+0.08 6.44 ± 0.08 6.60 ± 0.08 4.32--+0.04 7.00--+0.05 7.13-+0.04 7.30-+0.05 3.71..+0.06 5.98--+0.06 5.92--+0.06 6.17..+0.08 6.23--+0.04 9.66--+0-04 9.78-+0.04 9.92-+0.04 5.52--+0.07 8.84--+0.07 8.97--+0.07 9-11..+0.07 4'52--+0"04 7"20-+0"05 7'22--+0"05 7'46-+0"05 3'82±0"07 6"24--+0"08 6"13..+0"08 6"36-+0"08 3"98±0-05 6"68±0"05 6"74±0'05 6"88-+0'05 3"47-----0-08 5'92--.0"08 5'96-----0-08 6'01..+0"08 3"88--+0"07 6"42-+0"06 6'54--+0"06 6"73--+0'06 3.72±0.07 6.37±0.06 6.44-+0.06 6.53±0.06 3.54--+0.07 6.30--+0.08 6.34--+0.08 6.24--+0-08 3-38--+0.06 5.92--+0-08 5.94--+0.08 5.95-+0.08
R
I R=H X XI XII XIII XIV
R=Me R=OH R=OMe R=NO2 R = C1
1 R=H II llI IV V
R=Me R=OH R=OMe R=NO2
VI VII VIII IX
R=CI R=Br R=I R=SO3H
pounds were purified by r e p e a t e d crystallizations, their purities being a s c e r t a i n e d by their melting points. The metal solutions were prepared from the c o r r e s p o n d i n g nitrates (B.D.H. A n a l a R or M e r c k pro analysi) and standardized g r a v i m e t r i c a l l y [2]. KNOa was used to keep ionic c o n c e n t r a t i o n at 0.100M KNOa. All the titrations were done in 3:1 v/v a c e t o n e : w a t e r m e d i u m contining 0.100M K N O a at 25°C (___I°C) in the manner[3] described elsewhere. T h e following c onc e nt ra t i on sets were used for each m e t a l - l i g a n d sy stem: ( 1) 0.001M metal + 0.010M ligand, (2) 0.005M metal + 0.010M ligand, (3) 0.010M m e t a l + 0 . 0 1 0 M ligand, (4) 0.005M m e t a l + 0 . 0 2 0 M ligand, (5) 0.005M m e t a l + 0 . 0 3 0 M ligand, (6) 2. A. 1. Vogel, A Text Book of Quantitative Inorganic Analysis 3 rd Edn. Longma ns , L o n d o n (1962). 3. G u r C h a r a n Singh Manku, Austral. J. Chem. 24,92 5 ( 1971 ).
Notes
1093
I-i s u b s t i t u t e d p h e n y l ) a z o - 2 - n a p h t h o l s in 3 : 1 a c e t o n e : w a t e r m e d i u m at 25°C containing 0.100M KN O:~ IX 7.64+_0-02 3.92+--0.03 4.90+_0.04 4.08+_0-07 4.73+_0.05 3-99+_0-08 5.18+_0,05 4.62±0.07 6.50_+0-05 5.78+_0.06 4.52+_0.04 3.70_+0.06 4.00±0.05 3.18±0.07 6.28_+0.04 5.30_+0.06 4.20_+0-04 3-52±0-07 3.70_+0.06 2.96+_0.09 3.52+_0.07 3-29_+0.07 3.t8±0.08 3.00+_0,08
X
XI
XII
Xlll
13.11+_0.04 12.37±0.04 12.93±0.04 7.35+_0.05 7.24+_0.04 8.03±0.04 9.45+_0.04 11.96_+0-09 11.84+_0.08 8.35±0.09 11.25±0.15 11.03+-0.10 9.45+_0.04 9.04+_0.07 9.94+_0.04 8.26±0.08 8.24+--0.09 9.04±0.10 9-96+_0.05 9.95±0.06 10.55+_0.06 8.45±0.07 %16±0.09 9-75±0.09 11-35+_0.05 11.25±0-04 11-60+_0.04 9-97+_0-09 10,45+_0.09 10.73±0,09 8.95±0.04 8,66_+0.06 9.55+_0.04 7-42+_0.08 8,00_+0.07 8.83+_0,09 8.35+_0-04 8.16_+0.04 8.75-----0,04 7.03+_0-08 7,16+_0.09 7.43+_0,09 10.76±0-04 10,57+_0.05 11.28_+0,03 9.16+_0.09 9.85+_0.07 10.38_+0,07 8-55_+0.04 8.45_+0.06 9.20+_0.04 7.75+_0.10 7.83±0-09 8.45±0,07 7.76+_0.07 7.65_+0.05 8.19±0,05 6.36+_0.09 6.87±0.07 7.45_+0.06 7.26+_0.07 7.26_+0.08 7-96+_ff07 6.96+_0.07 6.98+_0.07 7.66±0.07 6.63+_0.08 6.60+_0.07 7-37+_0,08 6.42+_0.08 6.37+_0.07 6.97_+0-08
XIV
7.88+_0.02 11.67±0.04 4.07+_0.03 5.66+_0.05 4.42±0.04 6-75±0-04 5.81+-0.08 4.46±0.04 7.48+_0-05 3-31+_0.07 6.40+_0,08 4-97±0.04 8.26+_0.04 3.24±0-07 7.03+_0.07 6.04±0.06 9.77+_0.04 4.31+_0.09 7.51±0.08 4.03_+0.05 7.02_+0-04 2.92_+0.08 5.90±0.08 3.40+_0.05 6.51±0-05 5.36+_0.07 5.37±0.05 9.29+_0.04 3.79+_0.07 8.02+_0-08 3.80±0.08 6-83+_0.05 5.66_+0.09 3.17±0.06 6.24_+0.05 5.20_+0.09 3-07±0.07 6.03+_0.06 2-99±0.08 5.84_+0.06 2.75±0.08 5-72_+0.08 2.65+_0.09 5-53+_0.07
XV
XVI
XVII
11.20+_0,03 12.59+_0.04 12.62±0.04 6.02+_0.04 7.02+_0,04 7.27+_0.05 6.34±0.05 7.54+_0.06 7.80+_0.07 7.24+_0.05 5.33+_0,10 7.94+_0,05 6.01_+0-10 9,29+_0,05 7.84+_0.09 6.95+_0.04 5.05+_0.08 6.33+_0.04 4.74___0.08 8-79+_0.04 694+_0.08 6-54___0.05 4,94+_0.10 5-90±0,06 4.53+-0.11 5-72+-0.10 5,33_~0.09 5.20+_0.08 5,08+_0.10
8.05+_0.04 8.52±0.06 7-25+_0.07 7-86+_0.09 9.03+_0.05 9.57+_0.04 8.15+_0.07 8.75_+0.08 10,24+_0.04 10.76+_0.05 9.49+__0.09 9.93+_0.09 7.80_+0-05 8.24+_0.06 6-97+_0.07 7.35+_0-11 7.02+_0.04 7.80+_0.04 6.33±0.09 6-85±0-10 9.90_+0.06 10.44+_0.07 9.02±0.09 9.66+_0.09 7.32+_0.06 8.02±0.06 6.72+_0.09 6-95±0-09 6.70+_0-06 7-32+-0-07 6.02+_0.09 6.35+-0.12 6.44+_0.07 7.10+_0.07 6.03+_0.07 6-77+_0-07 5.85±0.10 6.42_+0-09 5-50+_0-10 6.02+_0.11
0"010M m e t a l + 0,020M ligand, (7)0.020M metal + 0 - 0 3 0 M ligand, (81 0.030M m e t a l + 0 . 0 5 0 M ligand. and (9) 0.050M metal + 0.050M ligand. CALCULATIONS
AND
RESUI.TS
The s t e p w i s e proton a s s o c i a t i o n c o n s t a n t s (Kt H and Ke H) for the ligands w e re d e t e r m i n e d from the c o r r e s p o n d i n g formation functions t~h(B) by the linear plots of the equations: hh log ]-~fih = log K f - - B fih - - 1
og ~
= log K~" -- B.
F r o m the titration curves, the formation functions f i ( L ) for the metal c o m p l e x e s were calculated using equations proposed by Irving and Rossotti[1] and were found to be coincident for all the above c o n c e n t r a t i o n sets showing the absence of any p o l y n u c l e a r or protonated complexes[4]. This is in confirmation with the o b s e r v a t i o n s of J o h n s o n et al. [5] who did not obtain any e vi de nc e for the formation of protonated cobaltazo dyes c o m p l e x e s , and conc l ude d that ionization of the reagent preceeds the c o m p l e x formation with metal ions. The respecti ve formation c ons t a nt s were then calculated from the linear equation: -- h K j L 1 --
~--~-fi LK2 = 1
12)
The results are given in T a b l e 1. DISCUSSION Fro m T ab le 1, it is o b s e r v e d that (1t Log K for the metal c o m p l e x e s for a metal ion with these ligands having p a r a substituents, 4. F. J. C. Rossotti and H. Rossotti, D e t e r m i n a t i o n o f S t a b i l i t y C o n s t a n t s , p. 62. M c G r a w - H i l l , N e w Y o r k (1 961 ). 5. A. J o h n s o n , M. S. Mort, R. H. Peters and M. J. Wada, Tex. 21,453 (1962).
1094
Notes
increase in the order SO3H < NO~ < CI ~< Br < I < OH < OMe < Me, which is similar to that observed for l-phenyl-3-methyl-4-(4'-substituted phenylazo)-pyrazolones[6]. In case of ortho substituents also, with the reversal of positions of Me and OMe, the above order holds. (2) In case of isomeric ligands containing OH and OMe substituents, log K for the metal complexes with ortho substituents are more than those for the para substituents, though log K1H are almost equal; and this may be due to the fact that the electron pair on oxygen atom of the ortho substituted ligand may be utilized in the formation of another chelate ring; of two similar ligands, one forming more annelated chelate rings forms more stable complexes [7]. (3) Log K for the trisubstituted derivative (XV) as well as for the naphthylazonaphthols (XVI) and (XVII) are less than that for the phenylazonaphthol (1), probably due to the steric hinderance. (4) In the case of most of these ligands, the stability sequence observed, i.e. Cu > UO~ z+ > Ni > Co > Zn > Pb > Cd > Hg > Mg > Ca > Sr > Ba, is similar to that observed for the bidentate azopyrazolones[6]. Further, (a) logK for most ligands are in the order Mn < Co < Ni < Cu > Zn, observed for many other ligands[8]; (b) in the same periodic group, log K increases with the decreasing size of the ions, viz. Zn > Cd > Hg and Mg > Ca > Sr > Ba; (c) log K for Cu and Ni complexes are more than those for the UO22+ and Zn complexes, probably due to the fact that the azo compounds are one O - and one N - donor ligands, the latter ions have considerable less affinity for N-donors. (5) In some cases, especially with OH and OMe as the substituents, it is observed that (a) log K for Fe ~÷ complexes are highest among all metals, and (b) log K for Co > Ni. According to the size of these ions, the order should be Fe < Co < Ni. These discrepancies may be due to the possible oxidations of Fe ~+ and Co s+ resulting in the formation of very stable complexes of the corresponding tervalent metal ions.
Department o f Chemistry Hans R a j College Delhi-7 India
GUR CHARAN SINGH MANKU RAMESH C H A N D E R C H A D H A NARESH K U M A R N A Y A R
Department o f Chemistry A.R.S.D. College, N e w Delhi-23 India
M A N M O H A N S I N G H SETHI
6. F. A. Snavely, W. C. Fernelius and B. P. Block, J. Am. chem. Soc. 79, 1028 (1957); F. A. Snavely, B. D. Krecker and C. G. Clark, J. Am. chem. Soc. 81, 2337 (1959); F. A. Snavely and B. D. Krecker, J. Am. chem. Soc. 81, 4199 ( 1959). 7. R. N. Hurd, G. De Lamater, G. C. McElkeny and J. P. McDermott, In Advances in the Chemistry o f Coordination Compounds (Edited by S. Kirschner), p. 355, MacMillan, New York (1961). 8. M. Calvin and N. C. Melchior, J. Am. chem. Soc. 70, 3270 (1948), K. Yamasaki and K. Jones, Nature 166, 998 (1950); B. E. Bryant, W. C. Fernelius and B. E. Douglas, Nature 170, 247 (1952); H. Irving and R. J. P. Williams, J. chem. Soc. 3192 (1953).
J. inorg, nucL Chem., 1972, Vol. 34, pp. 1094-1098.
Pergamon Press.
Printed in Great Britain
Thermal decomposition of commercial ferric sulphates (Received 7 April 1971 ) FERRIC sulphate is not as common as ferrous sulphate, owing probably to its limited industrial application. But it is beginning to find more industrial applications, particularly in the fields of catalysis and explosives. In connection with its use in explosives, a project was begun in this laboratory to develop a