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Thermodynamic parameters for the clathrate of benzene in tris(naphthyl-2,3-dioxy)cyclotriphosphazatriene
J.inorg. nucI.Chem.,1971,Vot. 33,pp. 2677to 2678. PergamonPress. PrintedinGreat Britain
NOTES
Thermodynamic parameters for the clathrate of benzene in tris(naphthyl-2,3-dioxy)cyclotriphosphazatriene (First received 14 October 1970; in revised form 9 January 1971) WE w l s n to report thermodynamic data for another clathrate-type compound in the cyclophosphazene host system. Previous studies have shown the general nature of clathration in cyclophosphazene systems [1 ]. The stoichiometry and gross structure of the title clathrate has been established by X-ray diffraction studies [2]. The equilibrium which we have studied by measurement of the dissociation pressures of the clathrate is: ([CloHaO2]aPaN3) • 2C6H~,~ ~ ([CIoH602]aPaN3)ts) + 2CsH~a~ Kp = P~H8
(I) (2)
Table 1 gives the equilibrium dissociation pressures at several temperatures. Table 1. Equilibrium dissociation pressures for Equation ( 1) T(°K)
P ( a t m . × 1 0 a)
310 315 320 324
1.89 2"55 3.92 5.29
The equation for the straight line resulting from a plot of log P vs. 1/ T is: IogP atm. = - ( 3 1 1 I/T) + 7-3111.
(3)
Equation (3) gives the experimental equilibrium benzene dissociation pressure within 5 per cent or better. The thermodynamic quantities for this equilibrium are given in Table 2. These thermodynamic Table 2. Thermodynamic quantities for Equation (l), 298°K AG ° (kcal)
AH ° (kcal)
AS° (cal/deg)
8'53+-0"90 28"4+_1.0 66.6+-2.6 1. (a) H. R. Ailcock, Heteroatom Ring Systems and Polymers pp, 256-258. Academic Press, New York (1967); (b) R. D. Whitaker, A. J. Barreiro, P. A. Furman, W. C. Guida and E. S. Stallings, J. inorg, nucl. Chem. 30, 2921 (1968); (c) R. D. Whitaker and W. C. Guida, J. inorg, nucl. Chem. 31,875 (1969). 2. H. R. Allcock and R. L. Kugel, lnorg. Chem. 5, 1016 (1966). 2677
2678
Notes
parameters (when reduced to a per guest-mole basis) are quite similar to those which have been found for other cyclophosphazene systems with quite different guest molecules [ l b, c]. The preparation and purification of tris(naphthyl-2,3-dioxy)-cyclotriphosphazatriene and its benzene clathrate have been described[2]. Dissociation pressure measurements were carried out by the method used in previous work [l b]. Department of Chemistry University of South Florida Tampa, Florida 33620 U.S ,4 .
R. D. W H I T A K E R JON SIMON D1LNA VICTOR
J. inorg, nucl. Chem., 1971, Vol. 33, pp. 2678 to 2680.
Pergamon Press.
Printed in Great Britain
A spectrophotometric determination of the stability constants of the iron(IH)acetoacetanilide chelate (Received 5 November 1970) OF THE various organic ligands that have been investigated, acetylacetone and other fl-diketones have received major attention from the standpoint of preparation[l], adduct formation[2], formation constant [3] magnetic and spectral studies [4] during the last few years. The ability of these compounds to form stable metal chelates is due to the presence of keto-enol tautomerism which results in the formation of 6-membered chelate ring, e.g. with acetoacetanilide. CoHs-- NH-C----CH-C-CHz
CeHs-NH-C-CH-----C-CH3
The acid dissociation constant reported by Harries [5, 6] show that acetoacetanilide (AAA) is a weaker acid than acetylacetone. The composition and stability constant of the chelate formed by the interaction of Fe(III) and A A A in 50% alcoholic solution, and determination of Fe(III) have been reported spectrophotometrically [7, 8]. The present investigation deals with the determination of first stability constant of the complex formed between Fe(III) and A A A using spectrophotometric method, described previously by Anderson and Nickless [9] in 50% and 75% dioxane. EXPERIMENTAL A solution of Fe(III) was prepared from a sample of ferric chloride (BDH) and iron contents were estimated. A A A was obtained from Aldrich Chemicals Co. Inc. Milwaukee U.S.A. All other chemicals used were of BDH AnalaR quality. Spectra was recorded using Hitachi Perkin Elmer Model 139 1. (a). G. T. Morgan and H. W. Moss, J. chem. Soc. 78, 103 (1913); (b). Roseheim and Mong, Z. anorg, allg. Chem. 25, 148 (1925); (c). M. M. Jones,J.Am. chem. Soc. 76, 5995 (1954). 2. R.T. Claunch, T. W. Martin and M. M. Jones, J. Am~ chem. Soc. 83, 1073 (1961). 3. Trujilo and Brito, Chem. Abstr. 50, 15320 (1956). 4. Selbin et al., lnorg. Chem. 2, 1315 (1963). 5. H.J. Harries,J. inorg, nucl. Chem. 25, 519 (1963). 6. H.J. Harries, S. Savage and G. Wright,J. inorg, nucl. Chem. 31, 2477 (1969i. 7. A. Korkuc~ S. Zommer and T: Lipiec, Theory andStructure of Complex Compounds pp. 551-56. Papere presented at the Symposium held in Wroclaw, Poland, (June, 1962). 8. K. P. Srivastave and A. D. Taneja,.4nalytica chim. Acta To be published. 9. R. G. Anderson and G. Nickless, A nalyticdl chim. A eta 3 9 , 4 6 9 (1'967).
NOTES
Thermodynamic parameters for the clathrate of benzene in tris(naphthyl-2,3-dioxy)cyclotriphosphazatriene (First received 14 October 1970; in revised form 9 January 1971) WE w l s n to report thermodynamic data for another clathrate-type compound in the cyclophosphazene host system. Previous studies have shown the general nature of clathration in cyclophosphazene systems [1 ]. The stoichiometry and gross structure of the title clathrate has been established by X-ray diffraction studies [2]. The equilibrium which we have studied by measurement of the dissociation pressures of the clathrate is: ([CloHaO2]aPaN3) • 2C6H~,~ ~ ([CIoH602]aPaN3)ts) + 2CsH~a~ Kp = P~H8
(I) (2)
Table 1 gives the equilibrium dissociation pressures at several temperatures. Table 1. Equilibrium dissociation pressures for Equation ( 1) T(°K)
P ( a t m . × 1 0 a)
310 315 320 324
1.89 2"55 3.92 5.29
The equation for the straight line resulting from a plot of log P vs. 1/ T is: IogP atm. = - ( 3 1 1 I/T) + 7-3111.
(3)
Equation (3) gives the experimental equilibrium benzene dissociation pressure within 5 per cent or better. The thermodynamic quantities for this equilibrium are given in Table 2. These thermodynamic Table 2. Thermodynamic quantities for Equation (l), 298°K AG ° (kcal)
AH ° (kcal)
AS° (cal/deg)
8'53+-0"90 28"4+_1.0 66.6+-2.6 1. (a) H. R. Ailcock, Heteroatom Ring Systems and Polymers pp, 256-258. Academic Press, New York (1967); (b) R. D. Whitaker, A. J. Barreiro, P. A. Furman, W. C. Guida and E. S. Stallings, J. inorg, nucl. Chem. 30, 2921 (1968); (c) R. D. Whitaker and W. C. Guida, J. inorg, nucl. Chem. 31,875 (1969). 2. H. R. Allcock and R. L. Kugel, lnorg. Chem. 5, 1016 (1966). 2677
2678
Notes
parameters (when reduced to a per guest-mole basis) are quite similar to those which have been found for other cyclophosphazene systems with quite different guest molecules [ l b, c]. The preparation and purification of tris(naphthyl-2,3-dioxy)-cyclotriphosphazatriene and its benzene clathrate have been described[2]. Dissociation pressure measurements were carried out by the method used in previous work [l b]. Department of Chemistry University of South Florida Tampa, Florida 33620 U.S ,4 .
R. D. W H I T A K E R JON SIMON D1LNA VICTOR
J. inorg, nucl. Chem., 1971, Vol. 33, pp. 2678 to 2680.
Pergamon Press.
Printed in Great Britain
A spectrophotometric determination of the stability constants of the iron(IH)acetoacetanilide chelate (Received 5 November 1970) OF THE various organic ligands that have been investigated, acetylacetone and other fl-diketones have received major attention from the standpoint of preparation[l], adduct formation[2], formation constant [3] magnetic and spectral studies [4] during the last few years. The ability of these compounds to form stable metal chelates is due to the presence of keto-enol tautomerism which results in the formation of 6-membered chelate ring, e.g. with acetoacetanilide. CoHs-- NH-C----CH-C-CHz
CeHs-NH-C-CH-----C-CH3
The acid dissociation constant reported by Harries [5, 6] show that acetoacetanilide (AAA) is a weaker acid than acetylacetone. The composition and stability constant of the chelate formed by the interaction of Fe(III) and A A A in 50% alcoholic solution, and determination of Fe(III) have been reported spectrophotometrically [7, 8]. The present investigation deals with the determination of first stability constant of the complex formed between Fe(III) and A A A using spectrophotometric method, described previously by Anderson and Nickless [9] in 50% and 75% dioxane. EXPERIMENTAL A solution of Fe(III) was prepared from a sample of ferric chloride (BDH) and iron contents were estimated. A A A was obtained from Aldrich Chemicals Co. Inc. Milwaukee U.S.A. All other chemicals used were of BDH AnalaR quality. Spectra was recorded using Hitachi Perkin Elmer Model 139 1. (a). G. T. Morgan and H. W. Moss, J. chem. Soc. 78, 103 (1913); (b). Roseheim and Mong, Z. anorg, allg. Chem. 25, 148 (1925); (c). M. M. Jones,J.Am. chem. Soc. 76, 5995 (1954). 2. R.T. Claunch, T. W. Martin and M. M. Jones, J. Am~ chem. Soc. 83, 1073 (1961). 3. Trujilo and Brito, Chem. Abstr. 50, 15320 (1956). 4. Selbin et al., lnorg. Chem. 2, 1315 (1963). 5. H.J. Harries,J. inorg, nucl. Chem. 25, 519 (1963). 6. H.J. Harries, S. Savage and G. Wright,J. inorg, nucl. Chem. 31, 2477 (1969i. 7. A. Korkuc~ S. Zommer and T: Lipiec, Theory andStructure of Complex Compounds pp. 551-56. Papere presented at the Symposium held in Wroclaw, Poland, (June, 1962). 8. K. P. Srivastave and A. D. Taneja,.4nalytica chim. Acta To be published. 9. R. G. Anderson and G. Nickless, A nalyticdl chim. A eta 3 9 , 4 6 9 (1'967).