Vanadium Compounds - American Chemical Society

Downloaded by UNIV OF MARYLAND BALTIMORE COUNTY on February 4, 2015 | http://pubs.acs.org Publication Date: December 10, 1998 | doi: 10.1021/bk-1998-0711.ch008

Chapter 8

Composition and Structure of Vanadium(V) Peroxo Complexes P. Schwendt and M. Sivák Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, SK 842 15 Bratislava, Slovakia

All of more than sixty known crystal structures of vanadium(V) peroxo complexes can be classified into several types closely related to peroxovanadate species formed under various conditions in aqueous solutions. The six- seven dichotomy of the coordination number for vanadium in these complexes is discussed and new data on structure of dinuclear vanadium peroxo complexes with chiral α -hydroxycarboxy-lato heteroligands are presented. Our contribution is an overview of vanadium(V) peroxo complexes discussing mainly their composition and structure. Why do we consider the summarization of these data to be useful? 1. The found insulin mimetic properties and discovery of vanadium haloperoxidases have considerably increased the interest in these complexes(7). 2. The recent review by Butler et al (2) was focused mainly on the reactivity. Moreover, since this review has been published in 1994, the number of solved crystal structures of vanadium peroxo complexes was doubled. 3. Some unreproducible and unreliable data have been published on these compounds even in prestigious journals; the duty of careful literature search was often ignored. For clarity, we shall distinquish, when needed, between the peroxovanadium species which are formed by dissolution of vanadates in a diluted H2O2 solution at various pH values and containing only oxo, peroxo, hydroxo and aqua ligands, and heteroligand complexes (the term introduced by Djordjevic(J)) in which other ligands (heteroligands) are also bound to vanadium .

©1998 American Chemical Society In Vanadium Compounds; Tracey, A., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1998.

117

118


Diluted hydrogen peroxide solutions of vanadates. The composition of peroxovanadium species in aqueous solution depends mainly on: a) H2O2 / V ratio in solution b) pH C) vanadium concentration d) ionic strength e) temperature Except of the number of coordinated water molecules, which still remains a matter of discussion, it is generally accepted that the principal mononuclear species and their protonation products are: tetraperoxovanadate [V(02)4] ", triperoxovanadates [VO(0 ) ] " and [Y(0H)(0 ) ] ', diperoxovanadates [YO(0 )2(OH) ] *(or [V0 (02)2] -), [VO(0 ) (OH)] -, [VO(02)2(H 0)]- and [HV0(0 ) (H 0)] (with unknown site of protonation), and monoperoxovanadium species [YO(0 )(OH) (H 0) ] - (or[Y0 (02)(OH)(H 0) ] - ) , [YO(0 )(OH)2(H 0) ]- , [YO(0 )(OH)(H 0) ] and [VO(0 ) ( H 0 ) ] (4, 5, 6, 7). The condensation of different mononuclear complex ions results in formation of various dinuclear species. The most probable reactions are: 2 [VO(0 ) (OH)] " „ [Y 03(0 )4] " + H 0 (1) 3

3

2

2

3

2

2

2

3

2

3

2

3

2

2

2

2

2

2

3

2

2

2

2

2

u

2

v

2

2

x

+

2

2

y

2

2

z

2

2

2

2

[VO(0 ) (OH)] - + [VO(02)2(H20)]-

3

2

2 [VO(02)2(H 0)]-

«

2

2

[V2O2 (0 ) (H 0)] - + H 0 2

»

2

[VO(02)(H20) ] + [VO(0 )2(H20)]2

2 [VO(0 )( H 0 ) ] 2

2

z

2

[V2O2 (0 )2(H 0)2 -i] 2

2

(2) (3)

2

2

+

+

4

[Y202(02)3(H 0) ] + H 0

+

z

2

[V202(OH)(02)4] - + H 0

2

2

4

2

Z

2

(4)

+ H 0 (5)

2+

Z

2

The formation constans have been determined for the majority of species formed (2, 4,8). Solid peroxovanadates. The best example for many inconsistent data concerning the composition of peroxovanadates is the variety of potassium peroxovanadates described in the literature: K [V(02)4], K V 0 . 2.5 H 0 , K 4 V 0 . 4 H 0 , K6H V 0i6 . H 0 , K4V2O11, K3HV2O11, K2H2V2O11, K H V 0 . H 0 , K V O 4 , K V O 5 . 0.5H O, K2H2V2O10 . 0.5H O, K V O 5 . H 0 . n H 0 and others. We consider only the following peroxovanadates to be the products of crystallization from solutions of vanadate in diluted hydrogen peroxide: a) Blue tetraperoxovanadates M [ V ( 0 2 ) 4 ] . aq which can be obtained from alcaline solutions with large excess of H2O2. b) (N(CH ) )2 [V(0 ) OH] (with a short structure announcement but no synthesis description in ref.77) C) Three types of dinuclear diperoxo complexes formed by crystallization from solutions with lower H 0 / V ratios: M [V20 (02)4] . aq, M [ Y 0 ( O H ) ( 0 ) 4 ] . aq and 1^2^202(02)4^20)]. aq. In spite of the fact that solid mononuclear monoperoxo- or diperoxovanadates have not been reliably characterized, and they presumably do not exist, the studies devoted to such „unprobable" compouds repeatedly occur up to date (e.g. 9,10). 3

3

6

2

2

2

2

2

2

6

1 2

2

2

2

2

2

2

2

3

3

4

2

3

I

2

2

4

I

3

3

2

2

In Vanadium Compounds; Tracey, A., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1998.

2

119

A detailed knowledge on the characteristics ( IR, X-ray) of solid peroxovanadates is required i f we are attempting to synthesize heteroligand complexes, since the peroxovanadates often form admixtures in the product expected. The ignorance of this requirement has led to serious mistakes.


Solid heteroligand vanadium(V) peroxo complexes. A l l heteroligand complexes can be derived from the peroxovanadate species found to be present in solution by formal substitution of H 0 or OH groups by one or more heteroligands. The following types of heteroligand complexes can thus be expected: 1. [VO(0 )L ] (n = 3,4) 2. [ V O ( 0 ) L ] (m=l,2) 3. [V(0 ) L] 4. [ V 0 ( 0 ) L ] (r = 4,5; bridging and/or non-bridging L ) 5. [ V 0 ( 0 ) 3 L ] (p = 3,4; non-bridging, eventually bridging and non-bridging L) 6. [V 0 (0 )4L] (non-bridging or bridging L ) where L stands for a monodentate ligand. Two L can be substituted by a bidentate ligand, three L by a tridentate or combination of a mono- and bidentate ligands and so on. With the exception of the type 3, in which a capped trigonal prismatic geometry can be expected, all other heteroligand complexes have a pentagonal pyramidal or pentagonal bipyramidal structure. For dinuclear complexes, various bridge configurations are possible; the configurations found so far are presented in Table I. The bridging bonds are usually complemented by weaker interactions of the A-F types. The review of structurally characterized vanadium(V) peroxo complexes is presented in Table II. There is no trinuclear structure known for vanadium(V) peroxo complexes. The tetranuclear anion in K [V404(0 )8(P04)]. 9 H 0 (27) is built up from two dinuclear V 0 ( 0 ) 4 units connected by P O 4 group. The polymeric structure of the [VO(0 )ida'] ion in NH4[VO(0 )ida] (28) and eventually that of the tVO(0 ) F ] ion in NH4[VO(0 ) F'] (weak interaction 0=V 0=V) (2) are formed due to special interactions in the solid state. The discussions about the coordination number of vanadium in monoperoxo and diperoxo complexes are focused mainly on the pentagonal pyramidal - pentagonal bipyramidal dichotomy. The V-Lax bond trans to the V=0 bond is due to the structural trans effect always relatively long (d (V-L^) = 2.1-2.6 A or more). For a geometry corresponding to d(V-Lax) -2.5 A , the term pseudopentagonal bipyramidal was suggested (29). Some correlations between the stretching mode absorptions and structure of vanadium(V) diperoxo complexes have been found (26, 30). Especially, there is a correlation between the position of the characteristic Raman band corresponding to the V-O oxo stretching and the V-Lax bond length. For d(V-Lax) > 2.6 A no effect of the distance on the characteristic band position was observed. With aim to simplify the problem , in structures with d(VLax) values smaller than approx. 2.6 A, we propose for vanadium to consider the coordination number seven, while for larger values, the pentagonal pyramidal arrangement. This classification is arbitrary, of course. Nevertheless, there are structures in which any cannot be found at distances considerably exceeding 3 A . In this case a pentagonal pyramidal structure is beyond doubt. 2

2

n

2

2

2

2

m

3

2

2

2

2

2

2

2

2

2

r

P

2

7

2

2

2

2

_

2

n

2

2

2

2

n

2

per

The number of structures with different coordination number of vanadium are


120

Table I. Bridge configurations found in dinuclear vanadium(V) peroxo complexes. Type Type of bridging Structure X


\

B

O

X

^

/ \ sft V—Y—V

O

| l - X , u-Y, nonplanar bridge

X

p,-X, | i - Y , planar bridge

V D

O

H-X-Y-Z

O

Q

O

JO

Q

o

P

Va-/

IM1VO2

H-TI :TI 02 2

2

X and Y are donor and Z are other atoms of ligand.

Table II. Structurally characterized vanadium(V) peroxo complexes (including peroxovanadates), Mononuclear CN Ligands Ref. Mononuclear CN Ligand(s) Ref. 2 12 [VO(0 ) L ] 6 NH [VO(0 )Ln] 6 giygiy 2 m=l,2 6 F(2) 2 n = 3,4 7 2C 0 (2) 6-7 F 2 2 dipic, 7 H 0 7 2F 2 2 7 pic, 2 H 0 C 0 (2) 2 7 13 7 bpy, 2 F 7 2 2 co 2bpy 7 2 7 bpy (2) 2 2 phen 7 7 pic 2 2 pic, bpy 7 7 picOH 2 14 2 pic 7 20 2,4 pdc 7 14 7 pic, phen a

b

2

2

2

2

m

3

4

c

2

2

2

4

3


121


Table II. - continued 3-acetpic, 3-acetoxypicolinato; 5-nitrophen, 5-nitro-l,10-phenanthroline; dpot, 1,3diamino-2-propanol-tetraacetato. In parenthesis is the number of structures with given ligand but different number of crystal water molecules or different cation. M . Sivak et al - to be published. P. Schwendt et al - to be published. 0

d

e

7

phen, 2 H 0 nta(4) Hedta(2) ada Hheida pan,py ceida bpg

14

7

3-acetpic

20

15 16 17 18 2

7 6 7

5-nitrophen imidazol OH F(?)

21 22 11 2 23

2

7 7 7 7 7 7 7 Dinuclear [ V 0 ( 0 ) 2 ) L ] r = 4,5 r=4,5

d

[VO(0 ) L] 2

3

3

[V(0 ) ] 2

4

8

19 Bridge C,-

CN Ligand(s) Ref. 1 citrato 2 24 malato 1 c,e B, A L-tartrato, H 0 1 e B, A 1 D-tartrato, H 0 e glycolato 6 c,e DL-lactato 6 c,e DL-mandelato 6 c,dpot A,D 7 25 [ V 0 ( 0 ) L ] p = 3,4 3F 2 A, F 7 [V 0 (0 ) L] 2 H 0 (3) E, 6 2 A, E 6-7 0 2 OH (2) A, E 6-7 26 D,E 7 P0 When possible, we use from space reasons the review (2) as reference and apologize for it to the authors of original papers. Abbreviations: glygly, glycylglycinato; dipic, pyridine-2,6-dicarboxylato; pic, picolinato; bpy, 2,2 -bipyridine; phen, 1,10-phenanthroline; nta, nitrilotriacetato; edta, etylenediaminetetraacetato; ada, N-(carbamoylmethyl)iminodiacetato; heida, N-(2-hydroxyethyl)iminodiacetato; pan l-(2-pyridylazo-)-2-naphtol; py, pyridine; ceida, N-(carbamoylethyl)iminodiacetato; bpg, N , N bis(2-pyridylmethyl)-glycine; picOH, 3-hydroxypyridine-2-carboxylato; 2,4 pdc, 2,4 pyridinedicarboxylato; 2

2

2

r

2

2

2

2

2

3

2

2

p

2

4

2

4

a


122

given in Table III, which is including also compounds with the same complex anion, but different cations or other components in a unit cell. As followsfromthis table, besides the common coordination number seven also the coordination number six is quite frequent.


Peroxo complexes of vanadium with chiral ligands. In spite of generally widespread interest paid to the enantioselective reactions, except for several reactivity studies (2), it is surprisingly little known on chiral peroxovanadium complexes. Using stereoisomers of a- hydroxycarboxylic acids (tartaric, lactic, mandelic and others) as ligands we have prepared dinuclear complexes: M [V202(02)2L2]. xH 0. We have not determined the crystal structures of all three compounds with possible combinations of ligands (L-L; D-D and D-L) in a dinuclear anion. Nevertheless the differences in the X-ray powder diffraction patterns and vibrational spectra unequivocally indicate that we have succeded in their preparation. The following compounds have been isolated and characterized: 1. K [V202(02)2(D-tartH2)2 (H 0)] . 5H 0, K [V 0 (02) (L-tartH )2 (H 0)] . 5H 0, (both with crystal structure determined) and K [V 0 (0 ) (D-tartH )(L-tartH )] . 6H 0(tart = C 0 H -). 2. (N(C H ) )2[V 0 (0 ) (D-lact)(L-lact)] . 2H 0 (crystal structure solved) and (N(C H ) ) [V 0 (0 ) (L-lact)(L-lact)]. 2H 0 (lact = C3O3HU -). In the dinuclear complexes with two bridging anions of the same stereoisomer, the configuration B (Table I) seems to be preferied. Two vanadium atoms, moreover bridged by one water molecule, are in these complexes seven- coordinated (Fig. 1). The L-D combination of heteroligands seems to enforce the C type of the bridge with pentagonal pyramidal surroundings of central atoms (Fig. 2). L-L (or D-D) and D-L complexes exhibit distinct V NMR solution spectra. This fact indicates that their mutually different structures are maintained in solution. The seventh position in the coordination polyhedron around vanadium atom is in these complexes vacant or occupied by a weakly bonded ligand (H 0). This fact, together with their solubilities which can be tuned by a cation, predestine these complexes as candidates for enantioselective oxygen transfer reactions in various media. 2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

2

4

2

9

4

4

9

4

2

4

6

2

2

4

2

2

2

2

2

2

2

2

2

2

5 1

2

Acknowledgements: Thanks are gratefully extended to the Ministry of Education of the Slovak Republic (Grant 1/2169/95) and Open Society Fund Slovakia for financial support. Literature cited: 1. Vanadium and its role in life. Sigel, H.; Sigel, A., Eds., Metal ions in biological systems. Vol. 31. Marcel Dekker, New York, Basel, Hong Kong 1995. 2. Butler, A.; Clague, M. J.; Meister, G.E., Chem. Rev. 1994, 94, 625-638. 3. Djordjevic, C., Chem. Brit. 1992, 554-557. 4. Harrison, A.T.; Howarth, O. W., J. Chem. Soc., Dalton Trans. 1985, 1173-1177. 5. Campbell, N. J.; Dengel, A. C.; Griffith, W. P., Polyhedron 1989, 11, 1379-1386.



123 Table III. Number of structures of vanadium(V) peroxo complexes classified according to coordination number. Type Total Coordination num ber 7 6 8 Mononuclear Monoperoxo 22 21 1 Diperoxo 12 16 4 Triperoxo 2 2 Tetraperoxo 2 2 Dinuclear Monoperoxo 5 8 3 Diperoxo 4 7 3 Triperoxodivanadates 1 1 Tetranuclear Diperoxo 1 1 Polymeric 1 Monoperoxo 1 47 2 60 11 X



124



125

6. Jaswal, J. S.; Tracey, A. C., Inorg. Chem. 1991, 30, 3718-3722. 7. Conte, V.; Di Furia, F.; Moro, S., J. Mol. Catal. A 1997, 139-149. 8. Clague, M. J.; Butler, A., J. Am. Chem. Soc. 1995, 117, 3475-3484. 9. Kwong, D. W. J.; Chan, O. Y.;Wong, R. N. S.; Musser, M. S.; Vaca L.; Chan, S. I., Inorg. Chem. 1997, 36, 1276-1277. 10. Rao, V. S. A.; Islam, N. S.; Ramasarma, T., Arch. Biochem. Biophys. 1997, 342, 289-297. 11. Drew, R. E.; Einstein, F. W. B.; Field, J. S.; Begin, D., Acta Crystallogr. 1975, A 31, 135. 12. Einstein, F. W. B.; Batchelor, R. J.; Angus-Dunne, S. J.; Tracey, A. S., Inorg. Chem. 1996, 35, 1680-1684. 13. Sergienko, V.S.; Borzunov, V. K.; Porai-Koshits, M.A., Dokl. Akad. Nauk SSSR 1983, 301, 1141-1144. 14. Sergienko, V.S.; Porai-Koshits, M.A.; Borzunov, V. K.; Ilyukhin, A. B., Koord. Khim. 1993, 19, 767-781. 15. Lapshin, A. E.; Smolin, J. Y.; Shepelev, Y. F.; Sivák, M.; Gyepesová, D., Acta Crystallogr. 1993, C 49, 867-870. 16. Schwendt, P.; Sivák, M.; Lapshin, A. E.; Smolin, J. Y.; Shepelev, Y. F.; Gyepesová, D., Transition Met. Chem. 1994, 19, 34-36. 17. Sivák, M.; Tyršelová, J.; Pavelčík, F.; Marek, J., Polyhedron 1996, 15, 10571062. 18. Colpas, G. J.; Hamstra, B. J.; Kampf, J. W.; Pecoraro, V. L., J. Am. Chem. Soc. 1994, 116, 3627-3628. 19. Colpas, G. J.; Hamstra, B. J.; Kampf, J. W.; Pecoraro, V. L., J. Am. Chem. Soc. 1996, 118, 3469-3478. 20. Shaver, A.; Hall, D. A.; Ng, J. B.; Lebnis, A. M.; Hynes, R. C.; Posner, B. I., Inorg. Chim. Acta 1995, 229, 253-. 21. Shaver, A.; Ng ,J. B.; Hynes, R. C.; Posner, B. I., Acta Crystallogr. 1994, C 50, 1044-. 22. Crans, D. C.; Keramidas, A. D.; Hoover-Litty, H.; Anderson, O. P.; Miler, M. M.; Lemoine, L. M.; Pleasic-Williams, S.; Vandenberg, M.; Rossomando, A. J.; Sweet, L. J., J. Am. Chem. Soc. 1997, 119, 5447-5448. 23. Won, T. J.; Barnes, Ch. L.; Schlemper, E. O.; Thompson, R. C., Inorg. Chem. 1995, 34, 4499-. 24. Djordjevic, C.; Lee-Rensloo, M.; Sinn, E., Inorg. Chim. Acta 1995, 233, 97-. 25. Kanamori, K.; Nishida, K.; Toda, A.; Okamoto, K., Abstracts, 31st ICCC, Vancouver, Canada 1996, p.32. 26. Schwendt, P.; Tyršelová, J.; Pavelčík, F., Inorg. Chem. 1995, 34, 1964-1966. 27. Schwendt, P.; Oravcová, A.; Tyršelová, J.; Pavelčík, F.; Marek, J., Polyhedron 1996, 15, 4507-4511, 28. Djordjevic, C.; Craig, S. A.; Sinn, E., Inorg. Chem. 1985, 24, 1281-1283. 29. Campbell, N. J.; Flanagan, J.; Griffith, W. P.; Skapski, A. C., Transition Met. Chem. 1985, 10, 353-. 30. Schwendt, P.;Volka, K.; Suchánek, M., Spectrochim. Acta 1988, 44A, 839-844.


Vanadium Compounds - American Chemical Society

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