was suggested to result from reaction between a triplet tautomer
state, wherein the C(3) hydroxyl proton has been transferred
to the C(4)-carbonyl moiety in a zwitterionic structure, and
ground state 3O2. We note that this chemistry is solvent
dependent, as in CH3OH, CH3CN, or CH2Cl2, photooxygenation
does not happen and instead photorearrangement to give
3-phenyl-3-hydroxy-1,2-inandione occurs.22,23
8 (a) G. Barath, J. Kaizer, G. Speier, L. Pa
A. Vertes, Chem. Commun., 2009, 3630–3632; (b) J. Kaizer,
G. Barath, J. Pap, G. Speier, M. Giorgi and M. Reglier, Chem.
Commun., 2007, 5235–5237.
9 K. Grubel, K. Rudzka, A. M. Arif, K. Klotz, J. A. Halfen and
L. M. Berreau, Inorg. Chem., 2010, 49, 82–96.
rkanyi, E. Kuzmann and
´ ´
´
10 S. Protti, A. Mezzetti, C. Lapouge and J. P. Cornard, Photochem.
Photobiol. Sci., 2008, 7, 109–119.
11 2: C45H35CdClN4O7, M = 891.62, monoclinic, a = 11.4616(2),
= 16.3861(3), c = 20.8770(4) A, U =
3905.89(12) A3,
Previously, the presence of metal ions was reported to
prevent the photoinduced rearrangment of neutral 3-Hfl, or
have no effect on the photochemical reaction.10,23a However, the
results presented herein show that metal 3-hydroxyflavonolate
complexes can undergo photoinduced dioxygenase-type
CO-release reactivity when irradiated with UV light. In these
complexes the coordinated flavonolate anion is akin to the
tautomeric structure of 3-Hfl,21 thereby enabling photo-
induced photooxygenation and CO-release reactivity. Notably
this reactivity occurs under conditions that are considerably
milder than those reported for thermal dioxygenase-type reactions
of Cu(3-Hfl) complexes.7 Overall, the results presented herein
suggest that the formation of metal-flavonolate species in
nature may enable light-induced dioxgyenase-type CO-release
reactivity under mild conditions.
b
T = 151(1)K,space group P21/n, Z = 4, 15965 reflections measured,
8943 unique (Rint = 0.0303) which were used in all calculations.
The final R values (I 4 2s(I)) are R1 = 0.0364 and wR2 = 0.0765.
3: C45H35HgClN4O7, M = 979.81, monoclinic, a = 11.4117(2),
b
= 16.3761(2), c = 20.9794(3) A, U =
3905.65(10) A3,
T = 151(1)K, space group P21/n, Z = 4, 16 904 reflections
measured, 8946 unique (Rint = 0.0366) which were used in all
calculations. The final R values (I 4 2s(I)) are R1 = 0.0364 and
wR2 = 0.0883.
12 The average M–N distance involving the chelate ligand increases
by Z 0.3 A for the Cd(II) and Hg(II) derivatives relative to 1
(avg. M–N: 1: 2.11 A; 2: 2.41 A; 3: 2.46 A).
13 CO formation was detected via GC and the PdCl2 method.
T. H. Allen and W. S. Root, J. Biol. Chem., 1955, 215, 309–317.
CO2 formation was minimal and within the error range of the GC
analysis.
14 (a) A. Tamayo, B. Pedras, L. Lodeiro, L. Escriche, J. Casabo,
J. L. Capelo, B. Covelo, R. Kivekas and R. Silanpaa, Inorg. Chem.,
¨
¨
¨
2007, 46, 7818–7826; (b) C. N. Burress, M. I. Bodine, O. Elbjeirami,
J. H. Reibenspies, M. A. Omary and F. P. Gabbaı, Inorg. Chem.,
2007, 46, 1388–1395.
We acknowledge support from the National Science
Foundation (Grants CHE-0848858 to LMB and CHE-0847132
to RCS).
¨
15 4: C45H35F3N4O7SZn, M = 898.20, monoclinic, a = 10.1785(2),
b = 16.3337(5), c = 24.1620(5) A, U = 4016.34(17) A3, T =
151(1)K, space group P21/c, Z = 4, 15 119 reflections measured,
9139 unique (Rint = 0.0342) which were used in all calculations.
The final R values (I 4 2s(I)) are R1 = 0.0432 and wR2 = 0.0883.
16 4t5 = 0.92; t5 is a parameter that describes the geometry of a five-
coordinate metal center. A trigonal bipyramidal geometry corre-
lates with t5 = 1, whereas a square pyramidal geometry has t5 = 0.
A. W. Addison, T. N. Rao, J. Reedijk, J. van Rijn and
G. C. Verschoor, J. Chem. Soc., Dalton Trans., 1984, 1349–1356.
17 Monodentate: Dd 4 0.6 A, Dy 4 281; bidentate: Ddo0.3 A,
Dyo141. G. J. Kleywegt, W. G. R. Wiesmeijer, G. J. van Driel,
W. L. Driessen, J. Reedijk and J. H. Noordik, J. Chem. Soc.,
Dalton Trans., 1985, 2177–2184.
Notes and references
1 (a) S. C. Bischoff, Curr. Opin. Clin. Nutr. Metab. Care, 2008, 11,
733–740; (b) L. H. Cazarolli, L. Zanatta, E. H. Alberton,
M. S. Figueiredo, P. Folador, R. G. Damazio, M. G. Pizzolatti
and F. R. Silva, Mini Rev. Med. Chem., 2008, 8, 1429–1440;
(c) A. W. Boots, G. R. Haenen and A. Bast, Eur. J. Pharmacol.,
2008, 585, 325–337; (d) M. Friedman, Mol. Nutr. Food Res., 2007,
51, 116–134; (e) D. Amic, D. Davidovic-Amic, D. Beslo,
V. Rastija, B. Lucic and N. Trinajstic, Curr. Med. Chem., 2007,
14, 827–845; (f) T. P. T. Cushnie and A. J. Lamb, Int. J.
Antimicrob. Agents, 2011, 38, 99–107.
2 (a) H. Yao, W. Xu, X. Shi and Z. Zhang, J. Environ. Sci. Health,
C: Environ. Carcinog. Ecotoxicol. Rev., 2011, 29, 1–31;
(b) S. Jagtap, K. Meganathan, V. Wagh, J. Winkler, J. Hescheler
and A. Sachinidis, Curr. Med. Chem., 2009, 16, 1451–1462.
3 (a) R. F. V. de Souza and W. F. De Giovani, Spectrochim. Acta,
Part A, 2005, 61, 1985–1990; (b) R. F. V. de Souza, E. M. Sussuchi
and W. F. De Giovani, Synth. React. Inorg., Met.-Org., Nano-Met.
Chem., 2003, 33, 1125–1144.
18 5: C46H38CdClN5O8, M = 936.66, triclinic, a = 14.2066(2), b =
13.24300(10), c = 14.3060(2) A, U = 2075.18(5) A3, T = 151(1)K,
%
space group P1, Z = 4, 17877 reflections measured, 9483 unique
(Rint = 0.0202) which were used in all calculations. The final R
values (I 4 2s(I)) are R1 = 0.0348 and wR2 = 0.0749.
19 Additional studies of the solution NMR properties of 6 are
currently in progress.
20 (a) T. Matsuura, H. Matsushima and H. Sakamoto, J. Am. Chem.
Soc., 1967, 89, 6370–6371; (b) T. Matsuura, H. Matsushima and
R. Nakashima, Tetrahedron, 1970, 26, 435–443.
4 R. A. Steiner, K. H. Kalk and B. W. Dijkstra, Proc. Natl. Acad.
Sci. U. S. A., 2002, 99, 16625–16630.
5 (a) H. Merkens, R. Kappl, R. P. Jakob, F. X. Schmid and S. Fetzner,
Biochemistry, 2008, 47, 12185–12196; (b) M. R. Schaab, B. M. Barney
and W. A. Francisco, Biochemistry, 2006, 45, 1009–1016;
(c) B. Gopal, L. L. Madan, S. F. Betz and A. A. Kossiakoff,
Biochemistry, 2005, 44, 193–201.
6 (a) L. Dangleterre and J. P. Cornard, Polyhedron, 2005, 24,
1593–1598; (b) C. Lapouge and J. P. Cornard, J. Phys. Chem. A,
2005, 109, 6752–6761.
21 S. L. Studer, W. E. Brewer, M. L. Martinez and P.-T. Chou, J. Am.
Chem. Soc., 1989, 111, 7643–7644.
22 I. Yokoe, K. Higushi, Y. Shirataki and M. Komatsu, Chem.
Pharm. Bull., 1981, 29, 894–898.
23 (a) M. Sisa, S. L. Bonnet, D. Ferreira and J. H. Van der
Westhuizen, Molecules, 2010, 15, 5196–5245; (b) T. Matsuura,
T. Takemoto and R. Nakashima, Tetrahedron Lett., 1971, 12,
1539–1540; (c) T. Matsuura, T. Takemoto and R. Nakashima,
Tetrahedron, 1973, 29, 3337–3340; (d) R. Ficarra, P. Ficarra,
S. Tommasini, S. Campagna and O. Guglielmo, Bull. Chim. Farm.,
1994, 133, 665–669.
7 (a) J. S. Pap, J. Kaizer and G. Speier, Coord. Chem. Rev., 2010,
´
254, 781–793; (b) J. Kaizer, E. Balogh-Hergovich, M. Czaun,
T. Csay and G. Speier, Coord. Chem. Rev., 2006, 250, 2222–2233.
c
This journal is The Royal Society of Chemistry 2011
Chem. Commun., 2011, 47, 10431–10433 10433