Paper
Dalton Transactions
pyridinium amidate (PYA) complexes: Preparation and
in vitro anticancer activity studies, Inorg. Chim. Acta, 2016,
50, 124–130.
1 (a) O. Belda and C. Moberg, Bispyridylamides-coordination
Crystallographic Data Centre (CCDC) as supplementary
publication numbers 2001555 (2), 2001556 (3), 2001557 (6),
2001558 (7). Details of data collection, structure solution,
and refinement are compiled in the ESI.†
4
1
chemistry and applications in catalytic reactions, Coord. 24 . Yields were low due to crystallization of the product. The
Chem. Rev., 2005, 249, 727–740; (b) A. Rajput and
R. Mukherjee, Coordination chemistry with pyridine/pyra-
product is sensitive to vacuum, as it leads to gradual
decomposition.
zine amide ligands. Some noteworthy results, Coord. Chem. 25 . O-coordination has been observed in neutral pyridine car-
Rev., 2013, 257, 350–368.
boxamides without N-deprotonation, see: W. Jacob and
R. Mukherjee, Synthesis, structure, and properties of
monomeric Fe(II), Co(II), and Ni(II) complexes of neutral N-
(aryl)-2-pyridinecarboxamides, Inorg. Chim. Acta, 2006,
359(14), 4565–4573.
1
1
1
1
2 M. Navarro, M. Li, H. Müller-Bunz, S. Bernhard and
M. Albrecht, Donor-Flexible Nitrogen Ligands for Efficient
Iridium-Catalyzed Water Oxidation Catalysis, Chem. – Eur.
J., 2016, 22, 6740–6745.
3 M. Navarro, C. A. Smith, M. Li, S. Bernhard and 26 A. Dorazco-González, H. Höpfl, F. Medrano and
M. Albrecht, Optimization of Synthetically Versatile
Pyridylidene Amide Ligands for Efficient Iridium-Catalyzed
Water Oxidation, Chem. – Eur. J., 2018, 24, 6386–6398.
A. K. Yatsimirsky, Recognition of Anions and Neutral
Guests by Dicationic Pyridine-2,6-dicarboxamide
Receptors, J. Org. Chem., 2010, 75, 2259–2273.
4 K. Salzmann, C. Segarra and M. Albrecht, Donor-flexible 27 (a) P. Melle, Y. Manoharan and M. Albrecht, Modular
bis-pyridine amide ligands for highly efficient ruthenium-
catalyzed olefin oxidation, Angew. Chem., Int. Ed., 2020, 59,
Pincer-type Pyridylidene Amide Ruthenium(II) Complexes
for Efficient Transfer Hydrogenation Catalysis, Inorg.
Chem., 2018, 57, 11761–11774; (b) P. Melle and
M. Albrecht, Ruthenium Complexes with PYA Pincer
Ligands for Catalytic Transfer Hydrogenation of
Challenging Substrates, Chimia, 2019, 73, 299–303.
8
932–8936.
5 (a) M. S. Chen and M. C. A. White, Predictably Selective
Aliphatic C–H Oxidation Reaction for Complex Molecule
Synthesis, Science, 2007, 318, 783–787; (b) M. Cianfanelli,
G. Olivio, M. Milan, R. J. M. Klein Gebbink, X. Ribas, 28 P. Melle, N. Segaud and M. Albrecht, Ambidentate bonding
M. Bietti and M. Costas, Enantioselective C–H
Lactonization of Unactivated Methylenes Directed by
Carboxylic Acids, J. Am. Chem. Soc., 2020, 142, 1584–1593.
and electrochemical implications of pincer-type pyridyli-
dene amide ligands in complexes of nickel, cobalt and
zinc, Dalton Trans., 2020, 49, 12662–12673.
1
6 C. Kim, K. Chen, J. Kim and L. Que Jr., Stereospecific 29 . Due to low solubility of 6 in MeCN, and reactivity of 7
Alkane Hydroxylation with H
Tris(2-pyridylmethyl)amine Complex, J. Am. Chem. Soc.,
997, 119, 5964–5965.
2
O
2
Catalyzed by an Iron(II)-
with DMF, the complexes could not be analyzed in the
same solvent, which limits a direct comparison of the oxi-
dation potentials.
1
1
7 P. Talsi and K. P. Bryliakov, Chemo- and stereoselective C– 30 . Low solubility of the complex hampered the accurate
H oxidations and epoxidations/cis-dihydroxylations with
H O , catalyzed by non-heme iron and manganese com-
measurement of its magnetic susceptibility by Evans
method.
2
2
plexes, Coord. Chem. Rev., 2012, 256, 1418–1434.
8 Z. Guan, Metal Catalysts for Olefin Polymerization, Top
Organomet Chem., Springer-Verlag Berlin Heidelberg, 2009,
vol. 26, ISBN 978-3-540-87750-9.
9 G. J. P. Britovsek, V. C. Gibson, B. S. Kimberley,
P. J. Maddox, S. J. McTavish, G. A. Solan, A. J. P. White and
31 . This shielding seems to be more relevant for first-row
transition metals with small ionic radii, since larger metal
ions such as Ir(III), Ru(II), and Pd(II) were previously shown
to coordinate to the amide nitrogen also in ortho-PYA com-
plexes, see ref. 9, 12 and 28, while amide O-coordination
was shown with Co and Ni, see ref. 28.
1
1
D. J. Williams, Novel olefin polymerization catalysts based 32 M. Ray, D. Ghosh, Z. Shirin and R. Mukherjee, Highly
on iron and cobalt, Chem. Commun., 1998, 849–850.
0 M. W. Bouwkamp, E. Lobkovsky and P. J. Chirik, Bis(imino)
pyridine Iron(II) Alkyl Cations for Olefin Polymerization,
J. Am. Chem. Soc., 2005, 127, 9660–9661.
1 A. Gonzalez-de-Castro and J. Xiao, Green and Efficient:
Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls 33 (a) G. L. Guillet, J. B. Gordon, G. N. Di Francesco,
Stabilized Low-Spin Iron(III) and Cobalt(III) Complexes of a
Tridentate Bis-Amide Ligand 2,6-Bis(N-phenylcarbamoyl)
2
2
2
pyridine.
Novel
Nonmacrocyclic
Tetraamido-N
Coordination and Two Unusually Short Metal-Pyridine
Bonds, Inorg. Chem., 1997, 36, 3568–3572.
with O
2
, J. Am. Chem. Soc., 2015, 137, 8206–8218.
M. W. Calkins, E. Čižmár, K. A. Abboud, M. W. Meisel,
R. García-Serres and L. J. Murray, A Family of Tri- and
Dimetallic Pyridine Dicarboxamide Cryptates: Unusual O,
N,O–Coordination and Facile Access to Secondary
Coordination Sphere Hydrogen Bonding Interactions,
Inorg. Chem., 2015, 54, 2691–2704; (b) . For a related
example with Ru, see also: J.-C. Waslike, G. Wu, X. Bu,
G. Kehr and G. Erker, Ruthenium carbene Complexes
2 . The solution state magnetic moment of 2 was determined
per iron center, indicating that the dimeric complex either
dissociates to monomeric Fe(L)Cl complexes in solution,
2
or that the Fe centers in the dimeric complex have a very
weak magnetic coupling if any at all.
2
3 . Crystallographic data of the complexes reported in this
paper have been deposited with the Cambridge
Dalton Trans.
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