@misc{10481/95486,
year = {2022},
month = {2},
url = {https://hdl.handle.net/10481/95486},
abstract = {The substitution of three water molecules around trivalent chromium in CrBr3·6H2O with the tridentate
2,2’:6’,2’’-terpyridine (tpy), N,N’-dimethyl-N,N’-di(pyridine-2-yl)pyridine-2,6-diamine (ddpd) or 2,6-di
(quinolin-8-yl)pyridine (dqp) ligands gives the heteroleptic mer-[Cr(L)Br3] complexes. Stepwise treatments
with Ag(CF3SO3) and KCN under microwave irradiations provide mer-[Cr(L)(CN)3] in moderate yields.
According to their X-ray crystal structures, the associated six-coordinate meridional [CrN3C3] chromophores
increasingly deviate from a pseudo-octahedral arrangement according to L = ddpd ≈ dpq ≪ tpy; a
trend in line with the replacement of six-membered with five-membered chelate rings around CrIII.
Room-temperature ligand-centered UV-excitation at 18 170 cm−1 (λexc = 350 nm), followed by energy
transfer and intersystem crossing eventually yield microsecond metal-centered Cr(2E → 4A2) phosphorescence
in the red to near infrared domain 13 150–12 650 cm−1 (760 ≤ λem ≤ 790 nm). Decreasing the
temperature to liquid nitrogen (77 K) extends the emission lifetimes to reach the millisecond regime with a
record of 4.02 ms for mer-[Cr(dqp)(CN)3] in frozen acetonitrile.},
organization = {Swiss National Science Foundation
is gratefully acknowledged (grant numbers: 200020_178758
and 206021_183324)},
publisher = {Royal Society of Chemistry},
title = {Heteroleptic mer-[Cr(N∩N∩N)(CN)3] complexes: synthetic challenge, structural characterization and photophysical properties},
doi = {10.1039/D2DT00126H},
author = {Chong, Julien and Besnard, Céline and Carlos M. Cruz, Carlos M. and Piguet, Claude and Jiménez Gallego, Juan Ramón},
}