Observation in the gas phase of the ligation of 1-methylimidazole to hemoprotein mimics.
Hemoprotein mimics, cobalt picket fence porphyrins have been prepared in the gas phase as neutral molecules for the first time. Their ligation properties have been studied with 1-methylimidazole and compared with those of other cobalt porphyrins, tetraphenyl porphyrin, and cobalt protoporphyrin IX chloride, in view of studying the sterical properties of the ligation. It is shown that the cobalt picket fence porphyrin can only accept one 1-methylimidazole ligand in contrast to less sterically crowded porphyrins like cobalt tetraphenylporphyrin that present two accessible ligation sites. The femtosecond dynamics of these ligated systems have been studied after excitation at 400 nm, in comparison with the unligated ones. The observed transients are formed in much shorter times, 30 fs for the ligated species, as compared to free species (100 fs), supporting the porphyrin to metal charge transfer nature of these transients. The similar decays of the ligated transients <1 ps reveal the absence of photodissociation of the cobalt-1-methylimidazole bond at this step of evolution.
Institut des Sciences Moléculaires d'Orsay UMR8214, CNRS Université de Paris-Sud, Bat 210, 91405 Orsay, Cedex, France.
Niloufar
N
Shafizadeh
Institut des Sciences Moléculaires d'Orsay UMR8214, CNRS Université de Paris-Sud, Bat 210, 91405 Orsay, Cedex, France.
Minh-Huong
MH
Ha-Thi
Laboratoire Francis Perrin CEA/DSM/IRAMIS/LIDyL - CNRS URA 2453, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
Lionel
L
Poisson
Laboratoire Francis Perrin CEA/DSM/IRAMIS/LIDyL - CNRS URA 2453, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France.
Benoît
B
Soep
Institut Curie, Section de Recherches, Bât 110-112, Centre Universitaire, F-91405 Orsay, France.
Philippe
P
Maillard
D005740:Gases / Q000737:chemistry*; D006420:Hemeproteins / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D015394:Molecular Structure; D011524:Protoporphyrins / Q000737:chemistry*
D005740:Gases; D006420:Hemeproteins; D007093:Imidazoles; D011524:Protoporphyrins; C007095:cobaltiprotoporphyrin; C018100:1-methylimidazole