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Octacarbonyl Anion Complexes of Group Three Transition Metals [TM(CO) 8 ] − (TM=Sc, Y, La) and the 18‐Electron Rule
Author(s) -
Jin Jiaye,
Yang Tao,
Xin Ke,
Wang Guanjun,
Jin Xiaoyang,
Zhou Mingfei,
Frenking Gernot
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201802590
Subject(s) - chemistry , valence (chemistry) , atomic orbital , molecular orbital , electron configuration , ground state , crystallography , transition metal , valence electron , photodissociation , electronic structure , singlet state , ion , ligand (biochemistry) , molecule , electron , photochemistry , atomic physics , computational chemistry , excited state , physics , biochemistry , receptor , organic chemistry , quantum mechanics , catalysis
We report the gas‐phase synthesis of stable 20‐electron carbonyl anion complexes of group 3 transition metals, TM(CO) 8 − (TM=Sc, Y, La), which are studied by mass‐selected infrared (IR) photodissociation spectroscopy. The experimentally observed species, which are the first octacarbonyl anionic complexes of a TM, are identified by comparison of the measured and calculated IR spectra. Quantum chemical calculations show that the molecules have a cubic (O h ) equilibrium geometry and a singlet ( 1 A 1g ) electronic ground state. The 20‐electron systems TM(CO) 8 − are energetically stable toward loss of one CO ligand, yielding the 18‐electron complexes TM(CO) 7 − in the 1 A 1 electronic ground state; these exhibit a capped octahedral structure with C 3 v symmetry. Analysis of the electronic structure of TM(CO) 8 − reveals that there is one occupied valence molecular orbital with a 2u symmetry, which is formed only by ligand orbitals without a contribution from the metal atomic orbitals. The adducts of TM(CO) 8 − fulfill the 18‐electron rule when only those valence electrons that occupy metal–ligand bonding orbitals are considered.