Chromium-manganese selenide carbonyl complexes: Paramagnetic clusters and relevance to C = O activation of acetone

Minghuey Shieh, Chien Nan Lin, Chia Yeh Miu, Miao Hsing Hsu, Yi Wen Pan, Li Fang Ho

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The paramagnetic even-electron cluster, [Et4N] 2[Se2Cr3(CO)10], was found to react readily with Mn(CO)5Br in acetone to produce two unprecedented mixed chromium-manganese selenide carbonyl complexes, [Et4N][Me 2CSe2{Mn(CO)4}{Cr(CO)5} 2] ([Et4N][1]) and [Et4N]2[Se 2Mn3(CO)10{Cr(CO)5}2] ([Et4N]2[2]). X-ray crystallographic analysis showed that anion 1 consisted of two Se-Cr(CO)5 moieties, which were further bridged by one isopropylene group and one Mn(CO)4 moiety. The dianionic cluster 2 was shown to display a Se2Mn3 square-pyramidal core with each Se atom externally coordinated by one Cr(CO)5 group. The formation of complex 1, presumably via C=O activation of acetone, was further facilitated by acidification of the reaction of [Et4N]2[Se2Cr3(CO)10] with Mn(CO)5Br in acetone. Complex 1 readily transformed into 2 upon treatment with Mn2(CO)10 in a KOH/MeOH/MeCN solution. Cluster 2 was a 51-electron species, which readily converted to the known 49-electron cluster [Se2Mn3(CO)9]2- upon heating and bubbling with CO. Magnetic studies of the even-electron cluster, [Et4N]2[Se2Cr3(CO) 10], and the odd-electron species, [Et4N]2[2] and [PPN]2[Se2Mn3(CO)9], were determined by the SQUID measurement to have 2, 3, and 1 unpaired electrons, respectively. In addition, the nature and formation of complexes 1 and 2 are discussed, and the magnetic properties and electrochemistry of [Se 2Cr3(CO)10]2-, 2, and [Se 2Mn3(CO)9]2- were further studied and elucidated by molecular orbital calculations at the PW91 level of density functional theory.

Original languageEnglish
Pages (from-to)8056-8066
Number of pages11
JournalInorganic Chemistry
Volume49
Issue number17
DOIs
Publication statusPublished - 2010 Sep 6

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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