Monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl and ketiminate ligands: Synthesis and structural characterization

Shih Mao Ho, Ching Sheng Hsiao, Amitabha Datta, Chen Hsiung Hung, Ling Chueh Chang, Ting Yu Lee, Jui Hsien Huang

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Abstract

A series of monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl or ketiminate ligands were synthesized, and characterized by NMR spectroscopy and single crystal X-ray diffractometry. The reaction of Ca[N(SiMe3)2]2(THF)2 with 1 equiv of [C4H3NH(2-CH2NEt2)] in toluene generates the dimeric complex, [Ca{N(SiMe3)}[μ-η1: η5-{C4H3N(2-CH2NEt 2)}]]2 (1) in which two substituted pyrrolyl ligands bind two Ca centers in a η1 and η5 fashion. The reaction between Ca[N(SiMe3)2]2(THF) 2 and 2 equiv of [C4H3NH(2-CH2NEt2)] in THF yields a monomeric calcium compound Ca[C4H 3N(2-CH2NEt2)]2(THF)2 (2) that exhibits a facial octahedral geometry on the central Ca atom. Similarly, the reactions of Ca[N(SiMe3)2]2(THF) 2 with 1 and 2 equiv of OCMeCHCMeNHAr (Ar = 2,6-diisopropylphenyl) generate [Ca(OCMeCHCMeNAr){N(SiMe3)2}]2 (3) and [Ca(μ-OCMeCHCMeNAr)-(OCMeCHCMeNAr)]2 (4), respectively. In 3, the Ca atom possesses a distorted tetrahedral geometry where as in 4, a square plane is developed by the two calcium atoms with the bridging participation of two oxygen atoms from two ketiminate ligands. The in situ reaction of OCMeCHCMeNHAr, Ca[N(SiMe3)2]2(THF)2, and isopropyl alcohol results in a trimeric calcium alkoxide compound Ca 3(μ-OCMeCHCMeNAr)2(OCMeCHCMeNAr)(μ3-O- iPr)22-O-iPr) (5). Compounds 1, 2, and 5 showed good catalytic activity in the ring-opening polymerization of ε-caprolactone and L-lactide.

Original languageEnglish
Pages (from-to)8004-8011
Number of pages8
JournalInorganic Chemistry
Volume48
Issue number16
DOIs
Publication statusPublished - 2009 Aug 17

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calcium compounds
Calcium Compounds
Ligands
Atoms
ligands
synthesis
calcium
atoms
isopropyl alcohol
2-Propanol
Geometry
Ring opening polymerization
alkoxides
Toluene
geometry
X ray diffraction analysis
Nuclear magnetic resonance spectroscopy
toluene
catalytic activity
oxygen atoms

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Ho, Shih Mao ; Hsiao, Ching Sheng ; Datta, Amitabha ; Hung, Chen Hsiung ; Chang, Ling Chueh ; Lee, Ting Yu ; Huang, Jui Hsien. / Monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl and ketiminate ligands : Synthesis and structural characterization. In: Inorganic Chemistry. 2009 ; Vol. 48, No. 16. pp. 8004-8011.
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abstract = "A series of monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl or ketiminate ligands were synthesized, and characterized by NMR spectroscopy and single crystal X-ray diffractometry. The reaction of Ca[N(SiMe3)2]2(THF)2 with 1 equiv of [C4H3NH(2-CH2NEt2)] in toluene generates the dimeric complex, [Ca{N(SiMe3)}[μ-η1: η5-{C4H3N(2-CH2NEt 2)}]]2 (1) in which two substituted pyrrolyl ligands bind two Ca centers in a η1 and η5 fashion. The reaction between Ca[N(SiMe3)2]2(THF) 2 and 2 equiv of [C4H3NH(2-CH2NEt2)] in THF yields a monomeric calcium compound Ca[C4H 3N(2-CH2NEt2)]2(THF)2 (2) that exhibits a facial octahedral geometry on the central Ca atom. Similarly, the reactions of Ca[N(SiMe3)2]2(THF) 2 with 1 and 2 equiv of OCMeCHCMeNHAr (Ar = 2,6-diisopropylphenyl) generate [Ca(OCMeCHCMeNAr){N(SiMe3)2}]2 (3) and [Ca(μ-OCMeCHCMeNAr)-(OCMeCHCMeNAr)]2 (4), respectively. In 3, the Ca atom possesses a distorted tetrahedral geometry where as in 4, a square plane is developed by the two calcium atoms with the bridging participation of two oxygen atoms from two ketiminate ligands. The in situ reaction of OCMeCHCMeNHAr, Ca[N(SiMe3)2]2(THF)2, and isopropyl alcohol results in a trimeric calcium alkoxide compound Ca 3(μ-OCMeCHCMeNAr)2(OCMeCHCMeNAr)(μ3-O- iPr)2(μ2-O-iPr) (5). Compounds 1, 2, and 5 showed good catalytic activity in the ring-opening polymerization of ε-caprolactone and L-lactide.",
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Monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl and ketiminate ligands : Synthesis and structural characterization. / Ho, Shih Mao; Hsiao, Ching Sheng; Datta, Amitabha; Hung, Chen Hsiung; Chang, Ling Chueh; Lee, Ting Yu; Huang, Jui Hsien.

In: Inorganic Chemistry, Vol. 48, No. 16, 17.08.2009, p. 8004-8011.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl and ketiminate ligands

T2 - Synthesis and structural characterization

AU - Ho, Shih Mao

AU - Hsiao, Ching Sheng

AU - Datta, Amitabha

AU - Hung, Chen Hsiung

AU - Chang, Ling Chueh

AU - Lee, Ting Yu

AU - Huang, Jui Hsien

PY - 2009/8/17

Y1 - 2009/8/17

N2 - A series of monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl or ketiminate ligands were synthesized, and characterized by NMR spectroscopy and single crystal X-ray diffractometry. The reaction of Ca[N(SiMe3)2]2(THF)2 with 1 equiv of [C4H3NH(2-CH2NEt2)] in toluene generates the dimeric complex, [Ca{N(SiMe3)}[μ-η1: η5-{C4H3N(2-CH2NEt 2)}]]2 (1) in which two substituted pyrrolyl ligands bind two Ca centers in a η1 and η5 fashion. The reaction between Ca[N(SiMe3)2]2(THF) 2 and 2 equiv of [C4H3NH(2-CH2NEt2)] in THF yields a monomeric calcium compound Ca[C4H 3N(2-CH2NEt2)]2(THF)2 (2) that exhibits a facial octahedral geometry on the central Ca atom. Similarly, the reactions of Ca[N(SiMe3)2]2(THF) 2 with 1 and 2 equiv of OCMeCHCMeNHAr (Ar = 2,6-diisopropylphenyl) generate [Ca(OCMeCHCMeNAr){N(SiMe3)2}]2 (3) and [Ca(μ-OCMeCHCMeNAr)-(OCMeCHCMeNAr)]2 (4), respectively. In 3, the Ca atom possesses a distorted tetrahedral geometry where as in 4, a square plane is developed by the two calcium atoms with the bridging participation of two oxygen atoms from two ketiminate ligands. The in situ reaction of OCMeCHCMeNHAr, Ca[N(SiMe3)2]2(THF)2, and isopropyl alcohol results in a trimeric calcium alkoxide compound Ca 3(μ-OCMeCHCMeNAr)2(OCMeCHCMeNAr)(μ3-O- iPr)2(μ2-O-iPr) (5). Compounds 1, 2, and 5 showed good catalytic activity in the ring-opening polymerization of ε-caprolactone and L-lactide.

AB - A series of monomeric, dimeric, and trimeric calcium compounds containing substituted pyrrolyl or ketiminate ligands were synthesized, and characterized by NMR spectroscopy and single crystal X-ray diffractometry. The reaction of Ca[N(SiMe3)2]2(THF)2 with 1 equiv of [C4H3NH(2-CH2NEt2)] in toluene generates the dimeric complex, [Ca{N(SiMe3)}[μ-η1: η5-{C4H3N(2-CH2NEt 2)}]]2 (1) in which two substituted pyrrolyl ligands bind two Ca centers in a η1 and η5 fashion. The reaction between Ca[N(SiMe3)2]2(THF) 2 and 2 equiv of [C4H3NH(2-CH2NEt2)] in THF yields a monomeric calcium compound Ca[C4H 3N(2-CH2NEt2)]2(THF)2 (2) that exhibits a facial octahedral geometry on the central Ca atom. Similarly, the reactions of Ca[N(SiMe3)2]2(THF) 2 with 1 and 2 equiv of OCMeCHCMeNHAr (Ar = 2,6-diisopropylphenyl) generate [Ca(OCMeCHCMeNAr){N(SiMe3)2}]2 (3) and [Ca(μ-OCMeCHCMeNAr)-(OCMeCHCMeNAr)]2 (4), respectively. In 3, the Ca atom possesses a distorted tetrahedral geometry where as in 4, a square plane is developed by the two calcium atoms with the bridging participation of two oxygen atoms from two ketiminate ligands. The in situ reaction of OCMeCHCMeNHAr, Ca[N(SiMe3)2]2(THF)2, and isopropyl alcohol results in a trimeric calcium alkoxide compound Ca 3(μ-OCMeCHCMeNAr)2(OCMeCHCMeNAr)(μ3-O- iPr)2(μ2-O-iPr) (5). Compounds 1, 2, and 5 showed good catalytic activity in the ring-opening polymerization of ε-caprolactone and L-lactide.

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