Monomeric, Dimeric, and Trimeric Calcium Compounds Containing Substituted Pyrrolyl and Ketiminate Ligands: Synthesis and Structural Characterization
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- 作者：Shih-Mao Ho ; Ching-Sheng Hsiao ; Amitabha Datta ; Chen-Hsiung Hung ; Ling-Chueh Chang ; Ting-Yu Lee ; Jui-Hsien Huang
- 刊名：Inorganic Chemistry
- 出版年：2009
- 出版时间：August 17, 2009
- 年：2009
- 卷：48
- 期：16
- 页码：8004-8011
- 全文大小：957K
- 年卷期：v.48,no.16(August 17, 2009)
- ISSN：1520-510X
文摘
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-CH2NEt2)}]]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[C4H3N(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 Ca3(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.