1992 Fiscal Year Final Research Report Summary
STUDIES ON COORDINATION STRUCTURE OF METAL COMPLEXES
| Project/Area Number |
02640487
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機・錯塩・放射化学
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| Research Institution | DAIDO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
YAMATERA Hideo DAIDO INSTITUTE OF TECHNOLOGY PROFESSOR DEPARTMENT OF CHEMISTRY, 工学部, 教授 (70022499)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Metal Complex / Coordination Structure / Inorganic Stereochemistry / Angular Overlap Model / Hybrid Orbital / 4-Coordinate Structure / 5-Coordinate Structure / 7-Coordinate Structure |
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| Research Abstract |
The angular overlap model (AOM) was suitably applied to the systematic studies of the coordination structure of ML_n-type complexes (n = 2-7). Structures which are otherwise hard to be explained were systematically elucidated.
1. The molecular shape was correlated with the electron configuration of the central ion M^<n+> of a complex ML_n regarded as M^<n+>(L^-)_n by using an extended AOM. The results showed a good agreement with observations.
2. Two-coordinate molecules were shown to have bond angles ranging from 54.74ﾟ to 180ﾟ. Molecules of barium halides as well as SrF_2, SrCl_2, and CaF_2 are bent, contrary to expectations from simple AOM and any other approaches. This unusual fact was elucidated by an extended AOM.
3. Among 3-coordinate structures, the T-shaped ClF_3 molecule with a central ion of s^2p^2 configuration was discussed and the bond angle smaller than 90ﾟ was explained.
4. As for 4-coordinate structures, an extended AOM approach to a complex with an s^2 central ion (SF_4 and the like) showed the stability of a peculiar shape in which all the ligands are located on one side of the xy plane.
5. As for 5-coordinate structures, both trigonal bipyramid and square pyramid are possible shapes for a complex with a closed-shell or d^8 central ion, whereas an s^2 central ion will lead exclusively to a square-pyramidal form with the central atom located below the basal square.
6. Octahedron is the most stable form of 6-coordinate systems ; a trigonal prismatic form can be take in some circumstances. The pentagonal bipyramid is the most stable form of 7-coordinate systems.
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