Group 6 metallacarborane chemistry : synthesis, structure, and redox reaction study = 6족 금속의 카보레인 착물의 합성, 산화 환원 반응의 연구와 구조분석 연구

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The synthesis and structural analysis of two novel families of three-component reversible redox cycles $[(C_2B_9H_11)M(μ-SPh)_2]_2^{n}PPN_{n}$ (M = Mo, n = 2-, 2; 1-, 3; 0, 4 and M = W, n = 2-, 6; 1-, 7; 0, 8), where the cleavage and reformation of the carborane cage C-C bond is observed during the redox reaction, are reported. Electronic saturation of the metal center (18e center) and the lack of bulky substituents on the carborane cage suggest that the deformed carborane cages in $2ㆍPPN_2$, $6ㆍPPN_2$ and 7ㆍPPN invoke a new kind of deformed cage ("semicloso" framework). The XPS results show that the unprecedented competition for electron density between the metal center and the carborane cage is involved in the cleavage and formation of the carborane C-C bond. The synthesis and structural analysis of $[Cr(CO)_3(μ-H-η^{5} -C_2B_9H_10)CuCl](NMe_4)_2$ $(3ㆍ(NMe_4)_2)$ and $[M(CO)_3((μ-H-η^{5} -C_2B_9H_10)Cu]_2PPN_2$ $(M = Cr for 4ㆍPPN_2, Mo for 7ㆍPPN_2, and W for 10ㆍPPN_2)$ are reported. All products show dative bonding from the 18 electron saturated group 6 metals to the electronically unsaturated Cu atom, which is supported by a B-H→Cu interaction. The dimetallic 3 shows short Cr-Cu distance, (2.494 Å) suggesting the presence of multibonding character. The structural characterizations of 4, 7, and 10 show parallelograms of the tetrametallic $M_2Cu_2$ core, where extremely short Cu-Cu distances of 2.3446, 2.3894, and 2.3883Å, are observed, respectively. The Cu-Cu distance in 4 sets a new lower limit of Cu-Cu distance. The synthesis and the reactivity study of $(C_2B_9H_11)Mo(CO)_3(MeCN)$ (2) is reported. 2 reacts with THF to give charge-compensated $(C_2B_9H_10-10-O(CH_2)_4)Mo(CO)_3)$ (3). Substitution reactions of 2 with $PPh_3$ gave $(C_2B_9H_11)Mo(CO)_3(PPh_3)$ (4) and $(C_2B_9H_11)Mo(CO)_2(PPh_3)(MeCN)$ (5) or $(C_2B_9H_11)Mo(CO)(PPh_3)_2(MeCN)$ (6}) when reacted in $CH_2Cl_2$ or MeCN, respectively, showing that the two ligands, CO and MeCN, can be substitu...
Advisors
Do, Young-Kyuresearcher도영규researcher
Description
한국과학기술원 : 화학과,
Publisher
한국과학기술원
Issue Date
2002
Identifier
177234/325007 / 000985408
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학과, 2002.8, [ vii, 101 p. ]

Keywords

redox reaction; carborane; metallacarborane; X-ray single crystal diffraction; 메탈라카보레인; 엑스선 단결정 구조분석; 산화환원 반응; 카보레인

URI
http://hdl.handle.net/10203/31595
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=177234&flag=dissertation
Appears in Collection
CH-Theses_Ph.D.(박사논문)
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