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Title: The synthesis and characterization of bis-substituted derivatives of the [a{sup 2}-B{sub 20}H{sub 18}]{sup 4{minus}} anion and the interconversion of isomers

Abstract

The apical-apical (a{sup 2}) isomer of [Et{sub 4}N]{sub 4}[B{sub 20H{sub 18}}] reacts with oxalyl chloride in dichloromethane to produce a protonated bis-substituted carbonyl species, [Et{sub 4}N][a{sup 2}-B{sub 20}H{sub 17}(CO){sub 2}] ([Et{sub 4}N][H1]), in 60% yield. Removal of the bridging hydrogen of the [H1]{sup {minus}} anion in aprotic media results in rearrangement to form the equatorial-equatorial [e{sup 2}-B{sub 20}H{sub 16}(CO){sub 2}]{sup 2{minus}} anion ([e{sup 2}-1]{sup 2{minus}}). The reaction of [Et{sub 4}N][H1] with sodium azide in acetonitrile produces [Et{sub 4}N]{sub 3}-[a{sup 2}-B{sub 20}H{sub 17}(NCO){sub 2}] ([Et{sub 4}N]{sub 3}[H2]) in 53% yield, which subsequently reacts with isopropylamine in acetonitrile to provide the urea derivative [a{sup 2}-B{sub 20}H{sub 16}(NH{sub 2}C(O)NH(i-Pr)){sub 2}]{sup 2{minus}} ([Et{sub 4}N]{sub 2}[4]) in 89% yield. The [H1]{sup {minus}} ion is hydrolyzed in aqueous acetonitrile to give a protonated [a{sup 2}-B{sub 20}H{sub 17}(CO{sub 2}H){sub 2}]{sup 3{minus}} ion ([H3]{sup 3{minus}}) in 61% yield. The a{sup 2} isomers of the bis-substituted species [B{sub 20}H{sub 16}(CO{sub 2}H){sub 2}]{sup 4{minus}} ([3]{sup 4{minus}}) ([2]{sup 4{minus}}), and [B{sub 20}H{sub 16}(NCO){sub 2}]{sup 4{minus}} ([2]{sup 4{minus}}), and [{sub 20}H{sub 16}(NH{sub 2}C(O)NH(i-Pr)){sub 2}]{sup 2{minus}}([4]{sup 2}), formed by the removal of the bridging proton from their protonated precursors, rearrange to form a mixture of ae isomers in solution.

Authors:
; ;
Publication Date:
Research Org.:
Univ. of California, Los Angeles, CA (US)
Sponsoring Org.:
USDOE; National Institutes of Health (NIH)
OSTI Identifier:
20075878
DOE Contract Number:  
FG03-95ER61975
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 39; Journal Issue: 9; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0020-1669
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BORON COMPLEXES; SYNTHESIS; MOLECULAR STRUCTURE; ISOMERS; NONAQUEOUS SOLVENTS; ANIONS; HYDROLYSIS

Citation Formats

Watson-Clark, R.A., Shelly, K., and Hawthorne, M.F. The synthesis and characterization of bis-substituted derivatives of the [a{sup 2}-B{sub 20}H{sub 18}]{sup 4{minus}} anion and the interconversion of isomers. United States: N. p., 2000. Web. doi:10.1021/ic991321i.
Watson-Clark, R.A., Shelly, K., & Hawthorne, M.F. The synthesis and characterization of bis-substituted derivatives of the [a{sup 2}-B{sub 20}H{sub 18}]{sup 4{minus}} anion and the interconversion of isomers. United States. doi:10.1021/ic991321i.
Watson-Clark, R.A., Shelly, K., and Hawthorne, M.F. Mon . "The synthesis and characterization of bis-substituted derivatives of the [a{sup 2}-B{sub 20}H{sub 18}]{sup 4{minus}} anion and the interconversion of isomers". United States. doi:10.1021/ic991321i.
@article{osti_20075878,
title = {The synthesis and characterization of bis-substituted derivatives of the [a{sup 2}-B{sub 20}H{sub 18}]{sup 4{minus}} anion and the interconversion of isomers},
author = {Watson-Clark, R.A. and Shelly, K. and Hawthorne, M.F.},
abstractNote = {The apical-apical (a{sup 2}) isomer of [Et{sub 4}N]{sub 4}[B{sub 20H{sub 18}}] reacts with oxalyl chloride in dichloromethane to produce a protonated bis-substituted carbonyl species, [Et{sub 4}N][a{sup 2}-B{sub 20}H{sub 17}(CO){sub 2}] ([Et{sub 4}N][H1]), in 60% yield. Removal of the bridging hydrogen of the [H1]{sup {minus}} anion in aprotic media results in rearrangement to form the equatorial-equatorial [e{sup 2}-B{sub 20}H{sub 16}(CO){sub 2}]{sup 2{minus}} anion ([e{sup 2}-1]{sup 2{minus}}). The reaction of [Et{sub 4}N][H1] with sodium azide in acetonitrile produces [Et{sub 4}N]{sub 3}-[a{sup 2}-B{sub 20}H{sub 17}(NCO){sub 2}] ([Et{sub 4}N]{sub 3}[H2]) in 53% yield, which subsequently reacts with isopropylamine in acetonitrile to provide the urea derivative [a{sup 2}-B{sub 20}H{sub 16}(NH{sub 2}C(O)NH(i-Pr)){sub 2}]{sup 2{minus}} ([Et{sub 4}N]{sub 2}[4]) in 89% yield. The [H1]{sup {minus}} ion is hydrolyzed in aqueous acetonitrile to give a protonated [a{sup 2}-B{sub 20}H{sub 17}(CO{sub 2}H){sub 2}]{sup 3{minus}} ion ([H3]{sup 3{minus}}) in 61% yield. The a{sup 2} isomers of the bis-substituted species [B{sub 20}H{sub 16}(CO{sub 2}H){sub 2}]{sup 4{minus}} ([3]{sup 4{minus}}) ([2]{sup 4{minus}}), and [B{sub 20}H{sub 16}(NCO){sub 2}]{sup 4{minus}} ([2]{sup 4{minus}}), and [{sub 20}H{sub 16}(NH{sub 2}C(O)NH(i-Pr)){sub 2}]{sup 2{minus}}([4]{sup 2}), formed by the removal of the bridging proton from their protonated precursors, rearrange to form a mixture of ae isomers in solution.},
doi = {10.1021/ic991321i},
journal = {Inorganic Chemistry},
issn = {0020-1669},
number = 9,
volume = 39,
place = {United States},
year = {2000},
month = {5}
}