Conformational and Isomeric Preferences of Six-Membered Inorganic Heterocycles [EtNP(E)(OR)](3) (E = Lone Pair, O, S, or Se): A Synthetic, Spectroscopic, Structural, and Computational Study
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Title |
Conformational and Isomeric Preferences of Six-Membered Inorganic Heterocycles [EtNP(E)(OR)](3) (E = Lone Pair, O, S, or Se): A Synthetic, Spectroscopic, Structural, and Computational Study
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Creator |
MURUGAVEL, R
PRABUSANKAR, G SHARMA, A SUNOJ, RB BUTCHER, RJ |
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Subject |
ray crystal-structure
ring contraction-rearrangement coordination chemistry negative hyperconjugation molecular-structure building-blocks main-group phosphorus nitrogen silanetriols |
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Description |
A silicophosphonate bearing four hydroxyl groups, [RSi(OH){OP(O)(H)(OH)}](2)O (2; R = (2,6-(i)Pr(2)C(6)H(3))N(SiMe(3))), has been isolated from the reaction between RSi(OH)(3) and [EtNPCl](3), In contrast, the reaction between the sodium salt of substituted phenols and [EtNPCl](3) yields [EtNP(OAr)](3) [Ar = -C(6)H(3)(i)Pr(2)-2,6 (3), -C(6)H(2)Me(3)-2,4,6 (4), -C(6)H(3)Me(2)-2,6 (5), -C(10)H(7)-1 (6), and -C(6)H(4)(i)Bu-4 (7)]. The cis isomers 3a-7a preferentially crystallize out from the cis/trans isomeric mixture. Single-crystal X-ray diffraction studies carried out for 3a, 4a, and 5a reveal that the P(3)N(3) ring adopts a flattened-chair conformation with the aryloxy substituent on all three phosphorus atoms occupying the axial position. Oxidation of the cis isomers 3 and 5 by H(2)O(2), sulfur, and selenium yields the trichalcogenides [EtNP(E)(OC(6)H(3)(i)Pr(2)-2,6)](3) (E = O (8), S (10), Se (12)) and [EtNP(E)(OC(6)H(3)Me(2)-2,6)](3) (E = O (9), S (11), Se (13)). The reaction leading to the formation of the triselenide 12 also produces small quantities of the diselenide [Et(3)N(3)P(3)(OR)(3)Se(2)] (R = -C(6)H(3)(i)Pr(2)-2,6) (14). The P(3)N(3) ring in these lambda(5)-phosphazanes is highly distorted and resembles more of a twist-boat conformation. The DFT calculations on model systems [HNP(S)(OMe)](3) (15) and [HNP(Se)(OMe)](3) (16) indicate five low-lying unique conformers A-E. The chair conformer with a triaxial-OMe group is identified as the lowest-energy conformer in both cases.
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Publisher |
AMER CHEMICAL SOC
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Date |
2011-07-13T20:36:50Z
2011-12-26T12:48:07Z 2011-12-27T05:44:58Z 2011-07-13T20:36:50Z 2011-12-26T12:48:07Z 2011-12-27T05:44:58Z 2009 |
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Type |
Article
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Identifier |
INORGANIC CHEMISTRY, 48(5), 2048-2059
0020-1669 http://dx.doi.org/10.1021/ic801945q http://dspace.library.iitb.ac.in/xmlui/handle/10054/3764 http://hdl.handle.net/10054/3764 |
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Language |
en
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