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Ring Currents as Probes of the Aromaticity of Inorganic Monocycles : P 5 − , As 5 − , S 2 N 2 , S 3 N 3 − , S 4 N 3 + , S 4 N 4 2+ , S 5 N 5 + , S 4 2+ and Se 4 2+
Author(s) -
De Proft Frank,
Fowler Patrick W.,
Havenith Remco W. A.,
Schleyer Paul von Ragué,
Van Lier Gregory,
Geerlings Paul
Publication year - 2004
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200305291
Subject(s) - electron , diamagnetism , physics , atomic physics , ring current , aromaticity , pi , crystallography , chemistry , nuclear physics , quantum mechanics , magnetic field , molecule , earth's magnetic field , biochemistry
Current‐density maps were calculated by the ipsocentric CTOCD‐DZ/6‐311G** (CTOCD‐DZ=continuous transformation of origin of current density‐diamagnetic zero) approach for three sets of inorganic monocycles: S 4 2+ , Se 4 2+ , S 2 N 2 , P 5 − and As 5 − with 6 π electrons; S 3 N 3 − , S 4 N 3 + and S 4 N 4 2+ with 10 π electrons; and S 5 N 5 + with 14 π electrons. Ipsocentric orbital analysis was used to partition the currents into contributions from small groups of active electrons and to interpret the contributions in terms of symmetry‐ and energy‐based selection rules. All nine systems were found to support diatropic π currents, reinforced by σ circulations in P 5 − , As 5 − , S 3 N 3 − , S 4 N 3 + , S 4 N 4 2+ and S 5 N 5 + , but opposed by them in S 4 2+ , Se 4 2+ and S 2 N 2 . The opposition of π and σ effects in the four‐membered rings is compatible with height profiles of calculated NICS (nucleus‐independent chemical shifts).