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α‐Tetraphosphorus Trichalcogenide Diamides and Imides containing both Sulfur and Selenium
Author(s) -
Tattershall Bruce W.,
Holmes Kathryn E.,
Tweedy Catherine,
Valks Gina C.
Publication year - 2008
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200800117
Subject(s) - selenide , chalcogen , chemistry , sulfide , sulfur , conformational isomerism , chalcogenide , telluride , medicinal chemistry , selenium , crystallography , organic chemistry , molecule
Reaction of a mixture of bicyclic phosphorus sulfide selenide iodides α‐P 4 S n Se 3−n I 2 ( n = 0–3) with Pr i NH 2 and Et 3 N gave corresponding diamides α‐P 4 S n Se 3−n (NHPr i ) 2 ( n = 0–3) and imides α‐P 4 S n Se 3−n ( μ ‐NPr i ) ( n = 2–3), identified in solution by 31 P NMR. In one isomer of α‐P 4 S 2 Se( μ ‐NPr i ), the C 2 symmetry of imides such as α‐P 4 S 3 ( μ ‐NPr i ) was broken, allowing relative assignment of 2 J NMR couplings to the PNP bridge and the PSP bridge opposite to it. The coupling through the sulfur bridge was found to be reduced to ca. zero, in contrast to previous assumptions for this class of compounds. Ab initio models were calculated at the MPW1PW91/svp level for the sulfide selenide imides and for a selection of bond rotamers of the diamides, and at the MPW1PW91/LanL2DZ(d) level for the sulfide selenide diiodides. Different skeletal isomers were prevalent for the mixed chalcogenide diamides than for the diiodides, showing that exchange of chalcogen between skeletal positions took place in the amination reaction even at room temperature. Similar differences to those observed were predicted by the models, suggesting that equilibrium was attained.