Smithson Chad S, MacDonald Daniel J, Matt Letvenuk T, Carello Christian E, Jennings Michael, Lough Alan J, Britten James, Decken Andreas, Preuss Kathryn E
Department of Chemistry, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
Dalton Trans. 2016 Jun 21;45(23):9608-20. doi: 10.1039/c6dt01249c. Epub 2016 May 24.
Under aprotic conditions, the reaction of 4-amino-1,2-naphthoquinone with excess S2Cl2 generates 4,5-dioxo-naphtho[1,2-d][1,2,3]dithiazol-2-ium chloride in a typical Herz condensation. By contrast, prior literature reports an imine (NH) product, 4,5-dioxo-1H-naphtho[1,2-d][1,2,3]dithiazole, for the same reaction performed in acetic acid. Herein, the cation product is isolated with four different counter-anions (Cl(-), GaCl4(-), FeCl4(-) and OTf(-)). Reduction of the cation generates a neutral radical 1,2,3-dithiazolyl-o-naphthoquinone, with potential ligand properties. Further reduction generates a closed shell anion, isolated as a water-stable Li(+) complex and exhibiting O,O-bidentate chelation. The hydroxy (OH) isomer of the original imine (NH) product is reported, and this can be readily deprotonated and acylated (OAc). All species are structurally characterized. Solution redox behaviour and EPR are discussed where appropriate.
在非质子条件下，4-氨基-1,2-萘醌与过量的S2Cl2反应，通过典型的赫兹缩合反应生成4,5-二氧代萘并[1,2-d][1,2,3]二噻唑-2-鎓氯化物。相比之下，先前的文献报道在乙酸中进行相同反应时会生成亚胺（NH）产物4,5-二氧代-1H-萘并[1,2-d][1,2,3]二噻唑。在此，阳离子产物与四种不同的抗衡阴离子（Cl(-)、GaCl4(-)、FeCl4(-)和OTf(-)）分离。阳离子的还原产生具有潜在配体性质的中性自由基1,2,3-二噻唑基-邻萘醌。进一步还原产生一个闭壳阴离子，以水稳定的Li(+)配合物形式分离出来，并表现出O,O-双齿螯合作用。报道了原始亚胺（NH）产物的羟基（OH）异构体，并且它可以很容易地去质子化并进行酰化（OAc）。对所有物种进行了结构表征。在适当的情况下讨论了溶液中的氧化还原行为和电子顺磁共振。
