DIPOLE-MOMENTS AND ELECTRONIC-STRUCTURE OF 2,6-BIS(DIALKYLAMINO) DERIVATIVES OF 4H-PYRAN-4-ONE(THIONE) AND 4H-THIOPYRAN-4-ONE(THIONE)

被引:1
|
作者
SCHROTH, W [1 ]
SPITZNER, R [1 ]
MINKIN, V [1 ]
机构
[1] ROSTOV UNIV,INST PHYS & ORGAN CHEM,ROSTOV NA DONU 344711,RUSSIA
关键词
D O I
10.1002/poc.610060902
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Dipole moments of a series of 2,6-bis(dimethylamino) and 2,6-bis(pyrrolidino) derivatives of 4H-pyran-4-one (2), 4H-thiopyran-4-thione (3), 4H-pyran-4-thione (4) and 4H-thiopyran-4-thione (5) were determined in benzene and dioxane solutions at 25-degrees-C. High values of the dipole moments (6.44-8.44 D) and mesomeric moments originated from delocalization of the nitrogen lone pairs into the pi-system of the heterocyclic moieties (1.11-3.08 D) indicate a strong polarization of the molecules 2-5 due to a tendency to stabilize pentamethinium and pyrylium (thiopyrylium) ionic structures. The MNDO-calculated electronic distribution in 2-5 compared with that for the parent 4H-pyran(thiopyran)-4-one(thione)s is in line with this conclusion
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页码:489 / 493
页数:5
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