P(O, S, Se, and Te)–π(Ar) Conjugations as Factors to Control Fine Structures of 1-(Chalcogena)naphthalenes

Abstract

The p(Z)–π(Ar) conjugation as the factors to control the fine structures of organic chalcogen compounds are investigated. The structures of 1-(arylchalcogena)naphthalenes [1-(p-YC₆H₄Z)C₁₀H₇, 1-ArZNap; 1 (Z = O) and 2 (Z = S)] are determined by the X-ray crystallographic analysis. The structures of 1, 2, and 1-ArTeNap (4) are also determined in solutions, together with 1-ArSeNap (3), employing the NMR data of 9-(arylselanyl)anthracenes (5) and 1-(arylselanyl)anthraquinones (6). NMR data of 5 and 6 can be used as the standard of the A and B structures, respectively, for all Y examined in solutions: The Se–C_Ar bond in 5 (A) is placed almost perpendicular to the anthryl plane in A, and the bond is located on the plane in 6 (B). Structures of 1–4 are A if Y are electronically accepting groups such as Y = Cl, but they are B with Y of donating groups such as Y = OMe both in crystals and solutions. It is interesting that δ(C_i: 1–4) are hardly affected from the conformation around the Z–C_Ar bonds, whereas δ(H: 1–4) and δ(Se: 3) change depending on the conformation, which enables us to determine the conformations.

Keywords:

• 1-(Arylchalcogena)naphthalenes
• lone pairs
• structure
• substituent dependence
• through-bond interactions

Acknowledgments

Dedicated to Professor Naomichi Furukawa on the occasion of his 70th birthday.

We thank K. Takada for technical assistance in the preparations. This work was partially supported by a Grant-in-Aid for Scientific Research (Nos. 16550038, 19550041, and 20550042) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.