Theoretical study of [3⁶]adamanzane (3⁶Adz) based alkalides with remarkable non-linear optical properties

Abstract

Herein, a series of 36Adamanzane (stable C-N bond) based alkalides possessing alkaline earth metal cation complexed by the 36Adz cage has been designed and studied with theoretical tools. All suggested complexes are within the range of effective NLO materials such as red-shifted λmax (1080 – 1241 nm), narrowed Eg (1.74 to 2.31 eV), lowered Eopt (0.9945– 1.1485 eV), enhanced ∆μ (5.3873-6.2544 au), ameliorated α_O (454.20 – 1400.34 au) and β_O (801301.48 – 819800.06 au) as compared to pure 36Adz (Eg = 10.2 eV, λmax = 179 nm, Eopt = 6.9217, α_O = 241.64 and β_O = 0.02 au). All of the aimed complexes have substantially large α_O as well as β_O values. NBO charges investigations reveal that one of the s-electrons has migrated from the inside metal atom to the outer one, resulting in not only alkalide characteristics but also significant NLO responses for the targeted compounds. This research is useful in the development of new types of excess electron compounds. The findings presented in this study may have implications for future research on high-performance NLO materials, as well as give important references for future research on various alkalides including non-alkali cations.

Superalkali-alkaline earthide ion pairs of δ+(AM-HMHC)-AM′δ− (AM = Li, Na and K; AM′ = Be, Mg and Ca) possessing large NLO responses and excellent electronic stabilities and alkalide characteristics: a DFT study

“…20 The β e 0 values of the alkaline-earthides of M + (3 6 Adz)M′ − are in the range of 8.01 × 10 5 – 8.20 × 10 5 a.u. 21 The β e 0 values of alkaline-earthides of Na(C 6 H 6 F 6 ) 2 Be, Na(C 6 H 6 F 6 ) 2 Mg, Li(C 6 H 6 F 6 ) 3 Mg, and Li(C 6 H 6 F 6 ) 3 Ca are 1.21 × 10 4 , 9.00 × 10 3 , 3.31 × 10 4 , and 3.43 × 10 4 a.u., respectively. 25 Among these β e 0 values, our superalkali-alkaline earthide ion pairs of both the chair and boat forms of δ + (AM-HMHC)-AM′ δ − (M = Li, Na, and K; AM′ = Be, Mg, and Ca) have excellent NLO responses.…”

“…To date, reported alkalides mainly refer to the following four categories: alkalide, 3,[6][7][8][9][10][11][12] coinage metalide, 13,14 superalkalide, [15][16][17][18] and alkalineearthide. [19][20][21][22][23][24][25] For example, Ayub et al obtained the alkalide of M@[15-crown-5] 11 and M-(C 6 F 6 H 6 ) 2 -M; 12 superalkalide of Li 3 O@[12-crown-4]M; 15 and alkaline-earthide of M + (calix [4] pyrrole)M 0À , M + (NH 3 ) 6 M 0À , and M + (3 6 Adz)M 0À (M = Li, Na, and K; M 0 = Be, Mg, and Ca). [19][20][21] However, doping atoms, particularly alkali metal atoms, are very active, and subsequently, the chemical environment for the achievement of alkalide species is quite rigorous.…”

“…[19][20][21][22][23][24][25] For example, Ayub et al obtained the alkalide of M@[15-crown-5] 11 and M-(C 6 F 6 H 6 ) 2 -M; 12 superalkalide of Li 3 O@[12-crown-4]M; 15 and alkaline-earthide of M + (calix [4] pyrrole)M 0À , M + (NH 3 ) 6 M 0À , and M + (3 6 Adz)M 0À (M = Li, Na, and K; M 0 = Be, Mg, and Ca). [19][20][21] However, doping atoms, particularly alkali metal atoms, are very active, and subsequently, the chemical environment for the achievement of alkalide species is quite rigorous. Additionally, in the preparation process of alkalides, it always needs resistance to the destructive behavior in the irreversible reductive process.…”