Table 3.

Comparison of the SHG/THG NLO properties of 1–4 compounds with the values of some selected compound in the literature (AISHG: acoustically induced second harmonic generation/DFWM: degenerate four wave mixing/AIOSHG: acoustically induced optical second harmonic generation/EFISH: electric field induced second harmonic).

Compounds	$\mathrm{\lambda }(\mathrm{nm})$	Technique	${\chi }^{(2)}$ (pm V−1)	${\chi }^{(3)}$ (10–20 m2 V−2)
1	1,064	SHG/THG	1.46	0.61
2	1,064	SHG/THG	0.69	0.35
3	1,064	SHG/THG	0.35	0.25
4	1,064	SHG/THG	5.41	0.27
Trans Ru(2,5-C≡CC-th-CHO)Cl(dppe)226	1,760/532	AISHG	0.4	–
Trans Ru(2,2′,5,5′-C≡C-th-th-CHO)Cl(dppe)212, 21,26	1,760/532	AISHG/DFWM	0.8	1.2
Trans Ru(2,2′,5,5′,2′′,5′′-C≡C-th-th-th-CHO)Cl(dppe)226	1,760/532	AISHG/DFWM	0.27	2.10
Trans Ru(-C≡C-th-(E)CH = CH-th-CHO)Cl(dppe)226	1,760/532	AISHG/DFWM	0.64	2.50
C30H28N4O4Sn72	1,300	THG	–	1.99
Pb3Ge5O1226	1,760	AIOSHG	0.61	–
Ru − X(CuCR)(dppe)221	1,064	EFISH	1.4	–
LiNbO326	1,760	AIOSHG	0.12	–