A DFT study on the mono lithium and sodium salts of N-(2-hydroxyphenyl)salicylaldimine

Quantification and Visualization of the Anisotropy Effect in NMR Spectroscopy by Through-Space NMR Shieldings

“…Scheme 3.10 and Fig. 3.35) [79] and complete the topic. In other complexes studied and where chelatoaromaticity was assumed (acetylacetonato chelato complexes, metallobenzenes complexes, orthohydroxy-para-pyrone chelato complexes and the molybdenum dithiolene complex 20a) [77] as well as in the corresponding free ligands chelatoaromaticity could not be identified [77].…”

Are lithium and sodium salts of N-(2-hydroxyphenyl)-salicylaldimine aromatic metalla-hetero[10]annulenes? An answer given by spatial magnetic properties (through space NMR shieldings—TSNMRS)

“…There are strong reservations to quantify aromaticity 22 from magnetic data only 23 because it was found to be a multidimensional characteristic 24 which is dependent on energetic, geometric and magnetic criteria. 25,26 Irshaidat 16 studied the aromaticity of the lithium and sodium salts of N-(2-hydroxyphenyl)salicylaldimine 2 and 3 by employing energetic (the induced aromaticity method introduced by Wannere and von Rague´Schleyer) 27 and geometric criteria, the harmonic oscillator measure of aromaticity (HOMA index) 28 and concluded that the two salts 2 and 3 are nearly as aromatic as the pyrano[2,3-b]pyrrole ring system 5 and are suggested to be the first examples of metalla-hetero [10]annulenes. 16 Magnetic criteria were not employed yet and these will be considered now.…”

“…2) with the difference in planar structures due to salt formation. Thus, from the magnetic criterion, in opposite to energetic and structural criteria, 16 the lithium (2) and sodium salts (3) of N-(2-hydroxyphenyl)salicylaldimine 1 are [10]annulene analogs but with knots at ca. 1 A ˚from the centre of the nine-membered ring; above the centres of the aryl units they are due to extended mesomerism even more aromatic as This result from spatial magnetic properties is corroborated by comparing the TSNMRS of N-(2-hydroxyphenyl)salicylaldimine 1 and the corresponding values of 1,3-dihydroxy-naphthyl-2-aldehyde 6 (Scheme 2) which was studied previously 7b and which was earlier suggested 8 to generate aromaticity in the exo-cyclic, via H-bonding generated 6-membered ring; the in-plane TSNMRS of the two structures (view from above) are given in Fig.…”

“…13,14 With the TSNMRS as the tool in hand to readily characterize electronic structures, we studied the chelatoaromaticity of lithium and sodium salts of N-(2-hydroxyphenyl)salicylaldimine which were recently assigned as the first examples of metallahetero [10]annulenes. 16 This is the topic of this paper.…”

Synthesis and Characterization of Some Unsymmetrical Schiff Bases and Their Copper ( II ) and Nickel ( II ) Complexes

“…[22] The structures were optimized using the B3LYP functional based on the default optimization criteria. Based on our own experience, [23] the 3-21G and SDD basis sets can produce good geometry results. The 3-21G basis set was assigned for carbon, hydrogen, nitrogen, and oxygen, while the SDD basis set was assigned for nickel and copper.…”