Naslov
Symmetrical Tetradentate Salicylaldimines Containing Even- and Odd-numbered Bridging Aliphatic Chain

Autori
Friščić, Tomislav ; Meštrović, Ernest ; Kaitner, Branko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
7th Slovenian-Croatian Crystallographic Meeting, Book of Abstracts and Programme / Leban, Ivan ; Petrovčič, Nina - Ljubljana : Univerza v Ljubljani, 1998

Skup
7th Slovenian-Croatian Crystallographic Meeting

Mjesto i datum
Ljubljana, Slovenija, 18.06.1998. - 20.06.1998

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Tetradentate Schiff bases; salycilaldimines; intramolecular hydrogen bonding

Sažetak
In the course of investigation of the solid-state stereochemistry of symmetrical bridged salicylaldiminic Schiff bases two novel compounds N,N'-nonylenebissalicylaldimine (1) and N,N'-dodecylenebissalicylaldimine (2) were prepared. The compounds contain bridging aliphatic chain built up of nine (1) and twelve (2) carbon atoms. The knowledge of solid-state stereochemistry of such ligands is essential for understanding the stereochemical change in the aliphatic chain conformation during the chelatation to the transition metal cations. It can also help elucidate the factors influencing to the structure of this sort of ligands as bridging bisbidentate or classic tetradentate ligands. Crystal data:(1) C23H30N2O2, Mr = 366.50, Monoclinic, Space group C 2/c, a = 44.020(7) A, b = 4.7998(8) A, c = 10.117(2) A, beta = 97.77(2) o, V = 2117.9(6) A3, Z = 4, Dx = 1.149 gcm-3, F(000) = 792, lambda(MoKa) = 0.71073 A, mi(MoKa) = 0.07 mm-1, R = 0.049, wR = 0.101 for 894 reflections (Inet gt 2s Inet) and 123 refined parameters. (2) C26H36N2O2, Mr = 408.58, Monoclinic, Space group P 21/c, a = 22.588(16) A, b = 5.582(2) A, c = 9.577(4) A, beta = 97.16(4) o, V = 1198.1(11) A3, Z = 2, Dx = 1.133 gcm-3, F(000) = 444, lambda(MoKa) = 0.71073 A, mi(MoKa) = 0.07 mm-1, R = 0.065, wR = 0.092 for 768 reflections (Inet gt 2s Inet) and 136 refined parameters. In compound 1 the bridging chain is built up of odd and in 2 of even number of methylene groups. The parity of the number of methylene groups in the chain of both 1 and 2 influences the symmetry of the Schiff base molecules. Thus, in compound 2 the molecule contains a centre of symmetry in the middle of the bridging chain, while in compound 1 it is a two-fold axis. The bridging chain carbon atoms in compounds 1 and 2 lay approximately in the plane. Due to the imposed crystallographic symmetry the planes of the terminal salicylaldiminic residues in 1 are not parallel [dihedral angle amounts 120.0(3)o] while in 2 two salicyladiminic moieties on the opposite sides of 12-membered aliphatic chain are mutually parallel. The molecules of both compounds 1 and 2 are enol tautomers containing the O-H...N type of intramolecular hydrogen bond with N...O bite distance amounting 2.564(4) in 1 and 2.573(5) A in 2.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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