Molecular structure of N,N 0 -o-phenylene-bis(salicylideneaminato)zinc(II), Zn(saloph), according to gas-phase electron diffraction and quantum-chemical calculations G.V. Girichev a, * , N.I. Giricheva b,1 , N.V. Tverdova a,2 , E.D. Pelevina a,b,2 , N.P. Kuzmina c,3 , O.V. Kotova c,3 a Ivanovo State University of Chemistry and Technology, Department of Physics, Engels av 7, 153 000 Ivanovo, Russia b Ivanovo State University, Department of Physical Chemistry, Ermak st. 39, 153 025 Ivanovo, Russia c Lomonosov Moscow State University, Department of Chemistry, Leninskie gory, 119899 Moscow, Russia article info Article history: Received 30 November 2009 Received in revised form 9 February 2010 Accepted 9 February 2010 Available online 16 February 2010 Keywords: Zinc (II) complexes Schiff bases Gas-phase electron diffraction abstract The molecular structure of N,N 0 -o-phenylene-bis(salicylideneaminato)zinc(II) has been determined by synchronous gas-phase electron diffraction (GED) and mass spectrometric experiment at 626(5) K and by density functional theory calculations (B3LYP/Stuttgart ECP(Zn), TZV (O, N, C, H) with the addition of d-polarization functions; in case of N, O with the addition of p-diffuse functions; B3LYP/Stuttgart ECP(Zn), cc-pVTZ (O, N, C, H)). Both experimental and theoretical approaches yielded the structure of C s -symmetry with a planar ZnN 2 O 2 coordination site. The overall ligand conformation is also planar with small distortion towards an umbrella-shape. The most important structure parameters are r h1 (Zn– N) = 2.072(12) Å; r h1 (Zn–O) = 1.926(7) Å; \NZnN = 77.4(1.4)°; \NZnO = 90.4(1.4)°; \OZnO = 101.9(2.5)°. Structural features of tetra-coordinate zinc complexes are discussed. Ó 2010 Elsevier B.V. All rights reserved. 1. Introduction Transition metal compounds containing Schiff base ligands were a subject of numerous investigations for many years due to their biological significance and applications in different fields such as catalysis, molecular architectures, magnetism, materials chemistry, etc. [1–7]. For example, luminescent transition metal compounds widely have been used as a sensors and a probers for a variety of chemical and biological substances; as emitters in or- ganic light-emitting diodes (OLED). Among luminescent metal complexes, Schiff’s base zinc complexes become popular due to their excellent fluorescent properties depending upon only the li- gand caused by filled d-shell of Zn 2+ ion. This peculiarity of zinc complexes opens possibility to create the new materials with de- sired functions by means of bringing different substituent to the frame of organic ligands. So far as unique chemical and physical properties of coordination compounds often are associated with the molecular structure it could be interestingly to examine influ- ence of different Schiff base ligands on overall structure of the zinc complexes with the aim of development of stereochemical theories of coordination chemistry. One of the trends of industry showing significant interest to these compounds is the chemical vapor deposition (MO CVD) tech- nology. Particularly in CVD processes a new type of the sufficiently volatile heteronuclear compounds made from lanthanide chelate complexes and 3d metal complexes with Schiff bases are mainly used as molecular precursors for the production of films for various purposes [8–10]. Therefore, investigation of the structure and properties of these compounds in the gas-phase is very important for understanding various types of the chemical processes in MO CVD technologies. The basic structural features and properties of metal bis-chelate complexes were summarized in review [11]. By now only the structure of several molecules among a great variety of Schiff base metal complexes have been determined by gas-phase electron dif- fraction. According to the references [12,13] the molecules N,N 0 - ethylene-bis(acetylacetoneaminato)zinc(II), (Zn(acacen)) and N,N- ethylene-bis(salicylideneaminato) zinc(II), (Zn(salen)) belong to C 2 -symmetry, the coordination fragment ZnN 2 O 2 possesses the structure in between planar and tetrahedral with dihedral angle between OZnN planes belonging to different moieties metallocy- cles 43° and 35°, respectively. The authors [14] supposed that in case the metal ion M 2+ possesses a spherical d-shell (d 0 ,d 10 and probably d 5 ) the chelate ligands are perpendicular to each other 0022-2860/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.molstruc.2010.02.023 * Corresponding author. Tel.: +7 4932 359874; fax: +7 4932 417995. E-mail addresses: girichev@isuct.ru, g.v.girichev@mail.ru (G.V. Girichev), tverdova@isuct.ru (N.V. Tverdova), kuzmina@inorg.chem.msu.ru (N.P. Kuzmina), kotova@inorg.chem.msu.ru (O.V. Kotova). 1 Tel.: +7 4932 373703. 2 Tel.: +7 4932 359874; fax: +7 4932 417995. 3 Tel.: +7 495 9393836. Journal of Molecular Structure 978 (2010) 178–186 Contents lists available at ScienceDirect Journal of Molecular Structure journal homepage: www.elsevier.com/locate/molstruc