Iron(II) and Nickel(II) Complexes of N‐Alkylimidazoles and 1‐Methyl‐1H‐1, 2, 4‐Triazole: X‐ray Studies, Magnetic Characterization, and DFT Calculations

Abstract

Using the ligands N-methylimidazole (MeIm), N-ethylimidazole (EtIm), N-propylimidazole (PrIm), and 1-methyl-1H-1,2,4-triazole (MeTz) three series with a total of 13 iron(II) complexes were isolated. The series comprise of the following complexes: (a) [Fe(MeIm) 6 ](ClO 4 ) 2 (1), [Fe(EtIm) 6 ](ClO 4 ) 2 (2), [Fe(PrIm) 6 ](ClO 4 ) 2 (3), [Fe(MeTz) 6 ](ClO 4 ) 2 (4), [Fe(MeIm) 6 ](MeSO 3 ) 2 (5), [Fe(EtIm) 6 ]-(MeSO 3 ) 2 (6), and [Fe(MeTz) 6 ](BF 4 ) 2 (10); (b) [Fe(MeIm) 4 (MeSO 3 ) 2 ] (7), [Fe(EtIm) 4 (MeSO 3 ) 2 ] (8), and [Fe(PrIm) 4 (MeSO 3 ) 2 ] (9); (c) [Fe(MeIm) 4 (NCS) 2 ] (15), [Fe(EtIm) 4 (NCS) 2 ] (16), and [Fe(MeTz) 4 -(NCS) 2 ] (17). Single crystal X-ray diffraction studies were performed on 7-10 and 15-17. Temperature dependent magnetic susceptibility * Dr. J. Klingele 925 measurements were performed on selective examples of all series, and confirmed them to be in the HS state over the range 6-300 K. DFT calculations were performed at BP86/def-SV(P) and TPSSh/def2-TZVPP level on all [FeL 6 ] 2+ complex cations and the neutral complexes 7-9 and 15-17. Additionally the four homoleptic nickel(II) complexes [NiL 6 ](ClO 4 ) 2 (11: L = MeIm; 12: L = EtIm; 13: L = PrIm; 14: L = MeTz) were synthesized and compounds 11-13 structurally characterized. UV/Vis/NIR spectroscopic measurements were carried out on all homoleptic iron(II) and nickel(II) complexes. The 10Dq values were determined to be in the range of 11547-11574 and 10471-10834 cm -1 for the iron(II) and nickel(II) complexes, respectively.azole group. 10Dq of homoleptic [M(azole) 6 ] n+ complexes is therefore significantly influenced by the ligand's electronic properties, which can be influenced by substituents. Therefore, those complexes provide a convenient way to investigate the ligand's electronic influence on 10Dq.In this context three series of complexes with the general formula [M II L 6 ] 2+ (M = Ni, Fe; L = N-methylimidazole, Nethylimidazole, N-propylimidazole, and 1-methyl-1H-1,2,4-triazole), [FeL 4 (MeSO 3 ) 2 ] (L = N-methylimidazole, N-ethylimidazole, and N-propylimidazole), and [FeL 4 (NCS) 2 ] (L = Nmethylimidazole, N-ethylimidazole, and 1-methyl-1H-1,2,4triazole) were synthesized and studied by DFT methods to determine the effect of the ligand's electronic properties on 10Dq of the resulting complexes. Results and Discussion Complex SynthesesThe primary intention of our studies was the syntheses and analyses of cationic homoleptic complexes of iron(II) with the general formula [FeL 6 ] 2+ , in which L represents one of the monodentate ligands N-methylimidazole (MeIm), N-ethylimidazole (EtIm), N-propylimidazole (PrIm), or 1-methyl-1H-1,2,4-triazole (MeTz). The latter was synthesized by methylation of 1,2,4-triazole with trimethyl phosphate following a protocol published by Yamauchi and Kinoshita. [4] By addition of ligand solutions of MeIm, EtIm, or PrIm in EtOH/2,2dimethoxypropane (1:1) or MeTz in MeOH to solutions of T. Huxel, S. Riedel, J. Lach, J. Klingele ARTICLE Fe(ClO 4 ) 2 ·6H 2 O in the respective solvent the homoleptic comp...

Mechanochemical Synthesis of 3d Transition‐Metal–1,2,4‐Triazole Complexes as Precursors for Microwave‐Assisted and Thermal Conversion to Coordination Polymers with a High Influence on the Dielectric Properties

“…These values are within expected ranges. Interatomic distances between the central metals and the axially coordinated nitrogen atoms are in the range of 2.153(2)–2.248(6) Å and in good accordance with literature values of similar compounds like [Fe(NCS) 2 (MeTzH) 4 ] (MeTzH=1‐methyl‐1,2,4‐1 H ‐triazole) . A comparison of the simulated powder pattern obtained from the single‐crystal X‐ray analysis with the experimental data shows good agreement without additional phases or residual reactants in the case of compound 2 (see Figures S1 and S2 in the Supporting Information).…”

Spin State Crossover, Vibrational, Computational, and Structural Studies of FeII 1‐Isopropyl‐1H‐tetrazole Derivatives

“…Fe–N–C (NCS) angles vs. Fe–N (NCS) bond lengths for the trans ‐[Fe II (L) 2 (NCS) 2 ] or trans ‐[Fe II (L) 4 (NCS) 2 ] complexes found for the published X‐ray structures from the CCDC database. Additionally, the results obtained from heptacoordinated systems described in ref .…”

Crystal structure of diaquatris(1-ethyl-1H-imidazole-κN3)(sulfato-κO)nickel(II)

“…Complexes with one Ni II ion and at least three 1-ethyl-1Himidazole ligands have already been reported in the literature (DEDLIJ: Huxel et al, 2012;IDEJAE: Ç etinkaya et al, 2013;WENYAK: Liu et al, 2006). Complexes have also been reported for Cu (GEVGEV: Hoogerstraete et al, 2012; UFOMIM: Liu et al, 2008;XIKXEV: Liu et al, 2007).…”