Synthesis, Properties, and Crystal and Molecular Structures of New Ni(II) Complexes with Sterically Hindered Methoxy-β-iminoketones

This paper describes a procedure for the synthesis of two new volatile complexes, C₂₂H₄₀N₂NiO₄ and C₂₀H₃₆N₂NiO₄, based on sterically hindered methoxy--iminoketones. The compounds were investigated by IR spectroscopy and DTA. Full crystal-chemical analysis has been carried out. The structures are molecular. The complexes have close geometrical characteristics; the distances are Ni–O 1.826 and Ni–N 1.842 ; the O–Ni–N chelate angle is 93.2°. The complexes have an intramolecular hydrogen bond N–H...O, estimated at 2.54 (2.08) . In both structures, the packing of complexes is similar to that in nickel(II) dipivalylmethanate.     

Volatile complexes of Pd(II) with methoxy-β-iminoketones: Synthesis,properties, and crystal and molecular structure

This paper describes a procedure for the synthesis of two new volatile complexes, Pd(L¹)₂ and Pd(L²)₂, from sterically hindered methoxy-β-iminoketones, where HL¹ = C(CH₃)₂(OCH₃)-C(NH)-CH₂-C(O)-C(CH₃)₃; HL² = C(CH₃)₂(OCH₃)-C(NH)-CH₂-C(O)-CH(CH₃)₂. Element analysis and IR spectral data are given. The results of full X-ray crystal structure analysis of the complexes are reported. The compounds have molecular structures; the crystals of the complexes have different symmetry groups and unit cell dimensions. The Pd(L¹)₂ complex molecule has a nonplanar structure; the Pd(L²)₂ complex has a cis-structure. The geometrical characteristics obtained for the coordination units are as follows: the Pd-O and Pd-N bond lengths and N-Pd-O chelate angles were estimated at 1.960 Å, 93.7° for Pd(L¹)₂, and 1.984 Å, 1.976 Å, 92.4° for Pd(L²)₂.     

New volatile complexes of Ni(II) and Pd(II) with 2,2,6,6-tetramethyl-3-amino-4-hepten-5-one: Structure and properties

New volatile β-iminoketonate complexes of Ni(L)₂ and Pd(L)₂ were obtained. β-Aminovinylketone C(CH₃)₃C(NH₂)CHC(O)C(CH₃)₃ was used as HL. Synthesis of the compound is described, and element analysis, DTA, and IR spectral data are given. The complexes were investigated by XRPA and XRD. The structures are molecular, consist of the trans complexes, and are isostructural. The central atoms have a square plane environment with a (MO₂N₂) coordination unit. The M-O and M-N distances and the N-M-O valence chelate angles are equal, 1.834 Å, 1.848 Å, and 94.2° for Ni(L)₂ and 1.972 Å, 1.975 Å, and 92.4° for Pd(L)₂.     

Properties and X-ray structural study of volatile dimethylgold(III) β-iminoketonates

Three complexes of dimethylgold(III) of a general formula of (CH₃)₂Au(R¹-CNH-CH-CO-R²) involving β-imino-derivatives of acetylacetone (k-acac), trifluoroacetylacetone (k-tfa), and pivaloyltrifluoroacetone (k-pta) are studied for the first time with single crystal X-ray diffraction. Synthesis and properties of these compounds are presented along with thermal properties determined by the DTA technique. The structures of the compounds in question are based on monomeric complexes. Gold atoms have a slightly distorted square-planar coordination involving oxygen and nitrogen atoms of the β-iminoketonate ligand and two methyl groups. Geometrical characteristics of the coordination cores are the following: bond lengths of Au-C_Me fall within 2.008–2.050 Å; average Au-O and Au-N distances are 2.094 Å and 2.068 Å respectively. In the structure of (CH₃)₂Au(k-acac) gold complexes are joined by hydrogen bonds to give infinite chains with the shortest Au...Au separation of 5.396 Å. In the crystals of the fluorinated compounds coplanar molecules make infinite stacks. The shortest intra-stack Au...Au separation of 3.416 Å is observed for the complex of (CH₃)₂Au(k-pta) that possesses the largest thermal stability among the investigated compounds.