0000000001061521
AUTHOR
Henri Kivelä
Imidotungsten(VI) complexes with chelating amino and imino phenolates
The reaction of WOCl(4) with 2,4-di-tert-butyl-6-((isopropylamino)methyl)phenol followed by the reaction with phenyl isocyanate leads to the formation of imidotungsten(VI) complex [W(NPh)Cl(3)(OC(6)H(3)(CH(2)NH-i-Pr)-2-t-Bu(2)-4,6)] 4 with a chelating aminophenolate ligand. When the same procedure was applied using aminophenols with bulkier substituents in the amino group, the final product was an unexpected Schiff-base complex [W(NPh)Cl(3)(OC(6)H(3)(CH=NPh)-2-t-Bu(2)-4,6)] 5, where the ligand is derived from 2,4-di-tert-butyl-6-((phenylimino)methyl)phenol. Complex 5 is also formed in the thermal degradation of 4. On the whole, 5 appears to be formed by a disproportionation of intermediate …
Synthesis and Conformational Analysis of Saturated3,1,2-Benzoxazaphosphinine 2-Oxides
N-Unsubstituted, N-methyl and N-benzyl cis- and trans-2(hydroxymethyl)cyclohexylamines were subjected to ring closure with phenylphosphonic dichloride, phenyl dichlorophosphate and bis(2-chloroethyl)phosphoramidic dichloride in order to synthesize P-epimeric diastereomers of the corresponding unsubsituted and N-substituted 2-phenyl-, 2phenoxy- and 2-[bis(2-chloroethyl)amino]octahydro-2H3,1,2-benzoxazaphosphinine 2-oxides. The stereochemistry and conformations of the prepared compounds were analyzed mainly by variable-temperature 1 H, 13 C and 31 P NMR spectroscopy. Geometry optimizations were performed for some trans-fused molecules by utilizing the B3LYP DFT method and a locally dense basi…
Study of the electrochemical and optical properties of fullerene and methano[60]fullerenediphosphonate derivatives in solution and as self-assembled structures
Four methanofullerenes with phosphonate groups attached to a C60 core were synthesized to probe their electrochemical and optical properties both in solution and as self-assembled monolayer structures (SAMs). As the methano[60]fullerenediphosphonate is a water soluble derivative of the fullerene it has high potential as an imaging molecule in biological applications and in optoelectronics. For the processing of fullerene based SAMs different electrode substrates (ITO, Au and Si) with specific anchoring groups (zirconium, cysteamine and amino-silane) were used. The formation of the C60-SAMs to the surfaces were investigated by atomic force microscopy (AFM), infrared spectroscopy, contact ang…
Vanadium complexes with multidentate amine bisphenols
The reaction of VO(acac)2 (acac(-) = acetyl acetonate) with tripodal glycine bisphenol H3L(1) under an ambient atmosphere yields a hexacoordinated vanadium(iv) complex [V(acac)(L(1))] (1). The corresponding reactions with tripodal 2-propanolamine bisphenol H3L(2) and potentially pentadentate ethoxyethanolamine bisphenol H3L(3) lead to the oxidation of the metal centre and formation of mononuclear oxovanadium(v) complexes [VO(L(2))] (2) and [VO(L(3))] (3), respectively. Alternatively, these latter two complexes can be prepared using VOSO4·5H2O or VO(OPr)3 as a precursor. The CV of 1 in an ACN solution shows a reversible one-electron process at E1/2 = +1.18 V, whereas 2 and 3 have an irrevers…
Aminobisphenolate supported tungsten disulphido and dithiolene complexes
Dioxotungsten(vi) complexes with tetradentate amino bisphenolates were converted into the corresponding Cs-symmetric amino bisphenolate disulphido complexes by a reaction with either Lawesson's reagent or P2S5. Further reaction with diethyl acetylenedicarboxylate leads to the formation of diamagnetic tungsten(iv) dithiolene compounds. The syntheses, crystal structures, spectroscopic and electrochemical characterization of such disulphido and dithiolene complexes are presented.
Oxidomolybdenum(VI) complexes with atrane-type [O3N] ligands
Abstract Dioxomolybdenum(VI) complex [MoO 2 Cl 2 (dmso) 2 ] reacts with a series of tetradentate O 3 N-type aminoalcohol–bisphenol ligands to form oxomolybdenum(VI) complexes of type [MoOCl(L n )]. The reaction of H 3 L 1 produces [MoOCl(L 1 )] as two separable isomers, whereas the reaction of H 3 L 2 or H 3 L 3 yields a single product. The X-ray analyses of cis - and trans -[MoOCl(L 1 )] reveal that the complexes are formed of monomeric molecules. The ligands have tetradentate coordination through three oxygen donors and one nitrogen donor, which is located trans to the terminal oxo group. The sixth coordination site is occupied by a chloro ligand.
Molybdenum(VI) complexes with a chiral L-alanine bisphenol [O,N,O,O’] ligand : Synthesis, structure, spectroscopic properties and catalytic activity
Dioxidomolybdenum(VI) compound [MoO2Cl2(dmso)2] reacts with a chiral tetradentate O3N-type L-alanine bisphenol ligand precursor (Et3NH)H2Lala to form an oxidochloridomolybdenum(VI) complex [MoOCl(Lala)] (1) as two separable geometric isomers with phenolate groups in cis or trans positions. The single crystal X-ray and NMR analyses of cis- and trans-1 reveal that the complexes are formed of monomeric molecules, in which the ligand has a tetradentate coordination through three oxygen donors and one nitrogen donor. The reaction of Na2MoO4·2H2O with the same ligand precursor in an acidic methanol solution leads to the formation of an anionic dioxido complex (Et3NH)[MoO2(Lala)] (2) with a trans …
Synthesis and NMR characterization of the cis and trans isomers of [Pt(II)(N9-adeH)2(pz)2] and X-ray crystallography of the trans isomer.
The reaction of tetrapyrazine Pt(II) with adenine under basic conditions yielded two products both disubstituted by adenine and bound in all cases to the N-9 nitrogen of adenine. Crystals amenable to X-crystallographic analysis were obtained for one product which was consequently identified as trans-[Pt(II)(N9-adeH)2(pz)2](NO3)(4).H2O. The other product, though, was identified as the cis isomer based on extensive and comparative NMR structural studies whereby the two compounds were examined as both neutral and tetraprotonated species in solution. The major product of the reaction was unexpectedly the cis isomer, thus obtained in contrast to the trans effect, and the reason for this result i…