C.M. Mikulski

Metal complexes of aromatic amine n-oxides

Darstellung, Eigenschaften, Substituenteneffekte und Donoreigenschaften aromatischer Amin-N-oxide werden zusammenfassend behandelt.

Further characterization of some metal perchlorate complexes with organophosphoryl ligands

Abstract Supplementary characterization studies of some phosphonate and phosphate ester metal complexes and Fe(TPPO)4(ClO4)3 (TPPO = triphenylphosphine oxide) led to the following conclusions. M(DIMP)4 (ClO4)2 (DIMP = diisopropyl methylphosphonate) complexes involves coordinated perchlorate and were formulated as [M(DIMP)4(OClO3)](ClO4). Dimethyl methylphosphonate (DMMP) complexes of the above type and Fe(TPPO)4(ClO4)3 dot not exhibit any evidence favoring the presence of coordinated perchlorate. For these compounds the presence of a bi- or poly-nuclear complex cation of the type [ML4]nx+, involving both terminal and bridging ligand groups and coordination number five for the metal ions, is proposed. Far infrared studies of the above complexes and a number of [ML5](ClO4)2, [ML6](ClO4)2,3 and [ML4(H2O](ClO4)2 complexes with DMMP and trimethyl phosphate and tentative assignments of vM−O are also reported.

Metal nitrate and thiocyanate complexes with 2,6-lutidine n-oxide

Abstract Complexes formed by interaction of excess 2,6-lutidine N-oxide (LNO) with various metal nitrates and thiocyanates were prepared and characterized by means of spectral, magnetic and conductance studies, as follows: [M(LNO) 6 ](NO 3 ) 3 (M = Cr, Fe), involving distorted octahedral complex cations and ionic nitrate; [M(LNO) 2 (ONO 2 )(O 2 NO)] (MMn, Co, Ni, Zn), pentaco-ordinated neutral complexes, containing one mono- and one bi-dentate nitrato groups; [Cu(LNO) 2 (ONO 2 ) 2 ], planar, and [Cd(LNO) 4 (ONO 2 ) 2 ], hexaco-ordinated, with monodentate nitrato ligands; [(LNO)(SCN) 2− Mg(LNO) 2 Mg(NCS) 2 (LNO)], dimeric, pentaco-ordinated, LNO-bridged, with N-bonded thiocyanate; [(NCS) 2 Hg(LNO) 2 Hg(SCN) 2 ], dimeric, tetrahedral, LNO-bridged, with S-bonded thiocyanate; [(LNO) 2 (SCN)M(NCS) 2 M(NCS)(LNO) 2 ] (M  Co, Ni), pentaco-ordinated dimers with terminal isothiocyanato as well as bridging NCS groups; and [Cu(LNO) 2 (NCS) 2 ] x , hexaco-ordinated polymeric complex with bridging NCS ligands. [Fe(LNO) 6 ](NO 3 ) 3 is the first example of a compound characterized by the Fe III O 6 moiety and exhibiting spin-free-spin-paired equilibria; the polymeric [Cu(LNO) 2 (NCS) 2 ] x exhibits a subnormal magnetic moment. The influence of the steric effects of LNO on the types of complexes formed is discussed.

Interactions of neutral phosphonate esters with metal halides

Abstract Interaction of diisopropyl methylphosphonate with trivalent metal chlorides at 50–200°C leads to the formation of tris-(isopropoxy methylphosphonato) metal complexes. Tetravalent metal chlorides yield under similar conditions bis-(methylphosphonato) complexes. During these reactions isopropyl chloride is evolved, which is partially decomposed to hydrogen chloride and propene by the catalytic action of the complex metal chloride residue. The general insolubility and the magnetic properties of the new complexes are suggestive of polynuclear configurations, involving eight-membered phosphonate bridges and, possibly, four-membered chelate rings. A distorted O h ligand-field symmetry is assigned to the metal ions.

New complexes of triphenylphosphine oxide with metal perchlorates

Abstract New metal perchlorate complexes of triphenylphosphine oxide (TPPO) were synthesized and characterized by means of spectral, magnetic, conductance and X-ray powder diffraction studies. Of particular interest is a pentacoordinated Cr(III) complex, which involves a trinuclear cation. Each Cr(III) ion is in a low symmetry trigonal bipyramidal ligand field, consisting of terminal and bridging TPPO molecules and one coordinated monodentate perchlorato group. The possibility of a polynuclear complex cation is also discussed for the Mg(II) complex on the basis of far i.r. evidence. This complex was formulated as [Mg(TPPO)4]n(ClO4)2n(n = 1,2, …). The rest of the complexes reported were formulated as follows: [M(TPPO)4(OClO3)2](ClO4) (M = Cr, Ce, In); [Fe(TPPO)4] (ClO4)2; [UO2(TPPO)4](ClO4)2; [Ca(TPPO)4(O2ClO2)]; [Th(TPPO)4(O2ClO2)](ClO4)3. In the case of the Th(IV) complex, its formulation as [Th(TPPO)4(O2ClO2)2](ClO4)2 can not be ruled out.

Polynuclear diorgano-phosphato and -phosphonato metal complexes. Characterization studies and physicochemical correlations

Abstract A series of new and previously reported M (III) ( M = Al, Ti, V, Cr, Fe, Dy) and M (IV) ( M = Th, U) polynuclear (-O-P-O-bridged) complexes with several diorgano-phosphato and -phosphanato ligands ( n - and iso -alkyl-, aralkyl- or aryl-substituted) were prepared and characterized by means of spectral, magnetic and X-ray powder diffraction studies. Spectral data ( V POO , V M −O , Dq ) were correlated to the σδ substituent constant (Hammett constants, as modified by Kabachnik for organophosphorus compounds). Linear V POO (asym) vs σδ plots were obtained; the V POO (asym) frequency increases with decreasing ligand-field strength. The V M −O vs σδ plots are considerably more complicated in the cases of 3 d metal ion than in Al(III) or Dy(III) complexes; Dq vs σδ plots for Ti(III) and V(III) complexes are also complicated. The non-linear trends observed in 3 d metal ion V M −O or Dq vs σδ plots are discussed in terms of the combination of inductive and steric effects in determining the degree of metal-ligand back-donation. The subnormal magnetic moments of several M (III) ( M = Ti, V, Cr, Fe) and U(IV) complexes suggest that the 3 d or 5 f electrons of these metal ions participate in magnetic exchange. The Dy(III) complexes are magnetically normal, as expected.

Tris-(isopropoxy methylphosphonato) complexes of trivalent rare-earth metal ions

Tris-(isopropoxy methylphosphonato) rare earth complexes were obtained by interaction of diisopropyl methylphosphonate with trivalent rare-earth chlorides at 50 °–100 °C. The complexes were characterized by means of infrared, magnetic and X-ray powder diffraction studies. A distorted Oh symmetry is assigned to the metal ions. Far infrared evidence indicates the presence of strong lanthanide (III)-oxygen bonds, possibly having partially covalent character. Possible structures of the new complexes, including monomeric chelates and oligomers or polymers, involving eight-membered phosphonate bridges and four-membered chelate rings, are discussed.

Uranium(IV) and thorium(IV) Tetrakis-(dialkoxyphosphato) and Tetrakis-(alkoxy alkylphosphonato) Polynuclear complexes☆

Abstract Reaction of UCl4and ThCl4 with neutral phosphate and phosphonate esters at elevated temperatures leads to the precipitation of tetrakis-(dialkoxyphosphato) and tetrakis-(alkoxy alkylphosphonato) MIV complexes. Characterization of these complexes by means of spectral, magnetic and X-ray studies led to the assignment of polymeric configurations involving octacoordinated metal ions, to these compounds. Solubility characteristics and magnetic moments, which are low for octacoordinated UIV compounds, are in favor of polynuclear structures. Significant differences in the positions of the νM-Obands of the complexes of various phosphato and phosphonato ligands are suggestive of formation of two types of polymers. The ethyl ethylphosphonato, dimethylphosphato and di-n-butylphosphato complexes were tentatively assigned a cross-linked double-bridged configuration, and the methyl methylphosphonato and isopropyl methylphosponato analogs a structure involving four-membered chelate rings and single phosphonato bridges. The n-butyl n-butyl-phosphonato complexes appear to be mixtures of these two types of polymers.

Mono- and bi-dentate nitrato and cationic 4-ethoxypyridine N-oxide complexes with metal nitrates

Abstract Synthetic and characterization studies of 4-ethoxypyridine N-oxide (EPNO) complexes with Co II , Ni II , Cu II and Zn II nitrates are reported. The following structural assignments were made on the basis of spectral, magnetic and conductance studies: [M(EPNO) 2 (O 2 NO) 2 ] (M = Co, Ni, Zn), essentially O h symmetry with coordinated bidentate nitrato groups; [Cu(EPNO) 2 (ONO 2 ) 2 ], essentially planar symmetry; [Co(EPNO) 3 (ONO 2 ) 2 ], involves penta-coordinated Co II ; the last two complexes have been coordinated monodentate nitrato groups; [M(EPNO) 6 ](NO 3 ) 2 (M = Co, Ni), distorted O h symmetry; [Cu(EPNO) 4 ](NO 3 ) 2 , essentially planar symmetry. Mono- and bi-dentate nitrato groups, as well as ionic NO 3 − , are easily distinguishable from the IR spectra of the new complexes. A C s symmetry was assigned to the coordinated monodentate nitrato group, and a C 2ν symmetry to the bidentate nitrato group.

Reactions of alkali metal iodides with diisopropyl methylphosphonate

Alkali metal iodides dissolve in diisopropyl methylphosphonate (DIMP) and react at elevated temperatures (70–120°C) to yield isopropoxy methylphosphonato (IMP) M1 (M=Li, Na, K) complexes and a mixture of isopropyl iodide, HI and propene. Li(IMP) was isolated in crystalline form. This complex redissolves in the reaction mixture at 125°C, while the Na1 and K1 analogs are soluble in the reaction mixture and were not obtained in crystalline form. Solutions of M(IMP) in the reaction mixture yield metal hydrogen methylphosphonate (M(MPH)), possibly through reaction with HI. M(MPH) is subsequently condensed to the corresponding metal pyromethylphosphonate (M2- (PMP); M=Li, Na, K), which is precipitated in crystalline form. Li(IMP) and the M2(PMP) complexes were characterized by means of infrared and conductance studies. Possible structures for these compounds are discussed.