Vladimir A. Ovchynnikov

Spectroscopic characterization of lanthanide complexes with N,N′-tetraethyl-N′′-benzoylphosphoryltriamide. Crystal structure of tris(N,N′-tetraethyl-N′′-benzoylphosphoryltriamide) cerium(III) trinitrate complex

Abstract A new range of lanthanide compounds of the formula Ln(HL)3(NO3)3, where Ln=La, CeNd, SmLu, Y; HL=C6H5C(O)N(H)P(O)[N(CH2CH3)2]2N,N′tetraethylN′′-benzoylphosphoryltriamide have been prepared and characterized by means of IR, 1H, 31P NMR and UV–Vis spectroscopies. The compounds are isomorphous according to X-ray powder diffraction studies. The crystal and molecular structure of Ce(HL)3(NO3)3 has been determined by X-ray diffraction studies. The complex has a molecular structure. The monodentate neutral phosphoryltriamide ligands are coordinated to the metal ion via phosphoryl oxygen atom. The coordination polyhedron of Ce is a tricapped trigonal prism, CN=9 [6O(NO3−)+3O(PO)]. By UV–Vis spectroscopy it was shown that in acetonitrile solution the neodymium complex with molar ratio 1:3 (Nd3+:HL) exists (stability constant=2.56).

Novel tetranuclear cubane-like Co(II) complexes involving chelate phosphoramide ligands

Abstract Interaction of cobalt(II) ions and sodium carbacylamidophosphates Na(L) (HL=PhC(O)NHP(O)(NR2)2; where NR2 are morpholyl, HL1; NMe2, HL2; NEt2, HL3) in methanol solution afforded polynuclear alkoxo complexes [Co4{L1}3(OCH3)4(OH)(H2O)5·3H2O] 1 and [Co4{L}4(OCH3)4(CH3OH)4] (L=L2 2, L3 3). Data of spectral and TGA studies are presented. Coordination compounds 1 and 3 have been characterized by means of X-ray diffraction. Both the structures consist of tetranuclear cubane alkoxo clusters with methoxide ions bridging three metal centers (CoO 2.068(3)–2.093(4) A) and phosphorylic ligands coordinated in a bidentatechelate fashion via the carbonyl oxygen atoms (CoO 1: 2.050(2); 3: 2.031(4) A) and the phosphoryl groups (2.093(2) and 2.106(4) A). Isolation of these cubane alkoxo complexes is an important proof for close resemblance in behavior of carbacylamidophosphate systems and β-diketonates towards transition metal ions.

Metal carbacylamidophosphates: ability of coordination patterns to di- and polymerization

Abstract Cobalt(II), nickel(II) and copper(II) complexes with carbacylamidophosphate ligands {Cl 3 C(O)NP(O)R 2 } − (R=OMe, NEt 2 , NHCH 2 Ph, N -morpholyl) were characterized by means of X-ray diffraction, IR, UV–Vis spectroscopy and thermal analysis. The organic ligands were coordinated via oxygen atoms of phosphoryl and carbonyl groups forming six membered chelate cycles. The molecular units M{L} 2 reveal ability for self-association and readily yield different di- and polymeric motifs either by μ 2 -phosphorylic bridges, donor atoms of the morpholine substitute or employing an additional bridging ligand. Cobalt and nickel solvates [M{L} 2 (Pr i OH)] 2 exist as characteristic dimers sustained by phosphoryl bridges between octahedral metal atoms, while copper complexes aggregate through self-complementary CuO interactions with a morpholine substitute forming one-dimensional chains [Cu{L} 2 ] n or dimers [Cu{L} 2 (Pr i OH)] 2 involving terminal 2-propanol ligands. The configuration of binding sites for [Cu{L} 2 ] (R= N -morpholyl) favors the densest pairwise association of the molecules with CuO (morpholine) at approximately 2.55 A.

Synthesis and spectroscopic characteristics of a new class of lanthanide compounds of formulae Ln(HX)3(NO3)3 and Ln(HX)3Cl3

Two series of the lanthanide (Eu, Pr) compounds of the formulae Ln(HX)3Cl3 (1); Ln(HX)3(NO3)3 (2) [where HX=CCl3CO–NH–PO(NEt2)2] with C.N.=6 and 9 were obtained in the form of monocrystals. The spectroscopic properties of these compounds were investigated at 293, 77 and 4.2 K and the results related to their structures. Correlation was made with the spectroscopic data and structure of the Eu and Nd respective chelates. Essential differences were found in coordination mode of ligand molecules in those systems. Intensity analysis of electronic transitions, electron–phonon coupling, as well as splitting and energies of electronic levels were used as tests of metal bonding in the systems under investigation. The electronic f–f transitions of praseodymium (1, 2) compounds show drastic differences in oscillator strength values, pointing thus at substantial differences in symmetry of the metal centre. Judd–Ofelt parameters were calculated with low errors of estimation. The relatively strong vibronic lines appear at displacement frequencies, corresponding to both ligand and Ln–Ln localised vibrational modes.

Dinuclear 3D metal complexes based on a carbacylamidophosphate ligand: redetermination of the ligand crystal structure

Dinuclear Ni(II), Co(II) and Zn(II) complexes of general formula

β-Diketonates and their Analogs: Stabilization of the Dimeric M2{L}4(D)2 (M = Co, Ni) Core in the Complexes with Dimethyl-N-trichloroacetylamidophosphate {Cl3C(O)NP(O)(OCH3)2}-

\left[ {{\text{M}}_{ 2}^{\text{II}} {\text{Cl}}_{ 4} \left( {\text{HL}} \right)_{ 4} \left( {\text{i-PrOH}} \right)_{ 2} \cdot 2\left( {\text{i-PrOH}} \right)} \right]

Coordination Compounds of Lanthanide Nitrates with Dimorpholido-N-trichloroacetylphosphorylamide. The Structure of Di(dimorpholido-N-trichloroacetylphosphorylamide)- diaqua Neodymium(III)trinitrate

with a carbacylamidophosphate ligand, namely 2,2,2-trichloro-N-(dipiperidine-1-yl-phosphoryl)acetamide (CCl3C(O)N(H)P(O)[N(CH2)5]2), were synthesized and characterized by physicochemical and spectroscopic methods. Electronic absorption spectra of the nickel and cobalt complexes were measured at room temperature in toluene and in the solid state. The crystal structures of HL and [Ni2Cl4(HL)4(i-PrOH)2·2(i-PrOH)] have been determined by single-crystal XRD studies. Earlier, the structure of a monoclinic C2/c modification of HL was reported. In this paper, redetermination of the structure of HL with triclinic crystal system, P