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Three manganese(II) N-oxide complexes have been synthesized from the reaction of manganese(II) chloride with either pyridine N-oxide (PNO), 2-methylpyridine N-oxide (2MePNO) or 3-methylpyridine N-oxide (3MePNO). The compounds were synthesized from methanolic solutions of MnCl2⋅4H2O and the respective N-oxide, and subsequently characterized structurally by single-crystal X-ray diffraction. The compounds are catena-poly[[aquachlorido-manganese(II)]-di-μ-chlorido-[aquachloridomanganese(II)]-bis(μ-pyridine N-oxide)], [MnCl2(C5H5NO)(H2O)]n or [MnCl2(PNO)(H2O)]n (I), catena-poly[[aquachloridomanganese(II)]-di-μ-chlorido-[aquachloridomanganese(II)]-bis(μ-2-methylpyridine N-oxide)], [MnCl2(C6H7NO)(H2O)]n or [MnCl2(2MePNO)(H2O)]n (II), and bis(μ-3-methylpyridine N-oxide)bis[diaquadichloridomanganese(II)], [Mn2Cl4(C6H7NO)2(H2O)4] or [MnCl2(3MePNO)(H2O)2]2 (III). The MnII atoms are found in pseudo-octahedral environments for each of the three complexes. Compound I forms a coordination polymer with alternating pairs of bridging N-oxide and chloride ligands. The coordination environment is defined by two PNO bridging O atoms, two chloride bridging atoms, a terminal chloride, and a terminal water. Compound II also forms a coordination polymer with a similar metal cation; however, the coordination polymer is bridged between MnII atoms by both a single chloride and 2MePNO. The distorted octahedrally coordinated metal cation is defined by two bridging 2MePNO trans to each other, two chlorides, also trans to one another in the equatorial (polymeric) plane, and a terminal chloride and terminal water. Finally, complex III forms a dimer with two bridging 3MePNOs, two terminal chlorides and two terminal waters forming the six-coordinate metal environment. All three compounds exhibit hydrogen bonding between the coordinating water(s) and terminal chlorides. [ABSTRACT FROM AUTHOR]

A novel 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX)/pyridine-N-oxide (PNO) cocrystal at 1:1 molar ratio was synthesized by a solvent evaporation method, and its crystal structure was determined using X-ray diffraction (XRD). It crystallizes in the orthorhombic system with thePbcn space group and cell parametersa = 12.712(3)Å,b = 9.315(3)Å,c = 12.909(3)Å. In addition, detonation performance of this cocrystal was estimated. The predicted detonation velocity and detonation pressure of this cocrystal are 7.47 km/s and 23.20 GPa, respectively, suggesting that it is less powerful than β-HMX. Finally, density functional theory, involving binding energy, atoms in molecule (AIM) theory, natural bond orbital (NBO) analysis, band structure, and density of states, was adopted to characterize the driving forces for the formation of this cocrystal. The results show that driving forces are dominated by the interactions between O atoms of PNO and methylene groups of HMX. It is expected that this research provides some bases for further HMX cocrystal design and preparation. [ABSTRACT FROM PUBLISHER]

Stepwise syntheses of 2-{[2-(diphenylphosphoryl)acetamido]methyl}pyridine 1-oxide, 2-[Ph2P(O)CH2C(O)-N(H)CH2]C5H4NO (6), 2-{[2-(diphenylphosphoryl)acetamido]methyl}-6-[(diphenylphosphoryl)methyl]-pyridine 1-oxide, 2-[Ph2P(O)CH2C(O)N(H)CH2]-6-[Ph2P(O)CH2]C5H3NO (7) and 2,6-bis{[2-(diphenylphosphoryl) acetamido]methyl}pyridine 1-oxide, 2,6-[Ph2P(O)CH2C(O)N(H)CH2]2C5H3NO (8), are reported along with spectroscopic characterization data and single crystal X-ray diffraction structure determination for 6·2H2O, 7 and 2,6-[Ph2P(O)CH2C(O)N(H)CH2]2C5H3N·MeOH 18·MeOH, the pyridine precursor of 8. Molecular mechanics computations indicate that 6, 7 and 8 should experience minimal steric hindrance to donor group reorganization that would permit tridentate, tetradentate and pentadentate docking structures for the respective ligands on lanthanide cations. However, crystal structure determination for the lanthanide complexes, {[Yb(6)(NO3)3]·(MeOH)}n, {[Lu(6)(NO3)3]·(MeOH)}n, [Er(6)2(H2O)2](NO3)3·(H2O)4}n, {[La(13)(NO3)3(MeOH)]·(MeOH)}n, {[Eu(7)(NO3)2(EtOAc)0.5(H2O)0.5](NO3)}2·MeOH and [Dy3(7)4(NO3)4(H2O)2]-(NO3)5·(MeOH)5·(H2O)2 reveal solid-state structures with mixed chelating/bridging ligand : Ln(III) interactions that employ lower than the maximal denticity. The binding of 6 and 7 with Eu(III) in the solid state and in MeOH solutions is also accessed by emission spectroscopy. The acid dependence for solvent extractions with 6 and 7 in 1,2-dichloroethane for Eu(III) and Am(III) in nitric acid solutions is described and compared with the behavior of n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (OPh-DiBCMPO, 1b) and 2-[(diphenyl)phosphinoylmethyl]pyridine N-oxide (DPhNOPO, 4a). [ABSTRACT FROM AUTHOR]

Syntheses for 2-[1-(diarylphosphinoyl)-1-(pyridin-2-yl)methyl]pyridines, ( 8a, b), and 2-[1-(diarylphosphinoyl)-1, 1-bis(methylpyridin-2yl)methyl]pyridines, ( 11a, b), (Ar = C6H5 and 2-CF3C6H4), based on substitution of 2-methylpyridine fragments onto the exo methylene carbon atom of 2-[(diaryl)phosphinoylmethyl]pyridine platforms, are described. N-oxidations of 8a, b and 11a, b produced the 2-[1-(diarylphosphinoyl)-1-(1-oxy-pyridin-2yl)methyl]pyridine N-oxides ( 5a, b) and the 2-[1-(diarylphosphinoyl)-1, 1-bis(1-oxy-methylpyridin-2-yl)methyl]pyridines ( 6a, b), respectively. The 'short-arm' pyridine fragment of 11a, b resists N-oxidation, and the fully oxidized molecules, 2-[1-(diarylphosphinoyl)-1, 1-bis(1-oxy-methylpyridin-2-yl)methyl]pyridine N-oxides ( 7a, b) were not isolated. Molecular mechanics calculations for gas phase 1:1 ligand/lanthanide complexes indicated that 5a should accommodate a tridentate NO(meNO)PO coordination mode with minimal steric strain. In contrast, 7a cannot form tetradentate NO(meNO)2PO chelates; however, tridentate binding should be accessible with minimal ligand strain. Coordination complexes of 8a, b, 5a, b, 6a, b and 11a, b with Ln(NO3)3 salts were isolated and a X-ray crystal structure for [Er( 8a)(NO3)3(MeOH)2]·CH2Cl2, revealed a monodentate Er-O=P interaction. On the other hand, complexes formed by a more symmetrical trifunctional phenylphosphino-bis-2-methylpyridine N, N, P-trioxide ligand, (meNO)2PO*, {La[( meNO)2PO*)](OTf)2(MeOH)3(H2O)+}(OTf-) and {Pr[ (meNO)2PO*)](OTf)(MeOH)4+}(OTf-)2, realized a tridentate coordination mode. Solvent extraction behaviors for EuIII and AmIII in nitric acid solutions using 5a, b, 6a, b, Ph3PO and the parent bifunctional ligand 2-[(diphenylphosphanyl)methyl]pyridine N, P-dioxide ( 3a) in 1, 2-dichloroethane were assessed, and 5a, b and 6a, b were found to behave more like Ph3PO than 3a. [ABSTRACT FROM AUTHOR]

Abstract: A series of new polyoxometalate(POM)-based mononuclear lanthanide(III)–bi pyridine-N-oxide complexes, [Ln(bpyno)4][PMo12O40]·2H2O (Ln=Dy (1), Tb (2), Er (3), Ho (4); bpyno=4,4′-dimethyl-2,2′-bipyridyl-N-N′-dioxide), have been synthesized by the reactions between LnPMo12O40 salts (Ln=Dy (1), Tb (2), Er (3), Ho (4)) and bpyno ligand. All compounds were characterized by elemental analyses, TG analyses, IR, powder X-ray diffraction and single-crystal X-ray diffraction. In 1–4, each mononuclear Ln center is coordinated by eight O atoms derived from four bpyno ligands, exhibiting an approximate square antiprismatic coordination geometry. Furthermore, the [Ln(bpyno)4]3+ units are well separated by the α-Keggin-type polyoxoanions. Magnetic measurements indicate that compound 1 exhibits frequency dependent ac magnetic susceptibilities indicative of slow relaxation of the magnetization. [Copyright &y& Elsevier]

The H-bonded complexes of pyridine N-oxide (PyO) with H2O, acetic, cyanoacetic, propiolic,tribromoacetic, trichloroacetic, trifluoroacetic, hydrochloric, andmethanesulfonic acids have been studied by FTIR and NMR spectroscopy,X-ray diffraction, and quantum chemical DFT calculations. Correlationsbetween vibrational frequencies of the NO stretching and PyO ringmodes and geometric parameters of the H-bond have been established.FTIR experiments show and DFT calculations confirm that definite discontinuityis present in the vicinity of the midpoint in the proton transferpathway. The established correlations significantly aid in the understandingof fine effects such as the isotope (deuteration) effect, crystal-to-solutiontransition, or criticality of aqueous solutions induced by ionic pairs.Geometric isotope effect in the ionic H-bond aggregate of PyO·H(D)Clwas found to be extraordinary large. Measured FTIR, CP/MAS, and high-resolution 13C NMR spectra indicate that H-bond in the PyO·HCl complexin polar solvent can potentially be more ionic than in the crystal.Vibrational modes of ionic pairs originating via proton transfer inH-bond complexes can provide new information concerning the interionicinteraction and its role in the phase separation and mezo-structuringprocesses. The results are compared to the relevant data for PyO·HClcomplex in argon matrix. [ABSTRACT FROM AUTHOR]

Carbene complexes of Ge(IV)- and Sn(N)- fluorides have been synthesized by oxidative addition of 2,2-difluoro-1,3-dimethylimidazolidine and bis- (dimethylamino)difluoromethane to GeCl2•dioxane and SnF2. Chloride analogs of the Ge(IV) complexes were also isolated. All compounds were characterized in the solid state by single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]