Biomedical subjects
Publications and source records attributed to Heinrich Nöth.
The preparation and characterization of selected ammonium and methylammonium tetraazidoaurates(III) are reported. All ammonium salts were shown to be highly explosive materials. The first crystal structure of such an ammonium salt, that of [Me(4)N][Au(N(3))(4)], features polymeric units of the anion, which are linked by weak Au...Au interactions.
A series of unusual dinuclear mu2-(eta2-NO)-nitrosoaniline-bridged complexes [[(CO)3Re(mu-X)]2ONC6H4NR2] (X = Cl, Br, I; R = Me, Et) with dichroic properties have been synthesised by reaction of pentacarbonylhalogenorhenium(I) [(CO)5ReX] (X = Cl, Br, I) with the corresponding nitrosoaniline derivatives R2NC6H4NO (R = Me, Et). The deeply coloured solutions in CH2Cl2 show broad UV/Vis absorptions from 595 to 620 nm depending on the halogen bridges and N substituents. Single crystals of all six compounds exhibit a pronounced linear dichroism. The molecular structures have been determined by single-crystal X-ray analyses. All the compounds contain two face-shared octahedra, with two halogens and one NO ligand as bridges. The NO ligand coordinates in a nonsymmetrical eta2-like fashion with N or O coordination to each Re centre. Therefore, the C-nitroso group and the planar NC2 moiety of NR2 both lie almost exactly within the symmetry plane of the dinuclear complexes. These complexes belong to the novel and simple class of neutral dinuclear C-nitroso complexes that include the rare, non-assisted mu2-(eta2-NO) ligand function and have only single halogen atoms in bridging positions.
The first tellurium compounds containing the extremely bulky tris(phenyldimethylsilyl)methyl (Tpsi) and 2,6-bis(2,4,6-triisopropylphenyl)phenyl (2,6-Trip(2)C(6)H(3)) moieties have been synthesized and isolated. Careful oxidation of the tellurolate TpsiTeLi (1) resulted in the formation of the crowded ditellane (TpsiTe)(2) (2), and iodination of 2 gave the alkanetellurenyl iodide TpsiTeI (3). In a similar fashion, the terphenyl-substituted ditellane (2,6-Trip(2)C(6)H(3)Te)(2) (9) and the arenetellurenyl iodide 2,6-Trip(2)C(6)H(3)TeI (10) were prepared. Reaction of the iodides TpsiTeI (3) and 2,6-Trip(2)C(6)H(3)TeI (10), as well as TripTeI, MesTeI (Trip = 2,4,6-triisopropylphenyl, Mes = 2,4,6-tri-tert-butylphenyl), and the donor-stabilized 2-Me(2)NCH(2)C(6)H(4)TeI, with AgN(3) resulted in the formation and isolation of the corresponding tellurenyl azides TpsiTeN(3) (4), TripTeN(3) (7), MesTeN(3) (8), 2,6-Trip(2)C(6)H(3)TeN(3) (11), and 2-Me(2)NCH(2)C(6)H(4)TeN(3) (12). Furthermore, the corresponding tris(ethyldimethylsilyl)methyl-containing (Tesi) tellurium compounds (TesiTe)(2), TesiTeI (5), and TesiTeN(3) (6) have been prepared but could not be isolated in pure form. The crystal structures of TpsiTeLi (1), (TpsiTe)(2) (2), TpsiTeN(3) (4), 2,6-Trip(2)C(6)H(3)TeI (10), 2,6-Trip(2)C(6)H(3)TeN(3) (11), and 2-Me(2)NCH(2)C(6)H(4)TeN(3) (12) have been determined by X-ray diffraction. Additionally, computational studies of the molecules for which experimental structural data were available were performed.
1,5-Diamino-1H-tetrazole (2, DAT) can easily be protonated by reaction with strong mineral acids, yielding the poorly investigated 1,5-diaminotetrazolium nitrate (2a) and perchlorate (2b). A new synthesis for 2 is introduced that avoids lead azide as a hazardous byproduct. The reaction of 1,5-diamino-1H-tetrazole with iodomethane (7a) followed by the metathesis of the iodide (7a) with silver nitrate (7b), silver dinitramide (7c), or silver azide (7d) leads to a new family of heterocyclic-based salts. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear NMR spectroscopy, mass spectrometry, elemental analysis, X-ray structure determination, and initial safety testing (impact and friction sensitivity). Most of the salts exhibit good thermal stabilities, and both the perchlorate (2b) and the dinitramide (7c) have melting points well below 100 degrees C, yet high decomposition onsets, defining them as new (7c), highly energetic ionic liquids. Preliminary sensitivity testing of the crystalline compounds indicates rather low impact sensitivities for all compounds, the highest being that of the perchlorate (2b) and the dinitramide (7c) with a value of 7 J. In contrast, the friction sensitivities of the perchlorate (2b, 60 N) and the dinitramide (7c, 24 N) are relatively high. The enthalpies of combustion (Delta(c)H degrees ) of 7b-d were determined experimentally using oxygen bomb calorimetry: Delta(c)H degrees (7b) = -2456 cal g(-)(1), Delta(c)H degrees (7c) = -2135 cal g(-)(1), and Delta(c)H degrees (7d) = -3594 cal g(-)(1). The standard enthalpies of formation (Delta(f)H degrees ) of 7b-d were obtained on the basis of quantum chemical computations using the G2 (G3) method: Delta(f)H degrees (7b) = 41.7 (41.2) kcal mol(-)(1), Delta(f)H degrees (7c) = 92.1 (91.1) kcal mol(-)(1), and Delta(f)H degrees (7d) = 161.6 (161.5) kcal mol(-)(1). The detonation velocities (D) and detonation pressures (P) of 2b and 7b-d were calculated using the empirical equations of Kamlet and Jacobs: D(2b) = 8383 m s(-)(1), P(2b) = 32.2 GPa; D(7b) = 7682 m s(-)(1), P(7b) = 23.4 GPa; D(7c) = 8827 m s(-)(1), P(7c) = 33.6 GPa; and D(7d) = 7405 m s(-)(1), P(7d) = 20.8 GPa. For all compounds, a structure determination by single-crystal X-ray diffraction was performed. 2a and 2b crystallize in the monoclinic space groups C2/c and P2(1)/n, respectively. The salts of 7 crystallize in the orthorhombic space groups Pna2(1) (7a, 7d) and Fdd2 (7b). The hydrogen-bonded ring motifs are discussed in the formalism of graph-set analysis of hydrogen-bond patterns and compared in the case of 2a, 2b, and 7b.
The molecular structures of dimethylamino[(dimethylboryl)methylamino]methylborane, Me2NBMeNMeBMe2 (1) and 1,1-bis(dimethylboryl)-2,2-dimethylhydrazine, (Me2B)2NNMe2 (2) have been determined by gas electron diffraction (GED), density functional theory calculations at the B3PW91/6-311++G** level and ab initio calculations at the MP2/6-311++G** level. 1 adopts an open structure similar to that of the isoelectronic hydrocarbon molecule permethylbutadiene; the central B-N bond distance at 148.0/149.3(7) pm (MP2/GED) corresponds to a single covalent N--B bond distance, the two terminal distances, 140.9/140.5(4) pm and 141.8/141.3(4) pm, correspond to the distance between N and B atoms joined by a covalent sigma-bond and a dative pi-bond. A closed form where the establishment of a dative bond between the terminal N and B atoms has led to the formation of a four-membered ring also corresponds to a minimum on the potential energy surface, but the energy is calculated to be 14.3 kJ mol(-1) higher at the MP2 level. This structure is also incompatible with the GED data. 2 adopts a structure in which a dative sigma-bond between the dimethylamino N atom and one of the boron atoms has led to the formation of a three-membered N(2)B ring. The dative sigma-bond distance is 165.5/164.0(13) pm, the two other bond distances in the ring are N-B=150.6/148.9(9) pm corresponding to a covalent sigma-bond and N-N=145.1/145.4(3) pm. The terminal B--N distance 139.6/138.9(9) pm is consistent with a covalent sigma-bond augmented by a dative pi-bond. An open Y-shaped structure also corresponds to a minimum on the potential energy surface, but the energy is 18.7 kJ mol(-1) higher (MP2) and it is incompatible with the GED data.
The synthesis and characterization of the dioxouranium(VI) dibromide and iodide hydrates, UO(2)Br(2)x3H(2)O (1), [UO(2)Br(2)(OH(2))(2)](2) (2), and UO(2)I(2)x2H(2)Ox4Et(2)O (3), are reported. Moreover, adducts of UO(2)I(2) and UO(2)Br(2) with large, bulky OP(NMe(2))(3) and OPPh(3) ligands such as UO(2)I(2)(OP(NMe(2))(3))(2) (4), UO(2)Br(2)(OP(NMe(2))(3))(2) (5), and UO(2)I(2)(OPPh(3))(2)(6) are discussed. The structures of the following compounds were determined using single-crystal X-ray diffraction techniques: (1) monoclinic, P2(1)/c, a = 9.7376(8) A, b = 6.5471(5) A, c = 12.817(1) A, beta = 94.104(1) degrees , V = 815.0(1) A(3), Z = 4; (2) monoclinic, P2(1)/c, a = 6.0568(7) A, b = 10.5117(9) A, c = 10.362(1) A, beta = 99.62(1) degrees , V = 650.5(1) A(3), Z = 2; (4) tetragonal, P4(1)2(1)2, a = 10.6519(3) A, b = 10.6519(3) A, c = 24.0758(6) A, V = 2731.7(1) A(3), Z = 4; (5) tetragonal, P4(1)2(1)2, a = 10.4645(1) A, b = 10.4645(1) A, c = 23.7805(3) A, V = 2604.10(5) A(3), Z = 4, and (6) monoclinic, P2(1)/c, a = 9.6543(1) A, b = 18.8968(3) A, c = 10.9042(2) A, beta =115.2134(5) degrees , V = 1783.01(5) A(3), Z = 2. Whereas 1 and 2 are the first UO(2)Br(2) hydrates and the last missing members of the UO(2)X(2) hydrate (X = Cl --> I) series to be structurally characterized, 4 and 6 contain room-temperature stable U(VI)-I bonds with 4 being the first structurally characterized room temperature stable U(VI)-I compound which can be conveniently prepared on a gram scale in quantitative yield. The synthesis and characterization of 5 using an analogous halogen exchange reaction to that used for the preparation of 4 is also reported.
The synthesis and characterization of the neutral uranylisocyanate UO(2)(NCO)(2)(OP(NMe(2))(3))(2) [crystal data: monoclinic, P2(1)/c, a = 8.512(2) A, b = 10.931(2) A, c = 14.329(3) A, beta = 103.923(3) degrees , V = 1294.0(4) A(3), Z = 2] and isocyanato uranate (Et(4)N)(6)[(UO(2))(2)(NCO)(5)O](2) x 2CH(3)CN x H(2)O [crystal data: monoclinic, P2(1)/c, a = 17.2787(2) A, b = 15.560(1) A, c = 32.7619(4) A, beta = 94.0849(5) degrees , V = 8786.5(2) A(3), Z = 4] are reported. Not only are these compounds the first unambiguously characterized uranium isocyanates regardless of the oxidation state for uranium, but they are also the first structurally characterized actinide isocyanates. Both compounds show coordination of the OCN moiety through nitrogen to uranium and were characterized using IR and (1)H, (13)C, (14)N, and (31)P NMR spectroscopy and X-ray diffraction.
The conversion of three equivalents of anhydrous oxalic acid with phosphorus pentachloride yields tris(oxalato)phosphorus acid 1, which crystallizes from diethyl ether solutions as protonated diethyl ether complex [(Et2O)2H](+)[P(C2O3)3)]-. The superacidic compound can be used as catalyst for Friedel-Crafts-type reactions. Upon neutralization with lithium hydride, the lithium salt Li[P(C2O3)3] 2 is obtained, which is highly soluble in aprotic solvents and which exhibits a wide voltage window. Thus, the lithium compound is a promising candidate as electrolyte for high performance non-aqueous batteries.
UO2I2(OH2)2.4Et2O has been synthesized and structurally characterized using X-ray diffraction. This thermally unstable species is the lightest missing member of the dioxouranium dihalide (UO2X2, X = F, Cl, Br, I)-containing series to be structurally characterized and is, to our knowledge, the first structurally characterized compound containing a U(VI)-I bond.
In this work we present the synthesis and structural and spectroscopic characterization of Cu(II), Co(II) and Zn(II) coordination compounds with the antibiotic metronidazole ([double bond]emni). Coordination to metal ions is through its imidazolic nitrogen, while the hydroxyethyl and nitro groups act as supramolecular synthons. [Co(emni)(2)Br(2)], and [Zn(emni)(2)X(2)] (X(-)=Cl, Br) stabilize zig-zag chains, and a 2D supramolecular structure is formed by inter-chain contacts through inter-molecular hydrogen-bonding. Pleated sheet or layers are formed by [Co(emni)(2)Cl(2)] and [Cu(emni)(2)Cl(H(2)O)](2)Cl(2), respectively. The dinuclear Cu(II) compound [Cu(emni)mu(O(2)CMe)(2)](2) gives a one-dimensional zig-zag arrangement. The contribution of metal ions in metronidazole coordination compounds is shown in the stabilization of the different aggregate structures.
Cationic, neutral, and anionic arsenic and antimony halides formed binary arsenic and antimony azide species M(N(3))(4)(+), M(N(3))(4)(-), and M(N(3))(6)(-) (M = As, Sb) upon reaction with trimethylsilyl azide or sodium azide. The compounds were obtained as pure substances or salts, and their identity was established by vibrational spectroscopy and multinuclear NMR spectroscopy and partially by elemental analysis. Attempts to synthesize pentaazides, M(N(3))(5) (M = As, Sb), failed due to spontaneous decomposition of the compounds. Density functional theory (B3LYP) was applied to calculate structural and vibrational data. Vibrational assignments of the normal modes for the isolated azide compounds were made on the basis of their vibrational spectra in comparison with computational results. The molecular structures and vibrational spectra of the arsenic and antimony pentaazides have been investigated theoretically. These calculations (B3LYP) show minima structures (NIMAG = 0) for all reported compounds. It is shown that the M(N(3))(4)(+) (M = As, Sb) cations exhibit ideal S(4) symmetry and the M(N(3))(6)(-) anions (M = As, Sb) ideal S(6) symmetry. The structure of the hexaazidoarsenate(V) has been determined by X-ray diffraction as its pyridinium salt. [py-H][As(N(3))(6)] crystallizes in the triclinic space group P with a = 6.8484(7), b = 7.3957(8), and c = 8.0903(8) A, alpha = 91.017(2), beta = 113.235(2), and gamma = 91.732(2) degrees, V = 376.29(7) A(3), and Z = 1. The structure of the As(N(3))(6)(-) anion exhibits only S(2) symmetry but shows approximately S(6) symmetry. The calculated and experimentally observed structure as well as the calculated and observed IR and Raman frequencies for all azide species (except M(N(3))(5)) are in reasonable agreement.
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The reactions of Me(2)SiCl(2), Ph(2)SiCl(2), and Ph(2)GeCl(2) with LiP(H)B(N(i)Pr(2))(2) in a 1:2 ratio and the reaction of Ph(2)SiCl(2) with LiP(H)B(N(i)Pr(2))[N(SiMe(3))(2)] in a 1:2 ratio give good yields of the respective diphosphinosilanes, Me(2)Si[P(H)B(N(i)Pr(2))(2)](2), Ph(2)Si[P(H)B(N(i)Pr(2))(2)](2), Ph(2)Ge[P(H)B(N(i)Pr(2))(2)](2), and Ph(2)Si[P(H)B(N(i)Pr(2))[N(SiMe(3))(2)]](2). These species, when combined with BuLi in a 1:2 ratio, give lithium diphosphinosilanes and -germanes of the general type (DME.Li)(2){[PB(NR(2))(2)](2)ER'(2)}. All of the species have been characterized by spectroscopic methods. The molecular structures of three of the lithio compounds, (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)SiPh(2)} (11), (DME.Li)(2){[PB(N(i)Pr(2))N(SiMe(3))(2)](2)SiPh(2)} (15), and (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)GePh(2)} (13), have been determined by X-ray diffraction techniques. 11 crystallized in the triclinic space group P&onemacr; with a = 11.071(2) Å, b = 14.937(3) Å, c = 18.080(4) Å, alpha = 91.31(3) degrees, beta = 101.23(3) degrees, gamma = 109.95(3) degrees, and Z = 2, and 13 crystallized in the triclinic space group P&onemacr; with a = 11.083(1) Å, b = 14.978(2) Å, c = 18.134(2) Å, alpha = 91.17(1) degrees, beta = 101.43(1) degrees, gamma = 110.05(1) degrees, and Z = 2. 15 crystallized in the monoclinic space group P2(1)/n with a = 11.939(2) Å, b = 24.516(3) Å, c = 21.572(3) Å, beta = 101.52(1) degrees, and Z = 4. The reactions of the lithio compounds were surveyed with R(2)ECl(2) reagents. The metathesis reactions are sluggish, but the 1:1 reaction of (DME.Li)(2){[PB(N(i)Pr(2))(2)](2)GePh(2)} with (t)Bu(2)SnCl(2) gave the four-membered-ring compound The 1:2 reaction of Me(2)(Cl)SiSi(Cl)Me(2) with LiP(H)B(N(i)Pr(2))(2) yielded the (borylphosphino)silane [Me(2)SiP(H)B(N(i)Pr(2))(2)](2).
The 1:1 reactions with (R(3)P)(2)MCl(2) (M = Ni, Pd, and Pt) have been surveyed, and bicyclic cage compounds containing boron, phosphorus and transition metal (Ni, Pd, or Pt) atoms have been isolated and characterized. The molecular structures of the species (Et(3)P)(2)Pd(PBN(i)Pr(2))(2) (2), (Et(3)P)(2)Pd(PBtmp)(2) (3), and (Et(3)P)(2)Pt(PBN(i)Pr(2))(2) (4) have been determined by single-crystal X-ray diffraction techniques. 2 crystallized in the monoclinic space group C2/c with a = 20.212(4) Å, b = 10.225(1) Å, c = 17.460(2) Å, beta = 107.72(1) degrees, and Z = 4. 3 crystallized in the orthorhombic space group P2(1)2(1)2(1) with a = 12.606(1) Å, b = 12.618(1) Å, c = 24.221(3) Å, and Z = 4. 4 crystallized in the monoclinic space group C2/c with a = 20.195(3) Å, b = 10.187(2) Å, c = 17.280(2) Å, beta = 107.53(7) degrees, and Z = 4. The spectroscopic and structural features of the new cage compounds are discussed in relation to their main group element cage analogs.
Synthesis of the tricoordinated alanyl-containing iron complex (tmp)(2)Al-Fe(cp)(CO)(2)] (1) (tmp = 2,2,6,6-tetramethylpiperidino) has been achieved in a straightforward salt elimination reaction of (tmp)(2)AlBr with Na[(cp)Fe(CO)(2)]. 1 crystallizes in the triclinic space group P&onemacr; (a = 8.347(4) Å, b = 10.044(5) Å, c = 15.087(8) Å, alpha = 94.01(1) degrees, beta = 91.18(1) degrees, gamma = 102.50(1) degrees ) and is an unassociated monomer with an Al-Fe bond length of 2.450(1) Å.