EFFECTS OF BOUND MONOCLONAL ANTIBODIES ON THE DECAY OF THE PHOTOTRANSFORMATION INTERMEDIATES I1,21700 FROM NATIVE Avena PHYTOCHROME*

Abstract–Thc kinetics of the microsecond phototransformation intermediates of 124 kDa Avena phytochrome (1700^1,2) were studied in the prcsence of bound monoclonal antibodies at various temperatures. A global analysis was applied to the decays at all wavelengths at each temperature in order to derive the rate constants and the decay-associated spectra of the three decay components. Monoclonal antibodies bound to specific epitopes altered the Arrhenius parameters of both 1700^1,2 decay components. The strongest influence on these parameters was observed with OAT 8 (epitope between residues 624 and 686), which decreased by more than 50% the activation parameters of both components. This decrease is interpreted to result from an increased flexibility induced by this antibody in the ground state or in the transition state of bonds changing during the decay of both 1700 transients. Thus, the OAT 8 cpitope appears to be functionally important during the decay of the 1700^1,2 intermediates. For the case of 1100¹ bound OAT 23 and OAT 25 (epitopes between residues 1 and 66) reduced even further the relatively small flexibility of these bonds in the red light-absorbing form of phytochrome (P1) without antibodies, as reflected by the high preex-ponential factors for its decay. This resulted also in higher activation energies for this decay in the presence of the antibodies. Thus, the amino-terminus should act as a rigid spacer of the chromophore cavity without affecting it during the microsecond transformation, because the Arrhenius parameters for these decays are similar to those for small phytochrome. The possible implications of the influence of the various antibodies on the bleaching remaining after the decay of 1700^1,2 are discussed.     

Synthese und Eigenschaften von Dimolybdän-μ-nitrido-heptachlorid Mo2NCl7

Synthesis and Properties of Di-molybdenum-μ-nitrido-heptachloride, Mo₂NCl₇ Mo₂NCl₇ was prepared by the reaction of molybdenum pentachloride with the bromide of Millon's base, [Hg₂N]Br, in boiling CCl₄. It forms a moisture sensitive, dark green crystal powder, the magnetic moment at 20°C (μ_eff = 0.95 B.M.) being strongly reduced. With acetonitrile the μ-nitrido complex Mo₂NCl₇ · 3CH₃CN is formed, with phosphoryl chloride the donor acceptor complex Mo₂NCl₇ · 2POCl₃, respectively. Partial oxidation of the latter complex with chlorine leads to very unstable Mo₂NCl₈ · 2POCl₃, from which (PPh₄)₃[Mo₃NCl₁₀] can be obtained by the reaction with PPh₄Cl. For the complex (PPh₄)₃[Mo₂NCl₁₀] is also found a reduced paramagnetism of μ_eff = 1.47 B.M. at 20°C. All complexes are characterized by i.r. spectroscopy.     

Dioxomolybdenum(VI) complexes of 2-hydroxybenzaldehyde 4-phenyl-S-methylthiosemicarbazone

Mixed ligand complexes of dioxomolybdenum(VI) with 2-hydroxybenzaldehyde 4-phenyl-S-methylthiosemicarbazone (H₂L) were prepared with the formula [MoO₂(L)D] (D = H₂O, methyl, n-butyl, and n-undecyl alcohol, DMF, DMSO, pyridine, 4-picoline, and 3,5-lutidine). The compounds were characterized by elemental analysis, IR and ¹H NMR spectroscopy. The thermal decomposition of the compounds were investigated by using TGA, DTG, and DTA methods in air, and the thermal behavior depending on the second ligand molecule was discussed. A single crystal of the DMF coordinated complex was studied by X-ray diffractometry. The text was submitted by the authors in English.     

Crystal structure and spectroscopic characterization of K8(VO)2O(SO4)6

Red and yellow dichroistic crystals of a vanadium(V) compound, potassium (mu-oxo, di-mu-sulfato)bis(oxodisulfatovanadate), K(8)(VO)(2)O(SO(4))(6), have been obtained from the ternary catalytic model melt system K(2)S(2)O(7)[bond]K(2)SO(4)[bond]V(2)O(5). By slow cooling of the melt from 420 to 355 degrees C, crystal growth occurred, using solid V(2)O(5) crystals present in the melt as nucleation promoter. The compound crystallizes in the monoclinic space group P2(l) with a = 13.60(9) A, b = 13.93(9) A, c = 14.05(9) A, beta = 90.286(10) degrees, and Z = 2. It contains two VO(6) octahedra linked together by a mu-oxo and two mu-sulfato bridges. Furthermore, each octahedron has two monodentate sulfate ligands, making the dimeric entity coordinatively saturated. IR spectroscopy shows bands arising from V[bond]O[bond]V and V[double bond]O stretches as well as splitting of sulfate bands due to the different degrees of freedom present for different conformations of sulfate ligands. The coordination of vanadium in K(8)(VO)(2)O(SO(4))(6) is discussed in relation to the reaction mechanism of SO(2) oxidation catalysis.     

Arbeiten über Phosphorsäure und Thiophosphorsäureester mit einem heterocyclischen Substituenten 9. Mitteilung 1. Aza-Analogie I: Aza-Analoge von Phthalimid-, Benztriazol- und 1,2,3-Benztriazin-4(3H)-on-Derivaten

Aza-analogues of the known pesticidal dithiophosphates 2, 4 and 5 have been prepared by replacing the phthalimide, benzotriazole and 1,2,3-benzotriazin-4(3H)-one moieties resp. in 2 by those of quinolinic acid imide (6), cinchomeronic acid imide (7) and pyrazine-2,3-dicarboxylic acid imide (12), in 4 by 1H-v-triazolo[4,5-b]pyridine (15) and in 5 by pyrido[2,3-e]1,2,3-triazin-4(3H)-one (21). Compared to the known compounds the new esters are less or at best equally pesticidal with an equal or even higher mammalian toxicity.     

Synthesis and characterization of crosslinked polydiacetylene and its two-component interpenetrating polymer networks

The synthesis of crosslinked polydiacetylenes and its two-component interpenetrating polymer networks (IPNs) was carried out utilizing its polar and flexible substituent groups. Polydiacetylenes were crosslinked by the formation of allophanate linkages utilizing urethane groups in the substituent groups of the polydiacetylenes. Elemental analysis, DSC, TMA, solvent resistance, and IR spectra are presented as evidence for the formation of crosslinked polydiacetylenes. IPNs of polydiacetylenes and an epoxy resin (diglycidyl ether of bisphenol A) were synthesized by using simultaneous and sequential methods of synthesis. A study of phase morphology of the simultaneous and sequential IPNs was carried out using electron microscopy, TMA, and DSC.     

Exploiting the regioselectivity of pyroglutamate alkylations for the synthesis of 6-azabicyclo[3.2.1]octanes and 4-azabicyclo[3.3.0]octanes

Depending on the N-protecting group of pyroglutamates, the reactivity can be directed to the formation of 6-azabicyclo[3.2.1]octanes or 4-azabicyclo[3.3.0]octanes, which are conformationally restricted glutamate analogues.     

α,ω-Diisocyanatocarbodiimides, -Polycarbodiimides,and Their Derivatives

Research in the field of low-molecular weight, oligomeric and polymeric α,ω-diisocyanatocarbodiimides and -polycarbodiimides has been fruitful, not only in connection with these compounds themselves, but also—as so often happens in chemistry—with quite different problems. Novel synthetic methods, discoveries concerning the properties of low-molecular weight carbodiimides and phosphane imide derivatives, as well as results on the fragmentation reactions of four-membered heterocyclic compounds containing oxygen, phosphorus, and nitrogen, and a better understanding of the diisocyanate polyaddition process are among the many by-products of this research. The “high- and low-temperature formation” of polycarbodiimides and the homogeneous and heterogeneous catalysis of this process are described, and the fundamental importance of four-membered ring fragmentation mechanisms resulting in the formation of phosphane imide derivatives is outlined. Interesting building blocks for the diisocyanate polyaddition and polycondensation processes can be synthesized by many derivatization reactions of oligomeric and high-molecular weight polycarbodiimides and polyuretonimines. The in situ production of polycarbodiimides via matrix reactions in flexible polyurethane foams leads to a cellular arrangement of the material due to the pronounced symmetrical growth processes. Combination-foams with increased carbonation tendencies are formed in this way. Attention is drawn to several industrial applications of α,ω-diisocyanatopolycarbodiimides, of high-molecular weight cross-linked polyuretonimines, and of polycarbodiimide foams.     

[(Mes3Sn)2MoO4], ein monomeres Triorganozinnmolybdat

[(Mes₃Sn)₂MoO₄], a Monomeric Triorganotin Molybdate Mes₃SnBr (Mes = 1, 3, 5‐trimethylphenyl) reacts with (NBu₄)₂[Mo₆O₁₉] in the presence of (NBu₄)OH (in CH₃CN as solvent) to form [(Mes₃Sn)₂MoO₄]. Alternatively the title compound can be obtained from the reaction of [MoO₂(acac)₂] (acac = 2, 4‐pentadionate) with Mes₃SnOH in isopropanol. [(Mes₃Sn)₂MoO₄] forms monoclinic crystals, space group C2/c, with a = 2271.6(3) pm, b = 825.2(1) pm, c = 2739.9(5) pm, β = 90.96(2)°. The crystal structure consists of isolated molecules in which a tetrahedral MoO₄ unit is connected to two terminal Mes₃Sn groups. The Mo‐O distances range from 169.6(4) to 181.1(3) pm and the Sn‐O distance is 204.8(3) pm.