Chloro Compounds Research Articles

Molecular mechanics calculations of conformational structures, energies and torsional force constants in some bromopropenes and bromobutenes

Gas-phase data on conformational energies and structures of the molecules BrH 2CHCCH 2, BrH 2CBrCCH 2, BrH 2C(CH 3)CCH 2 and BrH 2CCH 2HCCH 2 are used to establish parameter values for the nonbonding atom ⋯ atom interactions Br ⋯ C( sp 2) within the Morse potential formulation. Torsional potentials are calculated for the molecules mentioned above and in addition for cis- and trans-BrH 2CHCCHBr, transBrH 2CHCC(CH 3)H, (BrH 2C) 2CCH 2, cis-BrH 2CHCCHCH 2Br and CH 3BrCHHCCH 2. Torsional force constants for the molecules are obtained. A comparison with the corresponding chloro compounds is made.

ChemInform Abstract: New Total Synthesis of (.+-.)-Indolmycin.

The indolecarbaldehyde (I) is converted to the chloro compound (II) which reacts with the anion of the oxazolone (III) to form a mixture of (IV) and (V).

ChemInform Abstract: The Structure of an Iodide Complex of the Type Mo2X4(LL)2 Exhibiting Two Different Rotational Geometries in the Solid State.

AbstractThe title complex (I) which is prepared by reacting the corresponding chloro compound with NaI in Me2CO crystallizes in the space group P1 with Z=3.

The thermal, spectral and magnetic studies of chloro and bromo compounds of cobalt(II), nickel(II) and copper(II) with melamine

Compounds of melamine have been prepared with the chlorides and bromides of cobalt(II), nickel(II) and copper(II). The compounds, which have been characterised by analyses, magnetic moments, vibrational and electronic spectra, have polymeric octahedral structures. The thermal behaviour of these compounds has been studied by thermogravimetry (TG) and differential thermal analysis (DTA) techniques. The compounds, which are all hydrated, lose water of crystallisation followed by organic ligand to give the metal oxide.

Tc(NX)Y 3(Me 2PhP) 2 complexes (X = O or S; Y = Cl or Br). Preparation, characterization and EPR studies

The d 5-‘low-spin’ Tc(II) complexes tribromonitrosyl-bis(dimethylphenylphosphine)technetium(II) and tribromo-thionitrosyl-bis(dimethylphenylphosphine)technetium(II) were prepared by ligand exchange starting from the analogous chloro compounds. The complexes were characterized chemically and IR, UVVis and EPR spectroscopically. In the room temperature EPR spectra a well-resolved 99Tc hyperfine splitting is observed inidicating a ground state of the unpaired electron which is well separated from the other orbit states. The general features of the spectra at low temperatures are characteristic for an axially symmetric spin Hamiltonian. Analysis of the 99Tc and 31P hfs (hfs = hyperfine splittings) shows a marked covalency of the Tcligand bonds. A comparison is given between the chloro and bromo, as well as between the nitrosyl and thionitrosyl complexes.

ChemInform Abstract: Palladium(II) Complexes Containing Pyrazole‐Derived Ligands of Biological Interest. Four, Five and Six Coordinate Palladium(II) Complexes with 5(3)‐Methylpyrazole‐3(5)‐carboxamide and 5(3)‐Methylpyrazole‐3(5)‐carbohydrazide.

AbstractDichloro palladium complexes are prepared by reaction of PdCl2 in aqueous solution with a hot ethanolic solution of the respective ligand (I); the iodo compounds are obtained by anion metathesis from the chloro compounds.

Reactions of Difluorophosphoranes and P-Fluoro Ylids

Abstract MePF2 (NMe2)2 (1) reacts with n-butyl lithium in a molar ratio2 to the methylenediaminophosphorane 1 (2) and in a ratio of 1:2 to a diphosphete 2 (3). Silylsubstituted alkylidenefluorophosphoranes could be prepared from 1 and on silicon chloro compounds (2).

ChemInform Abstract: Synthesis of Organyltribromogermanes with the Germanium Dibromide‐Dioxane Complex.

AbstractThe germanium dibromide‐dioxane complex (IVb), which can be obtained from the corresponding germanium tetrahalide (I), the dioxane (II) and the siloxane (III) like the chloro compound (IVa), reacts with the organic bromides (V) to produce the tribromogermanes (VI).

ChemInform Abstract: Studies on Nucleosides. Part 13. Synthesis and Antiviral Activity of Acyclic Analogues of Spongosine.

AbstractThe synthesis of the acyclic spongosine analogues (V) and (VII) is carried out starting from the reaction of 2,6‐dichloropurine (I) with the chloro compounds (II) or (VI).

ChemInform Abstract: Polycyclic N‐Hetero Compounds. Part 20. Synthesis of 11,13,15‐Triaza‐steroid with an Alkyl Group in the D‐Ring and an Investigation of Its Antidepressive Activity.

AbstractStarting with the chloro compound (I), the azasteroids (IV), (VI), and (X) are synthesized.

ChemInform Abstract: Synthesis of Polycondensed Heterocycles from Benzopyrano‐1‐as‐triazinones.

AbstractThe benzopyranotriazinone (I) is converted to the chloro compound (IIa), from which the derivatives (IIb) ‐ (IIe) can be obtained.

4-Substituted 1-(1-(2-(arylthio)-5-halogenophenyl)ethyl)piperazines; Synthesis and biological screening

Reactions of 2,5-dichloroacetophenone and 2,5-dibromoacetophenone with a series of thiophenols gave the 2-(arylthio)-5-halogenoacetophenones VII and VIII which were reduced with sodium borohydride in ethanol to the secondary alcohols IX and X. Treatment with thionyl chloride afforded the chloro compounds XI and XII which were transformed by substitution reactions with correspondingly monosubstituted piperazines by two methods to the title compounds I-V. Their salts (maleates and hydrochlorides) showed in addition to antitussic activity some anthelmintic effects towards a series of the helminth species.

ChemInform Abstract: Polyynes. Part 6. Synthesis of Hexatriynamines.

AbstractThe reaction between the chloro compound (I) and the lithiumacetylides derived from (II) yields the stable hexenediynamines (III).

Selective toxicity of deoxyadenosine analogues in human melanoma cell lines

The in vitro toxicities of 19 analogues of deoxyadenosine were tested using a panel of human melanoma cell lines including two lines sensitive to deoxyadenosine and deoxyinosine. The 2-fluoro-, 2-chloro-, 2-bromo- and 2-amino-8-aza derivatives were the most toxic and showed selectivity against deoxyadenosine-sensitive cells. 2-Bromodeoxyadenosine (BrdAdo) and its 5'-phosphate were less potent than the chloro compound but showed the greatest selectivity. In further studies of BrdAdo a third sensitive melanoma line was identified of the eight tested. A treatment time of 24 hr or more was required to develop toxicity to BrAdo; this could be prevented by deoxycytidine or cytidine added to the medium but not by other nucleosides. Flow cytometry showed that BrdAdo blocked cells in the G1 and S phases of the cell cycle. DNA synthesis as judged by thymidine incorporation was rapidly inhibited by BrdAdo to an extent which reflected the sensitivity of the particular cell line; RNA synthesis was less affected. Exposure to BrdAdo for 48 hr induced breaks in the preformed DNA of sensitive but not resistant cells. The results suggest that the toxicity of BrdAdo is associated with prolonged inhibition of DNA synthesis and subsequent DNA fragmentation.

Molecular catalysis by quaternary ammonium salts: cyclisation of 2-(3-halopropyl)-4-nitrophenols

The cyclisation of 2-(3-halopropyl)-4-nitrophenols 4-6 is an intramolecular nucleophilic substitution with clean first-order kinetics. The rate is influenced by the macrotricyclic ammonium salt 2 by virtue of a 1:1 hostguest complex formation. Inhibition is observed with the chloro compound 4 and to a minor extent with the bromo analog 5, whereas a moderate rate acceleration was found with iodo compound 6. Inspection of the temperature dependence of the rate effects leads to the conclusion that 2 may be regarded as a dipolar aprotic microsolvent.

Iodo-bridged complexes of platinum(II) and synthesis of cis mixed-amine platinum(II) compounds

Iodo-bridged platinum(II) dimers, [Pt(L)I2]2 with ligands (L) containing nitrogen as the donor atom, have been synthesized from the reactions of cis-[Pt(L)2I2] with perchloric acid. The dimers can be cleaved in aqueous media by a second nitrogen ligand to produce isometrically pure cis-[Pt(L)(L′)I2].These compounds can finally be converted to the chloro or carboxylato compounds by precipitating the iodo ligands with a silver salt and adding KCl or a carboxylate salt. Several compounds of the types cis-[Pt(L)(L′)Cl2] and cis-[Pt(L)(L′)(dicarboxylate)] were thus prepared. A few dimers of the type [(L)(L′)Pt(tetra-carboxylate)Pt(L)(L′)] were also synthesized.

Solid state kinetic parameters of the first decomposition of potassium dichlorotetracyanoplatinate(IV), dibromotetracyanoplatinate(IV) and diiodotetracyanoplatinate(IV)

The first solid state reductive elimination of K 2[Pt(CN) 4X 2] (X = Cl, Br, I) has been studied by thermogravimetric measurements both in non-isothermal and isothermal conditions. The first decomposition reaction produces 1 2 (CN) 2 for one mole of the chloro and bromo compound and I 2 for one mole of the iodo compound. The activation energies obtained for these processes are: 240 kJ mol −1, 245 kJ mol −1 and 100 kJ mol −1 respectively. These values are found by the isothermal method and agree with with those obtained by the non-isothermal method. In both cases, all the expressions for the solid state model (growth, nucleation, nucleation-growth and diffusion) were applied. The real solid-state model (nucleation-growth according to the Avrami-Erofeev law) is obtained by comparison between the non-isothermal and isothermal methods and by studying the shape of the isothermal runs.

Dissociation rates of energy-selected dichloro- and dibromobenzene ions

The dissociation rates of internal-energy-selected o-, m-, and p-dichloro- and dibromobenzene ions have been measured by photoelectron photoion coincidence spectroscopy. The rate measurements indicate that these isomers rearrange to a common structure, the para isomer, prior to fragmentation to the C/sub 6/H/sub 4/X/sup +/ + X products. The activation energies for the loss of a halogen atom, determined by fitting RRKM calculated rates to the experimental values, are 3.35 +/- 0.1 and 2.8 +/- 0.1 eV for the chloro and bromo compounds, respectively. The results heats of formation of the C/sub 6/H/sub 4/Cl/sup +/ and C/sub 6/H/sub 4/Br/sup +/ fragments are 260 +/- 3 and 270 +/- 3 kcal/mol. From these values, the C-H bond energy in the chloro- and bromobenzene ions was calculated to be 3.88 +/- 0.10 eV. The dissociation limits to X/sub 2/ + C/sub 6/H/sub 4/ are 4.4 and 3.9 eV for the chloro and bromo compounds, respectively. However, even up to the limit of the hydrogen light source of 14.2 eV, no C/sub 6/H/sub 4//sup +/ signal was observed. This is consistent with the statistical theory that predicts the rate of X loss is more than 10/sup 4/ times faster than loss of X/sub 2/.

Brom- und Chlorthionitrenkomplexe des Rheniums. Die Kristallstruktur von (PPh4)2 [ReBr4(NS)(NSBr)]·CH2Br2 Bromo- and Chlorothionitrene Complexes of Rhenium The Crystal Structure of (PPh4)2[ReBr4(NS)(NSBr)]·CH2Br2

Abstract The thionitrosyl-halothionitrene com pounds (PPh4)2[ReX4(NS)(NSX)]·2 CH2X2, X = Cl or Br, are obtained by nucleophilic ring cleavage of the Re(N2S2) rings of complexes [ReX4(N2S2)]⊖ with PPh4X in CH2X2. (AsPh4)2[ReCl4(NS)(NSCl)] · CH2Cl2 can also be obtained by the reaction of [ReCl4(NSCl)(POCl3)] with S(NSiMe3)2 and subsequent addition of AsPh4Cl. The pyridine complex [ReBr2(NS)(NSBr)(NC5H5)2] · CH2Br2 forms by bromination of the corresponding chloro compound with Me3SiBr. The IR spectra are reported. The crystal structure of (PPh4)2[ReBr4(NS)(NSBr)] · CH2Br2 was determ ined by X-ray diffraction (4158 independent observed reflexions, R = 0.059). Crystal data: a = 1039.7, b - 1232.5, c - 2158.4 pm, α = 81.59, β = 87.05, γ = 77.06°, Z = 2, space group P1̄. The compound consists of PPh4 ⊕ ions, CH2Br2 molecules, and anions [ReBr4(NS)(NSBr)]2⊖ in which the rhenium atoms are coordinated by four bromine atoms, one thionitrosyl and one brom othionitrene group. The latter have cis arrangement and ReN bond lengths of 186 pm. W hereas the thionitrosyl group is nearly linear, the R = N = SBr group has an ReNS angle of 165°.

ChemInform Abstract: Experimental Characterization of an Electron‐Rich (σ2π4δ2δ*2) Metal‐Metal Triple Bond.

AbstractThe triply bonded Re complexes (III), prepared by an established procedure from (I), are oxidized to the paramagnetic salts (IV) and the chloro compound (IIIa) is converted to the mixed ligand complexes (VI).