Triiodide derivatives

The recommended enthalpies of formation of the gaseous triiodides derived from these values are shown in table 22, the mean bond energies derived from these values in fig. 44. 

If such reactions could be realized, the resulting products would be expected to have the structure analogous to the known Re2(02CR)4X2 derivatives (13) except that, upon addition of halogen, the Mo-Mo bond would decrease in bond order from 4 to 3. However, reactions with bromine lead to as yet undefined products, and, in the cases examined, the reactions with iodine lead to triiodide derivatives Mo2(02CR)4l3. 

In the reactions with iodine, it was established that the triiodide was the sole product when the I/Mo ratio was 0-1.5. Thus, neither mono-nor diiodide derivatives could be formed. When the I/Mo ratio was > 1.5, the reaction products approached the composition Mo2(02CR)4l -> as the I/Mo ratio became very large these compounds appear to lose iodine readily, and thus they are difficult to obtain in pure form. The reactions reported here lead cleanly to the triiodide derivatives when noncoordinating solvents are used at room temperature. In coordinating solvents... 

Finally, the magnetic properties reveal clearly that the triiodide derivatives are species that contain one unpaired electron per dimer as required by oxidation to the cations [M02(O2CR)4] Magnetic susceptibility data for [Mo2(02CC(CH3)3)4]l3 are presented in Table II. These data provide an excellent fit to the Curie equation and, from the slope, the magnetic moment fi = 1.66 BM was found. The crystalline triiodide... 

This procedure differs from those outlined for the bromo and chloro derivatives in that an appreciable excess of (dimethyl-amino) diflu orophosphine cannot be used because it is difficult to separate from iododifluorophosphine by fractional condensation. Typically, (dimethylamino)difluorophosphine (6.38 mmol) and hydrogen iodide (12.76 mmol) are condensed into a 500-ml. reaction bulb and allowed to warm slowly to 25°. As reaction ensues, f the white solids are discolored by formation of red phosphorus triiodide which probably results from a disproportionation 3PF2I —> 2PF3 + PI3. Thus, when the products are separated by fractional condensation through —126° (methylcyclohexane slush) to —196°, an appreciable amount of... 

ARENEDIAZONIUM OXIDES, DIAZONIUM CARBOXYLATES DIAZONIUM PERCHLORATES, DIAZONIUM SULFATES DIAZONIUM SULFIDES AND DERIVATIVES DIAZONIUM TETRAHALOBORATES, DIAZONIUM TRIIODIDES... 

Mattausch, H. et al Angew. Chem. (Int.), 1998, 37(4), 499 The MISi compounds of Lanthanum, Cerium and Praseodymium, and two slightly less iodinated lanthanum derivatives were prepared by fusing stoichiometric mixtures of the triiodides, the metal and silicon. They ignite violently on contact with water. 

While the ruthenium component is important and essential, the reasons for its behaviour are not always well understood. We will give some accounts of the chemical and catalytic properties of the ruthenium tricarbonyl triiodide species, [Ru(CO)3l3 ]", which is often the sole derivative detected in catalytic solutions under reaction conditions. This will contribute to a better understanding of the aspects of the catalytic behaviour and of the scope of catalytic capabilities. 

Furo[2,3- ]pyridines can be synthesized from alkynylpyridones and iodonium sources (Scheme 31) <20060L1113>. Iodine proved to be much more effective at promoting the iodocyclization reaction than other iodonium sources (ICl, A -iodosuccinimide (NIS)). The pyridinium triiodide salt, 104, can be converted into the corresponding pyridinone by treatment with an external source of iodide. In a variation of the reaction, a one-pot synthesis of the furopyridine derivatives 105 can be achieved, with overall yields of 79-92%, by treatment with iodine followed by sodium iodide without isolation of the triiodide salt. Another similar one-pot synthesis involves 3-iodo-2-pyridones, terminal alkynes, and organic halides in a series of two palladium cross-coupling reactions (Equation 45) <20030L2441>. This reaction could also be carried out in a two-step sequence, but the overall reaction yields were typically improved for the one-pot method. 

Ammino-arsenic Tri-iodides.—Several compounds of arsenic tri-iodide have been prepared. Bamberger and Philipp 4 obtained a compound, [As4(NII3)9JI, by passing dry ammonia gas into arsenic triiodide in ether, when a bulky white precipitate was produced. On heating to 50° C. it loses ammonia, and is completely decomposed at higher temperatures. Arsenic tri-iodide absorbs ammonia, slowly at first, and then more rapidly towards the point of saturation. The compound produced is a tetrammino-derivative.1... 

The crystals dissolve in carbon disulphide and ebullioscopic measurements indicate1 that the molecular formula is As2I4 they also dissolve in ether, alcohol and chloroform. When exposed to air, these solutions darken in colour owing to the formation of the triiodide, and the diiodide cannot be recovered bv evaporation owing to complete decomposition. Boiling acetic anhydride also dissolves the crystals but, on cooling, a yellow substance which appears to contain a derivative of the triiodide separates. The diiodide is also decomposed by pyridine with separation of arsenic, the triiodide being found in solution. 

The vapour density2 is 16-1 (air = l) corresponding to the molecular formula Asl3 (15-8), but the vapour, which is yellow, generally contains the products of thermal decomposition (see below). The heat of formation, according to Berthelot,3 is (As, 8lgas) 28,800 calories and (As, 3lsona) 12,600 calories. From measurements of density and coefficient of expansion at low temperatures the molecular volume at 0° Abs. has been calculated 4 to be 98-2, a value which corresponds with that similarly derived for the molecular volume of phosphorus triiodide. 

The aliphatic iodine derivatives are usually prepared by reaction of an alcohol with hydroiodic acid or phosphorus triiodide by reaction of iodine, an alcohol, and red phosphorus addition of iodine monochloride, monobromide, or iodine to an olefin replacement reaction by heating the chlorine or bromine compound with an alkali iodide in a suitable solvent and the reaction of triphenyl phosphite with methyl iodide and an alcohol. The aromatic iodine derivatives are prepared by reacting iodine and the aromatic system with oxidizing agents such as nitric acid, fuming sulfuric acid, or mercuric oxide. 

DIAZONIUM CARBOXYLATES DIAZONIUM PERCHLORATES DIAZONIUM SUEFATES DIAZONIUM SUEFIDES AND DERIVATIVES DIAZONIUM TETRAHALOBORATES DIAZONIUM TRIIODIDES See also TETRAZOLES... 

Diaza-2-boracycloalkanes, 93 Diazirines, 93 Diazoazoles, 94 Diazo compounds, 94 Diazoethers, 96 Diazomethane salts, 96 Diazonium carboxylates, 96 Diazonium perchlorates, 96 Diazonium salts, 97 Diazonium sulfates, 98 Diazonium sulfides and derivatives, 99 Diazonium tetrahaloborates, 100 Diazonium triiodides, 101 a-Diazo-/J-oxosulfones, 102 Diazotisation, 102... 

The names of anions usually end in -ide if there are monatomic or homopolyatomic, or -ate for heteropolyatomic anions and coordination compounds. Anionic ligands usually end in -o. Thus CP is chloride, I3 is triiodide and S042 is sulfate but become, chloro, triiodo and sulfato if they are coordinated as ligands. The names of complex anions are not always derived from the familiar name... 

The heat capacities for the other compounds were derived using the estimation procedure described for the trichlorides, i.e., from the lattice and excess contributions. The former was derived from the enthalpy measurements, the latter from the crystal field energies. As the crystal energies of the tribromides and triiodides are poorly known, we have used the values for the trichlorides to approximate Cexs- The results thus obtained are listed in tables 10 and 11. The calculated data for TmG agree within 2% with the DSC results of Gardner and Preston (1991). 

Le Floch reported that treatment of [K CH(PPh2NPri)2 ] with one molar equivalent of neodymium triiodide afforded 87, but when reacted with half a molar equivalent complex 88 was instead obtained 48 Complex 87 was converted to the bis-amide derivative 89 without any evidence of ligand scrambling. 

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