86,783 research outputs found
REDOX REACTIONS OF METAL-CARBONYLS OF GROUP-5A
No full textRedox reactions of V(CO)6w ith [Co(CO)4]-, [Mn(CO)5]-, [M2(C0),012-,o r [M(T~-C~H~) (C(OM) =~ ]C-r , Mo, W), or
C O ( ~ ~ - Co~ccHur~ ra)p~id ly at 25 "C and lower in hydrocarbons; on the other hand, V(C0)s is oxidized to
V(T-~-C~H~)(CbOy )M, n(q5-C5H5)o* r N i ( ~ f - c ~ Han~d )th~e two-electron oxidation of [Nb(CO)6]- to the
[Nb2X3(C0)8]a- nion (X = CI, Br, I, acetylacetonato), can be carried out using a number of oxidizing agents
(Hgll, Cull, Cul, Agl, or Fell')
Cyclo-octasulfur Adducts of WCl4S(thf) and WCl6. Crystal and Molecular Structure of WCl4S(thf).S8
No full textDichloro-derivatives of NN'-ethylenebis(salicylideneiminato)uranium(IV) and a redistribution reaction for a uranium(IV) chelate
No full textA ligand redistribution reaction in tetrahydrofuran between Usalen2 and UCI4 led to the formation of UsalenCI2,2THF, which was also prepared by an independent method
Mixed complexes of N,N'-ethylenebis(salicylideneiminato)uranium(IV)
No full textSome mixed N,N′-ethylenebis(salicylideneiminato), salen, complexes of uranium(IV) of formula U(salen)X2(X = Cl, acetylacetonato, dipivaloylmethanato, N-methylsalicylideneiminato, dibenzoylmethanato) are reported. It is shown that U(salen)2 and UCl4 undergo a ligand redistribution reaction in tetrahydrofuran (THF) leading to U(salen)Cl2,2THF. Chemical and mass spectrometric data are presented supporting the monomeric structure of the complexes of formula U(salen)(chelate)2. Evidence is presented suggesting the transitory formation of the adduct U(salen)2,UCl4 in the course of the redistribution reaction leading to U(salen)Cl2
Homonuclear and heteronuclear transition metal complexed by syn-proportionation reactions
No full textRedox processes consisting of disproportionation and syn-proportionation are reviewed with special
attention to metal complexes containing carbon-based ligands, i.e. carbon monoxide or unsaturated
hydrocarbons. An introduction and a survey of reactions aimed to show the large applicability of syn-proportionation
reactions in the field of coordination chemistry, is followed by examples of the use of these
redox processes for the preparation of catalytic precursors. The latter studies derive from the idea that if a
syn-proportionation reaction can be carried out between two complexes containing different metals in
different oxidation states, inter-metallic systems could be formed which may act as active catalysts,
e.g. for polymerization reactions
SYNTHESIS OF HEXACARBONYL DERIVATIVES OF GROUP-5 METALS AND ELECTRON-TRANSFER PROCESSES - CRYSTAL AND MOLECULAR-STRUCTURE OF TETRACARBONYL(1,2-BIS(DIPHENYLPHOSPHINO)ETHANE)IODOTANTALUM
No full textVanadium, niobium, and tantalum hexacarbonylmetalate(-I) derivatives of several heterocyclic nitrogen
bases, R,B[M(CO)& (R = H, Me; n = 1, Z), have been synthesized. In some cases an electron transfer
from the hexacarbonylmetalate to the protonated or methylated BW+ cation has been observed. Pyridinium
halides react with Na[M(CO)6] (M = Nb, Ta) in the presence of 1 equiv of 1,2-bl(diphenylphosphino)ethane
(diphos) to give high yields of the halo tetracarbonyl derivatives MX(CO)4(diphos). The red-orange
TaI(CO)4(diphosc)o mplex has been studied by X-ray diffraction methods. Crystal data: space group P2,/n;
M, 818.3; a = 14.864 (10) A, b = 9.875 (7) A, c = 19.335 (13) A; p = 105.61 ( 2 ) O ; U = 2733 (3) A3; 2 = 4;
Ddd = 1.988 g ~ m -F~(O;O 0) = 1568; ~ ( MKoa ).= 52.4 cm-'. The geometry of the seven-coordinatet antalum
atom is best described as a capped trigonal prism with the iodide ligand in the capping position. By reaction
of Na[Ta(CO)6] with 1 equiv of hydrogen chloride and diphos in toluene, the hydride TaH(CO),(diphos)
has been isolated in good yield
Re2I2(CO)6(Se7), a Coordination Compound of Elemental Selenium with a Transition Metal: a Solution- and Solid-State Study
No full textCoordination of cyclo-Ocatsulfur and cyclo-Heptaselenium to Dinuclear Rhenium(I) Systems
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