Kailash Chandra

Preparation and characterization of carboxylato derivatives of bis-(methyl cyclopentadienyl) titanium(IV)

Abstract Dicarboxylato complexes of bis-(methyl cyclopentadienyl) titanium(IV), of the type (CH 3 C 5 H 4 ) 2 TiA 2 (A = CH 3 COO, CH 3 CH 2 COO, CH 3 CH 2 CH 2 COO, C 6 H 5 COO, CH 2 ClCOO or CHCl 2 COO), have been prepared in aqueous as well as in nonaqueous medium, by the reaction of bis-(methyl cyclopentadienyl) titanium dichloride on appropriate sodium salt of the carboxylic acid. The carboxylato ligand is chelating and the carboxylato compounds are non electrolytic in nature. The bonding of carboxylato ligand in these complexes has been discussed and these complexes have been characterized by elemental analysis m.p. conductivity measurement and IR and NMR spectral studies.

Isolation and characterization of bis(η-methylcyclopntadienyl)dihalotitanium(IV)

Abstract (η-MeC 5 H 4 ) 2 TiX 2 9X = Br, I) have been prepared by the raction of appropriate boron trihalides on(ηMeC 5 H 4 ) 2 TiCl 2 . Improvements have been suggested over the know methods for preparing (η-MeC 5 H 4 ) 2 TiCl 2 and (η-MeC 5 H 4 ) 2 TiX 2 (X = Cl, Br, I) have also been prepared by an exchange reaction of haloacids on (η-MeC 5 H 4 ) 2 TiF 2 . The complexes have been characterized by elemetal analysis, conductivity measurements, i.r. and 1 H n.m.r. spectroscopy.

The preparation and characterization of acetylacetonato-bis(η-methylcyclopentadienyl)titanium(IV) complexes

SummaryA series of [L′2TiL]+X−compounds where L is the conjugate base of acetylacetone, L′=η-MeC5H4 and X−= ClO4−, BF4−, FeCl4−, ZnCl3(H2O)−, SnCl3−, CdCl42−, HgCl42−, Br− or I−, have been prepared by adding X− to the aqueous solution of [L′2TiL]+Cl−. Conductivity measurements in nitrobenzene for all compounds indicate that these complexes are electrolytes. The i.r. frequencies for various vibrational modes have been assigned. The ligand L appears to be chelating and the titanium atom is essentially tetracoordinate. The bonding in these complexes is discussed.

Stereochemically rigid 7-coordinate, tris(N-phenyl,N-methyldithiocarbamato) complexes of Ti(IV), Zr(IV) and Hf(IV)

Abstract Tris(N-phenyl,N-methyldithiocarbamato) complexes of the type η5-C5H5M[S2CN(C6H5)(CH3)]3 and η5-CH3C5H4M-[S2CN(C6H5)(CH3)]3 (where M = Ti, Zr or Hf) have been prepared by the reaction of (C5H5)2MCl2 or (MeC5H4)2MCl2 with anhydrous Na[S2CN(C6H5)(CH3)] in refluxing CH2Cl2 or THF. Conductivity measurements and molecular weight determinations indicate that these complexes are monomeric and nonelectrolytic. IR spectra indicate that these complexes are seven coordinate in which all the dithiocarbamate ligands are bidentate. 1H NMR spectra indicate that in these complexes the metal centered rearrangement and S2CN bond rotation both are slow on NMR time scale at ambient temperature. A capped octahedron configuration, a rare geometry is assigned to η5-C5H5Hf[S2CN(C6H5)(CH3)]3.

Stereochemically rigid hepta-coordinate, tris (N,N-diisopropyldithiocarbamato)- complexes of Ti(VI) and Zr(IV)

Abstract Tris (N,N-diisopropyldithiocarbamato)- complexes of the type CpM(S 2 CN i-pr 2 ) 3 and (MeC 5 H 4 )M(S 2 CN i-pr 2 ) 3 (where M = Ti, Zr), have been prepared by the reaction of Cp 2 MCl 2 or (MeC 5 H 4 ) 2 MCl 2 with anhydrous Na(S 2 CN i-pr 2 ) in refluxing CH 2 Cl 2 or THF. Conductivity measurements and molecular weight determinations indicate that these complexes are monomeric and nonelectrolytic. On the basis of the IR spectra coordination number of “Seven” is assigned to Ti(IV) or Zr(IV) in these complexes. Whilst 1 H NMR spectra indicate that these are stereochemically rigid complexes. A monocapped trigonal prism structure, a rare configuration is suggested for these complexes.

η-Methylcyclopentadienyltris(N, N-dimethyldithiocarbamato)-titanium(IV); a stereochemically rigid heptacoordinate chelate

Summaryη(-Methylcyclopentadienyltris(N,N-dimethyldithiocarbam-ato)titanium(IV), MeC5H4Ti(S2CNMe2)3 has been prepared from (MeC5H4)2TiCl2 and sodiumN,N-dimethyl-dithiocarbamate solution. On the basis of the i.r. spectrum a coordination number of seven is assigned to the complex whilst the1H n.m.r. spectrum indicates that it is a stereochemically rigid chelate. A pentagonal bipyramidal structure is suggested.

Pseudohalide derivatives of (η -cyclopentadienyl-η-methylcyclopentadienyl) titanium (IV)

SummaryPseudohalide complexes of the (η-cpL)TiXZ type (where cp = cyclopentadienyl, L = η-McCs5-H4 and X = N3, NCS, NCO or NCSe) have been prepared in aqueous and nonaqueous media and characterized by elemental analyses, i.r. and n.m.r. spectroscopy. I.r. spectroscopy shows that NCS, NCO and NCSe are bonded to the titanium atom through nitrogen in these complexes which are thus true isothiocyanato, isocyanato and isoselenocyanato derivatives respectively.

Mössbauer effect studies of addition complexes of hydroferro- and ferri-cyanide with organic bases

Abstract Mossbauer spectra of the addition complexes of hydro ferro- and ferri-cyanides with organic bases, viz. diethylene triamine, 1,2 diaminopropane, hexane-1,6 diamine, 4,4′-tetra methyldiaminodiphenylmethane, piperazine and triethylamine have been recorded at room temperature. It is concluded that in the case of hydroferrocyanide there is simple addition of the base through hydrogen bonding while in the case of hydroferricyanide the reaction of organic base with ferricyanic acid is first accompanied by reduction of ferricyanic acid to ferrocyanic acid, which is then followed by the addition of the organic base to the reduced acid. The values of the isomer shift and quadrupole splitting are discussed in terms of the possible symmetry around the iron.