Swiatoslaw Trofimenko

Hydridotris(3-t-butylpyrazolyl)boratothallium(I). A spectroscopic and structural study

The crystal structure of hydridotris(3-t-butyl-1-pyrazolyl)boratothallium(I) is reported. The compound crystallizes in the orthorhombic space group Pnma (No. 62) with a 14.431(4), b 16.299(3), and c 10.562(2) A. The T1 atom of each monomeric unit adopts a pyramidal geometry with respect to the three nitrogen atoms that constitute the “face” of the pyrazolylborate ligand. The average T1-N distance of 2.584(9) A possibly implies some ionic character.

An 1H and 13C NMR spectroscopic study of the structure of potassium and thallium salts of tris- and tetrakis-(pyrazol-1-yl) borates in solution. Some 13C11B and 13C205Tl residual coupling constants

Abstract The 1 H and 13 C NMR spectra of 18 tris- and tetrakis-pyrazolylborates in the form of potassium or thallium salts have been recorded. Four of these compounds are new. The results are discussed with regard to two main aspects: coupling constants with 205 Tl and positional isomerism of the pyrazole substituents. Most borates are symmetric compounds (all the pyrazole rings being identical isomers) corresponding to less hindered structures (all 3-aryl, 3-i-propyl-4-bromo, 3-t-butyl-5-methyl or 3-t-butyl-5-i-propyl pyrazoles). Only one derivative, potassium hydrotris(2,4,6-trimethylphenylpyrazol-1-yl)borate 5 , does not fit this pattern, being either a 3/3/3/ or a 3/3/5 isomer.

The tris[3-(9-anthryl)pyrazol-1-yl]hydroborato ligand, [TpAnt]: Compositional disorder between a vacancy and a chain of three atoms

Abstract A new tris(pyrazolyl)hydroborato ligand with anthryl susbtituents in the 3-position, tris[3-(9-anthryl)pyrazol-1-yl]hydroborate, [Tp Ant ], has been synthesized by the reaction of KBH 4 with 3-(9-anthryl)pyrazole and characterized as the thallium derivative, Tl[Tp Ant ]. The thallium reagent was used to prepare the cobalt and molybdenum derivatives, [Tp Ant ]CoNCS and [Tp Ant ]Mo(CO) 2 ( η 3 -CH 2 C(Me)CH 2 ). The molecular structure of [Tp Ant ]CoNCS, contaminated with ca 6% Tl[Tp Ant ], has been determined by X-ray diffraction, thereby providing an example of compositional disorder between a vacancy and a chain of three atoms.

Sterically-induced rearrangements of the tripodal ligand HB(PriMeC3N2H)3 in some molybdenum mononitrosyl derivatives

Abstract The new complexes [Mo(NO){HB(Pr i MeC 3 N 2 H) 3 }XY] (X = Y = CO, I, OMe, OEt; X = I and Y = OMe, OEt, OPr i , OBu t , OCH 2 SiMe 3 , OPh, OC 6 H 4 -4-Me, NHPh or NHC 6 H 4 -4-Me) have been synthesized. In the cases where X = I, or where X = Y = CO or I, these compounds were isolated as a mixture of at least two isomers. However, 1 H NMR studies show that the complexes with X = I and Y = OPr i , OBu t , NHPh, NHC 6 H 4 - 4-Me undergo rearrangement reactions at elevated temperature to give selectively a single isomer. These reactions involve 1,2-boratropic shifts of the substituted pyrazolyl moieties and appear to be promoted by the more bulky of the co-ligands X and Y.

A bis(pyrazolyl)borate complex of silicon(IV)

Abstract The first pyrazolylborate complex of silicon, [Ph2B(pz)2]2SiCl2, has been prepared via the reaction of K[Ph2B(pz)2] with SiCl4. The structure of this complex has been determined by X-ray crystallography. The bis(pyrazolyl)borate ligand behaves in a bidentate fashion and the silicon adopts a distorted octahedral geometry.

Syntheses of some transition-metal complexes containing the tripodal ligand HB(PriMeC3N2H)3 and the X-ray crystal structure of [Mo(No)-{HB(3-Pri-5-MeC3N2H)3}(OEt)2]

The new complexes [M{HB(PriMeC3N2H)3}X](M = Tl, X = nothing; M = Ni or Co, X = NCS or NCO; M = Zn, X = NCS or N3), [M{HB(PriMeC3N2H)3}2](M = Fe, Co, Ni, or Zn), [Mo{HB(PriMeC3N2H)3}{η3-CH2C(Me)CH2}(CO)2], and [Mo(NO){HB(PriMeC3N2H)3}X(Y)](X = Y = CO, I, OMe, or OEt; X = I, Y = OMe or OEt) have been synthesised. The compounds [Mo(NO){HB(PriMeC3N2H)3}X(Y)](X = Y = CO or I; X = I, Y = OMe or OEt); were isolated as a mixture of at least two isomers. A single-crystal X-ray diffraction study of [Mo(NO){HB(PriMeC3N2H)3}(OEt)2] shows that the molybdenum atom is in an approximately octahedral co-ordination environment. The bulky Pri groups on the tripodal ligand are all in the 3 position closest to the ethoxide ligands with Mo–O distances of 1.86(1) and 1.91(1)A and Mo–O–C(Et) angles both of 129(1)°.