G.P. Van Der Kelen

Transition metal chemistry: VIII. Synthesis and IR study of monosubstitution products of Cr(CO)6 and tertiary substituted aryl group VB derivatives

Abstract The synthesis of a series of compounds of general formula LCr(CO) 5 is presented, the ligands employeed being aryl Group VB derivatives of formuale (C 6 H 5 ) 3 E and ( 4- or 3-XC 6 H 4 ) 3 E with E = P, As, Sb and X = Cl, F. The ν(M—C) and δ(M—C—O) frequencies in the IR spectra have been assigned and are discussed. An assignment of the 12 CO 13 CO stretching fundamentals is also given. A possible explanation is presented for the anomalies observed in the ν(CO) spectrum and the CO frequency shifts are discussed in terms of σ and π bonding.

A study of the chemical bond in (CH3)nSn(SCH3)4−n (n=0, 1, 2, 3) by nmr (1H, 119Sn, 13C) spectroscopy

Abstract The 119 Sn and 13 C NMR spectra of (CH 3 ) n Sn(SCH 3 ) 4− n ( n =0, 1, 2, 3) compounds are presented. From the observed chemical shifts and by comparison with other groups of compounds, inductive and magnetic anisotropy effects seem to govern the shifts of the nuclei studied.

Normal coordinate analysis of α-FeOOH - a molecular approach

Abstract The infrared spectra of α-FeOOH and the deuteratad analogue have been interpreted by a normal coordinate analysis. The assumption was made of partial covalent bond formation between the oxy and hydroxy oxygen and iron. Frequencies and force constants involving the motion of the hydrogen atom and the Fe-OH bond are evaluated in a distorted Fe3OH tetrahedron. The Fe-O parameters are separately derived in a quasi planar trigonal Fe3O geometry.

An ESCA study of tin compounds

Abstract X-ray photoelectron spectra have been recorded for 60 solid tin compounds. A Sn 3d 5 /2 binding energy range of 3.1 eV was found. A qualitative analysls of the retults proved that ESCA Is not suited to determine either the degree of oxidation or the coordination number of tin. A quantitative analysis with the cheleq method suggests that besides the partial charge on tin also the potential at the site of the tin atom is important.

Organo group VB chemistry III. Synthesis and NMR spectra of some tertiary substituted arylstibines and arylbismuthines

An improved method for the synthesis of some stibines and bismuthines of the general formula (p-XC6H4)3E and (m-XC6H4)3E (X = Cl or F, E = Sb or Bi) is described. 1H and 19FSCENMR spectra are recorded for various compounds, and the results of a partial analysis of the NMR spectra are reported.

The proton magnetic resonance spectra and electrical dipole moments of methyltin halides

Abstract The PMR spectra and electric moments of (CH 3 ) n SnX 4− n compounds have been studied for X = Cl, Br and I. The trend of the chemical shifts is opposite to the inductive effect of the substituent, X, and can be explained by a diamagnetic anisotropy effect acting along the SnX bond. Also, the SnCH coupling constants do not agree with any additivity rule as a function of progressive halogenation, the deviations being higher for chlorides than for bromides or iodides. This has been ascribed to a strong distortion of the atomic orbitals of tin, increasing with electronegativity of the substituent. The eIectric moments can be explained by assuming resonance structures with a double-bond character in the SnX or the SnC bond.

A 29Si and 1H NMR study of (CH3)4-n SiXn compounds with X N(CH3)2, OCH3 and SCH3

Abstract The 1H and 29Si NMR spectra of (CH3)4−n SiXn compounds (X  N(CH3)2, OCH3 and SCH3) have been studied. The 29Si resonance shows an upfield shift with X  N(CH3)2, OCH3, and n = 2, 3, 4. This can be accounted for by increasing SiO and SiN back donation. Van der Waals interactions are proposed to explain certain NMR parameters. A linear correlation has been found between the 13CH coupling constants and the product of the electronegativity and Van der Waals radius in the (CH3)3 SiX compounds. This provides an explanation of the lower 13CH coupling constants of (CH3)3SiOCH3 and (CH3)3SiN(CH3)2 compared with those in Si(CH3)4.

A study of the structure of trimethyl-tinhaloacetates by N.M.R. and I.R. spectroscopy☆

Abstract The p.m.r. IR spectra of trimethyltinchloro-and-fluoroacetates have been studied. It could be established that these compounds in the solid state most probably are of a polymeric structure with five coordinated tin. In solution however, the molecules are mainly monomeric and tetragonal, but also some associated species must be present for the dichloro-, trichloro-, and trifluoroacetate. In the case of the monochloro- and dichloroacetate also the existence of rotational isomers could be established.

XPS Spectra of organometallic phenyl compounds of P, As, Sb and Bi

Abstract XPS spectra of 54 organometallic compounds of group V elements with various coordinations are measured in the solid state. Core level binding energy data for the various atoms present in the molecules are given.

Studies on trivalent boron compounds : I. The boron and proton magnetic resonance spectra of some trivalent boron compounds

Abstract The 11 B and 1 H magnetic resonance spectra of some trivalent boron compounds have been studied: X 2 BOR, XB(OR) 2 (R = CH 3 , C 2 H 5 ; X  F, Cl), B(OR) 3 , CH 3 B(OH) 2 , (CH 3 ) 2 BOH, (CH 3 BO) 3 , BCl 3 , CH 3 BCl 2 , (CH 3 ) 2 BCl, CH 3 BF 2 , (CH 3 ) 2 BF, (CH 3 ) 3 B. Evidence is found for considerable π-bonding in compounds of the type XBY 2 or X 2 BY in the bonds with the most electronegative atoms or groups. This study also provides another argument for the trimeric nature of alkyl difluoroborates in the liquid state. Dialkyl fluoroborates are shown to undergo disproportionation into B(OR) 3 and F 2 BOR.