R.V. Parish

Studies in mössbauer spectroscopy. Part II. The structures of some organotin halides, and a test of the point-charge model

Abstract Mossbauer spectroscopic data are presented for some organotin halides and their halide complexes. These data suggest that the halides R3SnX (R = alkyl) are strongly associated in the solid state, with five-coordinate tin atoms. The triphenyltin halides, apart from the flourine, are less strongly associated. The dihalides, R2SnX2, are also associated, but the structures differ from that of Me2SnF2. The data are correlated with the point charge model, and it is shown that a parameter, [L], may be ascribed to each ligand, L, which represents the contribution of L to the electric field gradient at the tin nucleus. Self-consistent, empirical values may be assigned to [L]. There is an approximately linear relationship between [L] and the Taft inductive constant σL*.

Studies in mössbauer spectroscopy.III. an analysis of the isomer shifts of substituted organotin(IV) compounds

Abstract The isomer shift in organotin(IV) compounds is examinded as a function of the polarity, number, and disposition of the tin-ligand bonds. In compounds of the type R 3 SnX and, to a lesser extent, R 2 SnC 2 the isomer shift is insensitive to the nature of the ligand X, owitn to changes in electronic shielding. The coordination number has no observable effect. Streochemistry plays an important rŏle, and the isomer shifts of di-alkyl and di-aryl compounds increase with increasing C-Sn-C bond angle, reflecting increasing involvement of s-orbitals in the bonding.

The donor properties of some α, ω-bis(diphenylphosphino)alkanes towards palladium(II). Polymeric, dimeric and monomeric trans-chelated complexes

Abstract Palladium(II) complexes of 1,6-bis(diphenylphosphino)hexane (dph), 1,8-bis(disphenylphosphino)octane (dpo), 1,10-bis(disphenylphosphino)decane (dpd), and 1,12-bis(disphenylphosphino)dodecane (dpdop) have been isolated. The structures of the complexes seem to be a function of the length of the alkane chain between the donor atoms; generally dph bridges two palladium atoms and forms polymeric complexes, dpo and dpd bridge two palladium atoms and form dimeric 22- or 26-membered rings and dpod acts as a trans -chelating ligand and forms a monomeric complex containing a 15-membered ring.

Palladium(II) and platinum(II) complexes of monodentate tertiary stibines

Abstract The ligands R 3 Sb (R = Et, cyclohexyl) and Ar 3 Sb (Ar = Ph; o,-m-, p-tolyl) form conventional planar palladium(II) and platinum(II) complexes, ML 2 X 2 (X = Cl, Br, I, SCN, NO 2 ). With bulky ligands such as cy 3 Sb and o-toyl 3 Sb it is found that complexes with trans geometry form, whereas the less bulky ligands generally form cis -platinum and cis -palladium chloro- and bromo-complexes. The thiocyanate complexes appear to undergo rearrangements in solution and complex equilibria are set up. The unique [Pt(Sbo-tolyl 3 ) 2 (SCN)(NCS)] has been isolated.

Four- and five-coordinate platinum(II) complexes with diphenylmethyl- and phenyldimethyl-stibine

Abstract The ligands SbPh 2 Me and SbPhMe 2 form conventional platinum(II) complexes, cis-PtL 2 X 2 (X = Cl, Br. I). In addition, the unusual purple five-coordinate complexes PtL 3 I 2 are formed in the solid state. These dissociate in solution by loss of ligand (L = SbPh 2 Me) or of iodide (L = SbPhMe 2 ). The presumably four-coordinate Pt( Sb Ph Me 2 ) 4 Cl 2 is also reported.

Arylarsonates of diorganotin(IV)

Arylarsonates of diorganotin(IV) of the general formula X-C6H4AsO3SnR2 (R = CH3, n-C4H9, n-C8H17, C6H5CH2; X = H, p-CH3, p-Cl, p-Br, p-OH, p-COOH, o-COOH, o-NH2, o-NO2) and [CH2As(C6H5)O2Sn(C8H17)2 have been prepared. The complexes are high melting solids, insoluble in the common organic solvents, and have been characterized by elemental analysis, molecular-weight determination, and infrared and Mossbauer spectroscopy. Five- and six-coordinate structures are postulated.

THE COORDINATION CHEMISTRY OF AMINO ACID SCHIFF BASES. PART I. HEXAAQUOIRON(II)BIS(N‐SALICYLIDENEGLYCINATO)FERRATE(III) TRIHYDRATE

Abstract A reinvestigation of the reaction between ferrous sulphate, glycine and salicylaldehyde has shown that the reaction product is the title compound, and not as had previously been reported a binuclear ferric N-salicylideneglycinato complex containing a bridging glycinato ligand.

Infrared and thermal studies of the interaction of transition-metal ions with the framework of type-X zeolites

Abstract Zeolites NaMX (m = Mn(II), Co(II), Ni(II), Cu(II)) were prepared by ion exchange and characterised by chemical analysis, sorption measurements, and X-ray powder photography. The cation-framework interactions were investigated using thermal methods (DTA) and infrared spectroscopy. During dehydration of the zeolites, changes occurred in the infrared spectra, associated with framework vibrations which were attributed (mainly) to cation migration and cation-framework interactions. The patterns of these changes for the Mn(II)-, Co(II),- adn Ni(II)-exchanged zeolites were similar but somewhat different from the observed for the NaCuX zeolites. The thermal stability of the zeolites, as measured by the temperature of the first exotherm (DTA), was not dependent on the extent of the cation exchange for the Mn(II), Co(II), or Ni(II) zeolites but, in the case of the NaCuX zeolites, decrease with increasing copper concentrations. This decrease in stability was correlated with the amount of reactive oxygen available in the NaCuX zeolites.

Cis- and Trans-Influences in Platinum(II) Iodide Complexes

Cis- and trans-influences in a number of squareplanar platinum(II) complexes have been studied by a CNDO-MO method. The series considered were Pt(L)I3−, trans-Pt(L)2I2 and cis-Pt(L)2I2, where ligand L was varied to include PH3, C2H4, CO, H2S, NH3, 1120, H , SiH3−, , CN−, C113-, r, Cl−, OH−, and NO2−. Comparison of the results between these series shows that the cis-influence is similar in magnitude to the trans-influence, although the two ligand sequences are not parallel. The variation in the iodine orbital populations within the cis-ligand series is in reasonable agreement with 1297 Mossbauer data.

Some new manganese(III) complexes of the tetradentate schiff base ligand 1,3-N,N′-propylenebis(salicydeneaminato), [Mn(ligand)X]

Abstract Some new complexes of type [Mn(saltm)X] (saltm = 1,3-N,N′-propylenebis(salicylideneaminato); X = F, Cl, Br, NCS, CN, CH 3 CO 2 ) have been isolated and characterised by a number of spectroscopic and magnetic techniques. The complexes (except for X = CH 3 CO 2 ) are assigned a pentaco-ordinate monomeric structure, and [Mn(saltm)(CH 3 CO 2 )] 2 is assigned a hexaco-ordinate dimeric structure. Unlike complexes of type [Mn(saltm)(H 2 O)] 2 2+ , none of the complexes described here exhibit photolysis behaviour in aqueous solution.