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The synthesis and crystal structure of the 1:1 complex formed between triphenyltin chloride and isoquinoline-1-carboxylic acid ([Ph3SnCl:C10H7NO2]) is described. The tin(IV) atom is found to be five coordinate, being bound to three phenyl groups, the chlorine atom, and an oxygen from isoquinoline-1-carboxylic acid. The geometry around the tin atom is that of a trigonal bipyramid, with the three phenyl groups occupying the equatorial positions, and the apical sites taken by the chlorine atom and a carboxyl oxygen from the isoquinoline-1-carboxylic acid. The crystals are triclinic, space group [Formula: see text] with a = 17.932(12) Å, b = 17.935(15) Å, c = 18.686(12) Å, α = 63.16(5)°, β = 81.70(6)°, γ = 68.45(6)°, V = 4986(6)(10) Å3Z = 8, and Dcalc = 1.486 Mg m−3 The final residual is RF = 0.050, on 8375 reflections with Inet > 2.5σ(Inet). Two of the cell dimensions are equivalent and there are four molecular units in the unit cell, so precautions are described for ensuring that correct space-group determination had been made and that some concealed symmetry in the final structure had not been overlooked. Keywords: triorganotin, complex, isoquinoline-1-carboxylic acid, fungicidal activity.

The reaction of the ditertiary arsines and phosphines fnfars, fnfos, and fnAsP, (L–L), with Fe(CO)5 at 150° is a superior route to the complexes (L–L)Fe2(CO)6. Two are reported for the first time (L–L = f6fars, f8fars). The complexes react with monodentate and certain potentially bidentate ligands on u.v. irradiation to afford the monosubstituted derivatives L(L–L)Fe2(CO)5 and (L–L)'(L–L)Fe2(CO)5. Spectroscopic studies, in particular magnetically perturbed Mössbauer spectra, indicate that the site of substitution is trans to the FeA—FeB bond and cis to the two group V atoms (on FeA). Disubstitution seems to result in further displacement of CO from either FeA or FeB.

Chlorine nuclear quadrupole resonance frequencies are reported for the compounds [Formula: see text] (n = 2,3,4; Y = H, CH3, C2H5, Si(CH3)3, F. OCH3, N3, NR2, Cl, SCH3, P(C6H5)2, As(CH3)2, Mn(CO)5, π-C5H5Fe(CO)2, but not all combinations). The values range from 38.999 MHz (n = 3; Y = F) to 34.668 MHz (n = 2; Y = π-C5H5Fe(CO)2) and are roughly related to the electronegativity of Y and to the ring size. The mean temperature coefficients of the frequencies lie in the range −0.9 × 10−4 to −8 × 10−4/°K.

The complexes (L—L)Fe2(CO)6 react with a range of bidentate ligands to give the complexes (L—L)′(L—L)Fe2(CO)4 ((L—L) = fluorocarbon-bridged ligand such as f4fars, f4AsP etc. (L—L)′ = fluorocarbon- and hydrocarbon-bridged ligands such as f4AsP diars etc.). Spectroscopic studies, in particular magnetically perturbed Mössbauer measurements, indicate that (L—L)′ in most complexes is chelated to one iron atom, FeA. This leaves one CO group on FeAcis to the FeA—FeB bond and three on FeB. A smaller class of derivatives appear to have (L—L)′ bridging the two iron atoms cis to the FeA—FeB bond. The sign of Vzz is positive at both iron sites in the bridged derivatives. It is negative at FeA and positive at FeB in the other complexes.

The n.q.r. spectra of a number of complexes of the type [Y3PCo(CO)3]2 have been recorded. The results are compared with those from related studies.

New polynuclear iron carbonyl complexes having the stoichiometry LFe3(CO)10 have been obtained from the reactions of Fe3(CO)12 with the di(tertiary arsine) ligands (CH3)2AsC(X)(Y)CF2As(CH3)2 (X = Y = H; X = H, Y = F; X = F, Y = CF3). The structures of the new cluster complexes have been investigated using i.r., n.m.r., and Mössbauer spectroscopies. Mössbauer data are also reported for LFe3(CO)10 and LFe3(CO)9 derivatives of the mixed ligand [Formula: see text].