William R. McWhinnie

Co-ordination behaviour of various 2-pyridyl ketones. Part I. Copper(II) halide and perchlorate complexes with di-2-pyridyl ketone and 2-benzoylpyridine

Copper(II) perchlorate yields the following hexaco-ordinate complexes with di-2-pyridyl ketone (pyCOpy) and 2-benzoylpyridine (PhCOpy): Cu(pyCOpy)2(ClO4)2(NN-co-ordination), [Cu(pyCOpy)2(H2O)2], (ClO4)2(NO-co-ordination), and Cu(PhCOpy)2(ClO4)2. The complexes M(PhCOpy)2X2(M = CuII or ZnII; X = Cl or Br) are hexaco-ordinate compounds with weak interaction between the carbonyl group and the metal ion. The nature of the complex Cu(pyCOpy)2Cl2,2H2O is discussed. The compounds Cu(pyCOpy)X2,ROH (X = Cl or Br; R = Et or Prn)(NO-co-ordination) possibly contain pentaco-ordinate copper(II) whereas Cu(PhCOpy)Cl2 and Cu(pyCOpy)Cl2(NN-co-ordination) are considered to be planar complexes. Red-brown Cu(PhCOpy)Br2 is suggested to be a tetrahedral compound.

An investigation of substituted tri-(2-pyridyl)amine complexes of nickel(II) and iron(II) by use of electronic and iron-57 Mössbauer spectroscopy

Complexes of nickel(II) and iron(II) of co-ordination number six with respect to the new potentially terdentate ligands 4-, 5-, and 6-methyl, and 5-nitro-2-pyridyldi-(2-pyridyl)amine are reported. Electronic and Mossbauer spectral data are analysed and it is noted that the influence of the substituent, though small, is detectable. The implications of the results in terms of σ and π covalency within the complexes is qualitatively discussed as are some factors influencing the bi- or ter-dentate co-ordination of the bases.

A study of the co-ordination behaviour of 2-pyridylketones Part III. Acetyl- and substituted benzoyl-2-pyridyl complexes of rhodium(III)

Abstract The electronic effect of the group R∗ in the ligands PyCOR (R = Me, 2-py, 2-(m-C6H4·NH2), 2-(m-C6H4·NO2)) on the following substitution reaction is considered: trans-[Rh(pyCOR)Cl2]+ → [Rh(pyCOR)(pyCOR-unidentate)Cl2·OH]. The preparations and characterisation of several new complexes of rhodium(III) with ketonic ligands are also reported.

Preparative routes to complexes of iridium(III) with 1,10 phenanthroline

Abstract Possible preparative routes to transdihalogenobis(1,10 phenanthroline) iridium(III) cations have been investigated and it is concluded that the existence of these ions is doubtful. Convenient syntheses of cis-Ir(phen)X2.X (X = Br, I) and also of [phen H][Ir(phen)Br4]are noted. It was found that pure products resulted only when the iridium was supplied to the reaction as iridium(IV). The reaction between solutions of [Ir(phen)X4]− (X = Cl, Br) in concentrated oxidising acids and pure nitric oxide was noted and is suggested as a sensitive colour test for [Ir(phen) X4]−.

The electronic and electron spin resonance spectra of complexes of the copper(II) ion with di-(2-pyridyl)amine

New and more extensive spectroscopic data (electronic, e.s.r., and i.r.) for complexes CuL2XY and CuL2Z2[L = di-(2-pyridyl)amine; X–= I–, NCS–, and Y–= ClO4–; Z–= ClO4–, PF6–, Cl–, Br–, I–, NO2–, and NO3–) are evaluated in terms of recent advances made in the understanding of the relationship between spectra and structure for copper(II) complexes. CuL2(ClO4)2 is isomorphous with ZnL2(ClO4)2 and contains non-planar CuL22+ ions as does CuL2(PF6)2, whereas CuL2(NO3)2 and CuL2Br2 are tetragonal complexes with planar CuL22+ units. There is good evidence that [CuL2Cl]Cl is trigonal bipyramidal but the nature of CuL2I2 is less certain. The remaining complexes are believed to contain six-co-ordinate copper(II) with cis-bis(di-2-pyridylamine)copper(II) units. Evidence is presented to suggest that a novel dimeric complex is [(dipyam)2(HF2)Cu(dipyam)Cu(HF2)(dipyam)2]-(PF6)2 with one bridging di-(2-pyridyl)amine group.

Complexes of tri-2-pyridylamine. Part III. Complexes with the thiocyanates and nitrates of cobalt(II), nickel(II), and copper(II): the three linkage isomers of (tri-2-pyridylamine)Cu(CNS)2

Seventeen compounds of cobalt(II), nickel(II), and copper(II) nitrates and thiocyanates with tri-2-pyridylamine (tripyam) and phenyldi-2-pyridylamine (dppa) are reported. The compounds are: [M(tripyam)2(NO3)2](M = Co or Cu), [M(tripyam)2](NO3)2(M = Co or Ni), [Co(tripyam)2][Co(X)4](X = NO3– or NCS–), [Ni(tripyam)(H2O)2NO3](NO3), [Cu(tripyam)(NO3)2], [M(tripyam)2(NCS)2](M = Coor Ni), [Ni(tripyam)(NCS)2], and CuL(CNS)2(L = tripyam or dppa). The spectra of the compounds are discussed in terms of their probable structures and in addition evidence is presented to show that the three possible linkage isomers of CuL(CNS) have been prepared.

A study of the co-ordination behaviour of various 2-pyridylketones. Part II. Rhodium(III) complexes of 2-benzoylpyridine

Reaction of rhodium trichloride and 2-benzoylpyridine (PhCOpy) in ethanol affords the complex Rh(PhCOpy)2Cl2,Rh(PhCOpy)Cl4. The cation has been obtained as perchlorate in yellow and orange isomeric forms. Both isomers have trans chloride ligands. Reaction of any of these compounds with boliing water gives Rh(PhCOpy)2Cl2,OH, a neutral six-co-ordinate rhodium(III) complex containing one unidentate 2-benzoyl-pyridine molecule co-ordinated via oxygen. Reflexing the last compound in aqueous ethanol gives a further neutral complex, Rh(PhCOpy)2Cl3 containing one molecule of benzoylpyridine co-ordinated through nitrogen only Another neutral complex [Rh(PhCOpy)Cl2,H2O],H2O is considered to arise from the aquation of the Rh(PhCOpy)Cl4– anion.Corresponding bromo-complexes have been prepared and spectroscopic data, including assignments of rhodium–halogen stretching frequencies, are presented.

Complexes of tri-(2-pyridyl)amine. Part II. Some complexes with metal halides. The ligand field strength of terdentate tri-(2-pyridyl)amine

The structure of some new complexes of tri-(2-pyridyl)amine with the chlorides and bromides of manganese(II), cobalt(II), nickel(II), copper(II), zinc(II), palladium(III), rhodium(III), and iridium(II) are discussed. Terdentate tri-(2-pyridyl)amine is recognised as a strong-field ligand (Δ= 12,820 cm.–1 with respect to NiII) thus indicating that strong conjugation between the aromatic centres in polypyridyl ligands is not a prerequisite for high ligand field strength.

Complexes of tri-(2-pyridyl)amine. Part I. Complexes with cobalt(II), nickel(II), and copper(II) perchlorates

The ability of tri-(2-pyridyl)amine (tripyam) to function as a terdentate ligand is established by the preparation of Mo(CO)3(tripyam). The octahedral complexes Co(tripyam)2(ClO4)2, Ni (tripyam)2(ClO4)2, and Cu(tripyam)2(ClO4)2 have been prepared and X-ray powder results suggest the nickel and copper complexes to be isomorphous. The blue copper complex is readily isomerised to a yellow-green modification which has similar spectroscopic properties to [Cu (dppa)2(ClO4)2][dppa = di-(2-pyridyl)phenylamine] and is formulated as a complex of bidentate tri-(2-pyridyl)amine. Solid-state infrared spectra suggest the perchlorate groups to be co-ordinated in yellow-green [Cu(tripyam)2(ClO4)2] and in [Cu(dppa)2(ClO4)2] but not in the complexes [Cu(tripyam)2(ketone)2](ClO4)2(ketone = acetone or ethyl methyl ketone). [Cu(tripyam)2l, ClO4] and [Cu(tripyam)2l](ClO4) are isomers. [Cu(tripyam)2l2] and [Cu(tripyam)2(SCN)](ClO4) are also reported. Spectroscopic results for all complexes prepared are presented and briefly discussed.