Properties of Some Compounds of the Metals of Medium Atomic Weight with Heterocyclic Ligands and the more readily Polarized Anions

Abstract

Part I
The coordination behaviour of 2-benzoylpyridine (PhCOpy )
with some transition metal cations was investigated. 2-benzoylpyridine
is believed to be a weak-field, bidentate (NO-co-ordination) ligand.
Complexes of 2-benzoylpyridine with the perchlorates, chlorides,
bromides and iodides of manganese (II), cobalt (II) and nickel (II)
are described. Some compounds of zinc (II), cadmium (II) and
magnesium (TI) were studied for comparison. With the exception of
Mn (PhCOpy )X_ (X = Cl or Br) and Cd(PhCOpy) C15, all compounds
isolated were bis-complexes but the metal ions are six-co-ordinate
in all cases.

The complexes, [Nn (PhCOpy){EtOH) 9] (C104 )o3
[Co(PhCOpy), (OH) 9] (C10, )o and [Ni (PhCOpy), (EtOH) 9] (C104) with
ionic perchlorate groups, and [Co(PhCOpy) (C104) 9] and
[Ni(PhCOpy), (C104) 9] with weakly coordinated perchlorate groups
were characterised. In nitromethane, it was established that -
[Co(PhCOpy ) Xo] (X = Cl or Br) dissociates to the pseudo-tetrahedral
complex, [Co(PhCOpy )X.] . The two forms of Ni (PhCOpy ) C1,
are believed to be the two isomers of the trans-dichloro-complex.
[Mn(PhCOpy)X,] (X = C1 or Br) and [Cd(PhCOpy )C1.] are polymeric.
The compounds M(PhCOpy oly. (M = Co, Ni, Zn or Cd) are isomorphous
and form isomorphous groups with M(PhCOpy)oClo.
{KM = Co, Ni(green and yellow)].

Part II
The compounds investigated have al] been of one or the
other of two types, namely [(pyridine base), (M)2*(13)] (M = first row divalent transition metal ion) or [(pyridine base),
(wr ys* (CNSTy)o] »(M' = Ni(II)) only and pyridine base = pu iine
B-picoline or y-picoline in both cases. Some I, compounds of
manganese (II), iron (11), cobalt (II) and cadmium (11) with pyridine
bases were crystallised from acetonitrile. Acetonitrile was retained
as an uncoordinated, lattice component. W'? (B-picoline)(13)9
(M = Fe, Mn or Cd) could not be crystallised.

Little information concerning the structure of the above
compounds was obtained from physical examinations. The most
informative data was derived from the measurement of the magnetic
susceptibilities. High-spin octahedral complexes, [M(pyridine base),
(15) 9] (M = Mn, Fe or Co) and planar or "tetragonally distorted
octahedral" nickel (II) complexes, Ni(pyridine base )X [X = I, or
(NCS-I5) J were characterised. Study of the magnetic susceptibilities
at various temperatures is described for nickel (11) complexes only.
The bonding nature of (CNS-I5) , as Ni-NCS-I, is discussed.

The compounds Cd(py)a(13)o5 Cd(y-pic)a(I3)o 2(CH2CN) , and
the polymerisation reactions involved in cadmium - y-picoline-iodine
are described.

The conductivity study of all compounds in nitromethane and
in dimethylsulphoxide, and the absorption spectra of 13 ions in
acetonitrile and in 1,2-dichloroethane are described.

Date of Award	1972
Original language	English
Awarding Institution	Aston University