REACTIONS OF AN AZINE DIPHOSPHINE WITH PLATINUM(II) AND PALLADIUM(II)AND THE FORMATION OF A NOVEL HETEROCYCLIC DIPHOSPHINE LIGAND - CRYSTAL-STRUCTURE OF [PDI2(PPH2CH=C(BUT)N-N=C(BUT)CH2PPH)]
Sd. Perera et al., REACTIONS OF AN AZINE DIPHOSPHINE WITH PLATINUM(II) AND PALLADIUM(II)AND THE FORMATION OF A NOVEL HETEROCYCLIC DIPHOSPHINE LIGAND - CRYSTAL-STRUCTURE OF [PDI2(PPH2CH=C(BUT)N-N=C(BUT)CH2PPH)], Journal of the Chemical Society. Dalton transactions, (24), 1993, pp. 3653-3659
The azine diphosphine Z,Z-PPh2CH2C(Bu(t))=N-N=C(Bu(t))CH2PPh2 I was tr
eated with [Pt-Me2(cod)] (cod = cycloocta-1,5-diene) to give the dimet
hylplatinum(II) complex [FtMe2{PPh2CH2C(Bu(t))=N-N=C(Bu(t))CH2PPh2}] 1
a containing a nine-membered chelate ring with an E,Z configuration fo
r the bidentate azine diphosphine ligand. This complex undergoes oxida
tive addition with Mel to give the fac-trimethylplatinum(iv) complex [
PtMe3I{PPh2CH2C(Bu(t))=N-N=C(Bu(t))CH2PPh2}]2. The corresponding plati
num(II) complexes [PtX2{PPh2CH2C(Bu(t))=N-N=C(Bu(t))CH2PPh2}] (X = C-C
C6H4 Me-p 1b or Cl 1c) were also prepared. Treatment of trans-[PtCl2(N
CR)2] (R = Me or Ph) with I gave a hexanuclear species ns-[{PtCl2[PPh2
CH2C(Bu(t))=N-N=C(Bu(t))CH2PPh2]}6] 3a in which the azine diphosphine
is acting as a bridging group and is still symmetrical, i.e. the confi
guration is still Z,Z. The palladium analogue 3b was made by treating
[PdCl2(NCPh)2] or Na2[PdCl4] with I but might only be binuclear. This
complex was unstable in hot chloroform and at 60-degrees-C (30 min) wa
s completely converted into the salt [PdCl{PPh2CH2C(Bu(t))=N-N=C(Bu(t)
)CH2PPh2}]Cl 4a in which the azine diphosphine is tridentate with E,Z
configuration and mutually trans-co-ordinated phosphorus donors and on
e of the azine nitrogens is co-ordinated. Treatment of [PtCl2(cod)] wi
th I and addition of NH4PF6 gave the platinum salt [PtCl{PPh2CH2C(Bu(t
))=N-N=C(Bu(t))CH2PPh2}]PF6 4c; [PtI{PPh2CH2C(Bu(t))=N-N=C(Bu(t))CH2PP
h2}]I 4d was also prepared. On prolonged (8 d) heating in chloroform s
olution the bridged complex 3b was quantitatively converted into the n
ovel and very stable heterocyclic complex [PdCl2{PPh2CH=C(Bu(t))N-N=C(
Bu(t))CH2PPh}] 5a with loss of a molecule of benzene. Treatment of 5a
with LiBr or Nal gave the corresponding dibromide 5b or diiodide 5c co
mplexes. The crystal structure of 5c has been determined. The correspo
nding platinum complexes [PtX2{PPh2CH=C(Bu(t))N-N=C(Bu(t))CH2PPh}] 5d-
5f (X = Cl, Br or 1) were also prepared and treatment of the dichloro
complex with MgMel gave the dimethyl complex 5g. Treatment of this dim
ethyl complex with an excess of Mel gave [PtMe3I{PPh2CH=C(Bu(t))N-N=C(
Bu(t))CH2PPh}] 6. Proton, C-13-{H-1} and P-31-{H-1} NMR and infrared d
ata are given.