Syntheses, Spectra, and Structures of (Diphosphine)platinum(II) Carbonate Complexes

A variety of (diphosphine)platinum(II)
carbonate complexes, (LL)Pt(CO3), are readily
prepared from the
corresponding (diphosphine)platinum dichlorides by treatment with
silver carbonate in dichoromethane solution
provided that water is present. This reaction also permits facile
preparation of analogous 13C-labeled
complexes.
The carbonate ligands in these complexes have been characterized
by IR and 13C NMR spectroscopy.
Alternative
preparative routes involve conversion of the precursor dichlorides to
the corresponding dialkoxides or diphenoxides,
followed by treatment with water and carbon dioxide. Various
reaction intermediates have been spectroscopically
observed in the latter syntheses. Two crystalline modifications of
(Ph2PCH2CH2CH2PPh2)Pt(CO3),
one with and
one without a dichloromethane of solvation, have been studied by
single-crystal X-ray diffraction. Crystal data
for PtP2O3C28H26: 
P21/c, Z = 4,
T = 200 K, a = 10.362(8) Å,
b = 14.743(6) Å, c = 19.183(10)
Å, β =
122.69(6)°. Crystal data for
PtP2O3C28H26·CH2Cl2:
P21/c, Z = 4,
T ≈ 298 K, a = 11.744(2) Å,
b = 15.526(3)
Å, c = 15.866(3) Å, β =
101.58(1)°.