in tetrahydrofuran addn. of Me2Sn(CCH)2 to a soln. of (Ph2PC2H4PPh2)PtCl2 in THF and refluxing for 4 h (N2); concn. of the clear soln. up to beginning turbidity, addn. of hexane orpentane and cooling on an ice bath, filtering off the ppt., repeated washings with hexane and drying at room temp. in vacuo;