(Ethane-1,2-di-yl)bis-[bis-(3-methoxy-prop-yl)methyl-phospho-nium] bis-(tetra-phenyl-borate) diethyl ether solvate.

In the course of substitution studies on the iron dihydrogen complex trans-[Fe(DMeOPrPE)(2)(H(2))H](BPh(4)) {DMeOPrPE = 1,2-bis-[bis-(methoxy-prop-yl)phosphino]ethane}, we discovered an unexpected transformation of the diphosphine ligand to a diphospho-nium dication without the use of any typical methyl-ating reagent. The P atoms in the dication of the title compound, C(20)H(46)O(4)P(2) (2+)·2C(24)H(20)B(-)·C(4)H(10)O, have a distorted tetra-hedral coordination with P-C(Me) distances of 1.791 (2) and 1.785 (2) Å. The P-C-C-P torsion angle about the central dimethyl-ene bridge is -168.3 (1)°.