Tungsten carbonyl complexes of 1H-diphosphirenes and diphosphirenylium salts

The 1,1,3-tris(diisopropylamino)diphosphirenium salt 1 reacts with lithium aluminium hydride leading to the P-hydrogeno-C-phosphinophosphaalkenes 2, w hich on treatment with a catalytic amount of BF3. OEt2 afford the 1,3-bis(d iisopropylamino)-1H-diphosphirene 3. The corresponding eta(1)-coordinated H -1-diphosphirene 6 can be prepared by treatment of 2 or 3 with one equivale nt of [W(CO)(5)(thf)]. Alternatively, the diphosphirenium salt 1 reacts wit h an excess of [W(CO)(5)(thf)], affording the corresponding eta(1)-coordina ted diphosphirenium salt complex 4, which is converted into the P-hydrogeno phosphaalkene complex 5 with lithium aluminium hydride, The dinuclear tungs ten complexes 7 and 8 are obtained by treatment of the free 1H-diphosphiren e 3 with two equivalents of [W(CO)(5)(thf)] or one equivalent of [W(CO)(4)( thf)(2)], respectively. Compound 6 reacts with two equivalents of hydrogen chloride, giving the 1-chloro-3-diisopropylamino-1H-diphosphirene 9, which can be subsequently converted into the 1-diisopropylamino-, 1-azido, or 1-p henyl-3-diisopropylamino-1H-diphosphirenes 6, 10 and 11 by nucleophilic sub stitution with diisopropylamine, azidotrimethylsilane or sodium tetraphenyl borate, respectively. The [eta(2)-(3-diisopropylaminodiphosphirenylium salt ). W(CO)(5)] complexes 12a-c can be prepared by reaction of 9 with silver t rifluoromethanesulfonate, aluminium or gallium trichloride or, alternativel y by treatment of 6 with two equivalents of trifluoromethanesulfonic acid. Reaction of 12a with diisopropylamine, water, bis(triphenylphosphoranyliden e) ammonium chloride or tetrabutylammonium fluoride gives the corresponding 1H-diphosphirene complexes 6, 13, 9, or 14, respectively. Compound 12a als o reacts with one or two equivalents of [W(CO)(5)(thf)], leading to the di- and trinuclear complexes 15 and 16, respectively.