No abstract

The dibenzyl-substituted carbamic acid (PhCH 2 ) 2 NC(O)OH (1), its deprotonation product [(PhCH 2 ) 2 NH 2 ]-[(PhCH 2 ) 2 NCO 2 ] (2) and CoCl(NO) 2 [PhP(OCH 2 CH 2 ) 2 N-C(O)OH]•2MeCOMe(3•2MeCOMe) are reported, the diffractometric study showing the carbamic acids 1 and 3 to be paired through hydrogen bonds.

Reaction between [MCl,(dme)] ( M = W or Mo; dme = 1.2-dimethoxyethane) with Li, [C,H,CMe,C,H,] gave the ansa-bridged metallocene dichlorides [M{(q-C,H,)CMe,(q-C,H,)}CI,]( M = W or Mo). Treatment of these with LiAIH, or ZnMe, gave respectively the dihydrides [M{(q-C,H,)CMe,(q-C,H,)}H,] (M = W or Mo) and the dimethyl derivatives [M{(q-C,H,)CMe,(q-C,H,)}Me,](M = W or Mo).Treatment of [W{(q-C,H,)CMe,(q-C,H,))Me,] with HX (X = PhCO, or NHJ) gave [W{(q-C,H,)CMe,-(q-C5H4)}Me(Y)] with Y = PhCO, or I, respectively. Both of these react with Na[AIH,(OCH,CH,OMe),] giving the methylhydride [W{(q-C,H,)CMe,(q-C,H,)}Me(H)].The latter is thermally stable in refluxing benzene. Ultraviolet photolysis of [Mo{(q-C,H,)CMe,(q-C,H,))H,] in benzene gave the phenylhydride derivative [ Mo{ (q-CsH4) CMe,(q -C,H,)}Ph( H )I ; the corresponding tungsten derivative [W{ (q -C,H,) -CMe,(q-C,H,)}H,] is not photosensitive. The crystal structures of [W{(q-C,H,)CMe,(q-C5H4)}Cf2],[W{(q-C,H,)CMe,(q-CsH4)}H2], (two modifications) and [Mo{(q-C,H,)CMe,(q-C,H,)}H,] have been determined by X-ray diffraction. The ansa-bridged bis(q-cyclopentadienyl) compounds show marked differences in reactivity compared to non-ansa analogues and this is discussed in terms of the modifications of the electronic structure as a consequence of the ansa bridge.

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