The properties of zerovalent nickel-carbonyl-diphosine complexes and their application to the synthesis of heterobimetallic systems

  • A.B.M. Rahman

    Student thesis: Master's Thesis


    This work involves the investigation of properties of zerovalent Ni-CO-di phosphine complexes and their application to the synthesis of heterobimetallic systems. Two Ni(O)-carbonyl-diphosphine complexes [Ni(CO)(dppe-PP')(dppe-P)J and [ Ni(CO)2(dppm-P)2J have been prepared. [Ni(CO)(dppe-PP')(dppe-P)J has been prepared by the reaction of Nicl2.6tt2o with dppe, NaBH4 and co. The dicarbonyl species [Ni(CO)2(dppm-P)2J has also been prepared in the same way but here dppm is used instead of dppe.

    The complex [Ni(CO)(dppe-PP')(dppe-P)J reacts with MeCOCl, PhCOCl, I2, HCl gas, air and some alkyl and aryl halides, e.g., Mel, EtI, PhCl, PhBr, c6tt11 Br. With MeCOCl and PhCOCl it gives no organometallic product but cis square planar Ni(II) complex [NiC12( dppe-PP')J found to be diamagnetic. The complex also reacts with I2 to give a Ni(II) complex [NiI2(dppe-PP')J. Protonation of the complex [Ni(CO)(dppe-PP')(dppe-P)J with HCl gas gives a mixture of a nickel hydride complex, possibly [NiH(dppe-PP' )2]+ and [NiCl2(dppe-PP')J. With alkyl and aryl halides [Ni(CO)(dppe-PP')(dppe-P)] produces a Ni(O) complex [ Ni( dppe-PP')2]. The dicarbonyl species reacts with I2 to give a mixture of [NiI2(dppm-PP')J and [NiI2(dppm-P)2]- In the reactions with air [Ni{CO)(dppe-PP')(dppe-P)] gives no oxidized product but loses co to give [ Ni(dppe-PP')2]. The same reaction with [Ni(CO)2(dppm-P)2] produces a mixture of oxides of dppm, [Ph2P(O)CH2PPh2J and [Ph2P(O)CH2P(O)Ph2J.

    [Ni(CO)(dppe-PP')(dppe-P)] and [ Ni(CO)2(dppm-P)2 J have been applied to the synthesis of heterobimetallic complexes by reaction with [PdC1 2(COD)], [ Mo (co) 3( c 7H8)], [Mo (co) 3( MeCN)3], [Rh2(µ-Cl)2(co) 4] and [ W(CO)4( MeCN) 2] under nitrogen. A Ni-Pd hetrobimetallic complex [ NiPdC12(µ-CO)(µ-dppm)2] has been identified together with a mixture of [PdC12(dppm-PP')] and [ Ni2(CO)2( µ-CO)(µ-dppm)2J from the reaction of [ Ni(CO)2(dppm-P)2] with [PdCl2(COD)] at room temperature. Attempts at reaction of [ Ni{CO )2(dppm-P)2J with [Mo(CO)3{C7Ha)J, [Mo(CO)3(MeCN)3] and [ W(CO)4( MeCN) 2] resulted in dimerization of[ Ni(CO)2(dppm-P)2] to [Ni2(CO)2(µ-CO)(µ-dppm)2J- This structure has been characterized by X-ray crystallography. Reactions of [PdC12(COD)] and [Mo(CO)3(C7Ha)J with [Ni(CO)(dppe-PP'(dppe-P)] produce [ NiC12(dppe-PP')] and [Ni(dppe-PP')2] respectively. A mixture of [RhCl(CO)(dppe-PP')], [RhCl(dppe-PP')2J and [ Ni ( dppe-PP')2 J has been obtained from the reaction of [Ni(CO)(dppe-PP'(dppe-P)] with [Rh2(µ-Cl)2(CO)4]. In the reaction of [Ni(CO)2(dppm-P)2 J with [Rh2(µ-Cl)2(CO)4] a mixture of dirhodium complexes trans-[RhCl(CO)(µ-dppm)J2 and [ Rh2c12( µ-CO)(µ-dppm)2] has been suggested.

    The complexes have been characterized from the results of IR, 1tt- NMR, 31P-NMR and UV/visible spectroscopy.
    Date of Award1993
    Original languageEnglish

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