Nobue Hagihara

Syntheses and properties of cis- and trans-dialkynyl complexes of platinum(II)

Abstract Selective syntheses of cis - and trans -platinum(II) acetylide complexes of the type (R 3 P) 2 Pt(CCR′) 2 (where R = Et or n-Bu, R′ = H, CHCH 2 , CCH, Ph or p -C 6 H 4 CCH), and systematic studies on characterization of the cis - and trans -isomers by spectroscopic methods are reported.

Linear polymers containing transition metals in the main chain

In recent years linear polymers containing transition metals have attracted much interest. There are two types of organometallic polymers in which the metal-containing portion is either a part of the polymer main chain or bound to the polymer as a pendant group. In this article the recent studies on the former type of linear polymers are reviewed on the basis of the following three parts: 1 metallocene-containing polymers; 2 linear “Werner-type” coordination polymers; 3 polymers containing sigma-bonded transition metals in the main chain. The main part of this review is devoted to a new class of soluble metal-poly-yne polymers in which transition metal atoms are joined in the main chain by a metal-carbon σ-bond.

Novel preparation of σ-alkynyl complexes of transition metals by copper(I) iodide-catalysed dehydrohalogenation

Transition metal alkynyl complexes have been prepared conveniently in high yields under mild conditions by the direct reaction of acetylenes with metal halides in the presence of catalytic amounts of copper(I) iodide in diethylamine.

Preparations of σ-bonded alkyl-, aryl- and alkynylnickel compounds

Abstract The preparations and some properties of π-C5H5Ni(L)X and π-C5H5Ni(L)R [X  halogens; L  (C6H5)3P, (CH3)(C6H5)2P, (n-C4H9)3P, (C6H5)3As and (C6H5)3Sb; R  CH3, C2H5, n-C3H7, n-C4H9, sec-C4H9, CH2C6H5, C6H5, p-ClC6H4, o-CH3C6H4, m-CH3C6H4, p-CH3C6H4, 2,4,6-(CH3)3C6H2, CHC and CCC6H5] are described.

Studies of poly-yne polymers containing transition metals in the main chain : III. Synthesis and characterization of a poly-yne polymer containing mixed metals in the main chain,

Abstract By the reaction of trans -(PBu 3 ) 2 Pt(CCCCH) 2 with trans -(PBu 3 ) 2 PdCl 2 , the title polymer, (II), has been prepared and characterized by spectral and analytical data. The alternating regularity of the metal arrangement in II was confirmed by the selective formation of the trinuclear complex trans,trans,trans -ClPd(PBu 3 ) 2 −CCC CPt(PBu 3 ) 2 −CC-CCPd(PBu 3 ) 2 (XXIII), in the depolymerization by trans- (PBu 3 ) 2 PdCl 2 using CuI as catalyst in XXNEt 2 .

Studies of poly-yne polymers containing transition metals in the main chain : VI. Synthesis of nickel-poly-yne polymers by alkynyl ligand exchange using a copper(I) catalyst.

Reactions of trans-bis(Tri-n-butlphosphine)diethynylnickel(Ia) with 1-alkynes in the presence of an amine complex of a copper(I) salt as a catalyst give quantitatively alkynyl ligand exchange products. By this method, complex(Ia) reacts with appropriate α,ω-diethynyl compounds to afford high molecular weight linear polymers in good yields. This procedure provides a convenient route to such nickel-poly-yne polymers.

Interaction of cumulene systems with organometallic π-complexes : I. Cumulene complexes

Abstract The reaction of tetraphenylallene and -butatriene with iron pentacarbonyl gave (C 6 H 5 ) 4 C 3 Fe(CO) 3 and (C 6 H 5 ) 4 C 4 Fe 2 (CO) 5 , as red and brownish red crystals, respectively. The unsubstituted butatriene complex, H 4 C 4 Fe 2 (CO) 5 was also prepared by the reaction of 1,4-dibromo-2-butyne with triiron dodecacarbonyl in the presence of zinc powder. The interaction of cumulene systems with a variety of metal carbonyls has been examined.

Insertion reactions of isocyanides into nickel-to-carbon sigma bonds

Abstract The treatment of isocyanides with π-C 5 H 5 Ni(PPh 3 )R in benzene at room temperature gave the complexes, π-C 5 H 5 Ni(CNR′)[C(R)NR] (I), the products of isocyanide insertion into nickel-alkyl sigma bonds. The reactions of isocyanides with π-C 5 H 5 (PR 3 )I (R=Ph, Et, OPh) produced the salt-like complexes (II), formulated as [π-C 5 H 5 Ni(CNR′)(PR 3 )]I and [π-C 5 H 5 Ni(CNR′) 2 ]I (R′ = Ph, Et). Based on the formation of (I) from the reactions of (II) with phenylmagnesium bromide, the mechanism of the insertion reaction of isocyanides into nickel-to-carbon bonds has been considered.

The infrared spectra of the square-planar dialkynyl complexes of nickel(II), palladium(II) and platinum(II)

Abstract The stability of the metal-carbon bond in bis(triethylphosphine)dialkynyl complexes of Ni II , Pd II and Pt II was investigated through the substituent effect exerted on metal-carbon stretching frequencies, and a linear relationship was established between the square of the frequencies and Tafts polar constants of the substituents on alkynyl groups. The relationship was interpreted in terms of d π- p π interaction between central metal and alkynyl groups. The interaction is considered to reinforce the metal-carbon bond.

The charge-transfer interaction of 7,7,8,8-tetracyanoquinodimethane with trans-bis(trialkylphosphine)-dialkynylplatinum(II) and related complexes

Abstract 7,7,8,8-Tetracyanoquinodimethane ★★ (TCNQ) showed charge-transfer interaction with trans -bis(trialkylphosphine)dialkynylplatinum(II), trans -[R′ 3 P) 2 Pt-(CCR) 2 ], (R′ = Me, Et, Pr, Bu, and R = H, Me, CH 2 CH, CH 3 CC or Ph), and their palladium(II) and nickel(II) derivatives. The following 1 1 adducts were isolated as stable purple-black crystals: These adducts showed a characteristic absorption band in the visible region (λ max ; 506–555 nm in CH 2 Cl 2 ). From the study of their formation constants and consideration of the molecular geometry of component molecules, it was deduced that electron was donated from the alkynyl groups to TCNQ. This characteristic property of the alkynyl group which coordinates to transition-metal atom is regarded as the consequence of the back-donation of electrons from the central metal which increases the electron density on the alkynyl groups and enhances their donor properties.