Transition-metal cyanotrihydroborate complexes

“…Only traces of metal (or boride) are formed when aqueous Nien,Cl, is treated with NaBH, (reflecting the greater stability of Nien," over Ni(NH,),,+) and reduction is suppressed completely in 50% en solutions. However, Nien,Cl, is rapidly reduced (8).…”

Section: Reactions With Nickel Complexes Containingmentioning

confidence: 99%

“…In the case of N-donors, Ni(I1) in liquid ammonia (5) or in the presence of an excess of concentrated ammonia (6,7) is not reduced by NaBH,, the product being Ni(NH,), (BH,),. The reaction of NaBH, with Nien,Cl, (en = ethylene diamine) in concentrated ammonia produces Nien,(BH,), (6), while Nien,Cl, is rapidly reduced to the metal or boride (8). Also, NaBH, does not reduce a variety of Ni(I1) -cyclic nitrogen base complexes (9) even at 60°C.…”

Section: Introductionmentioning

confidence: 99%

Ligand effects upon the reactions of Ni(II) with sodium tetrahydroborate: Ni(I) complexes of bipyridyl and 1,10-phenanthroline

Holah¹,

Hughes²,

Hui³

1977

Can. J. Chem.

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. Can. J. Chem. 55, 4048 (1977). The reactions between NaBH, and Ni(I1) have been studied in the presence of a variety of ligands in an effort to determine (a) the conditions under which reduction occurs, (b) the extent of the reduction (e.g. to Ni(I), Ni(0) complexes, or to Ni metal or boride), and (c) whether intermediate Ni complexes can be isolated.With ligands having no n-bonding capabilities (NH3, ethylenediamine, edta, citrate), reduction depends upon the Ni:ligand ratio and, in the presence of an excess of the ligand, reduction of Ni(1I) is very slow. When vacant coordination sites exist on the metal through dissociation of, for example, Ni(NH,),'+, allowing for the interaction of the BH4 group with the metal, then rapid reduction to the metal (or boride) takes place.With the K-bonding N-donor ligands 1,lO-phenanthroline (phen) and 2,2'-bipyridyl (bipy) reduction of the stable ML,'+ complexes probably occurs via an outer-sphere electron transfer mechanism but, in these cases, new species of the type NiL2X (L = phen, bipy; X = BH4, PF6, BPh4), which formally contain Ni(I), have been isolated. Lorsque les ligands n'ont pas de capacitt de liaisons n (NH,, tthylknediamine, edta, citrate), la reduction depend du rapport Ni : ligand et, en prtsence d'un exces de ligand, la reduction de Ni(I1) est tres lente. Quand des sites de coordination vacants existent sur le metal par I'intermtdiaire d'une dissociation, par exemple de Ni(NH,),'+, permettant une interaction du groupe BH4 avec le metal, il y a alors une rtduction rapide conduisant au mttal (ou borure).Avec des ligands donneurs par l'azote et pouvant crter des liens K comme la phtnanthroline-1,10 (phen) et bipyridyl-2,2' (bipy) la reduction des complexes stables ML,,+ se produit probablement par l'intermkdiaire d'un mtcanisme de transfert Clectronique au niveau de la sphere exttrieure mais dans ces cas on peut isoler de nouvelles esfices du type NiL,X (L = phen, bipy; X = BH,, PF,, BPh4) qui contiennent d'une f a~o n formelle du Ni(1). [Traduit par le journal] IntroductionIt is known that the presence of certain ligands prevents the rapid reduction by NaBH, of metal salts to the metal or to the insoluble borides (1). Without doubt, reactions between NaBH, and transition metal complexes containing phosphines are best documented and, in the case of nickel, these proceed by two different routes.

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“…Thus, nickel colnplexes of BH, and As well as being a powerful reducing agent BH,CN stabilized by nitrogen containing bases and an excellent source of hydride ion in the have been characterized (1 1,12) and complexes synthesis of metal hydrides, the BH,-group formulated as trans-(R,P),MH(BH,) (M = Ni, will coordinate to a variety of metals to form Pd, but not Pt; R = Pri or cyclohexyl) have covalent complexes such as M(BH,), (for an been prepared and briefly investigated as excellent review of metal tetrahydroborate reducing agents ( 1 3-1 5). Copper forms numerous derivatives see ref.…”

Section: Introductionmentioning

confidence: 99%

Reactions of Sodium Tetrahydroborate and Cyanotrihydroborate With Divalent Co, Ni, Cu, Pd, and Pt Chlorides In the Presence of Tertiary Phosphines

Holah¹,

Hughes²,

Hui³

et al. 1974

Can. J. Chem.

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. Can. J. Chem. 52.2990Chem. 52. (1974.The reactions of divalent Co, Ni, Cu, Pd, and Pt chlorides with NaBH, and NaBH,CN in the presence of tertiary phosphines under inert atmosphere conditions have been examined. The nature of the product varies enormously depending upon reaction conditions, and compounds obtained include complexes involving coordinated BH,-and BH,CN-of the type ML,, MBL,, and MHBL, (L = phosphine, B = BH,-or BH3CN-, n = 2, 3, or 4'). The first univalent nickel and cobalt BH, complexes are reported. Platinum abstracts the C N group from BH,CN-to form the species PtH(CN)L,. I~f r a r e d spectral data are reported and appear to indicate two types of bonding (M-N and M-H) between BH,CN-and metals. Some electronic reflectance spectra and magnetic properties are also reported, including those of Co(1) and Ni(1) species. Attempts are made to rationalize the data in terms of a suggested mechanism for the reduction of metal halides by NaBH,.

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Transition-metal cyanotrihydroborate complexes

Abstract: S.ummaryThe preparation of several transition-metal cyanotrihydroborate complexes is reported and their physical properties are shown to be consistent with an M-NCBH, type structure.

Cited by 24 publications

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Syntheses and crystal structures of group 6 metal complexes containing allyl and cyanotrihydroborate groups

Syntheses and crystal structures of group 6 metal complexes containing allyl and cyanotrihydroborate groups

Ligand effects upon the reactions of Ni(II) with sodium tetrahydroborate: Ni(I) complexes of bipyridyl and 1,10-phenanthroline

Reactions of Sodium Tetrahydroborate and Cyanotrihydroborate With Divalent Co, Ni, Cu, Pd, and Pt Chlorides In the Presence of Tertiary Phosphines

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