406676-47-9

Basic information

• Product Name: [Ni(SPh)(triphos)](BPh)4
• CAS NO: 406676-47-9
• Molecular Weight: 1021.65
• Mol File: 406676-47-9.mol

Chemical Properties

• CAS DataBase Reference: [Ni(SPh)(triphos)](BPh)4(CAS DataBase Reference)
• NIST Chemistry Reference: [Ni(SPh)(triphos)](BPh)4(406676-47-9)
• EPA Substance Registry System: [Ni(SPh)(triphos)](BPh)4(406676-47-9)

Safety Data

• Hazardous Substances Data: 406676-47-9(Hazardous Substances Data)

Upstream product

• 40326-49-6 [NiCl(bis(2-diphenylphosphinoethyl)phenylphosphine)](tetraphenylborate) 
• 2973-86-6 lithium thiophenoxide 

Downstream Products

• 406676-49-1 [Ni(SePh)(triphos)](BPh₄) 
• 406676-51-5 (Ni(SEt)((Ph₂PCH₂CH₂)2PPh))BPh₄ 
• 40326-49-6 [NiCl(bis(2-diphenylphosphinoethyl)phenylphosphine)](tetraphenylborate) 

Relevant articles and documents

Kinetic evidence for intramolecular proton transfer between nickel and coordinated thiolate

The complexes [Ni(YR)(triphos)]BPh4 {Y = S, R = Ph or Et or Y = Se, R = Ph; triphos = (Ph2PCH2CH2)2PPh} have been prepared and characterized, and the X-ray crystal structure of [Ni(SPh)(triphos)]BPh4 has been solved. In MeCN, [Ni(YR)(triphos)]+ are protonated by [lutH]+ (lut = 2,6-dimethylpyridine) to give [Ni(YHR)(triphos)]2+. Studies on the kinetics of these equilibrium reactions reveal an unexpected difference in the reactivities of [Ni(SPh)(triphos)]+ and [Ni(SEt)(triphos)]+. In both cases, the reactions exhibit a first-order dependence on the concentration of complex. When R = Ph, the dependence on the concentrations of [lutH+] and lut is given by kobs = k1Ph[lutH+] + k-1Ph[lut], which is typical of an equilibrium reaction where k1Ph and k-1Ph correspond to the forward and back reactions, respectively. Analogous behavior is observed for [Ni(SePh)(triphos)]+. However, for [Ni(SEt)(triphos)]+, the kinetics are more complicated, and kobs = {k1k2[lutH+] + (k-2 + k2)}/(k1[lutH+] + k--1[lut]), which is indicative of a mechanism involving two coupled equilibria in which the initial protonation of the thiolate is followed by a unimolecular equilibrium reaction that is assumed to involve the formation of an η2-EtS-H ligand. The difference in reactivity between the complexes with alkyl and aryl thiolate ligands is a consequence of the {Ni(triphos)}2+ site "leveling" the basicities of these ligands. The pKa's of the PhSH and EtSH constituents coordinated to the {Ni(triphos)}2+ are 16.0 and 14.6, respectively, whereas the difference in pKa's of free PhSH and EtSH differ by ca. 4 units. The pKa of [Ni-(SeHPh)(triphos)]+ is 14.4. The more strongly σ-donating EtS ligand makes the {Ni(triphos)}2+ core sufficiently electron-rich that the basicities of the sulfur and nickel in [Ni(SEt)(triphos)]+ are very similar; therefore, the proton serves as a bridge between the two sites. The relevance of these observations to the proposed mechanisms of nickel-based hydrogenases is discussed.