To Fuse or Not To Fuse? Reactions of [HM4(CO)12BH]- (M= Fe, Ru) with (Phosphine)gold(I) Chlorides. Molecular Structures of HFe4(CO)12BHAuP(2-Me-C6H4)3, [Au(PMePh2)2][{HFe4(CO)12BH}2Au], and [PPN][{HRu4(CO)12BH}2Au]

Sylvia M. Draper, Catherine E. Housecroft*, Jacqueline E. Rees, Musa S. Shongwe, Brian S. Haggerty, Arnold L. Rheingold

*Corresponding author for this work

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26 Citations (Scopus)


The reaction of [HFe4(CO)12BH] [PPN] (PPN = bis(triphenylphosphine)nitrogen(1+)) with 1 equiv of LAuCl (L = P(2-Me-C6H4)3, P(c-C6H11)3) yields HFe4(CO)12BHAuL, but of these two products only HFe4(CO)12BHAuP(2-Me-C6H4)3 (1) is stable in solution. Attempts to prepare other monogold derivatives with L = PMe3, PEt3, PMe2Ph, PMePh2 led instead to the ionic product [AuL2] [[HFe4(CO)12BH]2Au] ([AuL2][4]), which possesses the same stoichiometry as the target molecule HFe4(CO)12BHAuL but is produced as a result of Au-P bond cleavage and a ligand redistribution reaction. The ruthenium cluster HRu4(CO)12BHAuP(2-Me-C6H4)3 (2) may be prepared by a corresponding route to that used for 1, but unlike 1, formation of 2 competes not only with formation of [AuL2][{HRu4(CO)12BH}2Au] ([AuL2][5]) but also with that of the digold derivative Ru4(CO)12BHAu2(P(2-Me-C6H4)3)2 (3). Both 1 and 2 are readily deprotonated by NEt3 with loss of Fe–H–Fe or Ru–H–B protons, respectively. Treatment of [HFe4(C- O)12BH][PPN] with ClAu(dppm)AuCl (dppm = bis(diphenylphosphino)methane) leads to a mixture of the borido cluster HFe4(CO)12Au2(dppm)B (6; 40%) and the salt [PPN] [{HFe4(CO)12BH}2Au] ([PPN][4]; 30%), while in the analogous reaction of [HRu4(CO)12BH] [PPN] with ClAu(dppm)AuCl, the predominant cluster product is [PPN] [5]. The observed results are discussed in terms of (i) the differing sizes of the Fe4 and Ru4 butterfly frameworks and (ii) the steric constraints of the phosphine ligands. The molecular structures of 1, [Au(PMePh2)2][4], and [PPN] [5] are presented. 1: triclinic, P1; a = 10.023 (2) Å, b = 12.814 (3) Å, c = 15.231 (4) Å; α = 104.02 (2),° β = 90.47 (2)°, γ = 90.13 (2)°; V = 1897.8 (9) Å3 23; Z = 2; R(F) = 4.41%. [Au(PMePh2)2] [4]: monoclinic, C2/c; a= 21.704 (3) Å, b = 9.542 (2) Å, c = 29.717 (6) Å; β = 97.50 (1)°; V = 6102.0 (19) Å3; Z = 4; R(F) = 4.59%. [PPN][5]: triclinic, P1; a = 9.759 (4) Å, b = 13.898 (5) Å, c = 26.964 (17) Å; α = 96.68 (4)°, β = 97.31 (4)°,γ = 91.78 (4)°; V = 3599 (3) Å3; Z = 2; R(F) = 7.65%. The structure of each of the anions [4]- and [5]- exhibits two cluster subunits fused together in a “face-to-face” orientation via a single gold atom. In [4]- the subunits are mutually cis and there is a spiro twist of 30.9 (5)° at the gold atom. However, in [5]-, the cluster subunits are arranged in a trans configuration, as would be expected on the basis of steric arguments.

Original languageEnglish
Pages (from-to)2356-2367
Number of pages12
Issue number7
Publication statusPublished - Jul 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


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