Platinum-gold-mercury (PtAu8Hg2) and (PtAu7Hg2) cluster compounds: x-ray structure of [Pt(AuPPh3)8(Hg)2](NO3)4.3CH2Cl2

Mechanistic Insight into H/D Exchange by a Pentanuclear Ni–H Cluster and Synthesis and Characterization of Structural Analogues of Potential Intermediates

“…At −40 °C, the slow exchange limit 31 P­{ 1 H} NMR spectrum was observed, which features a doublet at δ 37.2 with a J PP = 12.9 Hz that corresponds to the 4 phosphines in the basal plane, and a pentet at δ 94.5 for the capping Ni with the same J PP = 12.9 Hz, but also 199 Hg satellites ( I = 1/2, 16.8%) with a J PHg of 1208 Hz. The observation of coupling to the Hg center for the phosphine on the capping Ni but not for the phosphines on the Ni centers in the square base is unique to 2 , and not observed in structurally related μ 4 -Hg Au clusters, where the 2 J HgP coupling to the phosphines in the basal plane is large. , Antipodal ligands in carborane and metallocarborane clusters have been reported to influence chemical shifts, but not coupling constants. , The 1 H NMR spectrum has the expected PCH and Me resonances for the five i Pr 3 P in rapid exchange, along with a resonance for the six hydrides at δ −28.62. The hydride resonance is exchange broadened, with a W 1/2 of 450 Hz.…”

“…Only a few Ni-Hg complexes have been reported in the Cambridge Structural Database; − Kubiak has reported a Hg center bound to four Ni centers, albeit in a distorted planar-Hg geometry . The closest structural analogues with respect to the capping μ 4 -Hg environment in 2 have been reported in Au, Au/Pd, and Au/Pt clusters. , Similarly to 1 , samples of 2 in C 6 D 6 were found to undergo H/D exchange with the solvent, which could be monitored by a decrease of the hydride resonance intensity in the 1 H NMR and an increase in the intensity of the C 6 D 5 H resonance. The exchange with 2 in neat C 6 D 6 is significantly slower than with 1 , with a t 1/2 of 4.76 × 10 4 s versus the t 1/2 of 1.8 × 10 3 s for 1 .…”

“…The observation of coupling to the Hg center for the phosphine on the capping Ni but not for the phosphines on the Ni centers in the square base is unique to 2, and not observed in structurally related μ 4 -Hg Au clusters, where the 2 J HgP coupling to the phosphines in the basal plane is large. 54,55 Antipodal ligands in carborane and metallocarborane clusters have been reported to influence chemical shifts, but not coupling constants. 56,57 The 1 H NMR spectrum has the expected PCH and Me resonances for the five i Pr 3 P in rapid exchange, along with a resonance for the six hydrides at δ −28.62.…”

Gold–Heterometal Interactions and Bonds

“…A similar metallic framework, that is, Pt-centered Au 8 cube with one missing vertex, was found in the related [{(Ph 3 P) Au} 7 Pt(H)(PPh 3 )](PF 6 ) 2 408 [554]. Trimetallic Hg-Au-Pt clusters based on a Ptcentered Au 8 square antiprism were also reported (see Section 2.2) [41][42][43][44].…”

“…The same structure of the cation [Au-Hg 3.0011(5)/3.0070(5) Å] was established for the 18-electron cluster [{(Ph 3 P) Au} 8 Pt(Hg) 2 ](NO 3 ) 4 13 [44]. The compound was isolated as red cubes by slow diffusion of diethyl ether into a methanol/CH 2 C1 2 solution of [{(Ph 3 P)Au} 8 Pt (HgNO 3 ) 2 ](NO 3 ) 2 , a cluster obtained by reacting [{(Ph 3 P)Au} 8 Pt](NO 3 ) 2 with Hg 2 (NO 3 ) 2 [43,44].…”