Synthesis and Structure of the new cluster [Hg10Se4(SePh)12(PPh2nPr)4] and its Conversion into [Hg32Se14(SePh)36]

Abstract

The reaction of HgCl2 and PPh2nPr with PhSeSiMe3 and Se(SiMe3)2 in THF at −30 °C results in the formation of yellow octahedral crystals of [Hg10Se4(SePh)12(PPh2nPr)4]. The molecular structure of the cluster is similar to structures of other [M10Se4(SePh)12(PR3)4] (M = Cd, Zn; R = organic group) cluster compounds although it is the first of its type with mercury as the group 12 metal atom. Dissolving [Hg10Se4(SePh)12(PPh2nPr)4] in benzene at 10 °C leads to the rapid formation of a dark red solution from which red crystals of the larger cluster [Hg32Se14(SePh)36] could be crystallized in 50% yield upon layering with pentane. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Controlled Synthesis of Ternary II−II‘−VI Nanoclusters and the Effects of Metal Ion Distribution on Their Spectral Properties

“…Clusters 4 and 5 crystallize in the cubic space groups I 4̄3 m and F 4̄3 c , respectively. Similar to clusters 2 and 3 , as well as recently reported binary HgSe clusters, the structures exhibit the well-known fused tetraadamantane cage architecture (Figure ) that also comprises the extended structure of bulk cubic HgSe. For cluster 5 , the phenyl groups and carbon atoms of the phosphine ligands are disordered over two positions with equal occupancy.…”

“…Examination of the bond distance data for cluster 5 (Table ) further supports the assignment of the metal positions discussed above. The Hg−μ-SePh and Hg−P1 bond distances are similar to those in other binary HgSe clusters 38a, suggesting predominantly Hg at the apical positions. The concentration of the lighter metal ion within the cores of clusters 4 and 5 contrasts with the metal ion distributions determined for the ZnCdSe and ZnCdTe complexes 2 and 3 , in which the zinc centers preferentially occupy peripheral sites in the cluster.…”

Controlled Synthesis of Ternary II−II‘−VI Nanoclusters and the Effects of Metal Ion Distribution on Their Spectral Properties

“…Clusters 4 and 5 crystallize in the cubic space groups I 4̄3 m and F 4̄3 c , respectively. Similar to clusters 2 and 3 , as well as recently reported binary HgSe clusters, the structures exhibit the well-known fused tetraadamantane cage architecture (Figure ) that also comprises the extended structure of bulk cubic HgSe. For cluster 5 , the phenyl groups and carbon atoms of the phosphine ligands are disordered over two positions with equal occupancy.…”

“…Examination of the bond distance data for cluster 5 (Table ) further supports the assignment of the metal positions discussed above. The Hg−μ-SePh and Hg−P1 bond distances are similar to those in other binary HgSe clusters 38a, suggesting predominantly Hg at the apical positions. The concentration of the lighter metal ion within the cores of clusters 4 and 5 contrasts with the metal ion distributions determined for the ZnCdSe and ZnCdTe complexes 2 and 3 , in which the zinc centers preferentially occupy peripheral sites in the cluster.…”

Molecular Fates of Organometallic Mercury in Human Brain

“…Both zincblende and wurtzite show four-coordinate Hg and four-coordinate Se and are expected to be difficult to distinguish by EXAFS . The core HgSe zincblende structure, with fused adamantane-type rings comprised of alternating Hg and Se separated by 2.63 Å, has been duplicated in a number of small molecule clusters with pendant selenolates, such as Hg 10 Se 4 (SeR) 12 , which can coalesce into clusters with larger cores . Naturally occurring tiemannite frequently occurs in combination with sulfur, as HgS x Se 1 –x , with nearly the entire range of x from β-HgS ( x = 1) to HgSe ( x = 0) having been observed .…”

Molecular Clusters of Binary and Ternary Mercury Chalcogenides: Colloidal Synthesis, Characterization, and Optical Spectra

“…At the earliest measured time (Spectrum 1 in Figure b), the absorption spectrum shows three well-resolved transitions. The energy of these three states (2.23, 2.40, and 2.61 eV) nearly coincide with those seen in the absorption spectrum of Hg 32 Se 50 clusters (2.27 eV, 2.48 eV, and ∼2.68 eV) . However, the third state (2.61 eV) is markedly pronounced whereas in the Hg 32 Se 50 absorption spectrum it is weak and rapidly evolves into a continuum of states toward higher energies.…”

“…For example, continued growth of HgTe QDs was observed, evidenced by a continuous red-shift of the absorption over a period of days 33a. Likewise, Hg 32 Se 50 clusters in THF or toluene, when warmed to room temperature, undergo rapid growth leading to a black precipitate,34b which is likely bulk HgSe or large NCs with broad size distributions, similar to those observed by Brennan …”

Controlled Synthesis of Ternary II−II‘−VI Nanoclusters and the Effects of Metal Ion Distribution on Their Spectral Properties

“…Clusters 4 and 5 crystallize in the cubic space groups I 4̄3 m and F 4̄3 c , respectively. Similar to clusters 2 and 3 , as well as recently reported binary HgSe clusters, the structures exhibit the well-known fused tetraadamantane cage architecture (Figure ) that also comprises the extended structure of bulk cubic HgSe. For cluster 5 , the phenyl groups and carbon atoms of the phosphine ligands are disordered over two positions with equal occupancy.…”

“…Examination of the bond distance data for cluster 5 (Table ) further supports the assignment of the metal positions discussed above. The Hg−μ-SePh and Hg−P1 bond distances are similar to those in other binary HgSe clusters 38a, suggesting predominantly Hg at the apical positions. The concentration of the lighter metal ion within the cores of clusters 4 and 5 contrasts with the metal ion distributions determined for the ZnCdSe and ZnCdTe complexes 2 and 3 , in which the zinc centers preferentially occupy peripheral sites in the cluster.…”

Molecular Fates of Organometallic Mercury in Human Brain

“…Both zincblende and wurtzite show four-coordinate Hg and four-coordinate Se and are expected to be difficult to distinguish by EXAFS . The core HgSe zincblende structure, with fused adamantane-type rings comprised of alternating Hg and Se separated by 2.63 Å, has been duplicated in a number of small molecule clusters with pendant selenolates, such as Hg 10 Se 4 (SeR) 12 , which can coalesce into clusters with larger cores . Naturally occurring tiemannite frequently occurs in combination with sulfur, as HgS x Se 1 –x , with nearly the entire range of x from β-HgS ( x = 1) to HgSe ( x = 0) having been observed .…”

Molecular Clusters of Binary and Ternary Mercury Chalcogenides: Colloidal Synthesis, Characterization, and Optical Spectra

“…At the earliest measured time (Spectrum 1 in Figure b), the absorption spectrum shows three well-resolved transitions. The energy of these three states (2.23, 2.40, and 2.61 eV) nearly coincide with those seen in the absorption spectrum of Hg 32 Se 50 clusters (2.27 eV, 2.48 eV, and ∼2.68 eV) . However, the third state (2.61 eV) is markedly pronounced whereas in the Hg 32 Se 50 absorption spectrum it is weak and rapidly evolves into a continuum of states toward higher energies.…”

“…For example, continued growth of HgTe QDs was observed, evidenced by a continuous red-shift of the absorption over a period of days 33a. Likewise, Hg 32 Se 50 clusters in THF or toluene, when warmed to room temperature, undergo rapid growth leading to a black precipitate,34b which is likely bulk HgSe or large NCs with broad size distributions, similar to those observed by Brennan …”

Controlled Synthesis of Ternary II−II‘−VI Nanoclusters and the Effects of Metal Ion Distribution on Their Spectral Properties

“…Clusters 4 and 5 crystallize in the cubic space groups I 4̄3 m and F 4̄3 c , respectively. Similar to clusters 2 and 3 , as well as recently reported binary HgSe clusters, the structures exhibit the well-known fused tetraadamantane cage architecture (Figure ) that also comprises the extended structure of bulk cubic HgSe. For cluster 5 , the phenyl groups and carbon atoms of the phosphine ligands are disordered over two positions with equal occupancy.…”

“…Examination of the bond distance data for cluster 5 (Table ) further supports the assignment of the metal positions discussed above. The Hg−μ-SePh and Hg−P1 bond distances are similar to those in other binary HgSe clusters 38a, suggesting predominantly Hg at the apical positions. The concentration of the lighter metal ion within the cores of clusters 4 and 5 contrasts with the metal ion distributions determined for the ZnCdSe and ZnCdTe complexes 2 and 3 , in which the zinc centers preferentially occupy peripheral sites in the cluster.…”

Molecular Fates of Organometallic Mercury in Human Brain

“…Both zincblende and wurtzite show four-coordinate Hg and four-coordinate Se and are expected to be difficult to distinguish by EXAFS . The core HgSe zincblende structure, with fused adamantane-type rings comprised of alternating Hg and Se separated by 2.63 Å, has been duplicated in a number of small molecule clusters with pendant selenolates, such as Hg 10 Se 4 (SeR) 12 , which can coalesce into clusters with larger cores . Naturally occurring tiemannite frequently occurs in combination with sulfur, as HgS x Se 1 –x , with nearly the entire range of x from β-HgS ( x = 1) to HgSe ( x = 0) having been observed .…”

Molecular Clusters of Binary and Ternary Mercury Chalcogenides: Colloidal Synthesis, Characterization, and Optical Spectra

“…At the earliest measured time (Spectrum 1 in Figure b), the absorption spectrum shows three well-resolved transitions. The energy of these three states (2.23, 2.40, and 2.61 eV) nearly coincide with those seen in the absorption spectrum of Hg 32 Se 50 clusters (2.27 eV, 2.48 eV, and ∼2.68 eV) . However, the third state (2.61 eV) is markedly pronounced whereas in the Hg 32 Se 50 absorption spectrum it is weak and rapidly evolves into a continuum of states toward higher energies.…”

“…For example, continued growth of HgTe QDs was observed, evidenced by a continuous red-shift of the absorption over a period of days 33a. Likewise, Hg 32 Se 50 clusters in THF or toluene, when warmed to room temperature, undergo rapid growth leading to a black precipitate,34b which is likely bulk HgSe or large NCs with broad size distributions, similar to those observed by Brennan …”