28
J. Oliver–Meseguer and A. Leyva–Pérez
Fig. 1.26 Crystal structures of the MOF without metal (a, 1), with Pt
+
2 (b, 2) and with the Pt 2 clusters
(c, 3). d. Perspective views, in detail, of a channel of 3 in the ab (left) and bc (right) planes. Copper and
calcium atoms from the network are represented by cyan and blue polyhedra, respectively, whereas
organic ligands are depicted as gray sticks. Yellow and purple spheres represent S and Pt atoms,
respectively. Dashed lines represent the Pt···S interactions. e. Fragment of a channel of 3 emphasizing
the interactions with the network. Pt–S and Pt…O interactions are represented by yellow and blue
dashed lines, respectively. f. Pt-catalyzed synthesis of HCN at room temperature: Equation shows
the reaction conditions: CO (4 bar, 1.5 mmol), NH 3 (2 bar, 0.75 mmol) and 0.0075 mmol Pt and
a plausible reaction mechanism. Table includes the set of Pt catalysts tested under these reaction
conditions (Fig. adapted from Ref. [45]. Copyright © 2018 by John Wiley & Sons, Inc.)
Cu clusters generated within a polymeric film show also activity for the C–N coupling
and are a good example of metal cluster storage with full stability for months.
1.3.3 Heteroatom–Heteroatom Bond-Forming Reactions
1.3.3.1 Hydrosilylation of Alcohols
Alcohol hydrosilylated compounds are traditionally used as intermediates in organic
synthesis. O–Silylation often competes so successfully with C–silylation that protective groups must be used to avoid O–silylation; however, only O–silylated compounds
are formed for Pt catalysts used in low concentrations. Specifically for allyl alcohols,
it was found that no O–silylation was obtained at 50 mM Pt catalyst concentration,
and ~3 and 7% O–silylation occurred when [Pt] is 20 and 10 mM, respectively
[75]. Furthermore, much more forcing conditions were required at the lower catalyst
concentrations. These results suggest a change in the nature of the active catalyst
species. Moreover, during the catalyst preparation, Pt 2 clusters were detected.
J. Oliver–Meseguer and A. Leyva–Pérez
Fig. 1.26 Crystal structures of the MOF without metal (a, 1), with Pt
+
2 (b, 2) and with the Pt 2 clusters
(c, 3). d. Perspective views, in detail, of a channel of 3 in the ab (left) and bc (right) planes. Copper and
calcium atoms from the network are represented by cyan and blue polyhedra, respectively, whereas
organic ligands are depicted as gray sticks. Yellow and purple spheres represent S and Pt atoms,
respectively. Dashed lines represent the Pt···S interactions. e. Fragment of a channel of 3 emphasizing
the interactions with the network. Pt–S and Pt…O interactions are represented by yellow and blue
dashed lines, respectively. f. Pt-catalyzed synthesis of HCN at room temperature: Equation shows
the reaction conditions: CO (4 bar, 1.5 mmol), NH 3 (2 bar, 0.75 mmol) and 0.0075 mmol Pt and
a plausible reaction mechanism. Table includes the set of Pt catalysts tested under these reaction
conditions (Fig. adapted from Ref. [45]. Copyright © 2018 by John Wiley & Sons, Inc.)
Cu clusters generated within a polymeric film show also activity for the C–N coupling
and are a good example of metal cluster storage with full stability for months.
1.3.3 Heteroatom–Heteroatom Bond-Forming Reactions
1.3.3.1 Hydrosilylation of Alcohols
Alcohol hydrosilylated compounds are traditionally used as intermediates in organic
synthesis. O–Silylation often competes so successfully with C–silylation that protective groups must be used to avoid O–silylation; however, only O–silylated compounds
are formed for Pt catalysts used in low concentrations. Specifically for allyl alcohols,
it was found that no O–silylation was obtained at 50 mM Pt catalyst concentration,
and ~3 and 7% O–silylation occurred when [Pt] is 20 and 10 mM, respectively
[75]. Furthermore, much more forcing conditions were required at the lower catalyst
concentrations. These results suggest a change in the nature of the active catalyst
species. Moreover, during the catalyst preparation, Pt 2 clusters were detected.