An easy way to Pd–Zn nanoalloy with defined composition from a heterobimetallic Pd(μ–OOCMe)4Zn(OH2) complex as evidenced by XAFS and XRD

Abstract

The heterobimetallic lantern complex Pd(l-OOCMe) 4 Zn(OH 2 ) was found to be readily reduced with H 2 under fairly mild conditions (150-250°C, 5-10% H 2 /He) both in the carbon-supported and crystalline states to afford a Pd-Zn nanoalloy as evidenced by the ICP elemental analysis, EXAFS, XANES and XRD data.

Mechanism of the chemo–bio catalyzed cascade synthesis of R-1-phenylethyl acetate over Pd/Al2O3, lipase, and Ru-catalysts

“…Furthermore, the reduction of Pd in Pd-Zn/Al 2 O 3 catalyst occurred at 115°C, whereas a hightemperature peak was obtained at 351°C; this most probably indicates reduction of Zn species. It was, however, confirmed by XAFS that alloy formation had already occurred at 250°C [16]. Results from the kinetic studies…”

“…The Pd-Zn/Al 2 O 3 catalyst was prepared using the wetness-incipient technique [16]. The above mentioned complex PdZn(OAc) 4 .H 2 O (82.6 mg) was dissolved in absolute methanol (3 mL) at room temperature.…”

Two-way synthesis of a double-lantern heterobimetallic complex [Pd(μ-OOCMe)4Co]2(μ-OOCMe)2Pd(py)2

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The lantern complex Pd II (l-OOCMe) 4 Co II (NCMe) (1) was transformed into the pentanuclear double-lantern acetate-bridged heterobimetallic complex [Pd(l-OOCMe) 4 Co] 2 (l-OOCMe) 2 Pd(py) 2 (py is pyridine) (2) by two routes: (i) reaction of 1 with pyridine and (ii) reaction of 1 with trans-Pd(py) 2 (OOCMe) 2 . Complex 2 · 3C 6 H 6 was characterised by single-crystal X-ray diffraction, DTA-TG and magnetic susceptibility data.

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“…Recently we have synthesised and structurally characterised a series of heterobimetallic Pd II -based lantern-type complexes of the general formula Pd II M II (l-OOCMe) 4 L (M = Mn, Co, Ni, Zn; L = H 2 O, MeCN) [3]. In these complexes the Pd II and M II atoms are drawn together by four acetate bridges, so that the PdÁ Á ÁM distances (2.46-2.68 Å ) are close to the sum of covalent radii, implying some metal-metal interaction.…”

“…Such a structure is favourable for keeping together the constituent metal atoms during chemical and thermal transformations. For example, the complex Pd II Zn II (l-OOCMe) 4 (OH 2 ) was easily reduced with H 2 to afford a catalytically active PdZn nanoalloy under fairly mild conditions (10% H 2 /He, 150°C) [4].…”