Discrete Sandwich Compounds of Monolayer Palladium Sheets

Abstract

Despite the abundance of "sandwich" complexes, in which two cyclic aromatic hydrocarbon ligands flank a metal center, this motif has not been extended to sheets of multiple metal atoms. We prepared and isolated two such compounds. In the first, three palladium centers form a planar triangular array, capped by chlorides, between two cycloheptatrienyl ligands. In the second, a pentapalladium sheet adopts an edge-sharing triangle-trapezoid skeleton between two naphthacene rings. The compounds were characterized by x-ray crystallography and nuclear magnetic resonance spectroscopy. The nature of bonding in the clusters was analyzed by quantum calculations.

A ladder polysilane as a template for folding palladium nanosheets

“…The supernatant was collected, layered with pentane (5 ml) and cooled to À 35°C to afford the dark green crystals of 2 (56 mg, 0.02 mmol, 65%). 1 Si (3) Pd (4) Pd (11) Si (6) Si (6) Pd (4) Si (3) Pd (11) Si ( 10 (2) (50 mg, 0.02 mmol) was dissolved in toluene (3 ml), and toluene (2 ml) solution of mesityl isocyanide (28 mg, 0.19 mmol) was added at À 35°C. After the resulting mixture was stirred for 12 h at À 35°C, the solvent was removed under reduced pressure.…”

“…A conceptual scheme to construct the folding Pd 11 (Si i Pr 2 ) 4 (Si i Pr) 2 (CNR) 10 nanosheet structure is depicted in Fig. 4 using compound 2 as a representative example.…”

“…Several unique points should be noted in the molecular structures of 2 and 3. First, both 2 and 3 consist of eleven palladium atoms, six organosilyl moieties and ten isocyanide ligands with formula Pd 11 (Si i Pr 2 ) 4 (Si i Pr) 2 (CNR) 10 . Second, both 2 and 3 have a pseudo twofold axis Pd(5) Pd(6) Pd (7) Pd (1) Pd (3) Pd (2) Pd (10) Pd (8) Pd (9) Pd (11) Pd (4) Si (2) Si (1) Si (3) Si (5) Si (4) Si (6) Pseudo 2-fold axis d h Pd(5) Pd(6) Pd (7) Pd (1) Pd (3) Pd (2) Pd (10) Pd (8) Pd (9) Pd (11) Pd (4) Si (2) Si (1) Si (3) Si (5) Si (4) Si ( (6) Pd (7) Pd (1) Pd (3) Pd (2) Pd (10) Pd (8) Pd (9) Pd (11) Pd (4) Si (2) Si (1) Si (3) Si (5) Si (4) Si (6) Pd(5) Pd(6) Pd (7) Pd (1) Pd (3) Pd (2) Pd (10) Pd (8) Pd …”

“…The synthesis of relatively small transition metal nanosheets has attained some success in organometallic and inorganic chemistry [6][7][8][9] . Among them, a novel methodology to synthesize Pd 3 to Pd 5 nanosheets was developed by Murahashi et al [10][11][12][13][14][15][16] using (poly)cyclic aromatic hydrocarbons as a template for the arrangement of Pd atoms in a two-dimensional sheet structure. The sandwich compound, [Pd 5 (naphthacene) 2 ] 2 þ , is the largest palladium nanosheet reported to date 10 .…”

“…Among them, a novel methodology to synthesize Pd 3 to Pd 5 nanosheets was developed by Murahashi et al [10][11][12][13][14][15][16] using (poly)cyclic aromatic hydrocarbons as a template for the arrangement of Pd atoms in a two-dimensional sheet structure. The sandwich compound, [Pd 5 (naphthacene) 2 ] 2 þ , is the largest palladium nanosheet reported to date 10 . Success of this template synthesis of transition metal nanosheets suggests a strategy to access new nanosheets using templates that force the metals into a planar arrangement owing to metal-metal bonding interactions.…”