Atomically Precise Ni–Pd Alloy Carbonyl Nanoclusters: Synthesis, Total Structure, Electrochemistry, Spectroelectrochemistry, and Electrochemical Impedance Spectroscopy

Abstract

The molecular nanocluster [Ni 36– x Pd 5+ x (CO) 46 ] 6– ( x = 0.41) ( 1 6– ) was obtained from the reaction of [NMe 3 (CH 2 Ph)] 2 [Ni 6 (CO) 12 ] with 0.8 molar equivalent of [Pd(CH 3 CN) 4 ][BF 4 ] 2 in tetrahydrofuran (thf). In contrast, [Ni 37– x Pd 7+ x (CO) 48 ] 6– ( x = 0.69) ( 2 6– ) and [HNi 37– x Pd 7+ x (CO) 48 ] 5– ( x = 0.53) ( 3 5– ) were obtained from the reactions of [NBu 4 ] 2 [Ni 6 (CO) 12 ] with 0.9–1.0 molar equivalent of [Pd(CH 3 CN) 4 ][BF 4 ] 2 in thf. After workup, 3 5– was extracted in acetone, whereas 2 6– was soluble in CH 3 CN. The total structures of 1 6– , 2 6– , and 3 5– were determined with atomic precision by single-crystal X-ray diffraction. Their metal cores adopted cubic close packed structures and displayed both substitutional and compositional disorder, in light of the fact that some positions could be occupied by either Ni or Pd. The redox behavior of these new Ni–Pd molecular alloy nanoclusters was investigated by cyclic voltammetry and in situ infrared spectroelectrochemistry. All three compounds 1 6– , 2 6– , and 3 5– displayed several reversible redox processes and behaved as electron sinks and molecular nanocapacitors. Moreover, to gain insight into the factors that affect the current–potential profiles, cyclic voltammograms were recorded at both Pt and glassy carbon working electrodes and electrochemical impedance spectroscopy experiments performed for the first time on molecular carbonyl nanoclusters.

Atomically Precise Platinum Carbonyl Nanoclusters: Synthesis, Total Structure, and Electrochemical Investigation of [Pt27(CO)31]4– Displaying a Defective Structure

“…Materials and apparatuses for electrochemistry and IR SEC have been described elsewhere. 43 EIS spectra were recorded using as E dc the E °′ of a reversible electrochemical reaction obtained from the voltammetric experiments. E ac was set to 0.005 V, and the frequency was scanned between 10000 and 1 Hz.…”

“…This behavior can be studied in detail by means of electrochemical methods as well as IR spectroelectrochemical (IR SEC) studies. 43 , 44 The fact that molecular metal nanoclusters can exist with a variable number of electrons is a direct consequence of the incipient metalization of their metal core with increasing size.…”

“…As a further point of interest, large molecular metal carbonyl clusters, including a few atomically precise platinum carbonyl nanoclusters, , are multivalent, displaying several reversible or quasi-reversible redox processes. This behavior can be studied in detail by means of electrochemical methods as well as IR spectroelectrochemical (IR SEC) studies. , The fact that molecular metal nanoclusters can exist with a variable number of electrons is a direct consequence of the incipient metalization of their metal core with increasing size.…”

Platonic and Archimedean solids in discrete metal-containing clusters

“…39c). [43][44][45] The 44-metal v 3octahedral structure is comprised of an octahedral Pt 6 core and a v 3 -octahedral Ni 38 shell (Fig. 39d).…”

“…Over the last two decades, due to their continuing enthusiasm and efforts, synthetic chemists have proposed and designed multiple feasible synthesis strategies, developed new synthesis methods, and improved technology for the growth of single-crystals, resulting in several very exciting achievements in the synthesis and applications of metal clusters with different structures (especially high-nuclearity metal nanoclusters), such as cubic-box-shaped {Mo 64 Ni 8 Ln 6 }, 31 dodecahedra-shaped {Mo 240 }, 32 hedgehog-shaped {Mo 368 }, 33 tetrahedral {Dy 30 Co 8 W 108 }, 34 dodecameric {(Ta/Nb) 3 P 2 -W 15 O 62 } 12 , 35 protein-sized {Nb 288 }, 36 C 60 -shaped {U 60 }, 37 fullerene-like {Ti 42 }, 38 wheel {Mn 84 }, 39 {Fe 168 }, 40 {Co 32 }, 41 ligand-free {As@Ni 12 @As 20 }, 42 {Pt 6 Ni 38 }, [43][44][45] ring {Pd 84 }, 46 {(PtPd) 165 }, 47 {Zn 14 }, 48 {Cd 66 }, 49 {Hg 32 }, 50 {Ce 100 }, 51 {Gd 140 }, 52 cubic {Ln 96 Ni 64 } (Ln = Gd, Dy, Y), 53 hexagon-shaped {Ni 36 Gd 102 }, 54 spherical {Ln 104 } (Ln = Gd, Nd), 55 {Gd 158 Co 38 }, 56 {Cu 179 }, 57 {Ag 374 }, 58 {Ag 490 }, 59 {Au 279 }, 60 {Al 77 }, 61 {Ga 84 }, 62 {In 68 }, 63 {Sn 34 }, 64 {Pb 18 I 44 }, 65 and {Bi 50 }. 66 Among them, highly symmetrical polyhedral structures (metal atoms or SBBs as vertices), ranging from simple tetrahedral ones to complex frameworks with multiple shells (Fig.…”