[Ni₆(SCH₂CH₂OH)₁₂]: A Double Crown [12]Metallacrown‐6 Nickel(II) Cluster

Abstract

Metallacrowns represent a new class of multinuclear clusters that are analogous to crown ethers in both structure and function. [1, 2] One may substitute heteroatoms, such as transition metals and nitrogen atoms, for the methylene carbon atoms of the parent ether complexes to form metallacrowns. There has been considerable interest in metallacrown chemistry owing to potential applications in chemically modified electrodes, anion-selective separation agents, liquid-crystal precursors, and magnetic materials. [3] Generally, the metallacrowns can be synthesized using either multidentate ligands that bridge two metal ions [4] or bridging chalcogen ligands, such as NaSR, [5] NaSeR, [6] and OR anions.[ (1), a novel [12]metallacrown-6 nickel cluster as shown by single-crystal X-ray diffraction. We repeated the experiment and were able to form this product in high yield. Herein we report the spontaneous self-assembly and crystal structure of compound 1 as well as investigations on its UV/Vis spectrum and thermal stability.The crystal lattice of compound 1 [8] is made up of a centrosymmetric [Ni 6 (SCH 2 CH 2 OH) 12 ] molecule (Figure 1). Each Ni atom is surrounded by four S atoms of the m 2 -SCH 2 CH 2 OH ligands in a distorted square-planar fashion. As a result, the edge-sharing NiS 4 planes connect to form a ring. The six nickel atoms approximately form a hexagon, with NiÀ Ni separations in the range of 2.9010(15)-2.9378(17) , vertex angles of 119.08(5)-121.38(5)8, and an average deviation of AE 0.001 from the best least-squares Ni 6 plane. The diameter of the ring, defined as the average distance between two opposing nickel atoms, is 5.84 . Two m 2 -S bridges

Synthesis and Structure Analysis of α and β Forms of [12] Metallacrown-6 Nickel(II) Complex: [Ni6(SCH2CH2CH3)12]

“…The Ni-S bond lengths are 2.199(2) to 2.230(2) Å for α form and 2.202(3) to 2.216(4) Å for β form, respectively, which are slightly longer than that found in another nickel(II) complex with square-planar coordination (2.172(2) Å) 20 but agreement with the similar nickel complex reported before (2.183-2.213 Å) 9 and (2.192-2.206 Å). 19 Within the Ni6 ring, the average Ni-Ni separations of 2.9367 for α form and 2.9258 Å for β form is significantly longer than the Ni-Ni separations between nearest neighbors in cubic close-packed nickel They are also longer than the mean Ni-Ni separations in nickel metal (2.49 Å), 22 Fig.…”

“…7 Cyclic polynuclear nickel thiolates have been known since the pioneering work by Woodward et al 8 on the structure of the hexanuclear [Ni(µ2-SCH2CH3)2]6 complex. Since that time, a considerable number of other geometrically similar cyclic [Ni(SR)2]6 ring-systems [9][10][11][12] that likewise contain sulfurbridged nickel hexagons and two palladium analogue 13,14 have been prepared and structurally characterized. So far, several tiara-nickel thiolates have been synthesized and characterized, including cyclic tetranuclear, 15 pentanuclear, 14,16 octanuclear complexes.…”

Synthesis of palladium and palladium sulfide nanocrystals via thermolysis of a Pd–thiolate cluster

“…According to theoretical investigation [50], the Pd-S π bonding orbitals distributing throughout the palladium ring play a pivotal role in constructing and stabilizing the characteristic tiara-like structure. Such atomic arrangement has a triple-layered tiara-like structure and has also been found in other analogous [Pd(SR) 2 [8][9][10].…”

“…Thiolate ligands (SR) could bond with metal atoms in different coordination modes, terminal, μ 2 -bridging or μ 3 -bridging modes [3][4][5]. A large variety of thiolated transition metal clusters have been extensively synthesized and characterized, such as iron [6], cobalt [7], nickel [8][9][10], copper [10,11], zinc [12,13], palladium [14,15], silver [4,16,17], platinum [18] and gold [5,19]. These metal-thiolate clusters exhibit intriguing properties and potential applications in the fields of catalysis [20,21], optics [22,23] and magnetism [24,25].…”

Tiara-like Octanuclear Palladium(II) and Platinum(II) Thiolates and Their Inclusion Complexes with Dihalo- or Iodoalkanes

“…15,[18][19][20][21] Tiara-like nickel complexes have received considerable attention resulting in the preparation of complexes with a variety of ring sizes [Ni(-SR) 2 ] n (n = [4][5][6][8][9][10][11][12]. 15,[17][18][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] In contrast, although several tiara-like hexanuclear palladium complexes have been reported, 9,14,19,[36][37][38][39][40][41][42][43] only one octanuclear complex, i.e., [Pd(-S n Pr) 2 ] 8 , is known, and was obtained as a mixture with hexanuclear [Pd(-S n Pr) 2 ] 6 . 19 For platinum, infinite thiolates and selenolates [Pt(-ER) 2 ] ∞ (E = S, Se) have been synthesized using a solvothermal method; …”