Sulfur-Bridged Cubane-Type Molybdenum−Gallium Clusters with Mo₃GaS₄ⁿ⁺ (n = 5, 6) Cores. X-ray Structures of [Mo₃GaS₄(H₂O)₁₂](CH₃C₆H₄SO₃)₅·14H₂O and [Mo₃GaS₄(H₂O)₁₂](CH₃C₆H₄SO₃)₆·17H₂O

Abstract

Sulfur-bridged cubane-type molybdenum-gallium clusters [Mo(3)GaS(4)(H(2)O)(12)](5+) (2) and [Mo(3)GaS(4)(H(2)O)(12)](6+) (3) have been synthesized from [Mo(3)S(4)(H(2)O)(9)](4+) (1) and gallium metal and have been isolated as 2(pts)(5).14H(2)O (2.pts) and 3(pts)(6).17H(2)O (3.pts) (Hpts = p-toluenesulfonic acid), whose structures have been characterized by X-ray crystallography. Crystal data for 3.pts: orthorhombic, space group Pca2(1), a = 11.188(1) Å, b = 30.936(4) Å, c = 23.987(2) Å, V = 8301(2) Å(3), Z = 4, D(calcd) = 1.628 g cm(-3), D(obsd) = 1.63 g cm(-3), R (R(w)) = 5.8% (6.3%) for 6102 reflections (I > 3.0sigma(I)). Crystal data for 2.pts: triclinic, space group P&onemacr;, a = 16.406(4) Å, b = 16.743(3) Å, c = 13.173(4) Å, alpha = 90.64 degrees, beta = 98.40(2) degrees, gamma = 89.32(2) degrees, V = 3579.2(14) Å(3), Z = 2, D(calcd) = 1.681 g cm(-3), D(obsd) = 1.68 g cm(-3), R (R(w)) = 6.7% (10.1%) for 7612 reflections (I > 3.0sigma(I)). The Mo-Ga distances (3.pts, 3.60[2] Å; 2.pts, 3.52[2] Å) are much longer than the corresponding Mo-Mo (3.pts, 2.679[7] Å; 2.pts, 2.713[3] Å) distances. At low H(+) concentrations, such as 0.5 M HCl, 2 is stable, and at H(+) concentration higher than 2 M HCl, 2 is oxidized by H(+) to give 3 with evolution of hydrogen gas. Chloride ion plays an important role in the oxidation of 2. Electronic spectra of 3.pts and 2.pts are very similar. Peak positions and epsilon values (lambda(max), nm (epsilon, M(-1) cm(-1))): 3.pts, 762 (447), 550 (204); 2.pts, 760 (404), 548 (205). The cyclic voltammogram of 3 shows three reduction processes (the cathodic peak potentials, E(pc), are -0.83, -1.20, and -1.74 V, respectively), where the first and second processes are quasi-reversible (the anodic peak potentials, E(pa), are -0.55 and -1.00 V, respectively). The reduction current of each process is close to 1:1:3.

Evaluation of Molybdenum−Sulfur Interactions in Molybdoenzyme Model Complexes by Gas-Phase Photoelectron Spectroscopy. The “Electronic Buffer” Effect

“…The importance of molybdosulfur complexes in biological and industrial catalysis has led to the study of a wide range of monomeric, dimeric, and cluster complexes .…”

Synthesis and structure of a paramagnetic Mo3S4 incomplete cuboidal cluster with seven cluster skeletal electrons

“…Liquid Ga has been found to be a soft and handy reducing agent, which can sometimes lead to compounds with transition metal-gallium bonds. 6 Although formation of the cubane-like clusters with the Mo 3 Q 4 Ga core cannot be in principle ruled out, 7 we have found that refluxing a suspension of [Mo 3 S 4 -(dppe) 3 Br 3 ]Br (1a) in THF in the presence of gallium smoothly leads to the one-electron reduction product Mo 3 S 4 (dppe) 3 Br 3 (2a) § (Scheme 1). Its structure as the toluene-diethyl ether solvate 2a•1.5C 7 H 8 •Et 2 O has been established by means of X-ray diffraction analysis.…”

Formation (and properties) of palladium derivatives of [Mo3Q4(H2O)9]4+: absence of similar derivatives of [W3Q4(H2O)9]4+ (Q = S, Se)

“…X-Ray crystallography has indicated Mo-Mo bonding in all of these cubes. [3][4][5][6][7][8][9][10][11][12][13] However, whereas the Mo-Pd bonds are short in the derivative from [Mo 3 S 4 (H 2 O) 9 ] 4ϩ (consistent with metal-metal bonding), 6 Mo-Sn separations are ≈1 Å longer with no evidence for metal-metal bonding. 13 In keeping with these findings the formalism Mo 3 S 4 4ϩ , Pd 0 and Mo 3 S 4 4ϩ , Sn II has been introduced.…”