The [Cl₂OMo(μ-OC₂H₅)₂(μ-HOC₂H₅)MoOCl₂]/PMe₃ System:  A Chameleon Yielding the X-ray Structures of MoOCl₂(PMe₃)₃, MoOCl₃(PMe₃)₂, Mo₄O₄Cl₄(μ₂-OEt)₄(PMe₃)₂(μ₃-O)₂, and MoOCl₃(OPMe₃)(PMe₃)

Abstract

The reaction of [Cl2OMo(μ-OC2H5)2(μ-HOC2H5)MoOCl2] (1) with 5 equiv of PMe3 provides a simple route to pure mer-MoOCl2(PMe3)3 (3), so that its crystal structure could be determined [C9H27Cl2MoOP3, monoclinic, P21/c, a = 17.138(3) Å, b = 12.808(3) Å, c = 19.226(4) Å, β = 115.99(1)°, Z = 8]. The mechanism of the conversion of 1 to 3 is complex, but one of the intermediates, MoOCl3(PMe3)2 (4), can be isolated and crystallized, if 1 is reacted only with 3 instead of 5 equiv of PMe3. 4 further reacts with an excess of PMe3 to yield 3, providing additional evidence for its intermediacy. The crystal structure of 4 could be determined [C6H18Cl3MoOP2, monoclinic, P21/n, a = 6.468(1) Å, b = 12.677(2) Å, c = 17.791(2) Å, β = 92.64(1)°, Z = 4]. If 4 is not isolated directly after the reaction and its crystallization is attempted from the raw mixture, two different compounds are obtained and their crystal structures were determined: MoOCl3(OPMe3)(PMe3) (5) [C6H18Cl3MoO2P2, monoclinic, P21/n, a = 6.783(3) Å, b = 12.623(4) Å, c = 18.298(8) Å, β = 98.58(3)°, Z = 4] and Mo4O4Cl4(μ2-OC2H5)4(PMe3)2(μ3-O)2 (6) [C14H38Cl4Mo4O10P2, monoclinic, P21/c, a = 1117.6(2) Å, b = 1161.6(2) Å, c = 1277.1(3) Å, β = 109.84(1)°, Z = 2]. 4 reacts slowly with CH2Cl2 producing [Me3PH]+[MoOCl4(PMe3)]- (7), which can also be found among the products of attempts to crystallize 4 from CH2Cl2/petroleum ether mixtures, while its treatment with an excess of HCl produces [Me3PH]2 +[MoOCl5]2- (8). The mechanism of the stepwise fragmentation of 1 yielding 3−7 is discussed.

Crystal structure and Hirshfeld surface analysis of the elusive trichlorobis(diethyl ether)oxomolybdenum(V)

“…The distance of the molybdenum centre from the centroid of the basal plane is 0.264 Å and the fractional coordinates from the atom projection to the plane are (0.134701, 0.460936, 0.478813). This centre-centroid distance is shorter than that reported for the MoCl 3 O(MeOH) 2 and MoCl 3 O[MeO(CH 2 ) 2 OCH 2 Cl] adducts, which display respective distances of 0.322 and 0.378 Å , but is similar to that of MoCl 3 O(PMe 3 )(O PMe 3 ), which has a distance of 0.256 Å (Marchetti et al, 2013;Limberg et al, 1996).…”

Synthesis, properties and structural features of molybdenum(v) oxide trichloride complexes with neutral chalcogenoether ligands

“…[4][5][6] Interest in high oxidation molybdenum complexes bearing sulfur donor ligands stems in part from the presence of Mo-S coordination in the molybdenum-containing enzymes, nitrate reductase, sulfite oxidase and Fe-Mo nitrogenases which involve (anionic) cysteine or sulfide ligands. [4][5][6] The chemistry with neutral P-and As-donor ligands with Mo(V) has also been investigated, [7][8][9][10][11] but sulfur-based ligands were mostly represented by charged thiolate and dithiocarbamate ligands. [2][3][4] More recent work has reported a series of extremely moisture sensitive Mo(VI) complexes [MoO 2 X 2 (dithioether)] (X = Cl or Br; dithioether = RS(CH 2 ) 2 SR, R = Me, Et, i Pr), which have distorted octahedral structures with the sulfur donor atoms trans to MovO; 12,13 there are also some thia-macrocyclic analogues.…”

Oxygen‐Transfer Reactions of Molybdenum‐ and Tungstendioxo Complexes Containing η2‐Pyrazolate Ligands

“…All solvents were purified by standard methods and distilled under a nitro- [63] P(C 6 H 4 F) 3 , [64] and t-Bu 2 pzK [42] were prepared according to literature procedures. All other chemicals mentioned were used as purchased from commercial sources.…”