C₃-symmetry Mo₃S₄ aminophosphino clusters combining three sources of stereogenicity: stereocontrol directed by hydrogen bond interactions and ligand configuration

Abstract

A diastereoselective synthesis of proline containing aminophosphino cubane-type Mo3S4 clusters, (P)-[Mo3S4Cl3((1S,2R)-PPro)3]Cl (Cl) and (P)-[Mo3S4Cl3((1S,2S)-PPro)3]Cl (Cl), has been achieved in high yields by reacting the corresponding enantiomerically pure PPro ((R)- and (S)-2-[(diphenylphosphino)methyl]pyrrolidine) ligands with the Mo3S4Cl4(PPh3)3(H2O)2 complex. Circular dichroism, nuclear magnetic resonance and X-ray techniques confirm that the Cl and Cl cluster cations are diastereoisomers which combine three sources of stereogenicity provided by the cluster framework, one carbon atom of the aminophosphine ligand and the nitrogen stereogenic center. The higher stability of the (+) cation is due to stabilizing vicinal ClHN interactions as well as due to the cis-fused conformation of the bicyclic system formed upon coordination of the aminophosphine ligand.

Coordination Modes of Aminodiphosphane Ligands to the Cuboidal Mo3S4 Cluster Unit

“…Our group has recently reported efficient synthetic strategies for the preparation of diphosphane, aminophosphane and diamino derivatives of the cuboidal Mo3S4 cluster unit starting from the [Mo3S4Cl4(PPh3)3(H2O)2] molecular precursor by simple ligand exchange reactions. [21,24] Motivated by these results, we decided to extend this (1)…”

“…[14,15] In contrast, functionalization with diphosphane, aminophosphane, diamine and diimine ligands takes place with one donor atom trans to the capping sulfur and the other trans to the bridging one resulting in chiral clusters with C3 symmetry, as depicted in Figure 1b. [7,12,13,[16][17][18][19][20][21][22][23][24][25] During the past years, research in our group has been devoted to the chemistry of chiral [Mo3S4X3(LL)3] + clusters derivatized with bidentate ligands containing phosphorous and/or nitrogen donor atoms. Up to date, a large number of complexes differing in the nature of the X ligands such as halide, pseudohalide, hydride, hydroxo, hydrosulphido, or alkoxo have been isolated.…”

“…Up to date, a large number of complexes differing in the nature of the X ligands such as halide, pseudohalide, hydride, hydroxo, hydrosulphido, or alkoxo have been isolated. [7,12,13,[16][17][18][19][20][21][22][23][24] Incidentally, the number of Mo3S4 derivatives bound to outer ligands coordinated in a tridentate fashion is limited to few examples Address correspondence to this author at the Department of Química Física i Analítica, Universitat Jaume I, Avda. Sos Baynat s/n, 12071, Castelló (Spain); Tel/Fax: +34964728086, +34964728066; E-mail: rosa.llusar@uji.es.…”

Molybdenum imidazole citrate and bipyridine homocitrate in different oxidation states – balance between coordinated α-hydroxy and α-alkoxy groups

“…[26][27][28][29][30][31] Molybdenum citrate has also been discovered in nifV nitrogenase and the sensor kinase CitA. 32,33 The incomplete cuboidal clusters Mo 3 S 4 , Mo 3 S 3 O, Mo 3 SO 3 and Mo 3 O 4 can form complexes with various types of ligands as a classic low-valence Mo skeleton structure, [34][35][36][37][38][39][40][41][42][43] which exists in Mo storage protein. 44 The latter also contains octanuclear molybdenum complexes [Mo 8 O 26 (im) 2 ] 4À with imidazole from histidine residue as polyoxometalates.…”

Studies on the Reactivity of the [W3S4Br3(edpp)3]+ [edpp = (2‐aminoethyl)diphenylphosphine] Cluster Cation towards Bases: The Active Role of the Amino Group

“…On the other hand, aminophosphine complexes have emerged as bifunctional catalysts that rely on metal–ligand cooperation . In all cases reported to date, the coordination of this kind of ligand to the cuboidal M 3 S 4 cluster unit invariably occurred with the phosphorus atoms trans to the capping sulfur atom, as depicted in Figure for the (2‐aminoethyl)diphenylphosphine (edpp) derivatives . Thus, the nitrogen atoms of the amino groups and the X ligand are located on the same side of the trimetallic plane in the crystal structures of the [M 3 S 4 X 3 (edpp) 3 ] + (M = Mo, W; X = halide or pseudohalide) cations.…”