Hexanuclear methanediolate bridged iron(III) complex

Abstract

The hexanuclear complex [Fe 6 (O) 2 (CH 2 O 2 )(OOCCMe 3 ) 12 (THF) 2 ]•THF was synthesized. The characteristic feature of this complex is the presence of the methanedithiolate bridge.

Carbon Dioxide Reduction by Terminal Tantalum Hydrides: Formation and Isolation of Bridging Methylene Diolate Complexes

“…Pale yellow crystals of 4 suitable for X-ray diffraction studies were grown from Et 2 O at −35 °C. The solid-state structure of 4 revealed geometric parameters consistent with a ‘TaOCH 2 OTa’ core (Figure ); 4 represents a unique example of a structurally characterized complex wherein a methylene diolate unit spans just two metal centers. ,, Despite possessing such an unusual bimetallic tether, complexes 3 r,m and 4 each appear to have appreciable thermal stability, as neither shows signs of decomposition for a period of 48 h at 70 °C (monitored by 1 H NMR, C 6 D 6 ).…”

“…Among processes effecting the hydrogenation of CO 2 , soluble transition-metal hydride complexes as well as heterogeneous systems featuring surface-bound hydrides have emerged as capable catalysts . A fundamental step of reaction sequences in each case is the insertion of a CO bond of CO 2 into a metal−hydride linkage to produce a metalloformate species, i.e., L n MOC(O)H; further reduction to generate the ultimate product from the bound formate may then occur by the action of additional metal hydride equivalents. − Seminal work by Floriani and co-workers exemplified the stepwise reduction of CO 2 to formaldehyde and methanol using Schwartz’s reagent, i.e., [Cp 2 Zr(Cl)H] n , and ensuing studies have served to elucidate CO 2 reduction pathways using metal hydrides. , In particular, spectroscopic evidence for a commonly alleged bridging intermediate within this class of reactions, L n MOCH 2 OML n , has been presented for both solid surfaces and in solution, , yet reports describing the isolation and structural characterization of such methylene diolate complexes have remained limited. , In pursuit of CO 2 reduction chemistry we targeted the preparation of tantalum hydride complexes, encouraged by their remarkable function in the hydrogenation of rather difficult substrates such as arenes, CO, and N 2 . In the present work, we report the reactions of new terminal Ta−H complexes with CO 2 to give bimetallic methylene diolate complexes.…”

Unusual Methylenediolate Bridged Hexanuclear Ruthenium(III) Complexes: Syntheses and Their Application

“…Apart from the usual bridging ligand mentioned above, precedents are known with unusual bridging ligands such as methylene diolate [(CH 2 O 2 ) 2– ], which could template the metal clusters. For example, when an iron­(III) oxo-centered triangle reacts with pyridine or THF, it results in formation of a Fe 6 cluster in which two Fe 3 O units are bridged by methylene diolate and the peripheral coordination sites are decorated by various carboxylates (see the magenta trace in Figure A) . A similar scenario, observed when a [Mn 12 (O) 12 ­(OAc) 16 ­(H 2 O) 4 ] cluster is recrystallized in CH 2 Cl 2 /nitromethane solvents, leads to a Mn 6 cluster which is structurally similar to the Fe 6 cluster bridged by a methylene diolate ligand .…”

Slow Relaxation of the Magnetization on Frustrated Triangular FeIII Units with S = 1/2 Ground State: The Effect of the Highly Ordered Crystal Lattice and the Counteranions

“…The distance between the M III atoms of neighboring [MCl 4 ] − units along the chain is 9.9936(8), 9.8612(14), and 10.1876(14) Å for 1-GaCl 4 , 1-FeCl 4 , and 1-FeBr 4 , respectively. It is important to note that very few M 3 O clusters with [MX 4 ] − anions have been reported. − …”