Complexes of molybdenum(VI) oxide tetrafluoride and molybdenum(VI) dioxide difluoride with neutral N- and O-donor ligands

Reactions of Molybdenum and Tungsten Oxide Tetrafluoride with Sulfur(IV) Lewis Bases: Structure and Bonding in [WOF4]4, MOF4(OSO), and [SF3][M2O2F9] (M = Mo, W)

“…Similarly, the MoO bond of MoOF 4 (OSO) (1.6465(14) Å) is slightly shorter than those of MoOF 4 {OP­(C 6 H 5 ) 3 } (1.6643(18) Å) and [Xe 2 F 11 ]­[MoOF 5 ] (1.664(3) Å) . In contrast, the M···O contact distances of MOF 4 (OSO) (M = Mo: 2.3988(12), W: 2.381(3) Å) are substantially longer than those in the (C 6 H 5 ) 3 PO adducts (M = Mo: 2.1533(16), W: 2.141(4) Å). This indicates that the M···O contacts in the SO 2 adducts are weak and SO 2 has a minimal trans influence on the MO bonds.…”

“…The WO bond (1.660(4) Å) in WOF 4 (OSO) is shorter than that in WOF 4 {OP­(C 6 H 5 ) 3 } (1.682(5) Å), WOF 4 (NC 5 H 5 ) (1.690(3) Å), and ordered [WOF 5 ] − in [1,10-phen]­[WOF 5 ] (1.698(2) Å) and [Xe 2 F 11 ]­[WOF 5 ] (1.698(3) Å) . Similarly, the MoO bond of MoOF 4 (OSO) (1.6465(14) Å) is slightly shorter than those of MoOF 4 {OP­(C 6 H 5 ) 3 } (1.6643(18) Å) and [Xe 2 F 11 ]­[MoOF 5 ] (1.664(3) Å) . In contrast, the M···O contact distances of MOF 4 (OSO) (M = Mo: 2.3988(12), W: 2.381(3) Å) are substantially longer than those in the (C 6 H 5 ) 3 PO adducts (M = Mo: 2.1533(16), W: 2.141(4) Å).…”

“…The 19 F NMR spectrum of MoOF 4 (OSO) in SO 2 at −60 °C consists of a broad singlet at 154 ppm (Figure S4, Δν 1/2 = 610 Hz), consistent with SO 2 coordination trans to the oxido ligand . The analogous sharp singlet for WOF 4 (OSO) (Figure S5, 74.9 ppm, 1 J WF = 65.4 Hz) is highly comparable to that reported at ambient temperature (73.9 ppm, 1 J WF = 64 Hz) .…”

“…35 The analogous sharp singlet for WOF 4 (OSO) (Figure S5, 74.9 ppm, 1 J WF = 65.4 Hz) is highly comparable to that reported at ambient temperature (73.9 ppm, 1 J WF = 64 Hz). 48 The chemical shifts of the SO 2 adducts are higher in frequency than those of adducts with stronger donor ligands, such as CH 3 CN (M = Mo: 146.5, W: 67.4 ppm) and (C 6 H 5 ) 3 PO (M = Mo: 139.1, W: 60.5 ppm), 20,35 which is attributed to weaker electronic shielding by SO 2 .…”

Lewis Acid Behavior of MoF5 and MoOF4: Syntheses and Characterization of MoF5(NCCH3), MoF5(NC5H5)n, and MoOF4(NC5H5)n (n = 1, 2)

“…In contrast to [MoF 5 ] 4 and [WOF 4 ] 4 , , MoOF 4 consists of distorted octahedra linked via asymmetric cis -fluorido bridges into infinite chains . Several molecular MoOF 4 adducts with monodentate bases, including MoOF 4 (L) [L = OP­(C 6 H 5 ) 3 , OP­(CH 3 ) 3 , O­(CH 2 ) 4 , OS­(CH 3 ) 2 , HCON­(CH 3 ) 2 ], have been synthesized from MoOF 4 (NCCH 3 ), which is conveniently prepared via O/F exchange between MoF 6 and (Me 3 Si) 2 O in CH 3 CN . The presence of singlets with resolved 95 Mo satellites in their 19 F NMR spectra and binomial quintets in their 95 Mo ( I = 5 / 2 , 15.9%) NMR spectra demonstrates that the incoming ligand occupies a coordination site trans to the MoO moiety .…”