Structure of tris(acetonitrile)tricarbonyltungsten

Abstract

W(CO)a(NCCH3)3], Mr=391.02, orthorhombic, Pnma, a=9.019 (3), b= 10.6204(17), c =12.3625 (16) A, V=l184.18A 3, Z=4, Dx= 2.193 g cm -3, 2(Mo Ka) = 0.71069 A, g = 99.61 cm -~, F(000)=728, room temperature, final R--0.0207 for 959 independent observed reflections. The structure is octahedral (fac) with effective Car and space-group-imposed C s symmetry. There are no unusual bond distances or angles.

Synthesis, electrochemistry, and crystal and molecular structures of some molybdenum(0) arene derivatives with fluorinated and phenyl-substituted arene ligands

“…The C-C and C-F bond distances of the arene ligand are comparable to those observed in Cr(g 6 -C 6 H 5 F)(CO) 2 (SiCl 3 ) 2 [C-C, mean value, 1.388 and C-F bond distance, 1.334 (9) A] within the 1:1 co-crystallite Cr(g 6 -C 6 H 5 F)(CO) 2 (SiCl 3 ) 2 Á Cr(g 6 -C 6 H 5 F)(CO)(H) 2 -(SiCl 3 ) 2 [33], and in Cr(g 6 -C 6 H 5 F)(CO) 2 (SnPh 3 ) 2 [C-C mean value, 1.402 A and C-F bond distance, 1.32 (2) A] [34].…”

“…However, we have found that Mo(CO) 6 in melting diphenyl (70°C) forms a metallic mirror. Alternative procedures consisting of treating a THF/Bu 2 O mixture as reaction medium with the Mo(CO) 6 /arene system or with the Lewis base adducts fac-Mo(CO) 3 (CH 3 CN) 3 [7][8][9][10][11][12][13] or fac-Mo(CO) 3 (DMF) 3 were equally unsuccessful, due to extensive formation of a metallic mirror.…”

Syntheses and Structures of Methyltris(pyrazolyl)silane Complexes of the Group 6 Metals

“…The average Mo−N bond distance (2.311 Å) in (Tps Me 2 )Mo(CO) 3 is only marginally longer (ca. 0.04 Å) than the corresponding values found in the few known molybdenum tris(pyrazolyl)borate tricarbonyl complexes. − While there are no structurally characterized Tp analogues of (Tps Me 2 )M(CO) 3 (M = Cr, W), the M−N bond lengths in all three species are comparable to the corresponding values reported for other neutral zerovalent tricarbonyl complexes L 3 M(CO) 3 (L = nitrogen donor ligand) of chromium (2.17−2.21 Å), , molybdenum (2.24−2.41 Å), − and tungsten (2.20−2.33 Å). ,, In addition, assuming a covalent radius of 0.70 Å for nitrogen 69 and by adoption of the covalent radii for octahedral Cr(0) and Mo(0) estimated by Cotton, the calculated Cr−N and Mo−N single bond lengths are 2.18 and 2.32 Å, values that are virtually identical to those observed for (Tps Me 2 )M(CO) 3 (M = Cr, Mo). Encouraged by these results but acknowledging that the covalent radius of tungsten is particularly ill-defined, we can similarly derive a value of 1.59 Å for the covalent radius of W(0) in an octahedral environment on the basis of the average W−N distance (2.29 Å) found in (Tps Me 2 )W(CO) 3 .…”

Experimental and Computational Studies of Binding of Dinitrogen, Nitriles, Azides, Diazoalkanes, Pyridine, and Pyrazines to M(PR3)2(CO)3 (M = Mo, W; R = Me, iPr).

“…The M-N bond distances for the complexes with nitrile adducts are consistent with literature values: 2.190(5) A ˚in fac-W(dppm)(CO) 3 (CH 3 CN), 37 2.227(12) and 2.204(12) A ˚for two separate forms of W(CO) 5 -(AdCN), 42 and 2.21 A ˚in W(CO) 3 (CH 3 CN) 3 . 43 The most remarkable feature of W(P i Pr 3 ) 2 (CO) 3 -(Me 2 NCN) is that the amide N exhibits trigonal planar geometry. This behavior has been previously reported for other complexes such as Cr(CO) 5 (NCNEt 2 ), 44 trans-[Fe- 45 and trans-Mo-(Ph 2 PCH 2 CH 2 PPh 2 ) 2 (NCNEt 2 )(N 2 ).…”