TY - JOUR
T1 - Synthesis and Structural Characterization of Low-Valent Group V Phosphine Complexes
AU - Protasiewicz, John D.
AU - Bianconi, Patricia A.
AU - Williams, Ian D.
AU - Liu, Shuncheng
AU - Rao, C. Pulla
AU - Lippard, Stephen J.
PY - 1992
Y1 - 1992
N2 - The compounds [Nb(CO)2(dmpe)2Cl] and [Ta(CO)2(dmpe)2Cl], where dmpe = 1, 2-bis(dimethylphosphino)ethane, are important precursors in chemistry leading to the reductive coupling of carbon monoxide ligands to form bis(trialkylsiloxy)acetylenes. Convenient, high-yield syntheses of these seven-coordinate niobium(I) and tantalum-(I) complexes have been devised by utilizing catalytic Mg(anthracene) to reduce either [NbCl4(dmpe)2] or [TaCl4-(dmpe)2] under an atmosphere of CO. With the use of Mg(anthracene)•3THF in the absence of CO, the complexes [TaCl2(dmpe)2] (1) and [Ta(η4-anthracene)(dmpe)2Cl] (2) were obtained, both of which have been structurally characterized by X-ray crystallography. The preparation of [V(CO)2(dmpe)2Me] and the crystal structure determinations of several related seven-coordinate [M(CO)2(dmpe)2X] complexes (M = V, X = Me (8); M = Nb, X = Cl (4), I (5); M = Ta, X = Me (7)) and [Ta(CO)2(depe)2Cl] (6), depe = 1, 2-bis(diethylphosphino)ethane, having the capped trigonal prismatic geometry, are also described. These complexes all have acute OC-M-CO angles, low vqo stretching frequencies, and close nonbonded C-C contacts, features which indicate their propensity to undergo reductive coupling reactions. The alkyl complexes [V(CO)2(dmpe)2Me] and [Ta(CO)2(dmpe)2Me] display abnormally long M-C σ bond lengths, 2.31 (1) and 2.32 (1) Å, respectively. Crystal data: (1) monoclinic, P21/n, a = 9.384 (1) Å, b = 12.863 (2) Å, c = 9.363 (1) Å, β = 95.04 (1)°, Z = 2, R = 0.030, Rw = 0.039; (2) triclinic, P1, a = 12.997 (6) Å, b = 13.495 (3) Å, c = 18.860 (4) Å, a = 75.38 (2)°, β = 84.75 (5)°, γ = 89.50 (5)°, Z = 4, R = 0.043, Rw = 0.063; (4) orthorhombic, Pna21 a = 16.106 (3) Å, b = 8.333 (1) Å, c = 33.881 (5) Å, Z = 8, R = 0.045, Rw = 0.060; (5) orthorhombic, Pnma, a = 16.571 (2) Å, b = 16.632 (2) Å, c = 8.439 (1) Å, Z = 4, R = 0.038, b = 0.046; (6) triclinic, FI, a = 11.245 (1) Å, b = 13.325 (2) Å, c = 10.881 (2) Å, α = 99.58 (1)°, β = 112.44 (1)°, γ = 70.24 (1)°, Z = 2, R = 0.018, Rw = 0.023; (7) orthorhombic, Fdd2, a = 10.615 (1) Å, b = 33.123 (7) Å, c = 12.766 (2) Å, Z = 8, R = 0.029, Fw = 0.037; (8) orthorhombic, F212121, a = 13.509 (3) Å, b = 13.777 (2) Å, c = 11.719 (2) Å, Z = 4, R = 0.050, Rw = 0.055.
AB - The compounds [Nb(CO)2(dmpe)2Cl] and [Ta(CO)2(dmpe)2Cl], where dmpe = 1, 2-bis(dimethylphosphino)ethane, are important precursors in chemistry leading to the reductive coupling of carbon monoxide ligands to form bis(trialkylsiloxy)acetylenes. Convenient, high-yield syntheses of these seven-coordinate niobium(I) and tantalum-(I) complexes have been devised by utilizing catalytic Mg(anthracene) to reduce either [NbCl4(dmpe)2] or [TaCl4-(dmpe)2] under an atmosphere of CO. With the use of Mg(anthracene)•3THF in the absence of CO, the complexes [TaCl2(dmpe)2] (1) and [Ta(η4-anthracene)(dmpe)2Cl] (2) were obtained, both of which have been structurally characterized by X-ray crystallography. The preparation of [V(CO)2(dmpe)2Me] and the crystal structure determinations of several related seven-coordinate [M(CO)2(dmpe)2X] complexes (M = V, X = Me (8); M = Nb, X = Cl (4), I (5); M = Ta, X = Me (7)) and [Ta(CO)2(depe)2Cl] (6), depe = 1, 2-bis(diethylphosphino)ethane, having the capped trigonal prismatic geometry, are also described. These complexes all have acute OC-M-CO angles, low vqo stretching frequencies, and close nonbonded C-C contacts, features which indicate their propensity to undergo reductive coupling reactions. The alkyl complexes [V(CO)2(dmpe)2Me] and [Ta(CO)2(dmpe)2Me] display abnormally long M-C σ bond lengths, 2.31 (1) and 2.32 (1) Å, respectively. Crystal data: (1) monoclinic, P21/n, a = 9.384 (1) Å, b = 12.863 (2) Å, c = 9.363 (1) Å, β = 95.04 (1)°, Z = 2, R = 0.030, Rw = 0.039; (2) triclinic, P1, a = 12.997 (6) Å, b = 13.495 (3) Å, c = 18.860 (4) Å, a = 75.38 (2)°, β = 84.75 (5)°, γ = 89.50 (5)°, Z = 4, R = 0.043, Rw = 0.063; (4) orthorhombic, Pna21 a = 16.106 (3) Å, b = 8.333 (1) Å, c = 33.881 (5) Å, Z = 8, R = 0.045, Rw = 0.060; (5) orthorhombic, Pnma, a = 16.571 (2) Å, b = 16.632 (2) Å, c = 8.439 (1) Å, Z = 4, R = 0.038, b = 0.046; (6) triclinic, FI, a = 11.245 (1) Å, b = 13.325 (2) Å, c = 10.881 (2) Å, α = 99.58 (1)°, β = 112.44 (1)°, γ = 70.24 (1)°, Z = 2, R = 0.018, Rw = 0.023; (7) orthorhombic, Fdd2, a = 10.615 (1) Å, b = 33.123 (7) Å, c = 12.766 (2) Å, Z = 8, R = 0.029, Fw = 0.037; (8) orthorhombic, F212121, a = 13.509 (3) Å, b = 13.777 (2) Å, c = 11.719 (2) Å, Z = 4, R = 0.050, Rw = 0.055.
UR - https://www.webofscience.com/wos/woscc/full-record/WOS:A1992JQ64100027
UR - https://openalex.org/W2084921912
UR - https://www.scopus.com/pages/publications/0001052785
U2 - 10.1021/ic00046a027
DO - 10.1021/ic00046a027
M3 - Journal Article
SN - 0020-1669
VL - 31
SP - 4134
EP - 4142
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 20
ER -