14405-84-6Relevant academic research and scientific papers
MONONUCLEAR ANIONIC FORMYL COMPLEXES; SYNTHESIS AND PROPERTIES
Selover, J.C.,Marsi, Marianne,Parker, David W.,Gladysz, J.A.
, p. 317 - 329 (1981)
A series of kinetically unstable mononuclear anionic formyl complexes have been prepared by the action of Li(C2H5)3BH on neutral metal carbonyl precursors.One of these, Li+-, is shown to decompose by a hydride transfer disproportionation mechanism involving the by-product (C2H5)3B.
Solid-state nuclear magnetic resonance studies of triphenylsilyl-, triphenyltin-, and triphenyllead(pentacarbonyl)manganese(I) complexes
Christendat, Dharamdat,Butler, Ian S.,Gilson, Denis F.R.,Morin, Frederick G.
, p. 1892 - 1898 (1999)
The solid-state CP MAS (29Si, 119Sn, and 207Pb) NMR spectra of the triphenylsilyl-, triphenyltin-, and triphenyllead(pentacarbonyl)manganese(I) complexes, (Ph3E)Mn(CO)5 (E = Si, Sn, Pb), have been analyzed to give the chemical shifts, one-bond spin-spin coupling constants, 1JE-Mn, the effective-dipolar coupling constants (D - ΔJ/3), the chemical shift tensors, and the spin-spin anisotropy (ΔJ), where the analysis permits. For the tin and lead compounds, three and four sets of chemical shifts, respectively, were observed, and two different polymorphs occur for the lead complex, depending on the solvent used for recrystallization. The average values of the reduced coupling constants, 1KMn-si (2.64 × 1020 T2 J-1), 1KSn-Mn (1.25 × 1020 T2 J1), and 1KPb-Mn (4.18 × 1020 T2 J-1) showed a linear correlation with the s-electron densities at the respective metal nuclei. The principal components of the chemical shift tensors have been determined for the tin and lead compounds.
Ultrahigh-field NMR spectroscopy of quadrupolar transition metals: 55Mn NMR of several solid manganese carbonyls
Ooms, Kristopher J.,Feindel, Kirk W.,Terskikh, Victor V.,Wasylishen, Roderick E.
, p. 8492 - 8499 (2008/10/09)
55Mn NMR spectra acquired at 21.14 T (νL( 55Mn) = 223.1 MHz) are presented and demonstrate the advantages of using ultrahigh magnetic fields for characterizing the chemical shift tensors of several manganese carbonyls: η5-CpMn(CO)3, Mn 2(CO)10, and (CO)5MnMPh3 (M = Ge, Sn, Pb). For the compounds investigated, the anisotropies of the manganese, chemical shift tensors are less than 250 ppm except for η5- CpMn(CO)3, which has an anisotropy of 920 ppm. At 21.14 T, one can excite the entire ml = 1/2 ? ml = -1/2 central transition of η5-CpMn(CO)3, which has a breadth of approximately 700 kHz. The breadth arises from second-order quadrupolar broadening due to the 55Mn quadrupolar coupling constant of 64.3 MHz, as well as the anisotropic shielding. Subtle variations in the electric field gradient tensors at the manganese are observed for crystallographically unique sites in two of the solid pentacarbonyls, resulting in measurably different CQ values. MQMAS experiments are able to distinguish four magnetically unique Mn sites in (CO)5MnPbPh3, each with slightly different values of δiso, CQ, and ηQ.
Bimetallic anionic formyl complexes: Synthesis and properties
Tam, Wilson,Marsi, Marianne,Gladysz
, p. 1413 - 1421 (2008/10/08)
Three bimetallic anionic formyl complexes, Li+[Mn2(CO)9(CHO)]- (2), Li+[ReMn(CO)9(CHO)]- (3), and Li+[cis-Re2(CO)9(CHO)]- (4), are prepared by the reaction of Li(C2H5)3BH with the corresponding neutral metal carbonyl dimers MM′(CO)10. Whereas 2 has a half-life of ca. 8 min at room temperature, 4 is stable for days and is easily isolated as a THF solvate. When 2-4 are treated with electrophiles such as benzaldehyde, Fe(CO)5, and n-octyl iodide, hydride transfer occurs to give benzyl alcohol (after protonation), Li+[Fe(CO)4(CHO)]-, and octane, respectively. Heterobimetallic formyl 3 is a weaker hydride donor than 2 and 4. Reaction of 4 with CH3I gives CH4 (ca. 50%). However, complex reactions occur when 2 and 4 are treated with CH3SO3F and strong acids, contrary to our original report of CH4 and H2 evolution. Formyl 2 is stabilized by added (C2H5)3B and decomposes disproportionatively to Mn2(CO)10 (0.5 equiv), Li+[Mn(CO)5]- (1.0 equiv), and H2 (0.5 equiv). An initial Mn-Mn bond cleavage step is proposed. The only characterizable product from the thermolysis of 4 is Re2(CO)10, but photolysis gives Li+[Re2(CO)9(H)]-. When K+[Re2(CO)9(CHO)]- is treated with 1 equiv of K(sec-C4H9)3BH, reduction to formaldehyde (21%) and K2[Re2(CO)9] (92%) occurs.
REDUCTIONS OF METAL CARBONYLS BY QUATERNARY AMMONIUM BOROHYDRIDES
Gibson, Dorothy H.,Ahmed, Fahim U.,Phillips, Kenneth R.
, p. 325 - 336 (2007/10/02)
Quaternary ammonium borohydrides, used directly or generated in phase transfer reactions, are highly effective reagents for preparing metal carbonyl anions from metal carbonyls 5-C5H5)2Mo2(CO)6> and from some metal carbonyl halides 5-C5H5Mo(CO)3Cl>.Where strongly basic anions would be fromed from a halide 5-C5H5Ru(CO)2Br>, the reactions provide efficient syntheses of the corresponding hydrides instead.The anion η5-C5H5Fe(CO)2- is not accessible bythese techniques; reaction of η5-C5H5Fe(CO)2Br yields the iron dimer (via the highly nucleophilic anion) and the dimer is unreactive toward Q+BH4-.Reductions of Re2(CO)10 conducted in CH2Cl2 provide Re2(CO)9Cl- in high yield.
PHASE TRANSFER CATALYZED REDUCTIONS OF METAL CARBONYLS
Gibson, Dorothy H.,Ahmed, Fahim U.,Phillips, Kenneth R.
, p. C17 - C20 (2007/10/02)
Reduction of metal carbonyl halides and some metal carbonyls by quaternary ammonium borohydrides in phase transfer catalyzed reactions are described.The method provides an efficient synthetic route to metal carbonyl anions from BrMn(CO)5, C5H5Mo(CO)3Cl, F
Mechanism of Reductive Elimination of Acetophenone from N(CH3)4+-
Casey, Charles P.,Scheck, Daniel M.
, p. 2728 - 2731 (2007/10/02)
Decomposition of N(CH3)4+- (1) in the presence og P(C6H5)3 gives N(CH3)4+Mn(CO)4- and provides evidence for a Mn(CO)4- intermediate.Decomposition of 90percent 13C-acetyl labeled N(CH3)4+- (1A) gave 42.7percent 13C-labeled acetophenone.Decomposition of 90percent 13C-benzoyl labeled N(CH3)4+- (1b) gave 6.0percent 13C-labeled acetophenone.These results are interpreted in terms of a mechanism involving loss of CO from 1 and formation of a five-coordinate intermediate Mn(CO)3(COCH3)(COC6H5)- (2), which is in rapid equilibrium with benzoylmethyl intermediate Mn(CO)4(CH3)(COC6H5)- (3).Conversion of 3 to the acetylphenyl intermediate Mn(CO)4(C6H5)(COCH3)- (4) is followed by reductive elimination to give acetophenone.
