TY - JOUR
T1 - Synthesis and structure of ferrocenylmethylphosphines, their borane adducts, and some related derivatives
AU - Pet, Mitchell A.
AU - Cain, Matthew F.
AU - Hughes, Russell P.
AU - Glueck, David S.
AU - Golen, James A.
AU - Rheingold, Arnold L.
N1 - Funding Information:
D.S.G. thanks the National Science Foundation for support, Dartmouth College for a Presidential Scholarship and Zabriskie Fellowship for M.A.P., and Cytec Canada for a gift of [P(CH 2 OH) 4 ][Cl]. We thank Professors William Henderson (University of Waikato) for helpful discussions and a generous gift of phosphine 1 and Evamarie Hey-Hawkins (University of Leipzig) for sharing results before publication, and Dr. Ilia Guzei (University of Wisconsin) for solid angle calculations. R.P.H. thanks the National Science Foundation for support, and Professor Clark Landis (University of Wisconsin) for valuable discussions.
PY - 2009/6/15
Y1 - 2009/6/15
N2 - Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1) and over-alkylated (FcCH2)2P(CH2OH) (9). Treatment of pure 9 with Na2S2O5 gave the secondary phosphine 3; slow addition of Na2S2O5 to 1 gave 2 in improved yield. Reaction of 1 with [FcCH2NMe3][I], followed by treatment with NEt3, gave the tertiary phosphine (FcCH2)3P (4), along with the known phosphonium salt [(FcCH2)4P][I] (5), which could be prepared in higher yield by adjusting the stoichiometry. Phosphine 4 oxidized slowly in air to yield (FcCH2)3P(O) (12), was protonated by HBF4(OMe2) to give [(FcCH2)3PH][BF4] (13), and reacted with Pt(COD)Cl2 or PtCl2 to yield a mixture of cis- and trans-Pt(P(CH2Fc)3)2Cl2 (14). Silylation of 2 with n-BuLi/Me3SiCl gave FcCH2P(SiMe3)2 (10); treatment of 1 with Me3SiCl/Et3N gave FcCH2P(CH2OSiMe3)2 (11). The phosphine-borane adducts FcCH2PH2(BH3) (6), (FcCH2)2PH(BH3) (7), (FcCH2)3P(BH3) (8) and (FcCH2)P(CH2OSiMe3)2(BH3) (15) were prepared from the corresponding phosphines and BH3(SMe2). The phosphines 2, 3, and 4, phosphonium salts 5 and 13, phosphine oxide 12, Pt complex trans-14, and phosphine-boranes 6, 7 and 8 were structurally characterized by X-ray crystallography. The solid cone angle of (FcCH2)3P, 139°, in Pt complex 14 showed that 4 was bulkier than PPh3, but less sterically demanding than P(t-Bu)3. The structural changes observed on quaternization of P (shorter P-C bonds and larger angles at P), along with results from NMR and IR spectroscopy and DFT calculations, were consistent with the expected rehybridization at phosphorus. Related observations for analogous methylphosphines suggest that methyl and ferrocenylmethyl phosphorus substituents have similar properties.
AB - Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc = (η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1) and over-alkylated (FcCH2)2P(CH2OH) (9). Treatment of pure 9 with Na2S2O5 gave the secondary phosphine 3; slow addition of Na2S2O5 to 1 gave 2 in improved yield. Reaction of 1 with [FcCH2NMe3][I], followed by treatment with NEt3, gave the tertiary phosphine (FcCH2)3P (4), along with the known phosphonium salt [(FcCH2)4P][I] (5), which could be prepared in higher yield by adjusting the stoichiometry. Phosphine 4 oxidized slowly in air to yield (FcCH2)3P(O) (12), was protonated by HBF4(OMe2) to give [(FcCH2)3PH][BF4] (13), and reacted with Pt(COD)Cl2 or PtCl2 to yield a mixture of cis- and trans-Pt(P(CH2Fc)3)2Cl2 (14). Silylation of 2 with n-BuLi/Me3SiCl gave FcCH2P(SiMe3)2 (10); treatment of 1 with Me3SiCl/Et3N gave FcCH2P(CH2OSiMe3)2 (11). The phosphine-borane adducts FcCH2PH2(BH3) (6), (FcCH2)2PH(BH3) (7), (FcCH2)3P(BH3) (8) and (FcCH2)P(CH2OSiMe3)2(BH3) (15) were prepared from the corresponding phosphines and BH3(SMe2). The phosphines 2, 3, and 4, phosphonium salts 5 and 13, phosphine oxide 12, Pt complex trans-14, and phosphine-boranes 6, 7 and 8 were structurally characterized by X-ray crystallography. The solid cone angle of (FcCH2)3P, 139°, in Pt complex 14 showed that 4 was bulkier than PPh3, but less sterically demanding than P(t-Bu)3. The structural changes observed on quaternization of P (shorter P-C bonds and larger angles at P), along with results from NMR and IR spectroscopy and DFT calculations, were consistent with the expected rehybridization at phosphorus. Related observations for analogous methylphosphines suggest that methyl and ferrocenylmethyl phosphorus substituents have similar properties.
KW - Ferrocenyl
KW - Phosphine
UR - http://www.scopus.com/inward/record.url?scp=65649146095&partnerID=8YFLogxK
U2 - 10.1016/j.jorganchem.2009.03.015
DO - 10.1016/j.jorganchem.2009.03.015
M3 - Article
AN - SCOPUS:65649146095
SN - 0022-328X
VL - 694
SP - 2279
EP - 2289
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 14
ER -