61726-36-1Relevant academic research and scientific papers
Bis(phosphino)borates: A new family of monoanionic chelating phosphine ligands
Thomas, J. Christopher,Peters, Jonas C.
, p. 5055 - 5073 (2008/10/08)
The reaction of dimethyldiaryltin reagents Me2SnR2 (R = Ph (1), p-MePh (2), m,m-Me2Ph (3), p-tBuPh (4), p-MeOPh (5), p-CF3Ph (6)) with BCl3 provided a high-yielding, simple preparative route to the corresponding diarylchloroboranes R2BCl (R = Ph (10), p-MePh (11), m,m-Me2Ph (12), p-tBuPh (13), p-MeOPh (14), p-CF3Ph (15)). In some cases, the desired diarylchloroborane was not formed from an appropriate tin reagent Me 2SnR2 (R = o-MeOPh (7), o,o-(MeO)2Ph (8), o-CF3Ph (9)). The reaction of lithiated methyldiaryl- or methyldialkylphosphines with diarylchloroboranes or dialkylchloroboranes is discussed. Specifically, several new monoanionic bis(phosphino)borates are detailed: [Ph2B(CH2PPh2)2] (25); [(p-MePh)2B(CH2PPh2)2] (26); [(p-tBuPh)2B(CH2PPh2)2] (27); [(p-MeOPh)2B-(CH2PPh2)2] (28) ; [(p-CF3Ph)2B(CH2PPh2) 2] (29); [Cy2B(CH2PPh2) 2] (30); [Ph2B(CH2P{p-tBuPh} 2)2] (31);[(p-MeOPh)2B-(CH2P{p- tBuPh}2)2] (32); [Ph2B(CH 2P{p-CF3Ph}2)2] (33); [Ph 2B(CH2P(BH3)(Me)2)2] (34); [Ph2B(CH2P(S)(Me)2)2] (35); [Ph2B(CH2P1Pr2)2] (36); [Ph2B(CH2PtBu2)2] (37); [(m,m-Me2Ph)2B(CH2PtBu 2)2] (38). The chelation of diarylphosphine derivatives 25-33 and 36 to platinum was examined by generation of a series of platinum dimethyl complexes. The electronic effects of substituted bis(phosphino)borates on the carbonyl stretching frequency of neutral platinum alkyl carbonyl complexes were studied by infrared spectroscopy. Substituents remote from the metal center (i.e. on boron) have minimal effect on the electronic nature of the metal center, whereas substitution close to the metal center (on phosphorus) has a greater effect on the electronic nature of the metal center.
Synthesis of biaryls using the coupling reaction of diaryldimethyltins with copper(II) nitrate
Harada, Genta,Yoshida, Masato,Iyoda, Masahiko
, p. 160 - 161 (2007/10/03)
The coupling of diaryldimethyltins with Cu(NO3)2·3H2O in THF proceeds smoothly at room temperature under ambient atmosphere to produce the corresponding biaryls in good to high yields. Diaryldimethyltins can be prepared in high yields by the reaction of aryllithiums with dichlorodimethyltin.
Reduction of Halosilanes by Organotin Hydrides
Wilt, James W.,Belmonte, Frank G.,Zieske, Paul A.
, p. 5665 - 5675 (2007/10/02)
A study of the reduction of halosilanes with organotin hydrides is described.The free radical chain mechanism indicated by the results obtained parallels that known for the comparable reduction of haloalkanes, but the reactivity of α-haloalkanes is considerable enhanced.Mechanistic studies suggest that the polar nature of the halogen abstraction step in the radical chain sequence, which places incremental negative charge adjacent to silicon, is the principal reason for this enhanced reactivity.Structure-reactivity studies indicat the gem-dimethylsilyl function to be an electronic transmitter.The ρ values for reduction of aryldimethyl(chloromethyl)silanes and substituted benzyl chlorides by tri-n-butyltin hydride are essentially identical (+0.45).Reduction of (chloromethyl)trimethylsiulane with aryldimethyltin hydrides, conversely, yielded a ρ value of -1.61.The reduction produced racemic product from an optically active α-chlorosilane, the synthesis of which appears to the first reported.Other syntheses of variuos halosilanes of interest are also described.The title reduction is specific for carbon-halogen bonds.Silicon-halogen bonds are not affected, a distinction that should make the reduction synthetically useful.Because the increased reactivity of α-halosilanes in the reduction has thus been ascribed to a kinetic polar effect in a critical step of the mechanism, no compelling argument for special thermodynamic stability in α-silyl radicals themselves can be made.
Electrochemical generation of stable cations of (arene)tricarbonyichromium complexes. Studies on thenoninteraction of the tricarbonyichromium groups in bis and tris complexes
Rieke, Reuben D.,Tucker, Indu,Milligan, Stuart N.,Wright, Dennis R.,Willeford, Bennett R.,Radonovich, Lewis J.,Eyring
, p. 938 - 950 (2008/10/08)
Complexes of the type (CH3)2Sn[ArCr(CO)3]2 were studied by cyclic voltammetry. The compounds can be made to undergo chemically reversible oxidation upon judicious choice of conditions and modification of Ar. The persistence of the cations seems to be a function of the steric bulk around the phenyl rings. Oxidation involves one electron per tricarbonylchromium group. The tricarbonylchromium moieties are essentially noninteracting and therefore adhere to the Bard-Anson-Saveant model. The same results are found for the bis and tris complexes of methyltriphenyltin where a dication and trication are formed, respectively. The structure of (CH3)2Sn[2,4,6-(CH3)3C 6H2Cr(CO)3]2 was determined from 5287 observed diffractometer data and refined to an R value of 4.4%. The compound crystallizes in space group P2l/c with Z = 4 and lattice constants of a = 15.514 (2) ?, b = 13.026 (2) ?, c = 15.709 (2) ?, and β= 119.51 (1)°. The structure consists of a tin atom that is bonded to two methyl and two mesityl groups in a distorted tetrahedral geometry. Each mesityl group is also bonded to a Cr(CO)3 moiety in a η6 fashion. The average Sn-C(methyl) and Sn-C(mesityl) distances are 2.149 (4) and 2.182 (3) ?, respectively. When the Cr-CO bonds are projected onto the mesityl plane, they eclipse the methyl-substituted ring carbon atoms.
