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Jason A. C. Clyburne

Publications and source records attributed to Jason A. C. Clyburne.

4 recordsLinked to original sources
PubMed1997

Bonding of Phosphinidene or Arsenidene Fragments to a Fluorenylidene. Interrelationships between Phosphaalkenes or Arsaalkenes and Donor-Acceptor Complexes.

The fluorenylidene-substituted phosphaalkene MesP=Fl (13) and arsaalkene MesAs=Fl (14) (Mes = 2,4,6-t-Bu(3)C(6)H(2), Fl = 2,7-di-tert-butylfluorenylidene) have been prepared by treatment of Fl(H)Li with MesECl(2) (E = P, As) followed by dehydrochlorination with DABCO (1,4-diazabicyclo[2.2.2]octane). In the synthesis of 13 it was possible to isolate the intermediate, Mes(Cl)P-(H)Fl (11). Attempts to prepare the stibaalkene, MesSb=Fl (15), resulted in an unstable product. Compounds 11, 13, and 14 were characterized by X-ray crystallography: 11, triclinic, P&onemacr;, a = 11.548(2) Å, b = 12.189(3) Å, c = 14.223(3) Å, alpha = 114.13(1) degrees, beta = 92.79(1) degrees, gamma = 107.14(1) degrees, V = 1712.8(2) Å(3), Z = 2, wR2 = 0.1344, R1 = 0.0560; 13, monoclinic, P2(1)/n, a = 24.597(7) Å, b = 11.185(2) Å, c = 26.914(7) Å, beta = 112.16(2) degrees, V = 6857(3) Å(3), Z = 8, wR2()()= 0.1477, R1 = 0.0794; 14.Et(2)O, monoclinic, P2(1)/n, a = 15.577(4) Å, b = 15.274(4) Å, c = 17.255(5) Å, beta = 108.17(2) degrees, V= 3901(2) Å(3), Z = 4, wR2()()= 0.1275, R1 = 0.0578. The P=C (1.686(5) Å) and As=C (1.807(3) Å) bond distances in 13 and 14 are consistent with double-bonding descriptions; moreover, there is a zero angle of twist between the E-C(Mes) moieties and the plane of the Fl() ligand in both molecules.

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PubMed1996

Ring Systems Containing Anionic and Cationic Gallium Centers: Structural and Bonding Considerations.

The metathetical reaction of 2-(dimethylamino)benzyllithium (Bz(N)Li) with GaCl(3) afforded the salt [Bz(N)(2)Ga][GaCl(4)] (4), the X-ray crystal structure of which revealed a four-coordinate cationic gallium center featuring two Ga-C sigma-bonds and two N-->Ga dative bonds. (Crystal data for 4: monoclinic, space group P2(1)/n, a = 11.519(2) Å, b = 18.254(4) Å, c = 12.506(3) Å, beta = 117.40(3) degrees, V = 2334.6(9) Å(3), Z = 4, R = 0.545). Two Ga.Cl interionic contacts, while somewhat long, are sufficiently strong to render the geometry of 4(+)() roughly midway between tetrahedral and octahedral. Treatment of 1,4-di-tert-butyl-1,4-diazabutadiene (DAB) with 2 equiv of GaCl(3) afforded [(DAB)GaCl(2)][GaCl(4)] (7), which, by means of X-ray analysis, was shown to possess a cation (7(+)()) with localized C=N bonds and N-->Ga dative interactions with a [GaCl(2)](+) moiety. (Crystal data for 7: orthorhombic, space group Pbca, a = 11.882(2) Å, b = 17.289(3) Å, c = 20.424(4) Å, V = 4195.5(11) Å(3), Z = 8, R = 0.460). The structure of 7(+)() is relevant to discussions of the bonding in both neutral DAB complexes of the group 13 elements and the skeletally isoelectronic anion [Me(4)C(4)GaCl(2)](-) (9(-)()). The structure of the [NEt(4)](+) salt of the latter (9) has been determined by X-ray diffraction. (Crystal data for 9: monoclinic, space group P2(1)/n, a = 9.967(1) Å, b = 13.073(2) Å, c = 15.345(2) Å, beta = 96.76(1) degrees, V = 1985.5(4) Å(3), Z = 4, R = 0.721).

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PubMed1996

Nucleophilic Addition of CH, NH, and OH Bonds to the Phosphadiazonium Cation and Interpretation of (31)P Chemical Shifts at Dicoordinate Phosphorus Centers.

The phosphadiazonium cation [MesNP](+) reacts quantitatively with the fluorenylide anion, MesNH(2), and MesOH (Mes = 2,4,6-tri-tert-butylphenyl), resulting in formal insertion of the N-P moiety into the H-Y (Y = C, N, O) bonds. Specifically, reaction of MesNPCl with fluorenyllithium gives the aminofluorenylidenephosphine [crystal data: C(31)H(38)NP, monoclinic, P2(1)/c, a = 9.568(8) Å, b = 24.25(2) Å, c = 11.77(1) Å, beta = 101.38(8) degrees, Z = 4]. Similarly, reaction of [MesNP][GaCl(4)] with MesNH(2) gives the diaminophosphenium salt [MesN(H)PN(H)Mes][GaCl(4)] [crystal data: C(36)H(60)Cl(4)GaN(2)P, monoclinic, C2/c, a = 24.921(2) Å, b = 10.198(4) Å, c = 16.445(2) Å, beta = 93.32(1) degrees, Z = 4], and reaction with MesOH gives the first example of an aminooxyphosphenium salt [MesN(H)POMes][GaCl(4)]. It is proposed that the reactions involve nucleophilic attack at phosphorus followed by a 1,3-hydrogen migration from Y to N. Experimental evidence for the formation of sigma-complex intermediates is provided by the isolation of [MesNP-PPh(3)][SO(3)CF(3)] [crystal data: C(37)H(44)F(3)NO(3)P(2)S, triclinic, P&onemacr;, a = 10.663(1) Å, b = 19.439(1) Å, c = 10.502(1) Å, alpha = 103.100(7) degrees, beta = 113.311(7) degrees, gamma = 93.401(7) degrees, Z = 2]. As part of the unequivocal characterization of the aminooxyphosphenium salt, detailed solid-state (31)P NMR studies and GIAO calculations on the phosphenium cations have been performed. Contrary to popular belief, the phosphorus shielding in dicoordinate cations is not caused by the positive charge but results from efficient mixing between the phosphorus lone pair and pi orbitals.

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