SYNTHESIS AND CHEMISTRY OF DIBORYLPHOSPHANES

Syntheses for (i-Pr2N)2BP(SiMe3)2 and (i-Pr2N)2BPH2 from (i-Pr2N)2BCl and LiP(SiMe3)2 or LiPH2 and for {[Li.DME][(i-Pr2N)2BP(H)]}2 from (i-Pr2N)2BPH2 and BuLi are described. The species {[Li.DME][(i-Pr2N)2BP(H)]}2 is a useful synthon for diborylphosphines, and preparations of [(i-Pr2N)2B]2PH, Ph2NB[P(H)B(i-Pr2N)2]2, and [(i-Pr2N)2B][(R2N)(Cl)B]PH (R2N = i-Pr2N, tmp, [Me3Si]2N) are presented. Metal carbonyl coordination chemistry and selected substitution chemistry of these reagents are also described. The molecular structures of {[Li.DME][(i-Pr2N)2BP(H)]}2 (3), [(i-Pr2N)2B][tmpB(Cl)]PH (7), [(i-Pr2N)2B][tmpB(Cl)]PH.Cr(CO)5 (13), and [(i-Pr2N)2B]2PH.Cr(CO)5 (12) have been determined by single-crystal X-ray diffraction analyses: 3 (C16H39BLiN2O2P) crystallizes in the monoclinic space group P2(1)/n with a = 9.458 (2) angstrom, b = 22.054 (3) angstrom, c = 11.574 (2) angstrom, beta = 111.86 (1)-degrees, and Z = 4; 7 (C21H47B2N3PCl) crystallizes in the monoclinic space group P2(1)/n with a = 16.661 (3) angstrom, b = 9.218 (2) angstrom, c = 18.068 (4) angstrom, beta = 103.88 (3) angstrom, and Z = 4; 13 (C26H47B2N3O5PClCr) crystallizes in the triclinic space group P1BAR with a = 10.395 (2) angstrom, b = 10.923 (2) angstrom, c = 15.800 (3) angstrom, alpha = 103.51 (2)-degrees, beta = 83.92 (2)-degrees, gamma = 104.45 (2)-degrees, and Z = 2; 12 (C29H57B2N4O5PCr) crystallizes in the monoclinic space group P2(1)/n with a = 10.534 (2) angstrom, b = 19.991 (4) angstrom, c = 18.005 (4) angstrom, beta = 95.16 (3)-degrees, and Z = 4.