SYNTHESIS AND CHARACTERIZATION OF RHODIUM(I) COMPLEXES CONTAINING THEDIHYDROBIS(PYRAZOLYL)BORATE LIGANDS [H2B(PZ')(2)](-) - THE X-RAY STRUCTURES OF BP-ASTERISK-RH(C2H4)(2) AND BPRH(PPH3)(2) (BP = H2B(PZ)(2), BP-ASTERISK = H2B(3,5-ME-2-PZ)(2)

The formation and some substitution chemistry of the bis(ethylene) com plexes Bp'Rh(C2H4)(2) (Bp'=Bp,1*;Bp'=Bp,1) are described. Reaction of 1 with 1 equiv. of N-donor ligands or monodentate phosphines (L) lea ds to the isolation of compounds of general formula BpRh(C2H4)(L). Ad dition of an excess of amine produces the eighteen electron complexes BpRh(C2H4)(L)(2) whereas in the case of thr PR3 ligands the second eq uivalent of the donor gives the disubstituted sixteen electron compoun ds BpRh(L)(2). The ethylene groups in 1* and 1 can also be replaced b y carbon monoxide and tert-butyl isocyanide, affording the complexes B pRh(L)(2)(L=CO, (CNBu)-Bu-t). The solid state structures of the compo unds BpRh(C2H4)(2) (1*) and BpRh(PPh3)(2) (9) have been determined by X-ray diffraction studies. Crystals of 1 are monoclinic, space group P2(1)/c, with a=15.129(3), b=17.501(3), c=13.425(8) Angstrom, beta=11 1.02(4)degrees, V=3318(2) Angstrom(3), and D-calc=1.06 g cm(-3) for Z= 8; R=4.3 and R-w=4.4. Crystals of 9 are triclinic, space group P (1) o ver bar, with a=10.281(2), b=11.637(2), c=17.836(8) Angstrom, alpha=90 .09(2), beta=95.77(2), gamma=108.410(13)degrees; V=2013(2) Angstrom(3) , and D-calc=1.4 g cm(-3) for Z=2; R=0.0302 and wR=0.0787. (C) 1998 El sevier Science S.A. All rights reserved.