화학공학소재연구정보센터
Inorganic Chemistry, Vol.33, No.17, 3666-3676, 1994
Homoscorpionate (Tris(Pyrazolyl)Borate) Ligands Containing Tethered 3-Phenyl Groups
Four new homoscorpionate ligands have been prepared, three of them involving a 3-phenyl substituent subject to steric control via tethering to the the 4-position of the pyrazole ring, The tethering prevents major departure from parallel alignment of the phenyl and pyrazolyl rings. In addition, the choice of the tether (methylene or 1,2-ethylene) results in the phenyl 6’-CH being either pulled away from the metal in the former case or thrust toward the metal in the latter. The effect of the 5-methyl substituent on the bite of the ligand was also explored. The new ligands were hydrotris(2H-benz[g]-4,5-dihydroindazol-2-yl)borate (= Tp(a)), hydrotris(3-methyl-2H-benz[g]-4,5-dihydroin-dazol-2-yl)borate (= Tp(a,Me)), hydrotris(1,4-dihydroindeno[1,2-c]pyrazol-1-yl)borate (=Tp(b)), and hydrotris(3-phenyl--5-methylpyrazol-1-yl)borate (= Tp(Ph,Me)), each of which differed subtly in its coordinative behavior from the other three. Complexes of the type L2M, LMX, LRh(COD), LRh(CO)2, LPd(eta3-methallyl), and LMO(CO)2(eta3-methallyl) were synthesized, and the structures of Tp(a)Rh(CO)2, Tp(a,Me)ZnI, Tp(b)Tl, and Tp(Ph,Me)ZnI were determined by X-ray crystallography. TPaRh(CO)2 crystallizes in the space group P1BAR, with a = 8.574(2) angstrom, b = 20.113(6) angstrom, c = 20.188(6) angstrom, alpha = 61.68(2)-degrees, beta = 84.14(2)-degrees, gamma = 85.15(2)-degrees, and V = 3046.0(15) angstrom3 for Z = 4. Tp(a,Me)ZnI crystallizes in the space group P2(1)2(1)2(1), with a = 10.002(1) angstrom, b = 16.237(3) angstrom, c = 19.952(3) angstrom, and V = 3240.3(8) angstrom3 for Z = 4. Tp(b)Tl crystallizes in the space group P2(1)/n, with a = 11.363(2) angstrom, b = 11.09692) angstrom, c = 21.010(4) angstrom, beta = 99.33(2)-degrees, and V = 2614.0(9) angstrom3 for Z = 4. The phenyl and pyrazolyl planes are essentially coplanar. Tp(Ph,Me)ZnI crystallizes in the spacegroup Pna2(1), with a = 32.645(6) angstrom, b = 11.327(3) angstrom, c = 16.180(3) angstrom, and V = 5983.1(22) angstrom3 for Z = 8. Cone and wedge angles were calculated for the new ligands and compared with revised previously reported values.