Bowl-shaped molybdenum complexes containing tris(3-p -methoxyphenylpyrazol-1-yl)borate (Tp(An)). Crystal structures of [Mo(Tp(An))(NO)(Cl)(NHC6H4-p-CH3)] and [Mo(Tp(An))(NO)(Cl){NHC6H4-p-N(CH3)(2)}]

New arylamide complexes of the type [Mo(Tp(An))(NO)(Cl)(NHC6H4-p-R)] (TpAn = hydrotris(3-p-methoxyphenylpyrazol-1-yl)borate: R = CH3O (1), N(CH3)(2) ( 2), Cl (3), CH3 (4)) have been prepared in order to deduce the influence di fferent arylamide para-substituents have on their molecular structure and p roperties. The single-crystal X-ray structures of [MO(TpAn)(No)(Cl) {NHC6H4 -p-N(CH3)(2)}] (2) and [Mo(Tp(An))(NO)(Cl)(NHC6H4-p-CH3)] (4) have been sol ved, both of them having a characteristic bowl-like molecular shape. The in fluence of electronic and steric factors on the shape of the bowl cavity is discussed. Both compounds have a columnar packing arrangement with molecul ar interpenetrating between neighbouring columns. Given that columnar stack ing could be appropriate for liquid crystal materials, new related complexe s bearing long-chain substituted arylamide ligands [Mo(Tp(An))(NO)(Cl)(NHC6 H4-p-CnH2n+1)] (n = 6, 10, 12, 14, 16; 5-9) have been prepared. (C) 2001 El sevier Science Ltd. All rights reserved.