Improved syntheses, and structural and electronic characterization of carboxamide-substituted Tp(CONHPh,Me) and Tp(CONHt-Bu,Me) ligands.

Improvements in the syntheses of the carboxamide-substituted tris(pyrazolyl)borate ligands Tp(CONHPh,Me) [tris(3-anilinocarbonyl-5-methylpyrazol-1-yl)borate] and Tp(CONHt-Bu,Me) [tris(3-tert-butylaminocarbonyl-5-methylpyrazol-1-yl)borate] are reported. Their Tl(I) salts, namely [tris(3-anilinocarbonyl-5-methylpyrazol-1-yl-κN(2))borato]thallium(I), [Tl(C33H31BN9O3)], (II), and [tris(3-tert-butylaminocarbonyl-5-methylpyrazol-1-yl-κN(2))borato]thallium(I), [Tl(C27H43BN9O3)], (III), as well as the Cu(I) carbonyl complexes (Tp(CONHPh,Me))Cu(CO), namely carbonyl[tris(3-anilinocarbonyl-5-methylpyrazol-1-yl-κN(2))borato]copper(I) tetrahydrofuran trisolvate, [Cu(C33H31BN9O3)(CO)]·3C4H8O, (IV), and (Tp(CONHt-Bu,Me))Cu(CO), namely carbonyl[tris(3-tert-butylaminocarbonyl-5-methylpyrazol-1-yl-κN(2))borato]copper(I) tetrahydrofuran hemisolvate, [Cu(C27H43BN9O3)(CO)]·0.5C4H8O, (V), have been prepared. Their spectroscopic properties and structures are compared with those of related compounds. The molecules of (II)-(V) show hydrogen bonding to either solvent molecules or neighboring complex molecules via amide groups. The title compounds feature the ability to engage other ligands in hydrogen bonding and they show strong electron-withdrawing character. Compound (V) displays voids of ca 800 Å(3) in the crystal structure.