Spin-tickling technique for the indirect measurements of the Rh-103 NMR parameters of organo-rhodium compounds

The extremely low gyromagnetic ratio of the Rh-103 nucleus hampers the measurement of NMR spectra via direct observation, particularly on a low-field spectrometer. In this study our approach has been to use the high sensitivity of the P-31 nucleus to obtain Rh-103 chemical shifts by the spin-tickling method, using a low field 1.4T, 60 MHz spectrometer. In addition to determining the Rh-103 chemical shifts, this type of experiments provide the relative signs of the coupling and reduced coupling constant. The compounds Ph2PLi, (MeO)(2)PCH2CH2P(OMe)(2) (L-L) [(Cod)Rh-(mu(2)-Cl)](2), [(Cot)Rh(mu(2-)Cl)](2), [(Cod)(2)Rh-2(mu(2)-Ph2P)(2)] (I), [(Cod)Rh-A(mu(2)-Ph2P)(2)Rh-B(Ph3P)](2) (II), [(Cod)Rh-A(mu(2)-Ph2P)(2)Rh-B (Ph3As)](2) (III) and [(MeO)(2)PCH2CH2P (OMe)(2)Rh(mu(2)-Cl)](2) (IV) were prepared. The NMR parameters of the organo-rhodium compounds J(Rh-P), J(Rh-Rh), delta(Rh-103) with their relative signs and the reduced coupling constants were investigated

1,2-Bis-(2-benzimidazolyl)-1,2-ethanediol and 1,4-bis-(2-benzimidazolyl)-1,2,3,4-butanetetraol PdCl2 complexes

The 1,2-bis-(2-benzimidazolyl)-1,2-ethanediol (EH2) and 1,4-bis-(2-benzimidazolyl)-1,2,3,4-butanetetraol (TH4) ligands form 4-coordinate mono- and bi-metallic complexes with PdCl2, respectively. In Pd(EH2)Cl-2 the ligand acts as a bidentate through two of the nitrogen atoms. On the other hand, in Pd-2(TH4)Cl-4 the ligand coordinates to two palladium atoms through both bis-benzimidazole nitrogen atoms and two oxygen atoms of the hydroxy groups, forming two different isomers. The complexes were characterised by analytical data, magnetic susceptibility, molar conductivity, and also by i.r., H-1- and C-13-n.m.r. spectra