Crystal Structure, Infrared and Solid State CP MAS NMR Characterization of [(PPh3)2AgO2CH] and of [(PPh3)2AgO2CH].cntdot.2HCO2H, a Complex of the H-Bonded [H2(HCO2)3]- Species
| Autor: | Peter Conrad Healy, Brian W. Skelton, John V. Hanna, Graham A. Bowmaker, Allan H. White, Effendy, Graeme J. Millar |
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| Rok vydání: | 1995 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry. 99:3909-3917 |
| ISSN: | 1541-5740 0022-3654 |
| Popis: | Bis(triphenylphosphine)silver(I) formate and its diformic acid adduct, [(PPh3)2AgO2CH]·2CHO2H have been prepared and characterized by infrared spectroscopy, solid state CP MAS 13C and 31P NMR spectroscopy, and single-crystal X-ray diffraction. Crystals of [(PPh3)2AgO2CH] are isomorphous, with [(PPh3)2CuO2CH] crystallizing as discrete monomeric units in the monoclinic space group C2/c with a 2-fold crystallographic axis of symmetry through the bisector of the P-Ag-P angle and the anion. The formate anion is symmetrically coordinated to the silver with an Ag-O distance of 2.425(3) A. The Ag-P distance is 2.4261(7) A, and the P-Ag-P angle 127.37(3)°. Crystals of the diformic acid adduct belong to the orthorhombic space group Pnma, in which the PPh3 ligands are related by a crystallographic mirror plane containing the silver atom, the formate anions, and the two molecules of formic acid. The anion is unsymmetrically coordinated with the Ag-O distances of 2.550(7) and 2.713(8) A, seemingly a consequence of strong hydrogen bond formation with each of the formic acid molecules, with O⋯O distances of 2.56(1) and 2.50(1) A. Although the Ag-P distance of 2.426(2) A is unchanged from that of [(PPh3)2AgO2CH], the P-Ag-P angle increases to 147.86-(7)°, the largest yet recorded for the [(PPh3)2Ag]+ cation. The compound can be regarded as a complex between the [(PPh3)2Ag]+ cation and the previously unknown doubly H-bonded [H2(HCO2)3]- "triformate" anion. Infrared bands due to this anion are assigned and discussed in relation to the metal-ligand and H-bonding in the complexes. The solid state cross-polarization magic angle spinning (CP MAS) 13C NMR spectra of [(PPh3)2AgO2CH] shows a single carbonyl peak at 169.7 ppm, while for the formic acid adduct, three distinct peaks at 163.5, 166.1, and 169.4 are observable. Simple doublets arising from 1J(AgP) coupling are observed in the 31P solid state NMR spectra of both complexes with a line spacing of 432 Hz for [(PPh3)2AgO2CH] and 517 Hz for [(PPh3)2AgO2CH]·2HCO2H. |
| Databáze: | OpenAIRE |
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