Alkyl-tethered bis-phosphoryl compounds with two 1,3,2-benzodiazaphosphorinone units; Oxidation, complexation, and X-ray structure analysis of selected compounds

The reaction of the bis-chlorophosphines 1a-1d with bis(2-chloroethyl)amine hydrochloride in the presence of triethylamine and with various trimethyls ilylamines led to a new class of his-phosphorus ligands 2a-2c and 3a-3g. P- 31- NMR studies suggested that the bis-phosphorus ligands undergo rotation reactions about the alkyl bridge in polar solvents. Compounds 2a-2c showed initially only one sharp singlet each in their P-31-NMR spectra. After a fe w days at room temperature, two signals were observed. Similar results were observed for 3a-3g. In the solid state, the two phosphorus atoms in 2c are not equivalent, as was confirmed by the observation of two signals in the solid state P-31-NMR spectrum. Oxidation reactions of 2a-2c by the hydrogen peroxide-urea 1:1 adduct (NH2)(2)C(:O) . H2O2 led to the formation of the corresponding phosphoryl compounds 4a-4c. Reaction of 2a and 3a with Pt[COD ]Cl-2 (COD = 1.5-Cyclooctadiene) furnished the complexes 5 and 6. The NMR s pectra suggested that the two chlorine atoms are in cis position. X-ray str ucture analyses were conducted for 2a, which exhibits twofold symmetry; 2c, which is linked into dimers by hydrogen bonds C-H ... O; and 6, confirming the cis configuration.