| Abstract
| - The reaction of 1,3,5-triaza-7-phosphaadamantane (PTA) with the rhenium(I) precursor [NEt4]2[ReBr3(CO)3] (1) under ambient conditions produces the complexes [NEt4][ReBr2(PTA)(CO)3] (2), [ReBr(PTA)2(CO)3] (3a), [ReBr(PTAH)2(CO)3]Br2 (3b), and [Re(PTA)3(CO)3]PF6 (4) in high yields. 31P NMR investigations of the formation of 3a in different solvent systems were performed, revealing a strong influence of the solvent on the number of intermediate species and the reaction kinetics but not on the final formation of 3a. X-ray structure analyses of complexes 2, 3a, 3b, and 4 are reported.
- Starting originally from [NEt4]2[ReBr3(CO)3] (1), the three novel complexes [NEt4][ReBr2(PTA)(CO)3] (2), [ReBr(PTA)2(CO)3] (3a), and [Re(PTA)3(CO)3]PF6 (4) (PTA = 1,3,5-triaza-7-phosphaadamantane) were prepared andcharacterized by IR, 1H, 13C, and 31P NMR spectroscopy and X-ray crystallography. These complexes are thefirst representatives of mixed carbonyl/PTA complexes of an element of the manganese row. All substitutionreactions have been performed under aerobic conditions at ambient temperature and the yields were in all thecases high. The disubstituted complex was isolated as the neutral species 3a and as the dicationic species [ReBr(PTAH)2(CO)3]Br2, 3b, which is protonated at one amine group of each of the two PTA ligands. The substitutionreaction leading to the formation of 3a was performed in H2O, methanol and DMSO/methanol (4:1) and thereaction was followed using 31P NMR techniques. These experiments revealed that the number and concentrationof intermediate species during the substitution reaction are strongly dependent on the solvent system. Furthermoredue to a completely different solubility behavior of 3a and 3b, a fully reversible phase transfer of the disubstitutedcomplex from the organic (THF) to the aqueous layer (2 M NaBr) and back could be induced by simply changingthe pH of the aqueous phase. In the 31P NMR experiment, the existence of the monoprotonated species [ReBr(PTA)(PTAH)(CO)3]Br (3c) could also be detected. X-ray data for complex 2: monoclinic P21/n, a = 8.6889(4)Å, b = 29.3089(14) Å, c = 9.3017(5) Å, β = 97.1520(10)°, Z = 4, R/Rw = 0.048/0.079. X-ray data for complex3a: monoclinic P21/c, a = 6.8581(40 Å, b = 21.9499(12) Å, c = 13.9526(8) Å, β = 94.6650(10)°, Z = 4, R/Rw= 0.036/0.042. X-ray data for complex 3b: triclinic P1̄ , a = 8.7051(5) Å, b = 11.9307(7) Å, c = 14.7458(8)Å, α = 78.9450(10)°, β = 87.2340(10)°, γ = 76.4770(10)°, Z = 2, R/Rw = 0.034/0.042. X-ray data for complex4: triclinic P1̄, a = 9.3842(50) Å, b = 13.5797(7) Å, c = 13.9499(7) Å, α = 105.5910(10)°, β = 91.8560(10)°,γ = 107.0190(10)°, Z = 2, R/Rw = 0.051/0.062.
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