Designed molecular sources for the synthesis of metal pnictides nanocrystals
Solid State and Surface Chemistry, Material Synthesis
Final Report Abstract
In conclusion, this project succeeded in the preparation of high potential single-source precursors (SSP) for the formation of several promising MxEy (M = In, Ga, Zn, Ge, Sn, Si; E = P, As) systems. In selected cases, the formation and characterization of NCs were successful. For the InP system, we accomplished the desired fragmentation of [In(P3C2tBu2)] (1a) and successive formation of well-defined NCs (average size of 6.5 nm, mixed composition: In(0), In2O3, InP3, InP). For the analogous arsenide-system, we developed the synthesis of unprecedented 1,2,4-tri- and tetraarsolyl ligands, which are 2,4,6-tri-iso-propylphenyl (trip) substituted. Despite the failed subsequent salt metathesis with InI (due to unselective decomposition of hypothetical [In(As4Ctrip)]), we notably pushed borders in the unprecedented isolation of heavier group 15 cyclo-pentadienyl ligand congeners. By applying the multisource approach for the InP system, we succeeded in the formation of NCs by the reaction of tris(trimethylsilyl)phosphine and tris(N,N’-diisopropylacetamidinato) indium(III) under various reaction conditions. By using H2 atmospheres and applying N-donor ligand systems (instead of O-donors), we accomplished the preparation of oxide-free InP NCs with diameters between 2.0 and 4.5 nm with a good size distribution and without surface oxidation. For the gallium system, we succeeded in the preparation of [LGa(PH2)2] (7a1, L = βdiketiminato) and investigated the decomposition in the Fischer-Porter Schlenk under thermolytic conditions. Exclusively one amorphous solid phase was isolated, which was identified by EDX as Ga4P3. To date, for this system we have unfortunately not been able to execute any control of size, morphology or crystallinity. For the Zn3P2 system a variety of different SSP2 systems were synthesized involving different ligand systems (Cp*, β-diketiminato and amidinato). Our attempts to synthesize Zn3P2 SSP2 by the substitution of halides (in the precursor molecules) or incorporation of polyphosphorus ligands by redox reactions with white phosphorus have failed so far. Exclusively the favoured formation of [ZnP(SiMe3)]x polymer was observed, which lacked the final abstraction of a remaining SiMe3 substituent and therefore preventing the desired formation of Zn3P2 NCs. For the germanium and the tin systems, we accomplished the SSP2 synthesis of βdiketiminato (L) complexes [LGeP(SiMe3)2] and [LSnE(SiMe3)2] (E =P, As). In the case of germanium phosphide, exclusively amorphous and very irregularly shaped NCs (sizes ranging from 7 to 90 nm) are obtained, which are heterogeneous from GeP to Ge4P3 in their composition. For the tin system, more regular Sn4P3 and Sn4As3 NCs (10-20 nm of diameter) were characterized. For the SixEy (E = P, As) systems, we succeeded in the synthesis of manifold, promising high potential SSP2s. The application of mono-chlorosilylene [PhC(NtBu)2SiCl] was most successful and its reaction with [LiAs(SiMe3)2] enabled the access to unprecedented silaarsene complexes. Moreover, its reaction with [Cp”2ZrE4] (E = P, As) as a polypnictogenide transfer reagent opens the way to isolate and characterize unprecedented pnictogen-silicon congeners of cyclo-butadiene and benzene. These important compounds represent highly promising SSP2 for future SixEy NCs formation.
Publications
- Transition-Metal Complexes Containing Parent Phosphine or Phosphinyl Ligands and Their Use as Precursors for Phosphide Nanoparticles. Inorg. Chem. 2014, 53, 11438-11446
S. Bauer, C. Hunger, M. Bodensteiner, W.-S. Ojo, A. Cros-Gagneux, B. Chaudret, C. Nayral, F. Delpech, M. Scheer
(See online at https://doi.org/10.1021/ic5012082) - Identifying short surface ligands on metal phosphide quantum dots. Phys.Chem.Chem.Phys., 2016, 18, 17330
E. A. Baquero, W.-S. Ojo, Y. Coppel, B. Chaudret, B. Urbaszek, C. Nayral and F. Delpech
(See online at https://doi.org/10.1039/c6cp03564g) - Pnictogen–Silicon Analogues of Benzene. J. Am. Chem. Soc. 2016, 138, 10433-10436
A. E. Seitz, M. Eckhardt, A. Erlebach, E. V. Peresypkina, M. Sierka, M. Scheer
(See online at https://doi.org/10.1021/jacs.6b07389) - Progresses in Polyarsolyl Chemistry. Chem. Eur. J. 2016, 22, 1944-1948
C. Heindl, E. V. Peresypkina, A. V. Virovets, G. Balázs, M. Scheer
(See online at https://doi.org/10.1002/chem.201504961) - Synthesis of Oxide-Free InP QDs: Surface Control and H2-Assisted Growth. Chem. Mater. 2017, 29, 9623-9627
E. A. Baquero, H. Virieux, R. A. Swain, A. Gillet, A. Cros-Gagneux, Y. Coppel, B. Chaudret, C. Nayral, and F. Delpech
(See online at https://doi.org/10.1021/acs.chemmater.7b04069)
