Controlled morphogenesis of organic polyhedral nanocrystals from cubes, cubooctahedrons, to octahedrons by manipulating the growth kinetics.
Morphological control of organic nanocrystals (ONCs) is important in the fields ranging from specialty chemicals to molecular semiconductors. Although the thermodynamic shape can be readily predicted, most growth morphologies of ONCs are actually determined by kinetic factors and remain poorly understood. On the basis of the reduction of zinc tetraphenylporphyrin perchlorate (ZnTPP(+)ClO(4)(-)) with sodium nitrite (Na(+)NO(2)(-)), we synthesized two series of ONCs of aquozinc tetraphenylporphyrin (ZnTPP·H(2)O), in the presence of either cetyltrimethylammonium bromide (CTAB) or poly(vinyl pyrrolidone) (PVP) as the capping ligands. As the cationic precursors of ZnTPP(+) are separated in the solution phase, smoothly controlled release of ZnTPP·H(2)O building blocks via the reduction reaction facilitates the separation between the nucleation and growth stages during the formation of ONCs and provides a high and tunable supersaturation unavailable by employing conventional crystallization techniques. We found that CTAB mainly serve as the colloidal stabilizer, while selective adhesion of PVP on the {020}s facet alters the crystal habits significantly. In both cases, manipulation of the growth kinetics had been achieved by adjusting the concentration of ZnTPP·H(2)O growth units, and consequently, the supersaturation for the crystallization, thus yielding ONCs with well-controlled sizes and shapes. Remarkably, thermodynamically stable octahedrons have been obtained at high supersaturation in both CTAB and PVP cases.
Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
Longtian
L
Kang
Hongbing
H
Fu
Xinqiang
X
Cao
Qiang
Q
Shi
Jiannian
J
Yao
D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D003102:Colloids; D007700:Kinetics; D008024:Ligands; D008665:Metalloporphyrins / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D011205:Povidone / Q000737:chemistry; D012977:Sodium Nitrite / Q000737:chemistry
D002593:Cetrimonium Compounds; D003102:Colloids; D008024:Ligands; D008665:Metalloporphyrins; D009930:Organic Chemicals; D011205:Povidone; D012977:Sodium Nitrite; D000077286:Cetrimonium