Structurally characterized luminescent lanthanide zinc carboxylate precursors for Ln-Zn-O nanomaterialsElectronic supplementary information (ESI) available: Additional data. CCDC reference numbers 753900-753923. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c002492a

A novel family of lanthanide zinc carboxylate compounds was synthesized, characterized (structural determination and luminescent behavior), and investigated for utility as single-source precursors to Ln-Zn-O nanoparticles. Carboxylic acids [H-ORc = H-OPc (H-O 2 CCH(CH 3 ) 2 , H-OBc (H-O 2 CC(CH 3 ) 3 , H-ONc (H-O 2 CCH 2 C(CH 3 ) 3 )] were individually reacted with diethyl zinc (ZnEt 2 ) to yield a set of previously unidentified zinc carboxylates: (i) [Zn(μ-ORc) 3 Zn(μ-ORc)] n [ORc = OPc ( 1 ), ONc ( 2 )], (ii) [(py)Zn] 2 (μ-ORc) 4 [ORc = OBc ( 3 ), ONc ( 4 ), and py = pyridine], or (iii) Zn(ORc) 2 (solv) 2 [ORc/solv = OPc/py ( 5 ), O c Nc/H 2 O ( 6 ) (O c Rc = chelating)]. Introduction of lanthanide cation [Ln[N(SiMe 3 ) 2 ] 3 , ZnEt 2 , and HOBc in py] yielded the mixed cationic species structurally characterized as: (i) (O c Bc)Ln[(μ-OBc) 3 Zn(py)] 2 [Ln = Pr ( 7 ), Nd ( 8 ), Sm ( 9 )] or (ii) (py) 2 Zn(μ-OBc) 3 Ln(O c Bc) 2 (py) [Ln = Tb ( 10 ), Dy ( 11 ), Er ( 12 ), Y ( 13 ), Yb ( 14 )]. Exploration of alternative starting materials [Ln(NO 3 ) 3 · n H 2 O, Zn(O 2 CCH 3 ) 2 , HOBc in py] led to the isolation of (NO 3 c )Ln[(μ-OBc) 3 Zn(py)] 2 [Ln = La ( 15 ), Ce ( 16 ), Pr ( 17 ), Nd ( 18 ), Sm ( 19 ), Eu ( 20 ), Gd ( 21 ), Tb ( 22 ) Dy ( 23 ), and Er ( 24 ); NO 3 c = chelating]. The UV- vis spectra of 7-24 revealed standard absorption spectra for the Ln cations. Representative compounds were used to generate nanoparticles from an established 1,4-butanediol-based solution precipitation route. The nanoproducts isolated adopted either a mixed zincite/lanthanum oxide ( 18n or 22n ) or pure zincite ( 8n or 10n ) phase dependent on NO 3 or OBc moiety. Fluorescence was not observed for any of these nanomaterials possibly due to phase separation, low crystallinity, surface traps, and/or quenching based on elevated Ln cation content. A series of single-source Ln-Zn-OBc derivatives ((O c Bc)Ln[(μ-OBc) 3 Zn(py)] 2 , [(py) 2 Zn(μ-OBc) 3 Ln(O c Bc) 2 (py)] or (NO 3 c )Ln[(μ-OBc) 3 Zn(py)] 2 (Eu ( 20 ) shown) were synthesized. The latter displayed luminescent behavior from red ( 20 ) to green ( 22 ) to blue but the subsequent nanoparticles ( 20n shown) from the OBc were not luminescent and the NO 3 phase separated into the oxides.