Reactivity of bis(long chain substituted β-diketonato)palladium(II) [Pd(OOR2)2] towards HBF4: formation of luminescent [BF2(OOR2)] derivatives. X-ray structure of [1,3-di(4-n-butoxyphenyl)propane-1,3-dionato]difluoroboron(III)

Reactions of [Pd(OOR2)2] (OOR2 = 1,3-di(4-n-alkyloxyphenyl)propane-1,3-dionato; R = C6H4OCnH2n+1, n = 14, 16, 4) with N,N′-bidentate ligands of the type bis(4-n-alkyloxyphenyl)-1-(pyridin-2-yl)-1H-pyrazol (pypzR2) in the presence of HBF4 gave rise to new dioxoborane derivatives [BF2(OOR2)] (1–3) as major products. Compounds 1–3 were also isolated by reaction of [Pd(OOR2)2] and HBF4, as well as by reaction of the corresponding β-diketones or sodium β-diketonates with HBF4. The new oxoboranes [BF2(OOR2)] (1–3) showed intense yellow or blue luminescence in the solid state and in the solution, respectively. The X-ray structure of 3 containing the shortest chain (R = C6H4OC4H9) evidenced the chelating coordination of the β-diketonate ligand to the acceptor BF2 group in a boron tetrahedral environment. The molecules were packed in layers showing weak C–H⋯F bifurcated interactions, which were responsible for a bi-dimensional network.