(Ln(BH4)2(THF)2] (Ln = Eu, Yb)-A Highly Luminescent Material. Synthesis, Properties, Reactivity, and NMR Studies

The divalent lanthanide borohydrides [Ln-(BH4)(2)(THF)(2)] (Ln = Eu, Yb) have been prepared in a straightforward approach. The europium compound shows blue luminescence in the solid state, having a quantum yield of 75%. Nonradiative deactivation of C-H and B-H oscillator groups could be excluded in the perdeuterated complex [Eu(BD4)2(d(8)-THF)(2)], which showed a quantum yield of 93%. The monocationic species [Ln(BH4)(THF)(5)][BPh4] and the bis(phosphinimino)methanides [{(Me3SiNPPh2)(2)CH}Ln(BH4) (THF)(2)] have been prepared from [Ln(BH4)(2)(THF)(2)]. They show significantly lower or no luminescence. Using the diamagnetic compound [{(Me3SiNPPh2)(2)CH}Yb(BH4)(THF)(2)), we performed a 2D (31)p/Yb-171 HMQC experiment.