A Triple-Site Gd₃ Carborane Metal-Organic Framework toward Scalable Quantum Computing

Metal-organic frameworks (MOFs) incorporating arrays of molecular spin qubits (quMOFs) offer a promising pathway toward scalable quantum computing. In this work, we introduce a novel quMOF, {[(Gd)₃(mCB-L)₄(NO₃)(DMF)_x]_n·Solv}, constructed with a carborane linker and Gd(III) ions at three distinct coordination sites. We thoroughly characterize its magneto-thermal properties using dc/ac magnetometry, X-ray absorption spectroscopy, X-ray magnetic circular dichroism, and heat capacity measurements. The quantum computing potential is demonstrated through ab initio calculations and pulsed electron paramagnetic resonance on GdY-diluted analogues, revealing T_m= 0.7 μs and Rabi oscillations persisting up to 50 K. Each of the three isolated Gd(i) sites in GdY-MOFs functions as an 8-level qudit, accessible via X-band transitions. Notably, the triple-site Gd₃ quMOF provides an unprecedented qudit with d = (2S + 1)³ = 512 states, capable of encoding up to 9 qubits, marking a significant advance in the scalability of molecular-based quantum computing systems.