In this context, a brief comment on the 95 Mo NMR shifts of the heterodimeric complexes is warranted. Because this molybdenum isotope is a spin 5/2 nucleus with low natural abundance (15.9%), an unfavorable gyromagnetic ratio and a low quadrupole moment, Mo NMR is not without challenges. Early work, however, had shown that the nuclei in dimeric MoMo complexes are strongly deshielded and can therefore be easily distinguished from other molybdenum species; 61 Table includes the data of some pertinent examples. Although the problems caused by the quadrupolar nature of Mo are massively enhanced by lowering symmetry and increasing the molecular weight of the compounds, we managed to record two distinct Mo resonances for the new heterodimeric complex 12: the sharper signal at 3260 ppm is tentatively attributed to the Mo(OtBu)3 unit, whereas a much broader signal at 3127 ppm likely stems from bound Mo[N(Ar)(tBu)]3. 62 For complex 14, however, only one very broad peak at 3314 ppm was detected even after 5 d acquisition time, likely belonging to the Mo center carrying the tripodal siloxide. In any case, Table shows that the Mo centers of the heterodimers are strongly deshielded (600-800 ppm) relative to relevant homodimeric siblings carrying the same or similar alkoxide, siloxide or dialkylamino ligands. Although the data set is currently too small for a generalization, the comparison seems to imply that a heterodimeric constitution results in a peculiar electronic character of the MoMo core, potentially with a higher paramagnetic contribution; the ultralong MoMo distances could be another manifestation thereof, even though the diamagnetism of 12 and 14 shows that net triple bonding is preserved. Importantly, however, the example of the homoleptic complex [Mo2(CH2CMe3)6] devoid of any -donating ligands must be taken as a warning against too rapid an interpretation: this complex resonates at Mo = 3695 ppm, 61 yet shows an extremely short MoMo bond (2.1654(7) Å). These ostensibly difficult-to-reconcile experimental results make a detailed yet non-trivial analysis of the 95 Mo NMR shift tensors and of the electronic character of the complexes necessary once additional data are available as indispensable calibration points for high-level computational studies. Until then, we have to leave the question open whether or not there exists an innate link between the remarkable spectroscopic fingerprints and the equally astounding structural attributes of the new family of heterodimeric complexes disclosed herein.