Recent advances in surface organometallic chemistry have enabled the detailed characterization of the surface species in single‐site heterogeneous catalysts. However, the selective formation of bis‐grafted surface species remains challenging because of the heterogeneity of the supporting surface. Herein, we introduce a metal complex bearing bidentate disilicate ligands, −OSi(OtBu)2OSi(OtBu)2O−, as a molecular precursor, which has a silicate framework adjacent to the metal (Pt) center. The grafting of the precursors on silica supports (MCM‐41 and CARiACT Q10) proceeded through a substitution reaction on the silicon atoms of the disilicate ligand, which was verified by the detection of isobutene and tBuOH as the elimination products, to selectively yield bis‐grafted surface species. The chemical structure of the surface species was characterized by solid‐state NMR, and the chemical shift values of the ancillary ligands and 195Pt nuclei suggested that the bidentate coordination sphere was maintained following grafting.

Radical hydrodehalogenation of aryl halides (Ar–X; X = Cl, Br, I) is achieved in the presence of atmospheric pressure H2 as a H-atom donor using a Co­(I) catalyst bearing a phenanthroline-based PNNP ligand (2,9-bis­((diphenylphosphanyl)­methyl)-1,10-phenanthroline). The reaction proceeds under mild conditions (1 atm H2) and is applicable to aryl bromides and aryl chlorides with various functional groups. A mechanistic study revealed that the PNNP–Co complex underwent facile H–H cleavage and facilitated a H-atom transfer. This process is mediated by a long-range metal–ligand cooperation of the PNNP–Co system, which includes the dearomatization/aromatization sequence of the phenanthroline ligand backbone. A radical clock experiment demonstrated the Ar–X bond cleavage via a radical mechanism. Further kinetic study supported that the rate-determining step includes electron transfer from the Co center to the substrate, affording a radical pair ArX•– and an odd-electron metal-halide complex [Co­(II) + ArX•–]⧧ as a transition state.

A series of low spin cobalt(I) complexes bearing a tetradentate phenanthroline-based PNNP ligand (2,9-bis((diphenylphosphanyl)methyl)-1,10-phenanthroline), [CoCl(PNNP)] (1), [CoMe(PNNP)] (2) and [Co(CH2SiMe3)(PNNP)] (3), were synthesized and structurally identified. Complex 3 underwent structural...