This thesis shed lights on metal-nitrogen organometallic fragments supported on silica surface for catalytic applications. It Focuses on group IV and V metal transition as a well-defined single-site catalysts, specifically titanium, hafnium, and tantalum to utilize them in the development of selective heterogeneous catalysis for imine metathesis, hydroamination and hydroaminoalkylation of olefins and alkynes. Developing new metal-nitrogen containing fragments by using easily available and abundant precursors which is silica SiO2 and metal amides complexes. Here, we describe metal fragments starting with hafnium-nitrogen fragment. All the catalysts were prepared by reacting homoleptic metal amido of group IV and V with partially dehydroxylated silica. In most cases the resulting surface amido is monopodal and leads to well defined single site catalysts precursors. In particular with Hf we have isolated hafniaaziridine 2.1 [(≡Si-O-)Hf(η2-MeNCH2)(η1-NMe2)(η1-HNMe2)], imido, and amido fragments 2.3 [(≡Si-O-)Hf(=NMe)(η1-NMe2)], and two intermediates the five-membered ring 2.2 [≡Si-O-Hf(HNMe2)(η2-NMeCH2CH(C6H13)CH2)(NMe2)] and 2.4 [(≡Si-O-)Hf(=NCH2Ar) (η1-NMe2)]. For tantalum 3.1 [(≡Si-O-)Ta=NtBu)(η1-NMeEt)2]; we have isolated two intermediates after treating 3.1 catalyst with aniline substrate lead to isolating 3.3 [(≡Si-O-)Ta(η1σ-NEtMe)2(η1σ-NHtBu)(NHC6H10)], and upon treating with 1-octyne lead to isolating 3.2 [(≡Si-O-)Ta(η1σ-NEtMe)2(η2-NtBuC=CC7H13)]. For titanium-nitrogen fragments, we isolated on silica SiO2-200 4.1 [(≡Si-O2-)Ti(NMe2)2 (η1-HNMe2)] and on SiO2-700 the titaniaaziridine 4.2a [≡Si-O-Ti(NMe2)3] 4.2b, [(≡Si-O-)Ti(η2-MeNCH2)(η1-NMe2)(η1-HNMe2)], the imido, and amido fragments 4.4 [(≡Si-O-)Ti(=NMe)(η1-NMe2)], and the five-membered ring intermediate 4.3 [≡Si-O-Ti(HNMe2)(η2-NMeCH2CH(C6H13)CH2)(NMe2)]. Research in this area has led to isolating several intermediates containing nitrogen fragments, this is the strength of surface organometallic chemistry which allows a deeper understanding of catalytic phenomena which could not be approached either in homogeneous catalysis or in classical heterogeneous catalysis. A molecular level characterization of the surface nitrogen containing fragments have been characterized by SOMC tools such as FTIR and EXAFS spectroscopy, elemental analysis, solid-state single and multiple quantum NMR, advanced DNP-SENS and DFT. A catalytic cycle was proposed based not only on the isolation of intermediates but also based on DFT calculations.

The invention of catalytic processes that convert feedstock chemicals into pharmacologically-privileged amines is a landmark challenge in organic synthesis. This thesis describes the development of three novel transition-metal catalyzed processes for the synthesis of alkylamines that attempts to meet this challenge. The first Pd-catalyzed methylene β-C−H carbonylation of alkylamines to form substituted β-lactams is reported. Through the synergistic use of a Pd-catalyst and Xanpthos ligand, secondary amines underwent exclusive methylene β-C−H activation in high yields and diastereoselectivities. Subsequently, the development of a remarkably selective methylene β-C−H carbonylation of α-tertiary amines (ATAs), is detailed. This methodology enables the C−H carbonylation of methylene C−H bonds over traditionally more reactive methyl and C(sp2)−H bonds. Importantly, a range of functional groups previously incompatible with C−H technologies were tolerated in good yields. Finally, the development of a novel multicomponent synthesis of tertiary amines is described. The novel photocatalytic single-electron reduction of alkyl iminium ions furnishes -amino radicals that engage alkenes forming a new C-C bond. The reaction exhibits broad functional group tolerance and enables the synthesis of amines not readily accessible by existing methods.