A series of nucleophilic addition reactions and α-C–H substitution reactions of an imine-containing ligand 2-(2-((((1H-pyrrol-2-yl)­methylene)­amino)­methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine (HL1) were reported. The reactions of HL1 with 0.5 and 2 equiv of n Bu2Mg, respectively, gave two complexes of compositions [Mg­(L1)2] (1) and [Mg2(L2)2] (2) (H2L2 = N-((1-(2-(dimethylamino)­ethyl)-1H-pyrrol-2-yl)­methyl)-1-(1H-pyrrol-2-yl)­pentan-1-amine). The nucleophilic addition of n Bu2Mg to the CN bond of the HL1 ligand occurred in the process for the formation of 2. Treatment of HL1 with 2 and 1 equiv of n BuLi generated [Li2(L3)2] (3) (HL3 = 2-(2-(((1-(1H-pyrrol-2-yl)­pentylidene)­amino)­methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine) and [Li2(L1)2] (4). An α-C–H substitution of the HCNR moiety of the HL1 ligand triggered by n BuLi was discovered in the preparation of 3. The formation of 3 demonstrates a new concept for the C–C coupling that involved inert C–H bond activation of HCNR skeleton. The reactions of HL1 with MeLi, sec-BuLi, and tert-BuLi, respectively, were also examined. The products for both the nucleophilic addition of organolithium reagents to the CN bond and α-C–H substitution of the HCNR moiety of the HL1 ligand were determined. The mechanisms for the formations of 2 and 3 were rationalized by DFT calculations. The hydroboration reactions catalyzed by 2 were investigated, and these reactions characterize ample substrate scope, very good yields, and high selectivity.

The organometallic compounds of lithium ions have garnered continuous interest as indispensable precursors for the syntheses of organometallic complexes of main-group metals, transition metals, lanthanide metals, and actinide metals. In this work, we present a strategy for the preparation of a series of polynuclear lithium complexes. This methodology features the utilization of organolithium reagents both as metal sources to coordinate with the ligands and as nucleophilic reagents to undergo nucleophilic addition to the C�N bonds of the ligands. Reaction of a ligand HL1amino)phenol]. One prominent feature regarding the formation of 1•1.5Tol is the occurrence of nucleophilic addition of n-BuLi to the C�N bond of HL1, leading to the generation of a new [L1a] 2− ligand that contains both aminophenol and 1-(2-pyrrolyl)alkylamine scaffolds. The developed protocol can be adapted to a series of organolithium reagents. Compounds [Li 8 (L1b) 4 ] (2) and [Li 8 (L1c) 4 ] (3) were afforded by treatment of HL1 with sec-BuLi and LiCH 2 SiMe 3 , respectively. Reaction of an analogous ligand HL2 [HL2 = 2-(((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2yl)methylene)amino)-4-methylphenol] with n-BuLi generated compound [Li 8 (L2a) 4 ] ( 4). C�N bond activation was not observed in the reaction of HL1 with NaO t Bu, and the complex [Na 4 (L1) 4 ]•Tol (5•Tol) was obtained. A decanuclear complex [Li 10 (L3a) 2 (L3b) 2 ] (6) was also prepared via the reaction of HL3 [HL3 = 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1Hpyrrol-1-yl)-N,N-dimethylethan-1-amine] with t-BuLi. A remarkable feature in terms of the synthesis of 6 is the simultaneous occurrence of hydrogen atom abstraction from the C−H bond of the pyrrolyl ring and nucleophilic addition to the C�N bond of the HL3 ligand by t-BuLi. A series of amines containing biologically and physiologically important moieties were achieved by hydrolysis of the crude products from the reactions of the HL1−HL3 ligands and organolithium reagents. This work provides an efficient approach to high-nuclearity lithium compounds as well as a series of amines.

The reactions of ZnEt2 with two pyrrolyl ligands 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1yl)-N,N-dimethylethan-1-amine (HL1) and N-((1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)methanimine (H2L2) generated a zinc ethyl compound [Zn(L1)Et] (1) and a dinuclear complex [Zn2(L2)2(THF)2] (2). The complexes were characterized by 1 H NMR, 13 C NMR, elemental analysis, and single-crystal X-ray diffraction. Complexes 1 and 2 were employed as catalysts for the borylation of aryl iodides with B2Pin2 (B2Pin2＝4,4,4',4',5,5,5',5'-octamethyl-2,2'-bis(1,3,2-dioxaborolane)). They were both active for this coupling reaction. Complex 1 displays higher activity than that of 2. This borylation transformation promoted by 1 features mild condition, wide substrate scope and high functional group compatibility. Moreover, the catalytic activities of two known compounds previously reported by our group, namely, [Li2(L1)2] (3) and [Mg(L1)2(THF)2] (4), toward borylation of aryl iodides with B2Pin2 were also explored. They cannot catalyze this coupling reaction. Nevertheless, complexes 3 and 4 were catalytically active toward hydroboration of aldehydes and ketones by pinacolborane (HBpin), giving a variety of borate esters in excellent yields in a very short time.

The syntheses, characterizations, and catalytic activities of three zinc complexes and one lithium compound based on β-diketiminate ligands are described. The reactions of ZnEt2 with one equivalent of and two...