A great variety of 2,2Ј-bipyridylamines can be synthesized starting from primary amines or 2-aminopyridines (for instance, symmetrically and unsymmetrically substituted as well as chiral ligands) by palladium-catalyzed aryl amination. The reaction of such ligands with [PdCl 2 (COD)] or [NiBr 2 (DME)] (COD = cycloocta-1,5-diene; DME = 1,2-dimethoxyethane) led to the corresponding dichloro or dibromo complexes. The results of X-ray crystal structure analyses of

Tris(aminopyridinato) zirconium and ansa‐aminopyridinato titanium complexes have been sythesized. The reaction of (TMS‐APy)3‐Zr‐Cl (4‐methyl‐2‐trimethylsilyl‐aminopyridine=TMS‐APy‐H) with trimethylsilylbutadiynyl lithium generated in situ affords (TMS‐APy)3ZrCCCCTMS (1). (TMS‐apy)3‐Zr‐Me2 (2). Compound 2 shows an agostic interaction of the dimethylamido moiety. The reaction of Ti(NMe,2),4 with silox(Apy‐H)21,3‐di(4′‐picolin‐2′‐yl‐amino)‐1,1,3,3‐tetraisopropyldisiloxane=silox (APy‐H)2] gives rise to silox(Apy)2‐Ti‐(NMe2)2‐Ti‐[NMe,2)2 (3). Complex 3 reacts with ε‐caprolactam to form a caprolactamato complex (4). X‐ray crystal structure analyses of 1, 2, 3 and 4 are reported. The complexes 1, 2, 3 and 4 may be considered to be strained donor‐functionalized amido(metal) complexes due to the η2 binding mode of the ligand cores, TMS‐APy and silox(APy)2, to meet the requirements of the ancillary coordinated substrates is observed. Thus, aminopyridinato complexes seem to be valuable model compounds for investigations of ligand‐substrate communications in early transition metal chemistry.

The reactions of 3 equiv of 4-methyl-2-aminopyridine and 4,6-dimethyl-2-aminopyridine with tris(bromodimethylsilyl)methane in the presence of 3 equiv of triethylamine gave respectively the two tris(aminopyridine) species HC(SiMe2NHC5NH3-4-Me)3 ((trisAP-4)H3, 1a) and HC(SiMe2NHC5NH2-4,6-Me2)3 ((trisAP-4,6)H3, 1b). Compound 1a reacted with (Me2N)3TiCl via amine elimination to give (trisAP-4)TiCl (2), a mononuclear titanium complex that is coordinated by six nitrogen atoms according to an X-ray analysis. The reaction of NbCl3(DME)(η2-PhC⋮CSiMe3) with trilithiated 1b (in situ) formed (trisAP-4,6)Nb(η2-PhC⋮CSiMe3) (3). The tris(aminopyridinato) ligand trisAP-4,6 in 3 acts as a pentadentate ligand, in contrast to the hexadentate coordination of trisAP-4 in 2 and 3. NMR investigations of the reaction of 3 with acetylene revealed neither alkyne exchange nor benzene formation.

The methylenecyclopropanes 7 and 8, with aryl substituents fixed in a coplanar conformation, show an extraordinary readiness to dimerize with formation of 10 and 11, respectively.

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