Factors controlling the structure of alkylzinc amidinates: on the role ofN-substituents

Abstract

Despite various applications of alkylzinc complexes supported by N,N-bidentate ligands in chemistry and materials science, the corresponding organozinc amidinates still represent an insufficiently explored area. To gain a more in-depth...

Tunable zinc benzamidinate complexes: coordination modes and catalytic activity in the ring-opening polymerization of l-lactide

“…Consequently, complexes 2 and 3 exhibit a dinuclear arrangement distinguished by bridging benzamidinate ligands and pendant functionalities, employing a μ 2 -κ 1 :κ 1 coordination mode of the benzamidinate ligands. 11 The geometry of each zinc center can be characterized as a distorted tetrahedron, with two nitrogen atoms [2.0105(13) and 2.0181(13) Å for 2 ; 2.0494(18) and 2.050(2) Å for 3 ] originating from distinct benzamidinate ligands. Furthermore, each metal center is associated with a dative atom originating from the pendant functionalities [Zn–O, 2.3601(12) Å for 2 ; Zn–N(3), 2.2887(19) Å for 3 ], as well as a carbon atom [Zn–C(17), 1.9778(16) Å for 2 ; Zn–C(18), 2.004(2) Å for 3 ] derived from the ethyl group.…”

“…Hence, complex 4 exhibits a dinuclear configuration and features a hybrid coordination mode with μ 2 -κ 1 :κ 1 and κ 2 -coordination of the benzamidinate ligands. 11 Diverging from the structures of complexes 1–3 , complex 4 lacks the presence of ethyl group. Despite possessing two zinc metal centers, complex 4 is characterized by four benzamidinate units.…”

“…The distinction in the molecular structure of complex 7 lies in its mononuclear arrangement, where the zinc coordination sphere is constituted by two pendant benzamidinate ligands, differing from the structures of the previous complexes. Nevertheless, in contrast to Zn(amidinate) 2 complexes that coordinate with four nitrogen atoms from two chelating amidinates, 12b,15 the zinc center in this case is surrounded by two nitrogen atoms from the NCN moiety (Zn-N NCN , 1.9668 (10) and 1.9441(11) Å) and two nitrogen atoms from pendant functionalities (Zn-N py , 2.0508 (11) and 2.0490 (10) Å), forming a distorted tetrahedral geometry. An analogous bonding mode is observed in calcium complexes that feature pendant functionalities.…”

“…Two nitrogen atoms from one benzamidinate ligand coordinate with a bite One nitrogen atom from the other benzamidinate group exhibits a bond distance of 2.1203(12) Å, slightly longer than those (2.038(2) and 2.101(3) Å) observed in zinc guanidinate or amidinate complexes. However, it falls between the two Zn-N bond distances (2.2065 (11) and 2.0626(12) Å) of the same benzamidinate ligand. Additionally, one carbon atom from the ethyl group has a bond distance of 1.9700(14) Å.…”

“…Complex 1 adopts a dinuclear configuration with μ 2 -κ 2 :κ 1 -coordination of the benzamidinate ligands. 11 One nitrogen atom of the benzamidinate ligand adopts a μ 2 coordination mode, bridging between two zinc metal centers. Three four-membered ring structures are formed around each zinc metal center.…”