Synthesis and structural characterization of four dichloridobis(cyclopropylalkynylamidine)metal complexes

Deliberate hydrolysis of lithium cyclopropylalkynylamidinates, Li[ c -C 3 H 5 —C[triple-bond]C(N R ′) 2 ] [ R ′ = i Pr, Cy = cyclohexyl)], afforded the hitherto unknown neutral cyclopropylalkynylamidine derivatives c -C 3 H 5 —C[triple-bond]C—C(N R ′)(NH R ′) [ R ′ = i Pr ( 1 ), Cy ( 2 )]. Subsequent reactions of 1 or 2 with metal(II) chlorides, M Cl 2 ( M = Mn, Fe, Co), provided the title complexes dichloridobis(3-cyclopropyl- N , N ′-diisopropylprop-2-ynamidine)manganese(II), [MnCl 2 (C 12 H 20 N 2 ) 2 ], ( 3 ), dichloridobis(3-cyclopropyl- N , N ′-diisopropylprop-2-ynamidine)iron(II), [FeCl 2 (C 12 H 20 N 2 ) 2 ], ( 4 ), dichloridobis( N , N ′-dicyclohexyl-3-cyclopropylprop-2-ynamidine)iron(II), [FeCl 2 (C 18 H 28 N 2 ) 2 ], ( 5 ), and dichloridobis( N , N ′-dicyclohexyl-3-cyclopropylprop-2-ynamidine)cobalt(II), [CoCl 2 (C 18 H 28 N 2 ) 2 ], ( 6 ), or more generally M Cl 2 [ c -C 3 H 5 —C[triple-bond]C—C(N R ′)(NH R ′)] 2 [ R ′ = i Pr, M = Mn ( 3 ), Fe ( 4 ); R ′ = Cy, M = Fe ( 5 ), Co ( 6 )] in moderate yields (30–39%). Besides their spectroscopic data (IR and MS) and elemental analyses, all complexes 3 – 6 were structurally characterized. The two isopropyl-substituted complexes 3 and 4 are isotypic, and so are the cyclohexyl-substituted complexes 5 and 6 . In all cases, the central metal atom is coordinated by two Cl atoms and two N atoms in a distorted-tetrahedral fashion, and the structure is supported by intramolecular N—H...Cl hydrogen bonds.