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

Deliberate hydrolysis of lithium cyclo­propyl­alkynylamidinates, Li[c-C(3)H(5)—C≡C(NR′)(2)] [R′ = (i)Pr, Cy = cyclo­hex­yl)], afforded the hitherto unknown neutral cyclo­propyl­alkynyl­amidine derivatives c-C(3)H(5)—C≡C—C(NR′)(NHR′) [R′ = (i)Pr (1), Cy (2)]. Subsequent reactions of 1 or 2 with metal(II) chlorides, MCl(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 MCl(2)[c-C(3)H(5)—C≡C—C(NR′)(NHR′)](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.