Description:
<jats:title>Abstract</jats:title><jats:p>The current library of amidinate ligands has been extended by the synthesis of two novel dimethylamino‐substituted alkynylamidinate anions of the composition [Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NR)<jats:sub>2</jats:sub>]<jats:sup>−</jats:sup>(R =<jats:sup><jats:italic>i</jats:italic></jats:sup>Pr, cyclohexyl (Cy)). The unsolvated lithium derivatives Li[Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NR)<jats:sub>2</jats:sub>] (<jats:bold>1</jats:bold>: R =<jats:sup><jats:italic>i</jats:italic></jats:sup>Pr,<jats:bold>2</jats:bold>: R = Cy) were obtained in good yields by treatment of<jats:italic>in situ‐</jats:italic>prepared Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−Li with the respective carbodiimides, R−N=C=N−R. Recrystallization of<jats:bold>1</jats:bold>and<jats:bold>2</jats:bold>from THF afforded the crystalline THF adducts Li[Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NR)<jats:sub>2</jats:sub>] ⋅ <jats:italic>n</jats:italic>THF (<jats:bold>1 a</jats:bold>: R =<jats:sup><jats:italic>i</jats:italic></jats:sup>Pr,<jats:italic>n</jats:italic>=1;<jats:bold>2 a</jats:bold>: R = Cy,<jats:italic>n</jats:italic>=1.5). Precursor<jats:bold>2</jats:bold>was subsequently used to study initial complexation reactions with selected di‐ and trivalent transition metals. The dark red homoleptic vanadium(III) tris(alkynylamidinate) complex V[Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NCy)<jats:sub>2</jats:sub>]<jats:sub>3</jats:sub>(<jats:bold>3</jats:bold>) was prepared by reaction of VCl<jats:sub>3</jats:sub>(THF)<jats:sub>3</jats:sub>with 3 equiv. of<jats:bold>2</jats:bold>(75 % yield). A salt‐metathesis reaction of<jats:bold>2</jats:bold>with anhydrous FeCl<jats:sub>2</jats:sub>in a molar ratio of 2 : 1 afforded the dinuclear homoleptic iron(II) alkynylamidinate complex Fe<jats:sub>2</jats:sub>[Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NCy)<jats:sub>2</jats:sub>]<jats:sub>4</jats:sub>(<jats:bold>4</jats:bold>) in 69 % isolated yield. Similarly, treatment of Mo<jats:sub>2</jats:sub>(OAc)<jats:sub>4</jats:sub>with 3 or 4 equiv. of<jats:bold>2</jats:bold>provided the dinuclear, heteroleptic molybdenum(II) amidinate complex Mo<jats:sub>2</jats:sub>(OAc)[Me<jats:sub>2</jats:sub>N−CH<jats:sub>2</jats:sub>−C≡C−C(NCy)<jats:sub>2</jats:sub>]<jats:sub>3</jats:sub>(<jats:bold>5</jats:bold>; yellow crystals, 50 % isolated yield). The cyclohexyl‐substituted title compounds<jats:bold>2 a</jats:bold>,<jats:bold>4</jats:bold>, and<jats:bold>5</jats:bold>were structurally characterized through single‐crystal X‐ray diffraction studies.</jats:p>