From the room temperature reaction of the transition metal alkynyl Fischer carbene complexes (CO)₅M

C(OEt)(C⋮CPh) (M = Cr, W) with the homochalcogenide compounds Fe₂(CO)₆(μ-E₂) (E = S, Se, Te), the following new trimetallic adducts were obtained: [(CO)₆Fe₂E₂{μ-PhCCC(OEt)}M(CO)₅] (1−5; 1, 30%, E = S, M = Cr; 2, 85%, E = Se, M = Cr; 3, 85%, E = Se, M = W; 4, 28%, E = Te, M = Cr; 5, 25%, E = Te, M = W). Alkoxy groups are readily replaced by amino groups in adducts 2, 3, and 5 at room temperature as syn- and anti-isomers, [(CO)₆Fe₂E₂{μ-PhCCCN(H)R}M(CO)₅] (syn-8a−f and anti-8a−f; where R = CH₃, CH₂Ph, CH₂CHCH₂), in 70−90% yield. When a methanolic solution of [(CO)₆Fe₂EE‘{μ-PhCCC(OEt)}M(CO)₅] (E ≠ E‘; E = S, Se; E‘ = Se, Te; M = Cr, W) was stirred at room temperature for 1−2 days, the ester and ortho ester derivatives (CO)₆Fe₂{μ-EC(Ph)C(CO)(OR)E‘} (12−15) and (CO)₆Fe₂{μ-EC(Ph)CC(OR)(OMe)₂E‘} (16−19) (R = CH₃, C₂H₅) were formed. All compounds were characterized by IR and ¹H, ¹³C, ⁷⁷Se, and ¹²⁵Te NMR spectroscopies. Crystallographic analysis of the compound Fe₂(CO)₆{μ-SC(Ph)CC(OCH₃)₂(OC₂H₅)Te} (17) established its structure as a Fe₂STe tetrahedral butterfly core containing the ortho ester unit, C(Ph)CC(OCH₃)₂(OC₂H₅)} as a bridge between the two wing-tip chalcogens.