Zum Koordinationsverhalten von Alkinylphosphanen R_nP(CC–R')_3–n

Abstract

Coordination Ability of Alkynylphosphines RnP(CC – R')3 – n Alkynylphosphines RP(CC–R')2 (2) react with one equivalent of octacarbonyldicobalt to yield selectively the η2‐μ side‐on‐coordinated alkyne complexes (R)(R' – CC)P[(η2‐CC–R')Co2(CO)6] (6); with another equivalent of Co2(CO)8 the dicoordinated compounds (R)P[(η2‐CC–R')Co2(CO)6]2 (7) are obtained. 7 may also be synthesized directly by the reaction of 2 with two equivalents of Co2(CO)8. However, P(CC–Ph)3 yields with two equivalents of Co2(CO)8 the cyclic Co2P2C2 system {(Ph–CC)(R')P[(η2‐CC–Ph)Co2(CO)5]} 2 (4) [R' = (η2‐CC–Ph)Co2(CO)6]. Decarbonylation of 6a gives the six‐membered cyclic compound {(Ph)(Ph – C  C)P[(η2‐C  C – Ph)Co2(CO)5]}2 (8), while 6b yields the cluster Co3(CO)9(μ3‐PtBu) (9). The structure of (tBu)P[(η2‐C  C – H)Co2)CO)6]2 (7b) is elucidated by an X‐ray analysis.

Synthesis and reaction chemistry of [(μ-SeR)(μ-σ,π-CCPh)]Fe2(CO)6

“…The reaction of RSeC"CPh (1a, R = Et; 1b, R = n-Bu; 1c, R = Ph; 1d, R = 2,4,6-Me 3 C 6 H 2 ) with equimolar amounts of Fe 2 (CO) 9 (2) produces, upon evolution of CO and colour change from yellow to dark red, the diiron hexacarbonyl complexes [(l-SeR)(l-r,p-C"CPh)]Fe 2 -(CO) 6 (3a, R = Et; 3b, R = n-Bu; 3c, R = Ph; 3d, R = 2,4,6-Me 3 C 6 H 2 ) in tetrahydrofuran at 25°C (Eq.…”

“…Recently, Seyferth et al [1,2] reported on the synthesis and reaction chemistry of [(l-SR)(l-r,p-C"CR 0 )]-Fe 2 (CO) 6 (R = R 0 , R 6 ¼ R 0 ; R,R 0 = singly bound organic ligand) (type A molecule) by reacting Fe 2 (CO) 9 with RSC"CR 0 . A further possibility to prepare structural type A molecules is given by the reaction of [Et 3 NH][(l-SR)(l-CO)Fe 2 (CO) 6 ] with allylic or propargylic halides [1][2][3].…”

“…The reaction chemistry of related thio-and phosphido-bridged acetylide diiron hexacarbonyl complexes was explored [1,[4][5][6][7]. For example, the reactions of structural type A molecules with diverse transition metal carbonyls, such as Fe(CO) 5 , Fe 2 (CO) 9 and Co 2 (CO) 8 , respectively, were used to good advantage for the preparation of higher nuclearity, homoand heterometallic acetylide clusters [1,3]. These multimetallic species possess novel properties [1][2][3][4][5][6][7].…”

“…

RSeC"CPh (1a, R = Et; 1b, R = n-Bu; 1c, R = Ph; 1d, R = 2,4,6-Me 3 C 6 H 2 ) reacts with equimolar amounts of Fe 2 (CO) 9 (2) to give [(l-SeR)(l-r,p-C"CPh)]Fe 2 (CO) 6 (3a, R = Et; 3b, R = n-Bu; 3c, R = Ph; 3d, R = 2,4,6-Me 3 C 6 H 2 ).Complexes 3a-3d exist as two isomers, depending on the axial or equatorial position of R at selenium.Addition of P(O i C 3 H 7 ) 3 (4) to 3d affords {(l-Se-2,4,6-Me 3 C 6 H 2 )[l-g 1 -C@CPh(P(O i C 3 H 7 ) 3 )]}Fe 2 (CO) 6 (5) along with {(l-Se-2,4,6-Me 3 C 6 H 2 )[l-g 1 :g 1 -PhC@C(P(O i C 3 H 7 ) 3 )]}Fe 2 (CO) 6 (6).The solid-state structures of 3d, 5 and 6 were determined by single X-ray structure analysis.In mononuclear 3d the Fe(CO) 3 fragments are bridged by a l-Se-2,4,6-Me 3 C 6 H 2 and a l-r,p-C"CPh unit, resulting in an over-all butterfly arrangement.Due to steric reasons, the mesityl group is pointing away from the PhC"C entity and hence, is located in an equatorial position.Compounds 5 and 6, which cocrystallise in the ratio of 7:93, feature al-bridging 2,4,6-Me 3 C 6 H 2 Se unit and either a vinylidenic C@CPh(P(O i C 3 H 7 ) 3 ) (complex 5) or a olefinic PhC@C(P(O i C 3 H 7 ) 3 ) (complex 6) building block of which the latter entity is part of a diiron cyclobutene ring.

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“…RSeC"CPh (1a, R = Et; 1b, R = n-Bu; 1c, R = Ph; 1d, R = 2,4,6-Me 3 C 6 H 2 ) reacts with equimolar amounts of Fe 2 (CO) 9 (2) to give [(l-SeR)(l-r,p-C"CPh)]Fe 2 (CO) 6 (3a, R = Et; 3b, R = n-Bu; 3c, R = Ph; 3d, R = 2,4,6-Me 3 C 6 H 2 ).Complexes 3a-3d exist as two isomers, depending on the axial or equatorial position of R at selenium.Addition of P(O i C 3 H 7 ) 3 (4) to 3d affords {(l-Se-2,4,6-Me 3 C 6 H 2 )[l-g 1 -C@CPh(P(O i C 3 H 7 ) 3 )]}Fe 2 (CO) 6 (5) along with {(l-Se-2,4,6-Me 3 C 6 H 2 )[l-g 1 :g 1 -PhC@C(P(O i C 3 H 7 ) 3 )]}Fe 2 (CO) 6 (6).…”