TY - JOUR
T1 - Bidentate chelate complexes of palladium(II) with the carbanion 2-C 6F4PPh2 and their transformation into complexes containing bridging 2-C6F4PPh2
AU - Bennett, Martin A.
AU - Kar, Gopa
AU - Mirzadeh, Nedaossadat
AU - Privér, Steven H.
AU - Rae, A. David
AU - Wagler, Jörg
AU - Willis, Anthony C.
AU - Bhargava, Suresh K.
PY - 2011/7/25
Y1 - 2011/7/25
N2 - Reaction of the organotin compound 2-Me3SnC6F 4PPh2 (7) with the cycloocta-1,5-diene complexes [PdX 2(cod)] at room temperature gives dinuclear halide-bridged palladium(II) complexes [Pd2(μ-X)2(κ2- 2-C6F4PPh2)2] [X = Cl (5), Br (8)] in which the carbanions are present as four-membered chelate rings. The bridging halides can be replaced by various anions, giving the corresponding dinuclear complexes having X = O2CCH3 (9), O2CPh (10), I (12), and SCN (15), and by acetylacetonate anion (acac) to give mononuclear [Pd(acac)(κ2-2-C6F4PPh2)] (17). In solution at room temperature the four-membered κ2-2- C6F4PPh2 rings open, probably by one-ended dissociation of a Pd-P bond, to give compounds of the same composition containing bridging 2-C6F4PPh2 units, e.g., [Pd4(μ-X)4(μ-2-C6F4PPh 2)4] [X = Cl (6), I (13)], [Pd2(μ-O 2CCH3)2(μ-2-C6F 4PPh2)2] (11), and [Pd2(acac) 2(μ-2-C6F4PPh2)2] (18). In some cases, only half the available chelate rings open; for example, complex 15 gives [Pd4(μ-SCN)4(μ-2-C 6F4PPh2)2(κ2-2- C6F4PPh2)2] (16) and complex 12 gives [(κ2-2-C6F4PPh2)Pd(μ- I)(μ-2-C6F4PPh2)Pd(μ-I) 2Pd(μ-I)(μ-2-C6F4PPh2) Pd(κ2-2-C6F4PPh2)] (14), in addition to 13. Ring-opening also occurs on addition of acetonitrile to 5 or 8, forming [Pd2X2(NCMe)2(μ-2-C 6F4PPh2)2] [X = Cl (19), Br (20)]. Treatment of 8 with two equivalents of PPh3 forms [PdBr(κ2-2-C6F4PPh2)(PPh 3)] (21) as a cis-trans mixture, which reacts with more PPh 3 to give trans-[PdBr(κC-2-C6F4PPh 2)(PPh3)2] (23) by displacement of the Pd-P bond of the chelate ring. The bulkier ligand tricyclohexylphosphine reacts with 8 to give an analogue (22) of 21, but it does not open the chelate ring. The X-ray structures of compounds 7-11, 13-21, and 23 are reported.
AB - Reaction of the organotin compound 2-Me3SnC6F 4PPh2 (7) with the cycloocta-1,5-diene complexes [PdX 2(cod)] at room temperature gives dinuclear halide-bridged palladium(II) complexes [Pd2(μ-X)2(κ2- 2-C6F4PPh2)2] [X = Cl (5), Br (8)] in which the carbanions are present as four-membered chelate rings. The bridging halides can be replaced by various anions, giving the corresponding dinuclear complexes having X = O2CCH3 (9), O2CPh (10), I (12), and SCN (15), and by acetylacetonate anion (acac) to give mononuclear [Pd(acac)(κ2-2-C6F4PPh2)] (17). In solution at room temperature the four-membered κ2-2- C6F4PPh2 rings open, probably by one-ended dissociation of a Pd-P bond, to give compounds of the same composition containing bridging 2-C6F4PPh2 units, e.g., [Pd4(μ-X)4(μ-2-C6F4PPh 2)4] [X = Cl (6), I (13)], [Pd2(μ-O 2CCH3)2(μ-2-C6F 4PPh2)2] (11), and [Pd2(acac) 2(μ-2-C6F4PPh2)2] (18). In some cases, only half the available chelate rings open; for example, complex 15 gives [Pd4(μ-SCN)4(μ-2-C 6F4PPh2)2(κ2-2- C6F4PPh2)2] (16) and complex 12 gives [(κ2-2-C6F4PPh2)Pd(μ- I)(μ-2-C6F4PPh2)Pd(μ-I) 2Pd(μ-I)(μ-2-C6F4PPh2) Pd(κ2-2-C6F4PPh2)] (14), in addition to 13. Ring-opening also occurs on addition of acetonitrile to 5 or 8, forming [Pd2X2(NCMe)2(μ-2-C 6F4PPh2)2] [X = Cl (19), Br (20)]. Treatment of 8 with two equivalents of PPh3 forms [PdBr(κ2-2-C6F4PPh2)(PPh 3)] (21) as a cis-trans mixture, which reacts with more PPh 3 to give trans-[PdBr(κC-2-C6F4PPh 2)(PPh3)2] (23) by displacement of the Pd-P bond of the chelate ring. The bulkier ligand tricyclohexylphosphine reacts with 8 to give an analogue (22) of 21, but it does not open the chelate ring. The X-ray structures of compounds 7-11, 13-21, and 23 are reported.
UR - http://www.scopus.com/inward/record.url?scp=79960528280&partnerID=8YFLogxK
U2 - 10.1021/om200179v
DO - 10.1021/om200179v
M3 - Article
SN - 0276-7333
VL - 30
SP - 3749
EP - 3762
JO - Organometallics
JF - Organometallics
IS - 14
ER -