Synthesis and coordination of hybrid phosphinoferrocenes with extended donor pendants

Abstract

Combining a phosphinoferrocene fragment with flexible multidonor moieties affords novel, flexible multidonor pro-ligands. This contribution describes the synthesis of two structurally similar functional phosphines, Ph2PfcNHC(O)CH2PPh2 (1) and Ph2PfcNHCH2CH2PPh2 (2, fc...

Tailoring the Fe → Pd interaction in cationic Pd(ii) complexesviastructural variation of the ligand scaffold of sterically demanding dppf-analogs and their P,N-counterparts

“…Whereas all previously reported azaphospha-substituted ferrocene ligands have been synthesized starting from BH 3 -protected ferrocenyl phosphanes, 33,54,67,71 the synthesis of azaphosphanes 3 (with generic structure of E, depicted in Fig. 1) hinges upon successful and large-scale preparation of an unsymmetrically substituted 1,1′-azabromoferrocene 1.…”

“…Known 1,1'-diphospha substituted dppf-analogues A: R = R' = Ph, Mes, t Bu etc. ; 23,27,32,[38][39][40][41][42][43][44][45][46][47][48] 1,1'unsymmetrically substituted diphenylphosphano ferrocenes B: X = CHO, 49,50 COOH, 51 COOMe, 51 CONEt 2 , 52 CvCBr 2 , 49 CuCH, 49 HCvCH 2 , 53 CuN, 54 CH 2 OH, 34 SH, 55 oxazoline, 56 PO(OEt) 2 , 57 COOH, 58,59 OMe, 60 C 5 H 4 N, 61 bipyridine, 62 HCvN(C 6 F 5 ), 63,64 CH 2 NH (CHMePh), 50 CHN(CHMePh), 50 3,5-dihydroazepine, 65 NuC, 54 NvC (NH i Pr) 2 , 66 NvC(NHC 6 H 11 ) 2 , 66 NvC(NHXyl) 2 , 66 NH(CO)CH 2 PPh 2 , 67 and NH(CH 2 ) 2 PPh 2 ; 67 1,1'-unsymmetrically substituted di-tert-butylphosphano ferrocenes C; 68,69 and bis( phosphinimine) ligands D: R = Et and Ph. 70 Analogous heteroditopic P,N-ligands, presented in this report, E: R = Ph and Mes.…”

“…1). 33,54,[66][67][68][69]71 The simultaneous presence of P and N donor atoms in a single molecule, are attractive to differentiate between their softness according to the HSAB concept and to foster hemilabile coordination. Recently the chemistry of κ 3 -bis(donor)ferrocenyltransitionmetal interactions has been reviewed as well.…”

“…The Fe-Pd distance in 11 is 2.7384 (18), which is shorter than previously reported values for such complexes ranging between 2.7590(5) to 2.7956(5) Å (entries 7 and 8, Table 1). 66,67 By contrast, for the dicationic Pd complexes 12-15 derived from P,N ligand 3a, the longest Fe-Pd distances are also observed (2.811(3)-2.8349(11) Å, entry 9, Table 1), as compared to the previously reported complexes with ferrocene based P,N ligands (2.7590(5)-2.7956(5) Å, entries 7 and 8, Table 1). 66,67 The short Fe-Pd distance in complex 10 may be interpreted as an attractive bonding interaction between these two metal centers.…”

“…66,67 By contrast, for the dicationic Pd complexes 12-15 derived from P,N ligand 3a, the longest Fe-Pd distances are also observed (2.811(3)-2.8349(11) Å, entry 9, Table 1), as compared to the previously reported complexes with ferrocene based P,N ligands (2.7590(5)-2.7956(5) Å, entries 7 and 8, Table 1). 66,67 The short Fe-Pd distance in complex 10 may be interpreted as an attractive bonding interaction between these two metal centers. However, such a short contact may also be considered as a consequence of a large torsion (τ) or bite angle (β n ) at the structurally flexible ferrocene scaffold owing to steric repulson between substituents R's around Pd (Fig.…”