Synthesis, coordination and catalytic use of 1-(diphenylphosphino)-1′-carbamoylferrocenes with pyridyl-containing N-substituents

Abstract

Ferrocene phosphinocarboxamides, 1-(diphenylphosphino)-1'-{N-[(2-pyridyl)methyl]carbamoyl}ferrocene (1) and 1-(diphenylphosphino)-1'-{N-[2-(2-pyridyl)ethyl]carbamoyl}ferrocene (2) were prepared from 1-(diphenylphosphino)-1'-ferrocenecarboxylic acid and studied as ligands for palladium. Starting with [PdCl2(cod)], the reactions at a 2 : 1 ligand-to-metal ratio gave uniformly the bis-phosphine complexes [PdCl2(L-kappaP)2] (3, L = 1; 4, L = 2) whereas those performed at a 1 : 1 ratio yielded distinct products: [PdCl2(1-kappa(2)P,N)] (5) with 1 coordinating as a trans-spanning P,N-donor, and the symmetric, P,N-bridged dimer [(micro-2-N,P)2{PdCl2}2] (6), respectively. The crystal structures of 1, 2, 4.4CHCl3, 5.AcOH, and 6.8CHCl3 as determined by X-ray diffraction showed the compounds to form well defined solid-state assemblies through hydrogen bonds. Testing of the phosphinocarboxamides in the palladium-catalysed Suzuki cross-coupling reaction revealed 1 and 2, combined with Pd(OAc)2 to form efficient catalysts for the reactions of aryl bromides while aryl chlorides coupled only when activated with electron-withdrawing groups.

Heterometallic complexes with the mono and disubstituted [(4-pyridylamino)carbonyl]ferrocene ligands

“…In both the silver center is found in a trigonal planar environment, with slightly distorted angles, the angles being for one of them N(4)eAg(1)eN(2) 91. 8(2), N(4)eAg(1)eP(1) 140.67 (18) and N(2)eAg(1)eP(1) 124.81(17) . The AgeN distances for one of the molecules are 2.291(7) and 2.327(7) Å and the AgeP is 2.365(2), which are similar to those found in three coordinated silver(I) complexes such as [Ag 2 {3,5e(CF 2 ) 2 CF 3 etriaz} 2 (PPh 3 ) 2 ] [31].…”

Synthesis, coordination studies and redox properties of a novel ditertiary phosphine bearing two ferrocenyl groups

“…Ferrocenyl derived phosphines have been accessed through a number of established methods previously [1a, 2,6,8,12,14]. In our work we have found that phosphorus based Mannich condensation reactions are extremely flexible procedures for preparing highly functionalised phosphines [41] and even nonsymmetric diphosphines [42] by employing two consecutive elimination steps.…”

“…The versatility of the Fc group in synthesis can be illustrated by some of the diverse compounds (Chart 1) previously documented in the literature. The Fc group can be employed either as a substituent bonded to phosphorus [6] or a metal centre [7] through an ethynyl linker or alternatively as a backbone for accessing primary and secondary phosphines [8], di-and polyphosphines [9,10], nonsymmetric ligands [11][12][13][14] and chiral systems [15][16][17][18]. To date, 1,1 0 -bis(diphenylphosphino)ferrocene (dppf) possibly remains the most iconic example of a phosphorus(III) based ligand containing the Fc moiety [4,[19][20][21][22][23].…”

The Coordination Behaviour of Ferrocene‐based Pyridylphosphine Ligands towards AgI and AuI

“…Neutral P , N , P ‐ligands based on a central pyridine unit are currently attracting great interest as versatile non‐innocent scaffolds for homogeneous catalysis 31. Compound 4 was synthesised in analogy to 1 by Negishi cross‐coupling of Ph 2 PfcZnCl with 2,6‐dibromopyridine 4a. It was structurally characterised by single‐crystal X‐ray diffraction analysis (Figure 7).…”