Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/94947
Title: Substituted metal carbonyls. 27.1 Synthesis, structures, and metal-metal bonding of a ferrocenylphosphine exo-bridged cluster with two heterometallic triangles, [AuMn2(CO)8(μ-PPh2)]2(μ-dppf), and a twisted-bowtie cluster, PPN+[Au{Mn2(CO)8(μ-PPh2)} 2]-
Authors: Low, P.M.N.
Tan, A.L. 
Hor, T.S.A. 
Wen, Y.-S.
Liu, L.-K.
Issue Date: 28-May-1996
Source: Low, P.M.N.,Tan, A.L.,Hor, T.S.A.,Wen, Y.-S.,Liu, L.-K. (1996-05-28). Substituted metal carbonyls. 27.1 Synthesis, structures, and metal-metal bonding of a ferrocenylphosphine exo-bridged cluster with two heterometallic triangles, [AuMn2(CO)8(μ-PPh2)]2(μ-dppf), and a twisted-bowtie cluster, PPN+[Au{Mn2(CO)8(μ-PPh2)} 2]-. Organometallics 15 (11) : 2595-2603. ScholarBank@NUS Repository.
Abstract: Redox condensation of PPN[Mn2(CO)8(μ-PPh2)] (1; (PPN = N(PPh3)2) with Au2Cl2(μ-P-P) (P-P = (C5H4PPh2)2Fe (dppf), Ph2PC2H4PPh2 (dppe)) gives two hexanuclear Au-Mn clusters [AuMn2(CO)8(μ-PPh2)]2(μ-P-P) (P-P = dppf, (2), dppe (4)), both of which contain a diphosphine bridging two Mn2Au triangles. Complex 2 is formed via an intermediate, AuCl-(μ-dppf)[AuMn2(CO)8(μ-PPh2)], (3), which was isolated. Bridge cleavage of 2 occurs at thf reflux with PPh3 and room temperature with P(OEt)3 to give the triangular clusters [(PR3)-AuMn2(CO)8(μ-PPh2)] (R = Ph (5), OEt (6)), respectively. The latter exchange of dppf with P(OEt)3 is reversible in solution. Condensation of 1 with AuCl(SMe2) gives an anionic pentanuclear cluster, PPN[Au{Mn2(CO)8(μ-PPh2)}2] (7). Complexes 2 and 7 were structurally characterized by single-crystal X-ray diffractometry. Complex 2, which is centrosymmetric with Fe in dppf at a crystallographic inversion center, consists of a ferrocenylphosphine bridging two heterometallic triangles (Au-Mn = 2.660(1) and 2.776(1) Å; Mn-Mn = 3.049(2) Å). Complex 7 is made up of two planar AuMn2P metallacycles fused at Au at an angle of 85.50(4)°. With crystallographic C2 symmetry, a twisted-bowtie skeleton resulted with gold at its center. Both Au-Mn (mean 2.806(1) Å) and (PPh2-bridged) Mn-Mn (3.105(2) Å) lengths are significantly longer than those in 2. The Mn-Mn bond of 2 is also significantly longer than that of 1. Fenske-Hall MO calculations on 1, 2, and 7 together with Mn2(CO)8(μ-H)(μ-PPh2) (8) and (PPhMe2)AuMn2(CO)8(PPh2) (9) indicate that aside from 1, all the complexes, including 2 and 7, give a negative overlap population in the Mn-Mn interactions. The Mn-Mn distance appears to be determined by the strength of the AuMn2 interaction and/or the size of H compared to Au. The weaker Mn-Mn and Au-Mn interactions in 7 (as compared to those in 2 and 9, respectively) are likely to be caused by the absence of Au orbital reinforcement in the direction of the Mn2 moiety as a consequence of symmetry.
Source Title: Organometallics
URI: http://scholarbank.nus.edu.sg/handle/10635/94947
ISSN: 02767333
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

40
checked on Feb 24, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.