Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; 31P NMR, cyclic voltammetric and ESI mass spectrometry studies

F. Foster Mbaiwa; C. A.L. Becker

doi:10.1016/j.ica.2005.11.006

Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; ³¹P NMR, cyclic voltammetric and ESI mass spectrometry studies

F. Foster Mbaiwa, C. A.L. Becker

Chemical & Forensic Sciences

Research output: Contribution to journal › Article › peer-review

5 Citations (Scopus)

Abstract

Five new complexes of the type [Co(CNC₆H₃iPr ₂-2,6)₄PPh₂-R′-PPh₂]X, X = BF₄, ClO₄; R′ =-(CH₂)₂- (1), -(CH₂)₃- (2), -CHCH-trans (3), -CC- (4) and -C ₆H₄-p (5); and two new bimetallic complexes, [{Co(CNC ₆H₃iPr₂-2,6)₄}₂(μ- PPh₂(CH₂)₃PPh₂)](ClO ₄)₂ (6) and [{Co(CNC₆H₃iPr ₂-2,6)₄}₂(μ-PPh₂C ₆H₄PPh₂-p)](ClO₄)₂ (7), have been synthesized and characterized by various spectroscopic methods.Known monometallic and bimetallic complexes bearing the ligand CNC₆H ₃Et₂-2,6 instead of CNC₆H₃iPr ₂-2,6 have been included in the ³¹P NMR, cyclic voltammetric and mass spectrometry studies.Comparison of the CNC ₆H₃iPr₂-2,6 with the CNC₆H ₃Et₂-2,6 complexes shows that the increased steric bulkiness of the former makes it more suitable for synthesis of the monometallic complexes, whilst the CNC₆H₃Et₂-2,6 is more apt to give bimetallic complexes.Thus, the two arylisocyanides are complementary with respect to synthesis of the monometallic and bimetallic complexes.The ³¹P NMR indicates that the diphosphines in monometallic complexes behave as non-fluxional, monodentate ligands at ambient temperature, with ³¹P-³¹P coupling shown for the PPh₂CH ₂PPh₂, PPh₂(CH₂)₂PPh ₂ and PPh₂CCPPh₂ ligands. Cyclic voltammetry fails to show electronic communication in the bimetallic complexes, and mass spectrometry indicates significantly greater stability for fragments containing potentially chelating diphosphines as compared to diphosphines that cannot chelate.

Original language	English
Pages (from-to)	1041-1049
Number of pages	9
Journal	Inorganica Chimica Acta
Volume	359
Issue number	4
DOIs	https://doi.org/10.1016/j.ica.2005.11.006
Publication status	Published - Mar 1 2006

All Science Journal Classification (ASJC) codes

Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

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10.1016/j.ica.2005.11.006

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@article{76a87d7082fd46528fb98471d2b38951,

title = "Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; 31P NMR, cyclic voltammetric and ESI mass spectrometry studies",

abstract = "Five new complexes of the type [Co(CNC6H3iPr 2-2,6)4PPh2-R′-PPh2]X, X = BF4, ClO4; R′ =-(CH2)2- (1), -(CH2)3- (2), -CHCH-trans (3), -CC- (4) and -C 6H4-p (5); and two new bimetallic complexes, [{Co(CNC 6H3iPr2-2,6)4}2(μ- PPh2(CH2)3PPh2)](ClO 4)2 (6) and [{Co(CNC6H3iPr 2-2,6)4}2(μ-PPh2C 6H4PPh2-p)](ClO4)2 (7), have been synthesized and characterized by various spectroscopic methods.Known monometallic and bimetallic complexes bearing the ligand CNC6H 3Et2-2,6 instead of CNC6H3iPr 2-2,6 have been included in the 31P NMR, cyclic voltammetric and mass spectrometry studies.Comparison of the CNC 6H3iPr2-2,6 with the CNC6H 3Et2-2,6 complexes shows that the increased steric bulkiness of the former makes it more suitable for synthesis of the monometallic complexes, whilst the CNC6H3Et2-2,6 is more apt to give bimetallic complexes.Thus, the two arylisocyanides are complementary with respect to synthesis of the monometallic and bimetallic complexes.The 31P NMR indicates that the diphosphines in monometallic complexes behave as non-fluxional, monodentate ligands at ambient temperature, with 31P-31P coupling shown for the PPh2CH 2PPh2, PPh2(CH2)2PPh 2 and PPh2CCPPh2 ligands. Cyclic voltammetry fails to show electronic communication in the bimetallic complexes, and mass spectrometry indicates significantly greater stability for fragments containing potentially chelating diphosphines as compared to diphosphines that cannot chelate.",

author = "Mbaiwa, {F. Foster} and Becker, {C. A.L.}",

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T1 - Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; 31P NMR, cyclic voltammetric and ESI mass spectrometry studies

AU - Mbaiwa, F. Foster

AU - Becker, C. A.L.

PY - 2006/3/1

Y1 - 2006/3/1

N2 - Five new complexes of the type [Co(CNC6H3iPr 2-2,6)4PPh2-R′-PPh2]X, X = BF4, ClO4; R′ =-(CH2)2- (1), -(CH2)3- (2), -CHCH-trans (3), -CC- (4) and -C 6H4-p (5); and two new bimetallic complexes, [{Co(CNC 6H3iPr2-2,6)4}2(μ- PPh2(CH2)3PPh2)](ClO 4)2 (6) and [{Co(CNC6H3iPr 2-2,6)4}2(μ-PPh2C 6H4PPh2-p)](ClO4)2 (7), have been synthesized and characterized by various spectroscopic methods.Known monometallic and bimetallic complexes bearing the ligand CNC6H 3Et2-2,6 instead of CNC6H3iPr 2-2,6 have been included in the 31P NMR, cyclic voltammetric and mass spectrometry studies.Comparison of the CNC 6H3iPr2-2,6 with the CNC6H 3Et2-2,6 complexes shows that the increased steric bulkiness of the former makes it more suitable for synthesis of the monometallic complexes, whilst the CNC6H3Et2-2,6 is more apt to give bimetallic complexes.Thus, the two arylisocyanides are complementary with respect to synthesis of the monometallic and bimetallic complexes.The 31P NMR indicates that the diphosphines in monometallic complexes behave as non-fluxional, monodentate ligands at ambient temperature, with 31P-31P coupling shown for the PPh2CH 2PPh2, PPh2(CH2)2PPh 2 and PPh2CCPPh2 ligands. Cyclic voltammetry fails to show electronic communication in the bimetallic complexes, and mass spectrometry indicates significantly greater stability for fragments containing potentially chelating diphosphines as compared to diphosphines that cannot chelate.

AB - Five new complexes of the type [Co(CNC6H3iPr 2-2,6)4PPh2-R′-PPh2]X, X = BF4, ClO4; R′ =-(CH2)2- (1), -(CH2)3- (2), -CHCH-trans (3), -CC- (4) and -C 6H4-p (5); and two new bimetallic complexes, [{Co(CNC 6H3iPr2-2,6)4}2(μ- PPh2(CH2)3PPh2)](ClO 4)2 (6) and [{Co(CNC6H3iPr 2-2,6)4}2(μ-PPh2C 6H4PPh2-p)](ClO4)2 (7), have been synthesized and characterized by various spectroscopic methods.Known monometallic and bimetallic complexes bearing the ligand CNC6H 3Et2-2,6 instead of CNC6H3iPr 2-2,6 have been included in the 31P NMR, cyclic voltammetric and mass spectrometry studies.Comparison of the CNC 6H3iPr2-2,6 with the CNC6H 3Et2-2,6 complexes shows that the increased steric bulkiness of the former makes it more suitable for synthesis of the monometallic complexes, whilst the CNC6H3Et2-2,6 is more apt to give bimetallic complexes.Thus, the two arylisocyanides are complementary with respect to synthesis of the monometallic and bimetallic complexes.The 31P NMR indicates that the diphosphines in monometallic complexes behave as non-fluxional, monodentate ligands at ambient temperature, with 31P-31P coupling shown for the PPh2CH 2PPh2, PPh2(CH2)2PPh 2 and PPh2CCPPh2 ligands. Cyclic voltammetry fails to show electronic communication in the bimetallic complexes, and mass spectrometry indicates significantly greater stability for fragments containing potentially chelating diphosphines as compared to diphosphines that cannot chelate.

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Diphosphine substitution in pentakis(arylisocyanide)cobalt(I) complexes; ³¹P NMR, cyclic voltammetric and ESI mass spectrometry studies

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