Mononuclear and Binuclear Chromium (III) Picolinate Complexes

Diane M. Stearns; William H. Armstrong

doi:10.1021/ic00051a007

Mononuclear and Binuclear Chromium (III) Picolinate Complexes

Diane M. Stearns, William H. Armstrong

Chemistry and Biochemistry

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

111 Scopus citations

Abstract

The chromium(III) picolinate complexes [Cr(pic)₃] (1) and [Cr(pic)₂OH]₂(2) (where pic = 2-carboxypyridine) have been isolated from the reaction of chromium(III) chloride and picolinic acid in aqueous solution. The monomeric complex 1-H₂O (CrC₁₈H₁₄N₃O₇) crystallizes in the monoclinic space group C2/c with a = 30.219 (3) Å, b = 8.529 (1) Å, c = 13.942 (2) Å, β = 95.141 (1)°, V= 3579 (2) Å³, Z = 4, R = 0.032, and R_w= 0.043 for 1815 reflections (I > 3σ(I)). The binuclear complex 2.5H₂O (Cr₂C₂₄H₂₈N₄O₁₅) crystallizes in the monoclinic space group P2₁/n with a = 12.569 (2) Å, b = 18.839 (3) Å, c = 13.000 (4) Å, β = 105.823 (3)°, V= 2962 (2) Å³, Z = 8, R = 0.046, R_W, = 0.067 for 3250 reflections (I > 3σ(I)). The mononuclear complex 1 is the meridional isomer, not the facial isomer as previously assumed. For 2 the bridging geometry is as follows: Cr-Cr = 2.999 (1) Å; Cr-O(bridge) range = 1.934 (3)-1.980 (3) Å; Cr-O-Cr = 99.0 (1), 101.6(1)°; O-Cr-O = 79.4 (1), 79.9 (1)°. Magnetic susceptibility data for 2 were measured from 280 to 6 K and can be fit using an isotropic spin-exchange Hamiltonian, Ή = -2JŜ₁Ŝ₂, with a weak antiferromagnetic interaction (J = -8.02 (4) cm^-1), g = 1.844, and a 2.23 (4) mol % paramagnetic impurity. The extent of magnetic coupling in 2 is compared to predictions made by the Glerup-Hodgson-Pedersen (GHP) equation. Compounds 1 and 2 are discussed in the general context of biologically active chromium.

Original language	English (US)
Pages (from-to)	5178-5184
Number of pages	7
Journal	Inorganic Chemistry
Volume	31
Issue number	25
DOIs	https://doi.org/10.1021/ic00051a007
State	Published - Dec 1 1992

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry

Access to Document

10.1021/ic00051a007

Cite this

@article{308ddd5e818c4947918ac6f62b752027,

title = "Mononuclear and Binuclear Chromium (III) Picolinate Complexes",

abstract = "The chromium(III) picolinate complexes [Cr(pic)3] (1) and [Cr(pic)2OH]2(2) (where pic = 2-carboxypyridine) have been isolated from the reaction of chromium(III) chloride and picolinic acid in aqueous solution. The monomeric complex 1-H2O (CrC18H14N3O7) crystallizes in the monoclinic space group C2/c with a = 30.219 (3) {\AA}, b = 8.529 (1) {\AA}, c = 13.942 (2) {\AA}, β = 95.141 (1)°, V= 3579 (2) {\AA}3, Z = 4, R = 0.032, and Rw= 0.043 for 1815 reflections (I > 3σ(I)). The binuclear complex 2.5H2O (Cr2C24H28N4O15) crystallizes in the monoclinic space group P21/n with a = 12.569 (2) {\AA}, b = 18.839 (3) {\AA}, c = 13.000 (4) {\AA}, β = 105.823 (3)°, V= 2962 (2) {\AA}3, Z = 8, R = 0.046, RW, = 0.067 for 3250 reflections (I > 3σ(I)). The mononuclear complex 1 is the meridional isomer, not the facial isomer as previously assumed. For 2 the bridging geometry is as follows: Cr-Cr = 2.999 (1) {\AA}; Cr-O(bridge) range = 1.934 (3)-1.980 (3) {\AA}; Cr-O-Cr = 99.0 (1), 101.6(1)°; O-Cr-O = 79.4 (1), 79.9 (1)°. Magnetic susceptibility data for 2 were measured from 280 to 6 K and can be fit using an isotropic spin-exchange Hamiltonian, Ή = -2JŜ1Ŝ2, with a weak antiferromagnetic interaction (J = -8.02 (4) cm-1), g = 1.844, and a 2.23 (4) mol % paramagnetic impurity. The extent of magnetic coupling in 2 is compared to predictions made by the Glerup-Hodgson-Pedersen (GHP) equation. Compounds 1 and 2 are discussed in the general context of biologically active chromium.",

author = "Stearns, {Diane M.} and Armstrong, {William H.}",

year = "1992",

month = dec,

day = "1",

doi = "10.1021/ic00051a007",

language = "English (US)",

volume = "31",

pages = "5178--5184",

journal = "Inorganic Chemistry",

issn = "0020-1669",

publisher = "American Chemical Society",

number = "25",

}

TY - JOUR

T1 - Mononuclear and Binuclear Chromium (III) Picolinate Complexes

AU - Stearns, Diane M.

AU - Armstrong, William H.

PY - 1992/12/1

Y1 - 1992/12/1

N2 - The chromium(III) picolinate complexes [Cr(pic)3] (1) and [Cr(pic)2OH]2(2) (where pic = 2-carboxypyridine) have been isolated from the reaction of chromium(III) chloride and picolinic acid in aqueous solution. The monomeric complex 1-H2O (CrC18H14N3O7) crystallizes in the monoclinic space group C2/c with a = 30.219 (3) Å, b = 8.529 (1) Å, c = 13.942 (2) Å, β = 95.141 (1)°, V= 3579 (2) Å3, Z = 4, R = 0.032, and Rw= 0.043 for 1815 reflections (I > 3σ(I)). The binuclear complex 2.5H2O (Cr2C24H28N4O15) crystallizes in the monoclinic space group P21/n with a = 12.569 (2) Å, b = 18.839 (3) Å, c = 13.000 (4) Å, β = 105.823 (3)°, V= 2962 (2) Å3, Z = 8, R = 0.046, RW, = 0.067 for 3250 reflections (I > 3σ(I)). The mononuclear complex 1 is the meridional isomer, not the facial isomer as previously assumed. For 2 the bridging geometry is as follows: Cr-Cr = 2.999 (1) Å; Cr-O(bridge) range = 1.934 (3)-1.980 (3) Å; Cr-O-Cr = 99.0 (1), 101.6(1)°; O-Cr-O = 79.4 (1), 79.9 (1)°. Magnetic susceptibility data for 2 were measured from 280 to 6 K and can be fit using an isotropic spin-exchange Hamiltonian, Ή = -2JŜ1Ŝ2, with a weak antiferromagnetic interaction (J = -8.02 (4) cm-1), g = 1.844, and a 2.23 (4) mol % paramagnetic impurity. The extent of magnetic coupling in 2 is compared to predictions made by the Glerup-Hodgson-Pedersen (GHP) equation. Compounds 1 and 2 are discussed in the general context of biologically active chromium.

AB - The chromium(III) picolinate complexes [Cr(pic)3] (1) and [Cr(pic)2OH]2(2) (where pic = 2-carboxypyridine) have been isolated from the reaction of chromium(III) chloride and picolinic acid in aqueous solution. The monomeric complex 1-H2O (CrC18H14N3O7) crystallizes in the monoclinic space group C2/c with a = 30.219 (3) Å, b = 8.529 (1) Å, c = 13.942 (2) Å, β = 95.141 (1)°, V= 3579 (2) Å3, Z = 4, R = 0.032, and Rw= 0.043 for 1815 reflections (I > 3σ(I)). The binuclear complex 2.5H2O (Cr2C24H28N4O15) crystallizes in the monoclinic space group P21/n with a = 12.569 (2) Å, b = 18.839 (3) Å, c = 13.000 (4) Å, β = 105.823 (3)°, V= 2962 (2) Å3, Z = 8, R = 0.046, RW, = 0.067 for 3250 reflections (I > 3σ(I)). The mononuclear complex 1 is the meridional isomer, not the facial isomer as previously assumed. For 2 the bridging geometry is as follows: Cr-Cr = 2.999 (1) Å; Cr-O(bridge) range = 1.934 (3)-1.980 (3) Å; Cr-O-Cr = 99.0 (1), 101.6(1)°; O-Cr-O = 79.4 (1), 79.9 (1)°. Magnetic susceptibility data for 2 were measured from 280 to 6 K and can be fit using an isotropic spin-exchange Hamiltonian, Ή = -2JŜ1Ŝ2, with a weak antiferromagnetic interaction (J = -8.02 (4) cm-1), g = 1.844, and a 2.23 (4) mol % paramagnetic impurity. The extent of magnetic coupling in 2 is compared to predictions made by the Glerup-Hodgson-Pedersen (GHP) equation. Compounds 1 and 2 are discussed in the general context of biologically active chromium.

UR - http://www.scopus.com/inward/record.url?scp=25544463063&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=25544463063&partnerID=8YFLogxK

U2 - 10.1021/ic00051a007

DO - 10.1021/ic00051a007

M3 - Article

AN - SCOPUS:25544463063

SN - 0020-1669

VL - 31

SP - 5178

EP - 5184

JO - Inorganic Chemistry

JF - Inorganic Chemistry

IS - 25

ER -

Mononuclear and Binuclear Chromium (III) Picolinate Complexes

Abstract

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this