Metal complexes have extensive applications in catalysis, however, the efficient evaluation of Lewis acidity of metal complexes is still a challenge. Herein, we report a method by using electrospray ionization mass spectrometry (ESI-MS) to evaluate the Lewis acidity of metal complexes in the presence of a reference Lewis base, in which the value of the Lewis acidity can be quantized by the bond dissociation energy (BDE) of the resultant Lewis acid-base pairs. Using this method, the Lewis acidity of tetradentate Schiff-base metal complexes (designated as salenMX), a class of common metal complexes in the homogeneous catalysis, was studied in detail. For the salenM(III)X complexes (M = Al, Cr, Fe, Co), the Lewis acidity tendency is Al > Cr > Fe > Co due to a strong affinity between the Al complex and the reference Lewis base while a weak affinity concerning on the Co complex. Additionally, the effect of ligand steric and electronic nature on the Lewis acidity was studied by using Co complex. Furthermore, density functional theory (DFT) was employed to calculate the BDE, which consists with the results obtained from ESI-MS. The ESI-MS method provides a convenient and efficient method for evaluating the Lewis acidity of metal complexes.
LawranceGA.Introduction to coordination chemistry.
UK: Pergamon Press, 2010. pp. 225–237.
2.
RaoDYLiBZhangR, et al.
Binding of 4-(N,N-dimethylamino)pyridine to salen- and salan-Cr(III) cations: a mechanistic understanding on the difference in their catalytic activity for CO2/epoxide copolymerization. Inorg Chem2009;
48: 2830–2836.
3.
DiCiccioAMLongoJMRodriguez-CaleroGG, et al.
Development of highly active and regioselective catalysts for the copolymerization of epoxides with cyclic anhydrides: an unanticipated effect of electronic variation. J Am Chem Soc2016;
138: 7107–7113.
4.
KoreRBertonPKelleySP, et al.
Group IIIA halometallate ionic liquids: speciation and applications in catalysis. ACS Catal2017;
7: 7014–7028.
5.
ScharfLTWeismannJFeichtnerKS, et al.
Versatile modes of cooperative B-H bond activation reactions in ruthenium-carbene complexes: addition, ring-opening and insertion. Chemistry2018;
24: 3439–3443.
6.
MayerUGutmannVGergerW.The acceptor number – a quantitative empirical parameter for the electrophilic properties of solvents. Monatsh Chem1975;
106: 1235–1257.
7.
BeckettMAStricklandGCHollandJR, et al.
A convenient N.M.R. method for the measurement of Lewis acidity at boron centres: correlation of reaction rates of Lewis acid initiated epoxide polymerizations with Lewis acidity. Polymer1996;
37: 4629–4631.
8.
BranchCSBottSGBarronAR.Group 13 trihalide complexes of 9-fluorenone: a comparison of methods for assigning relative| Lewis acidity. J Organomet Chem2003;
666: 23–34.
9.
BohnASenechal-DavidKVanoutryveJ, et al.
Synthesis and characterization of iron(II) complexes with a BPMEN-type ligand bearing π-accepting nitro groups. Eur J Inorg Chem2017;
2017: 3057–3063.
10.
AcevedoO.Determination of local effects for chloroaluminate ionic liquids on Diels–Alder reactions. J Mol Graph Model2009;
28: 95–101.
11.
Perez-BitrianABayaMCasasJM, et al. (
CF3)3Au as a highly acidic organogold(III) fragment. Chemistry2017;
23: 14918–14930.
12.
AdeevaVDehaanJWJanchenJ, et al.
Acid sites in sulfated and metal-promoted zirconium dioxide catalysts. J Catal1995;
151: 364–372.
13.
KobayashiSBusujimaTNagayamaS.A novel classification of Lewis acids on the basis of activity and selectivity. Chem Eur J2000;
6: 3491–3494.
14.
FukuzumiS.New perspective of electron transfer chemistry. Org Biomol Chem2003;
1: 609–620.
15.
KogelJFSorokinDAKhvorostA, et al.
The Lewis superacid Al[N(C6F5)2]3 and its higher homolog Ga[N(C6F5)2]3-structural features, theoretical investigation and reactions of a metal amide with higher fluoride ion affinity than SbF5. Chem Sci2018;
9: 245–253.
16.
BritovsekGJPUgolottiJWhiteA.From B(C6F5)3 to B(OC6F5)3: synthesis of (C6F5)2BOC6F5 and C6F5B(OC6F5)2 and their relative Lewis acidity. Organometallics2005;
24: 1685–1691.
17.
Graham CooksRPatrickJSKotiahoT, et al.
Thermochemical determinations by the kinetic method. Mass Spectrom Rev1994;
13: 287–339.
18.
KebarleP.Gas phase ion thermochemistry based on ion-equilibria from the ionosphere to the reactive centers of enzymes. Int J Mass Spectrom2000;
200: 313–330.
LinZTanLYangY, et al.
Gas-phase reactions of cyclopropenylidene with protonated alkyl amines. Analyst2016;
141: 2412–2417.
21.
KumarMKPrabhakarSKumarMR, et al.
Coordination chemistry of chromium-salen complexes studied by electrospray ionization mass spectrometry. Rapid Commun Mass Spectrom2004;
18: 1103–1108.
22.
BowersMTKemperPRVon HeldenG, et al.
Gas-phase ion chromatography: transition metal state selection and carbon cluster formation. Science1993;
260: 1446–1451.
23.
Casas-HinestrozaJLBuenoMIbanezE, et al.
Recent advances in mass spectrometry studies of non-covalent complexes of macrocycles – a review. Anal Chim Acta2019;
1081: 32–50.
24.
ChaiYShenSWengG, et al.
Gas-phase synthesis and reactivity of Cu+-benzyne complexes. Chem Commun (Camb)2014;
50: 11668–11671.
25.
KimYMChenP.Ligand binding energy in [(bipy)Rh(P≡CH)]+ by collision-induced dissociation threshold measurements. Int J Mass Spectrom2000;
202: 1–7.
26.
KrouseIHWentholdPG.Bond dissociation energy and Lewis acidity of the xenon fluoride cation. Inorg Chem2003;
42: 4293–4298.
27.
ChenPChisholmMHGallucciJC, et al.
Binding of propylene oxide to porphyrin-and salen-M(III) cations, where M=Al, Ga, Cr, and Co. Inorg Chem2005;
44: 2588–2595.
28.
CanaliLSherringtonDC.Utilisation of homogeneous and supported chiral metal(salen) complexes in asymmetric catalysis. Chem Soc Rev1999;
28: 85–93.
29.
RodgersMTArmentroutPB.Noncovalent metal-ligand bond energies as studied by threshold collision-induced dissociation. Mass Spectrom Rev2000;
19: 215–247.
30.
FraileJMGarciaJIMayoralJA.Noncovalent immobilization of enantioselective catalysts. Chem Rev2009;
109: 360–417.
FrańskiR.Gas-phase stability of sandwich complexes of crown ethers with metal cations – as studied by collision-induced dissociation tandem mass spectrometry. Rapid Commun Mass Spectrom2018;
32: 1651–1657.
33.
SlenoLVolmerDA.Ion activation methods for tandem mass spectrometry. J Mass Spectrom2004;
39: 1091–1112.
34.
BeckeAD.Density-functional exchange-energy approximation with correct asymptotic behavior. Phys Rev A Gen Phys1988;
38: 3098–3100.
DitchfieldRHehreW.PopleJ.Self-consistent molecular-orbital methods. IX. An extended Gaussian-type basis for molecular-orbital studies of organic molecules. J Chem Phys1971;
54: 724–728.
37.
HehreWJDitchfieldRPopleJA.Self-consistent molecular orbital methods. XII. further extensions of Gaussian-type basis sets for use in molecular orbital studies of organic molecules. J Chem Phys1972;
56: 2257–2261.
38.
HariharanPCPopleJA.The influence of polarization functions on molecular orbital hydrogenation energies. Theoret Chim Acta1973;
28: 213–222.
39.
HäussermannUDolgMStollH, et al.
Accuracy of energy-adjusted quasirelativistic ab initio pseudopotentials. Mol Phys1993;
78: 1211–1224.
40.
KüchleWDolgMStollH, et al.
Energy-adjusted pseudopotentials for the actinides. Parameter sets and test calculations for thorium and thorium monoxide. J Chem Phys1994;
100: 7535–7542.
41.
LeiningerTNicklassAStollH, et al.
The accuracy of the pseudopotential approximation. II. A comparison of various core sizes for indium pseudopotentials in calculations for spectroscopic constants of InH, InF, and InCl. J Chem Phys1996;
105: 1052–1059.
42.
GrimmeSAntonyJEhrlichS, et al.
A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J Chem Phys2010;
132: 154104.
43.
SchäferAHuberCAhlrichsR.Fully optimized contracted Gaussian basis sets of triple zeta valence quality for atoms Li to Kr. J Chem Phys1994;
100: 5829–5835.
44.
van DuijneveldtFBvan Duijneveldt de RijdtJvan LentheJH.State of the art in counterpoise theory. Chem Rev1994;
94: 1873–1885.
45.
BoysSFBernardiF.The calculation of small molecular interactions by the differences of separate total energies. Some procedures with reduced errors. Mol Phys1970;
19: 553–566.
46.
RosaAEhlersAWBaerendsEJ, et al.
Basis set effects in density functional calculations on the metal-ligand and metal-metal bonds of Cr(CO)5-CO and (CO)5Mn-Mn(CO)5. J Phys Chem1996;
100: 5690–5696.
47.
VoskoSHWilkLNusairM.Energy approximants and perturbation theory for screened coulomb potentials. Can J Phys1980;
58: 1200–1211.
48.
PerdewJP.Density-functional approximation for the correlation energy of the inhomogeneous electron gas. Phys Rev, B Condens Matter1986;
33: 8822–8824.
49.
TaoJPerdewJPStaroverovVN, et al.
Climbing the density functional ladder: nonempirical Meta-generalized gradient approximation designed for molecules and solids. Phys Rev Lett2003;
91: 146401.
50.
PerdewJPErnzerhofMBurkeK.Rationale for mixing exact exchange with density functional approximations. J Chem Phys1996;
105: 9982–9985.
51.
ZhaoYTruhlarD.The M06 suite of density functionals for main group thermochemistry, thermochemical kinetics, noncovalent interactions, excited states, and transition elements: two new functionals and systematic testing of four M06-class functionals and 12 other functional. Theor Chem Account2008;
120: 215–241.
52.
DasPLinertW.Schiff base-derived homogeneous and heterogeneous palladium catalysts for the Suzuki-Miyaura reaction. Coord Chem Rev2016;
311: 1–23.
53.
LiuYRenWMLiuJ, et al.
Asymmetric copolymerization of CO2 with meso-epoxides mediated by dinuclear cobalt(III) complexes: unprecedented enantioselectivity and activity. Angew Chem Int Ed Engl2013;
52: 11594–11598.
54.
LiuYWangMRenWM, et al.
Stereospecific CO2 copolymers from 3,5-dioxaepoxides: crystallization and functionallization. Macromolecules2014;
47: 1269–1276.
55.
LanghoffSRBauschlicherCWPartridgeH, et al.
Theoretical study of one and two ammonia molecules bound to the first-row transition metal ions. J Phys Chem1991;
95: 10677–10681.
56.
TilsetMFjeldahlIHamonJR, et al.
Adsorption dynamics of gases and vapors on the nanoporous metal organic framework material Ni2(4,4(4,4′-bipyridine)3(NO3)4: guest modification of host sorption behavior. J Am Chem Soc2001;
123: 9984–10000.
57.
RydeUMataRAGrimmeS.Does DFT-D estimate accurate energies for the binding of ligands to metal complexes. Dalton Trans2011;
40: 11176–11183.
58.
LiXZKongXJLiCQ, et al.
Syntheses and structures of eight-semi-coordinate M(II) (M=Mn, Fe, Co, Ni, Cu, Zn) complexes and density functional theory study of bond dissociation energies for the MO semi coordinate bonds. Inorg Chem Commun2013;
27: 114–118.
59.
WalterDArmentroutPB.Sequential bond dissociation energies of M+ (NH3)x (x=1-4) for M=Ti-Cu. J Am Chem Soc1998;
120: 3176–3187.
DucéréJMGoursotABerthomieD.Comparative density functional theory study of the binding of ligands to Cu+ and Cu2+: influence of the coordination and oxidation state. J Phys Chem A2005;
109: 400–408.
62.
QuZWHansenAGrimmeS.Co-C bond dissociation energies in cobalamin derivatives and dispersion effects: anomaly or just challenging. J Chem Theory Comput2015;
11: 1037–1045.
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