Instrumental Parameters Used for ESI/QIT-MS

Supporting Information

Table of contents

Instrumental parameters used for ESI/QIT-MS

Table S1. Atoms in molecules (AIM)and Natural population analysis (NPA)atomic charges for the ground state structures of the Yb(OH)2+(H2O)n (H2O)m ; n = 0-4, m=0-2.

Table S2.Atoms in molecules (AIM) and Natural population analysis (NPA) atomic charges for the ground state structures of the YbF2+(H2O)n (H2O)m ; n = 0-4, m=0-2.

Table S3.Atoms in molecules (AIM) and Natural population analysis (NPA)atomic charges for the ground state structures of the YbF(OH)+(H2O)n (H2O)m ; n = 0-4, m=0-2.

Table S4. Atoms in molecules (AIM) and Natural population analysis (NPA)atomic charges for the ground state structures of the YbCl2+ (H2O)n (H2O)m ; n = 0-4, m=0-2.

Table S5. Atoms in molecules (AIM) and Natural population analysis (NPA)atomic charges for the ground state structures of the YbCl(OH)+(H2O)n (H2O)m ; n = 0-4, m=0-2.

AIM and NPA analyses: discussion

Figure S1. Alternative YbF(OH)+(H2O)3 structures (PBEZORA/TZ2P level of theory). Relative energies (RE) are calculated with respect to the ground-state isomer.

Complete Reference 41

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Instrumental parameters used for ESI/QIT-MS.

Spectra for the YbCl3 and TmCl3 solutions were acquiredusing the following instrumental parameters: Solution flow rate, 60 µl/min; Nebulizer gas pressure, 15 psi; Dry gas flow rate, 5 L/min; Dry gas temperature, 325°C; Capillary voltage, -4500 V; Capillary exit voltage, 119.5 V; Skimmer voltage, 27.8 V; Octopole 1 and 2 DC voltage, 11.58 V and 3.13 V; Octopole RF amplitude, 94.7 Vpp; Lens 1 and 2 voltage, -7.1 V and -100.0 V; Trap drive, 199.3. The same parameters were used for the YbBr3 and YbI2 solutions except for the following: Capillary exit voltage, 170.8 V; Skimmer voltage, 26.3 V; Octopole 1 and 2 DC voltage, 9.95 V and 3.46 V; Octopole RF amplitude, 95.8 Vpp; Lens 1 voltage, -6.5 V; Trap drive, 194.3.

Table S1 : AIM and NPA(in parentheses) atomicchargesfor the ground state structures of the Yb(OH)2+(H2O)n(H2O)m; n = 0-4, m=0-2.1

1In a.u., 2Second-sphere water molecules, 3O atom of OH groupforming H-bonds with the second-sphere molecule, 4 H atom of OH group forming H-bond with second-sphere water molecules,5O atom of first sphere water molecules forming H-bond with second-sphere water molecules, 6H atom of first sphere water molecules forming H-bond with second-sphere water molecules.7H atom of second sphere water molecule forming H bond with OH group.Free H2O: qO = -1.098 (-0.913); qH = 0.549 (0.456). Q are total charges on the indicated fragments.

Table S2 : AIM and NBO (in parentheses) atomic charges for the ground state structures of the YbF2+(H2O)n (H2O)m ; n = 0-4, m=0-2.1

1In a.u., 2Second-sphere water molecules, 3F atom forming H-bond with second sphere water molecule, 4O atom of first sphere water molecule forming H-bond with second sphere water molecule. 5 H atom of first sphere water molecules forming H-bond with second sphere water molecule, 6H atom of second sphere water molecule forming H-bond with F atom. Free H2O: qO = -1.098 (-0.913); qH = 0.549 (0.456). Q are net charges on the indicated fragments.

Table S3 : AIM and NPA (in parentheses) atomic charges for the ground state structures of the YbFOH+ (H2O)n (H2O)m ; n = 0-4, m=0-2.1

1In a.u., 2Second-sphere water molecules, 3 F atom forming H-bond with second sphere water molecule. 3O atom of first sphere water molecules forming H-bonds with the second-sphere molecule, 4O atom of first sphere water molecules forming H-bond with second sphere water molecule, 5H atom of first sphere water molecule forming H-bond with second sphere water molecule. 6H atom of second sphere water molecule forming H-bond with F atom.7O atom of OH group forming H-bond with second sphere water molecule. 8H atom of OH group forming H-bond with second sphere water molecule. Free H2O: qO = -1.098 (-0.913); qH = 0.549 (0.456). Q are total charges on the indicated fragments.

Table S4: AIM and NPA (in parentheses) atomic charges for the ground state structures of the YbCl2+(H2O)n (H2O)m ; n = 0-4, m=0-2.1

1In a.u., 2Second-sphere water molecules,3O atom of first sphere water molecules forming H-bonds with the second-sphere molecule, 4H atom of first sphere water molecules forming H-bond with second-sphere water molecules.5H atom of second sphere water molecule forming H-bond with first sphere water molecules.Free H2O: qO= -1.098 (-0.913); qH = 0.549 (0.456). Q are total charges on the indicated fragments.

Table S5 : AIM and NBO (in parentheses) atomic charges for the ground state structures of the YbClOH+ (H2O)n (H2O)m ; n = 0-4, m=0-2.1

1In a.u., 2Second-sphere water molecules, 3O atom of OH group forming H-bond with second sphere water molecule. 4 H atom of OH group forming H-bond with second sphere water molecule. 5O atom of first sphere water molecules forming H-bonds with the second-sphere molecule, 6H atom of first sphere water molecules forming H-bond with second sphere water molecules, 7H atom of second sphere water molecules forming H-bond with OH group. Free H2O: qO= -1.098 (-0.913); qH = 0.549 (0.456). Q are total charges on the indicated fragments.

AIM and NPA analyses: discussion

Atomic charges calculated using AIM and NPA analyses for all of the bare and hydrated cations are summarized in tables S1 to S5 (Supporting Information). Both population analyses predict a decrease in the YbX2+ and YbX(OH)+charges resulting from a partial charge transfer from the first coordination shell of water molecules to the complex. The amount of charge transferred to the YbX2+ or YbX(OH)+ unit after adding the first four water molecules ranged from 0.29 e- for YbF2+ to 0.19 e- for Yb(OH)2+. Therefore, the first solvation shell significantly stabilizes the charge of the cations through electron donation.

Addition of a second solvation shell induces a charge transfer from the outer sphere to the inner sphere which further spreads the positive charge. The amount of the charge transferred correlates fairly well with the net charge of the first coordination shell. The largest charge transfer from the second solvation shell is seen in YbF2+ (0.094 e-), which bears the highest positive charge (0.254 e-) in the first solvation shell. In the case of YbF2+, the distribution of the charge between the first and second solvation shell slightly decreases the net charge of the ytterbium difluoride by 0.004 e- after the fifth and sixth hydration. However, for the other species, the addition of waters in the second coordination shell induces an increase in the positive charge of the YbX2+ or YbX(OH)+ unit from 0.012 e-, in the case of YbCl2+, to 0.030 e-, in the case of YbFOH+. This behavior contrasts the trends found in the bare trivalent lanthanide cations. Clark and Kuta[16] have recently studied the trends in aqueous hydration of bare trivalent lanthanide cations and found that, in general, the addition of a second solvation shell induces a charge transfer from exterior to interior coordinated waters, which further decreases the charge on the metal by between 0.05 e- and 0.16 e-. In this same study, which used a level of theory comparable to that used in this work, it was found that the NPA metal charge in Yb(H2O)83+ is 1.786 au; on average, each water molecule donates 0.13 e- to the metal center. However, in the case of the YbX2+ and YbX(OH)+ cations studied here, the addition of the second shell of water molecules increases the positive charge of the core unit because of the direct interaction established between the second shell water molecules and the X ligands. In the case of YbF2+, the strong hydrogen bond formed between the fluorides and the second shell of water molecules increases the negative charge of the fluorides and is higher than the increase of the positive charge of the metal atom. The net effect is a decrease of the charge associated with the YbX2+ or YbX(OH)+ moieties. In contrast, the negative charge on the Cl atom in YbCl2+ when going from tetra to penta and hexahydrates is practically constant (within 0.003 e-). Consequently, the increase in charge on the base unit is dominated by a +0.018 e- increase of charge on the metal atom.

Figure S1

Complete Reference 41

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