Structures of [M₂(dimen)₄](Y)₂ (M = Rh, Ir; dimen = 1,8-Diisocyanomenthane; Y = PF₆, Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, B(C₆H₅)₄) Crystals Featuring an Exceptionally Wide Range of Metal−Metal Distances and Dihedral Twist Angles

Abstract

Crystal Data for [M 2 (dimen) 4 ](Y) 2 salts. [Rh 2 (dimen) 4 ](TFPB) 2 : C 1 12 H 9 B 2 F 4 8 N 8 Rh 2 , M = 2693.40, orange irregular crystal (0.60 x 0.50 x 0.30 mm), triclinic, space group P 1 (No. 2), a = 13.287 (3) A, b = 13.792 (6) A, c = 17.953 (7) A, a = 86.90 (3)0, 0 = 89.44 (3)0, y= 69.76 (3)o, V = 3082 (4) A3, Pcalc = 1.451 g cm-3 , Z = 1; 20max = 43.90; 7940 reflections (7539 unique, Rint = 0.037), T = 24.0 oC, 3729 observations (338 parameters) converged to R = 0.093 (Rw = 0.106). [Rh 2 (dimen) 4 1[B(C 6 Hs) 4 1 2 : C 9 6 H 1 12 B 2 N 8 Rh 2 , M = 1605.428, red prism (0.30 x 0.33 x 0.41 mm), space group Pbca (No. 61), a = 19.390 (5) A, b = 29.492 (7) A, c = 30.970 (7) A,V= 17710 (7) A3, Pcalc = 1.204 g cm-3 , Z= 8; 26max = 40,00; 16793 reflections (7821 unique, Rint = 0.03 1), T = 23.0 oC, 7817 observations (505 parameters) converged to R = 0.104 (R, = 0.080). [Ir 2 (dimen) 4 1(PF 6) 2 : C 4 8 H 7 2 F 1 2 Ir 2 N 8 P 2 , M = 1435.53, dark prism (0.45 x 0.75 x 0.08 mm), triclinic, space group P 1 (No. 2), a = 13.605 (8) A, b = 14.196 (4) A, c = 9.464 (7) A, a = 94.96 (4)0, 0 = 104.21 (5)0, Y = 61.83 (3)O, V= 1561 (3) A3, Pcalc = 1.527 g cm-3 , Z= 1; 20max = 52.00; 6497 reflections (6045 unique, Rint = 0.048), T = 24.0 oC, 3520 observations (194 parameters) converged to R = 0.073 (Rw = 0.075). [1r 2 (dimen) 4 1(TFPB) 2 : C 1 12 H 9 6 B 2 F 4 8 Ir 2 N 8 , M = 2872.03, purple plate (0.30 x 0.25 x 0.05 mm), triclinic, space group P 1 (No. 2), a = 13.110 (5) A, b = 13.513 (3) A, c = 17.770 (4) A, a = 87.61 (2)0, P = 90.43 (2)0, y 70.10 (2)0, V= 2970 (3) A3, Pcalc = 1.606 g cm-3 , Z= 1; 26max = 32.00; 3211 reflections (2893 unique, Rit = 0.066), T=-101.0 oC, 1976 observations (330 parameters) converged to R = 0.079 (R, = 0.067). [Ir 2 (dimen) 4 1[B(C 6 Hs) 4)1 2 : C 9 6 H 1 12 B 2 Lr 2 N 8 , M = 1784.05, black prism (0.240 x 0.140 x 0.130 mm), orthorhombic, space group Pbca (No. 61), a = 19.32 (1) A, b = 29.45 (1) A, c = 30.92 (3) A, V= 17600 (33) A3, Pcalc = 1.346 g cm-3 , Z = 8; 20max = 43.90; 10753 reflections (all unique), T =-101.0 oC, 4771 observations (359 parameters) converged to R = 0.061 (Rw = 0.062).

Transient Changes in Molecular Geometries and How to Model Them

“…9 and accompanying text). This isomerism has previously been observed [31], and is supported computationally by constrained mappings of the energy landscapes, made in-house by T. B. van Driel [26] (see fig. 8) and elsewhere [32], and is reflected in the double-peak in the absorption spectrum of the complex ( fig.…”

Electronic structures and photophysics of d8-d8 complexes

“…As an alternative to self-assembled dimers and oligomers, the use of designed bridging ligands enabled construction of binuclear complexes with well-defined and controllable structures ( Figure 2). Diisocyanide ligands "bridge" (1,3-diisocyanopropane) and TMB (2,5dimethyl-2,5-diisocyanohexane) were used to make Rh 2 (bridge) 4 2+ (Rh(bridge)) and Rh 2 TMB 4 2+ (Rh(TMB)) that have relatively short metal-metal distances (3.24 Å in Rh(bridge); 3.26 Å in Rh(TMB) [5], 3.12 Å in Ir(TMB) [6]). Each of these complexes exhibits a strong dσ*→pσ visible absorption band that arises from the metal-metal interaction.…”

Atomistic characterization of the active-site solvation dynamics of a model photocatalyst

“…When the driving forces for solvation transition from physical to chemical interactions, the importance of site-specific interactions and dynamics becomes more prominent, as does the need for experimental probes that robustly sample the dynamics of solute–solvent interactions with atomic resolution. Here we present a femtosecond resolution hard X-ray scattering study of the electronic excited state dynamics of the model photocatalyst [Ir 2 (dimen) 4 ] 2+ (dimen=diisocyano-para-menthane) in acetonitrile solution910111213. Figure 1a shows the molecular structure, and Fig.…”

“…Excitation thus leaves both the and orbitals partially occupied, making the excited state molecule both a better oxidant and reductant than the ground state molecule. Since both orbitals extend outside the molecule along the metal–metal axis, the metal atoms become open coordination sites for photoactivated reduction, oxidation and atom transfer reactions9101516. These photoreactions either directly involve the solvent, or happen in competition with active site coordination of the solvent.…”

“…The properties of ultrafast diffuse X-ray scattering make the method an optimal approach to study the dynamics occurring locally around the photocatalytically active Ir atoms where the largest changes in intramolecular electronic and nuclear structure of [Ir 2 (dimen) 4 ] 2+ occur10. Since the change in the XDS signal depends on the change in the interatomic distances between pairs of atoms and their electron density, the time resolved signal is very sensitive to changes in the structure surrounding the electron rich Ir atoms.…”