Simon Grabowsky a * Technology Organisation, New Illawarra Road, Lucas Heights NSW 2234 Australia,

Transcription

1 1 Predicting the position of the hydrogen atom in the short intramolecular hydrogen bond of the hydrogen maleate anion from geometric correlations (Supporting Information) Lorraine A. Malaspina, a Alison J. Edwards, b Magdalena Woińska, c Dylan Jayatilaka, d Michael J. Turner, d Jason R. Price, e Regine Herbst-Irmer, f Kunihisa Sugimoto, g Eiji Nishibori h and Simon Grabowsky a * a Institute for Inorganic Chemistry and Crystallography, University of Bremen, Leobener Str. NW2, Bremen Germany, b Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights NSW 2234 Australia, c Biological and Chemical Research Centre, Chemistry Department, University of Warsaw, Zwirki i Wigury 101, Warsaw Poland, d School of Molecular Sciences, Chemistry M313, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009 Australia, e Australian Synchrotron, 800 Blackburn Rd, Clayton VIC 3168 Australia, f Institute for Inorganic Chemistry, University of Göttingen, Tammannstr. 4, Göttingen Germany, g Japan Synchrotron Radiation Research Institute (JASRI) 1-1-1, Kouto, Sayo-cho, Sayo-gun, Hyogo Japan, and h Division of Physics, Faculty of Pure and Applied Sciences, TIMS and CiRfSE, University of Tsukuba, Tsukuba Japan. simon.grabowsky@uni-bremen.de

2 2 Table S1: Details of Crystallization. Compound Solvent reagent solution conc. Crystal size (mm) Crystal color Na H 2 O solid maleic acid 0.03 mol x 0.9 x colourless solid NaOH 0.03 mol Mg H 2 O solid maleic acid 0.06 mol 0.9 x 1.5 x 1.5 colourless solid MgCO 3 hydrate 0.03 mol Ca H 2 O solid maleic acid 13.5 mmol 0.7 x 0.7 x colourless solid Ca(OH) mmol 8HQ H 2 O solid maleic acid 3.0 mmol x 0.9 x yellow solid 8-hydroxyquinoline 3.0 mmol K H 2 O solid maleic acid 6.0 mmol 0.4 x 1.5 x colourless + EtOH solid K 2 CO mmol Li H 2 O solid maleic acid 3.0 mmol 0.2 x 0.3 x colourless + EtOH solid LiOH 3.0 mmol 4AP H 2 O solid maleic acid 3.0 mmol 0.9 x x colourless + EtOH solid 4-aminopyridine 3.0 mmol Ba H 2 O solid maleic acid 3.0 mmol 0.2 x 0.2 x 0.4 colourless + EtOH solid Ba(OH) mmol Table S2: Dihedral angles ( ) between planes involving C1-C4 and C1,O1,H1,O2,C4 atoms. HM unit Dihedral angle K 0.71(4) PhAla 4(9) 2Ba 9.9(3) Mg 5.47(4) 4AP 3.84(10) Ca 1.38(8) 3Ba 1.7(3) 1Ba 2.5(3) 4Ba 7.6(3) Li 2.74(8) Na 0.42(4) 8HQ 2(9)

3 3 Table S3: Intramolecular hydrogen bonds for HM anions, results from neutron diffraction data. Distances in Å, angles in. HM unit Donor H Acceptor D - H H A D A D - H A K O(1) H(1) O(1) 134(4) 134(4) 251(6) (13) PhAla O(1) H(1) O(2) 08(2) 10(2) 160(15) 175.9(2) 2Ba O(12) H(12) O(22) 1.196(10) 14(10) 07(5) 173.9(8) Mg O(1) H(1) O(2) (17) 180(17) 035(10) (14) 4AP O(1) H(1) O(2) 1.194(3) 34(3) 27(2) 176.9(2) Ca O(1) H(1) O(2) 1.125(3) 1.310(3) 329(17) 176.6(2) 1Ba O(1) H(1) O(2) 1.125(8) 1.316(8) 40(5) 176.0(6) 3Ba O(13) H(13) O(23) 1.113(10) 1.315(10) 27(5) 176.2(7) 4Ba O(14) H(14) O(24) 1.118(8) 1.327(8) 43(5) 175.4(7) Li O(1) H(1) O(2) 1.109(3) 1.319(3) 263(18) 176.6(3) Na O(1) H(1) O(2) 813(11) (11) 483(8) (11) 8HQ O(1) H(1) O(2) 72(4) 1.379(4) 50(2) 177.3(3) Table S4: Intramolecular hydrogen bonds for HM anions from X-ray diffraction data, IAM freely refined H1. Distances in Å, angles in. HM unit Donor H Acceptor D - H H A D A D - H A K O(1) H(1) O(1) 143(8) 143(8) 270(5) 176(2) PhAla O(1) H(1) O(2) 1.18(2) 3(2) 116(7) 174(3) 2Ba O(12) H(12) O(22) 0.94(7) 1.514(6) 34(10) 165.2(5) Mg O(1) H(1) O(2) 1.152(10) 53(10) 040(6) 177.5(10) 4AP O(1) H(1) O(2) 1.157(14) 78(14) 286(4) 172.1(12) Ca O(1) H(1) O(2) 1.104(12) 1.361(19) 29(2) 176.1(11) 1Ba O(1) H(1) O(2) 38(7) 96(7) 54(11) 15(5) 3Ba O(13) H(13) O(23) 43(11) 4Ba O(14) H(14) O(24) 1.18(13) 8(12) 37(9) 164(11) Li O(1) H(1) O(2) 8(2) 1.326(12) 343(6) 17(17) Na O(1) H(1) O(2) 41(10) 3(4) 428(3) 174.6(9) 8HQ O(1) H(1) O(2) 3(4) 04(10) 47(7) 170(3)

4 Table S5: Intramolecular hydrogen bonds for previously reported neutron-derived structures of HM anions. NR stands for not reported. * sign designates deuterated structures. Atom labels reported as in the original structures, therefore Donor and Acceptor correspond to O1 and O2 (in our labeling scheme), respectively. Distances in Å, angles in. HM unit CSD refcode Temp. Donor H(1) Acceptor D - H H A D A D - H A Mg CIRVAA01 RT O(3) H O(1) 1.186(7) 28(7) 14(5) 176(1) Imidazolium IMZMAL11 RT O(4) H(10) O(2) 1.196(4) 1.197(4) 2.393(3) 176.8(4) Imidazolium* IMZMAL13* RT O(2) D(10) O(4) 1.186(6) 14(6) 2.399(5) 177.3(5) K KHMALA02 RT O(2) H(1) O(2 ) 2(NR) 2(NR) 4(NR) NR K F. Fillaux 300K O(1) H(1) O(1 ) 149(7) 149(7) NR(NR) 175.3(2) K F. Fillaux 14K O(2) H(1) O(2 ) 131(4) 131(4) NR(NR) 175.8(1) K F. Fillaux 5K O(2) H(1) O(2 ) 145(7) 145(7) 27(1) 175.7(2) Na NAHMAL01 120K O(2) H(1 ) O(3) 79(2) 1.367(2) 45(2) 176.1(2) Ca CAHMAL11 RT O(3) OHO O(1) 1.121(3) 1.305(3) 24(2) 175.9(3) Ca CAHMAL01 RT O(1) H(1) O(2) 1.13(3) 1.31(3) 26(1) 171(3) Zn MALAQZ01 RT O(4) H(7) O(2) 1.125(NR) 1.308(NR) 30(NR) (NR) Zn MALAQZ03 RT O(3) H(3) O(2) 97(7) 1.316(5) 10(4) 174.7(4) Methylamonium* POVHEN02* 122K O(2) D(2) O(2 ) 134(6) 134(6) 214(5) (NR) Methylamonium* POVHEN02* 122K O(4) D(1) O(4 ) 101(5) 101(5) 183(5) (NR) 4

5 Table S6: Calculated distances using the correlation developen this study applied to the synchrotron X-ray data sets, compared to distances from neutron diffraction experiment (see Figure 6). Distances in Å, angles in. HM unit calc x calc y neutron(x) neutron(y) diff from diff from neutron x neutron y K 85(6) 1.144(7) 134(4) 134(4) PhAla 15(6) 1.198(6) 10(2) 08(2) Ba 1.316(11) 1.119(16) 14(10) 1.196(10) Mg 25(6) 1.181(6) 181(17) (17) AP 92(6) 1.138(6) 33(3) 1.194(3) Ca 94(6) 1.137(7) 1.309(3) 1.124(3) Ba 06(11) 49(16) 1.316(8) 1.125(8) Ba 1.357(11) 88(16) 1.315(10) 1.113(10) Ba 1.330(11) 1.109(16) 1.327(8) 1.118(8) Li 1.317(6) 1.118(7) 1.319(3) 1.109(3) HQ 1.364(6) 82(7) 1.378(4) 72(4) Na 1.356(6) 88(7) (11) 813(11) Table S7: Calculated distances using the correlation developen this study applied to previously reported neutron-derived structures, compared to distances from neutron diffraction experiment. NR stands for not reported. Distances in Å, angles in. CSD refcode calc x calc y x (neutron) y(neutron) diff from diff from neutron x neutron y CIRVAA01 26(14) 1.190(14) 28(7) 134(4) IMZMAL11 63(11) 1.131(11) 1.197(4) 1.196(4) IMZMAL13* 42(14) 1.158(13) 14(6) 1.186(6) KHMALA (8) 98(7) 2(NR) 2(NR) NAHMAL (9) 81(8) 1.367(2) 79(2) CAHMAL11 71(10) 1.155(10) 1.305(3) 1.121(3) CAHMAL01 80(9) 1.148(8) 1.31(3) 1.13(3) MALAQZ01 98(8) 1.133(7) 1.308(NR) 1.125(NR) MALAQZ03 08(12) 04(12) 1.316(5) 97(7) POVHEN02* 59(8) 1.164(8) 134(6) 134(6) POVHEN02* 45(8) 1.175(8) 101(5) 101(5)

6 6 Table S8: Intermolecular hydrogen bonds for K HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry C(2) H(2) O(1) 863(12) (14) (9) (6) 3-x,-1/2+y,z Table S9: Intermolecular hydrogen bonds for Ba HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry O(51) H(51) O(58) 0.973(10) 2.108(10) 3.006(6) 152.7(7) x,y,z O(52) H(52) O(33) 0.962(10) 47(9) 2.782(5) 163.4(7) x,y,1+z O(53) H(53) O(42) 0.967(9) 93(9) 2.828(6) 162.1(9) -x,-1/2+y,1-z O(54) H(54) O(55) 0.975(9) 83(9) 2.809(6) 157.5(7) 1+x,y,z O(55) H(55) O(24) 0.948(10) 84(10) 3.026(7) 17(7) x,y,z O(56) H(56) O(57) 0.975(8) 86(8) 2.817(5) 158.8(7) -1+x,y,z O(57) H(57) O(44) 0.974(8) 54(8) 2.812(5) 167.2(7) 1+x,y,z O(58) H(58) O(52) 0.966(9) 1.979(9) 2.921(6) 164.4(6) x,y,z O(51) H(61) O(14) 0.943(11) 1.965(10) 2.905(6) 173.9(7) 1-x,-1/2+y,1-z O(52) H(62) O(54) 0.948(8) 1.950(8) 2.816(6) 15(7) -1+x,y,z O(53) H(63) O(56) 0.959(9) 34(9) 2.882(6) 146.4(7) x,y,z O(54) H(64) O(3) 0.999(9) 13(9) 2.780(6) 16(7) 1-x,1/2+y,1-z O(55) H(65) O(53) 0.972(10) 1.949(9) 2.910(6) 169.3(8) x,y,z O(56) H(66) O(33) 0.972(9) 00(9) 2.763(5) 170.2(7) x,y,z O(57) H(67) O(3) 0.985(8) 1.781(8) 2.764(6) 176.2(7) 1-x,1/2+y,-z O(58) H(68) O(22) 0.961(11) 37(10) 2.974(7) 164.4(7) x,y,z

7 7 Table S10: Intermolecular hydrogen bonds for Mg HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry O(5) H(4) O(4) (18) 042(18) (11) (17) 1+x,1/2-y,1/2+z O(5) H(5) O(3) (18) (17) (11) (16) x,y,z O(6) H(6) O(3) (15) 960(16) (10) 177(16) x,1/2-y,1/2+z O(6) H(7) O(4) (16) (16) (10) (15) x,-y,1-z O(7) H(8) O(3) (16) (16) (10) (16) x,1/2-y,-1/2+z O(7) H(9) O(2) (18) 086(18) (11) (13) -x,-1/2+y,1/2-z C(3) H(3) O(1) 910(14) 045(17) (10) (15) -x,-1/2+y,1/2-z Table S11: Intermolecular hydrogen bonds for 4AP HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry N(1) H(4) O(4) 22(3) 86(3) (17) 16(2) 1+x,1+y,z N(1) H(5) O(2) 24(2) 1.915(3) (15) 160.3(3) 1-x,1/2+y,2-z N(2) H(8) O(3) 55(3) 88(3) (18) 170.5(2) x,-1+y,z C(6) H(6) O(4) 90(3) 75(3) 3.306(2) (18) 1+x,1+y,z C(7) H(7) O(3) 96(2) 35(2) (16) 163.3(2) 1-x,-1/2+y,1-z C(9) H(10) O(1) 96(2) 06(3) (18) 140.3(3) 1-x,-1/2+y,2-z Table S12: Intermolecular hydrogen bonds for Ca HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry O(5) H(51) O(4) 0.983(3) 44(3) (15) 157.6(2) 1/2-x,-y,1/2+z O(6) H(61) O(4) 0.972(3) 1.729(3) (17) 178.0(3) x,-y,2-z O(6) H(62) O(2) 0.976(3) 1.782(3) (18) 173.1(2) 1/2-x,-y,1/2+z O(7) H(71) O(3) 0.963(3) 1.988(3) (18) 158.4(2) -1/2+x,y,3/2-z O(8) H(81) O(6) 58(6) 2.134(6) 3.163(3) 163.5(5) x,y,-1+z O(8) H(82) O(5) 0.958(4) 1.917(4) 2.866(3) 170.5(4) -1/2+x,1/2-y,3/2-z Table S13: Intermolecular hydrogen bonds for Li HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry O(5) H(4) O(4) 0.968(3) 24(3) (19) 175.5(3) 1/2+x,3/2-y,-1/2+z O(5) H(5) O(3) 0.967(3) 00(3) 2.940(2) 163.4(3) 1+x,y,z O(6) H(6) O(4) 0.981(3) 1.722(3) 2.699(2) 173.7(3) 1-x,1-y,1-z O(6) H(7) O(2) 0.978(3) 1.797(3) (19) 172.5(3) -x,1-y,1-z C(2) H(2) O(1) 83(3) 2.599(3) (18) 131.3(2) 1+x,y,z

8 Table S14: Intermolecular hydrogen bonds for Na HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry O(5) H(4) O(4) (12) (13) (9) (12) 1-x,1-y,-z O(5) H(5) O(2) (13) 235(13) (9) 175(12) 2-x,1-y,-z O(6) H(6) O(3) (13) 858(14) (9) (12) -1+x,y,z O(6) H(7) O(4) (14) (15) (10) (15) 1-x,-y,-z O(7) H(8) O(5) (14) 491(14) (9) (12) x,-1+y,z O(7) H(9) O(4) (12) (13) (9) (11) x,y,1+z Table S15: Intermolecular hydrogen bonds for 8HQ HM, distances in Å, angles in. Donor H Acceptor D - H H A D A D - H A symmetry N(1) H(4) O(4) 70(3) 74(3) (17) 166.5(3) -1+x,y,z O(5) H(5) O(4) 0.997(3) 63(3) 2.652(2) 170.9(3) -1/2+x,1/2-y,1-z C(2) H(2) O(3) 88(3) 2.512(3) (19) 127.6(2) 1/2+x,3/2-y,1-z C(8) H(7) O(3) 94(4) 92(4) 3.309(2) 153.8(3) 1+x,-1+y,z C(13) H(11) O(2) 94(3) 2.142(3) 3.052(2) 138.9(2) -1+x,y,z Table S16: Other short contacts for K HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry K(1) O(1) (12) -1+x,y,z K(1) O(3) (10) -1+x,y,z K(1) O(3) (10) x,1/2-y,1-z K(1) O(3) (7) 2-x,-y,1-z K(1) O(1) (8) x,1/2-y,1-z K(1) K(1) (11) 1-x,-1/2+y,z 8

9 9 Table S17: Other short contacts for Ba HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry Ba(1) O(2) 2.924(5) x,y,z Ba(1) O(4) 2.903(5) x,y,z Ba(1) O(32) 2.697(5) x,y,z Ba(1) O(42) 2.801(5) 1-x,-1/2+y,1-z Ba(1) O(43) 2.729(5) 1-x,1/2+y,-z Ba(1) O(51) 2.825(5) x,y,z Ba(1) O(52) 2.854(5) x,y,z Ba(1) O(54) 2.769(5) x,y,z Ba(1) O(55) 2.932(6) x,y,z Ba(2) O(4) 2.772(5) x,y,z Ba(2) O(23) 2.925(5) 1-x,1/2+y,-z Ba(2) O(34) 2.696(5) 1-x,-1/2+y,-z Ba(2) O(43) 2.868(5) 1-x,1/2+y,-z Ba(2) O(44) 2.786(5) x,y,z Ba(2) O(53) 2.859(6) 1+x,y,z Ba(2) O(56) 2.842(5) x,y,z Ba(2) O(57) 2.809(6) x,y,z Ba(2) O(58) 2.883(5) x,y,-1+z O(1) H(33) 2.543(8) x,y,1+z O(2) C(42) 3.081(5) 1-x,-1/2+y,1-z O(12) C(4) 3.183(5) 1-x,1/2+y,1-z O(12) H(24) 12(8) x,y,1+z O(13) H(3) 56(8) x,y,z O(22) C(1) 3.087(5) 1-x,1/2+y,1-z O(22) H(34) 2.611(8) x,y,1+z O(51) H(32) 2.705(9) 1-x,-1/2+y,1-z Table S18: Other short contacts for Mg HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry O(1) H(3) 045(17) -x,1/2+y,1/2-z C(1) C(2) (10) x,1/2-y,1/2+z C(4) C(4) (10) x,1/2-y,-1/2+z H(2) O(6) (18) x,y,z

10 10 Table S19: Other short contacts for 4AP HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry O(1) H(10) 06(3) 1-x,1/2+y,2-z O(3) C(3) 3.140(2) x,1+y,z O(4) C(1) 3.174(2) x,-1+y,z O(4) H(2) 2.692(3) -x,-1/2+y,1-z C(1) C(7) (19) x,y,z C(4) C(6) (18) -1+x,y,z C(2) H(3) 2.687(3) -x,1/2+y,1-z C(7) H(2) 2.770(3) 1-x,-1/2+y,1-z C(9) H(9) 2.856(3) 1-x,1/2+y,2-z H(2) H(7) 18(4) 1-x,1/2+y,1-z Table S20: Y-X Cg(Ring) interactions for 4AP HM, distances in Å, angles in. Cg=Center of gravity. Y X Cg X..Cg Y-X..Cg Y..Cg C(4)-O(4) Cg (16) 89.99(10) (13) where: 6-Membered Ring N(2) C(7) C(6) C(5) C(9) C(8) Table S21: Ring-Interactions with Cg-Cg Distances < 6.0 Å for 4AP HM, distances in Å, angles in. Cg=Center of gravity. Cg(I) Cg(J) Cg-Cg symmetry Cg(1) Cg(1) (15) x,-1+y,z Cg(1) Cg(1) (15) x,1+y,z Cg(1) Cg(1) (14) 1-x,1/2+y,2-z Table S22: Other short contacts for Ca HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry O(1) C(4) (17) 1/2-x,-y,-1/2+z O(1) H(2) 2.630(3) 1/2+x,y,3/2-z O(2) H(3) 2.667(3) 1/2+x,y,3/2-z Ca(1) O(3) 178(18) x,1/2-y,z Ca(1) O(5) 49(2) x,y,z Ca(1) O(6) (19) x,1/2-y,z Ca(1) O(7) 71(2) x,y,z Ca(1) O(8) 2.350(3) x,y,z

11 11 Table S23: Other short contacts for Li HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry O(1) C(4)g (16) -x,2-y,1-z O(1) C(4)f (16) -x,1-y,1-z O(1) H(5) 2.618(3) -1+x,y,z O(1) H(2) 2.599(3) -1+x,y,z O(2) C(1)f (15) -x,1-y,1-z O(2) C(1)g (15) -x,2-y,1-z O(2) H(3) 2.651(4) -1+x,y,z O(6) Li(1) 1.992(4) 1/2-x,-1/2+y,1/2-z Li(1) O(6) 38(3) x,y,z Li(1) Li(1) 3.168(4) 1/2-x,-1/2+y,1/2-z Li(1) O(5) 1.923(5) x,y,z Li(1) O(3) 1.960(4) x,y,z Li(1) H(2) 2.791(5) x,y,z Table S24: Other short contacts for Na HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry Na(1) Na(1)b (12) 2-x,1-y,1-z Na(1) O(3) (10) x,y,z Na(1) O(5) (11) x,y,z Na(1) O(6) (10) x,y,z Na(1) O(7) 003(11) x,y,z O(1) C(4) (10) 2-x,-y,-z O(1) C(4) (10) 2-x,1-y,-z O(2) C(1) (10) 2-x,-y,-z O(1) H(2) (13) 1+x,y,z Table S25: Other short contacts for 8HQ HM, distances in Å, angles in. I (atom) J (atom) d(i,j) symmetry O(1) C(12) (19) 1-x,1/2+y,3/2-z O(1) C(13) (19) x,y,z O(2) C(5) (19) x,y,z O(2) H(9) 2.640(3) 2-x,1/2+y,3/2-z O(3) H(10) 2.702(3) 1-x,1/2+y,3/2-z C(1) C(4) (17) -1+x,y,z C(2) H(6) 2.792(3) -1/2+x,1/2-y,1-z C(3) H(2) 2.844(4) 1/2+x,3/2-y,1-z C(12) H(8) 2.877(3) 2-x,1/2+y,3/2-z H(7) H(10) 2.346(5) 2-x,-1/2+y,3/2-z

12 Table S26: Ring-Interactions for 8HQ HM with Cg-Cg Distances. Cg=Center of gravity. Cg(I) Cg(J) Cg-Cg Alpha Beta Gamma symmetry(j) Cg(1) Cg(1) (13) 0.02(5) x,y,z Cg(1) Cg(1) (13) 0.02(5) x,y,z Cg(1) Cg(1) (13) 84.21(5) x,-1/2+y,3/2-z Cg(1) Cg(2) (11) 1.32(5) x,y,z Cg(1) Cg(2) (13) 85.21(5) x,1/2+y,3/2-z Cg(2) Cg(1) (11) 1.32(5) x,y,z Cg(2) Cg(1) (13) 85.21(5) x,-1/2+y,3/2-z Cg(2) Cg(2) (13) 0.04(5) x,y,z Cg(2) Cg(2) (13) 0.04(5) x,y,z 12 Restraints used for Ba HM The X-ray refinement of Ba HM shows that this structure was twinned by inversion at low temperatures (forthcoming studies will be performed to determine the temperature of the phase transition from P 2 1 /c at high temperatures to P 2 1 at low temperatures). This allowed the use of restraints based on the fact that two HM units (and 4 water molecules) are related to the other two (and four) by a non-crystallographic symmetry. Different refinement strategies were addopted (isotropic refinement only, isotropic with the hydrogen atoms in question being refined anisotropically, and anisotropic refinement for all atoms using restraints). The CIFs for these three refinement strategies can be downloaded from the supporting information. For the restrained model the following restraints were used: Thermal similarity restraints applied to atoms: Ba(1), Ba(2), C(4), C(2), O(3), O(52), O(56), O(44), C(24), C(44), C(14), O(57), O(51). This corresponds to 78 restraints (13 atoms x 6 Uijs). Additionally the anisotropic displacement parameters for atoms Ba(1) and Ba(2) were restrained to be similar along the direction of the bond between the two Ba atoms, totalizing 80 restrains.

13 13 (a) 1 Ba HM (b) 2 Ba HM (c) 3 Ba HM (d) 4 Ba HM Figure S1: Hirshfeld surfaces with dnorm mapped onto them. All Hirshfeld surfaces were generated using the same color range from (for de + di smaller than the sum of the vdw radii - red) to 21 (de + di bigger than the sum of the vdw radii blue).

14 14 (a) K HM (b) PhAla HM (c) Mg HM (d) 4AP HM (e) Ca HM (f) Li HM (g) Na HM (h) 8HQ HM Figure S2: Hirshfeld surfaces with dnorm mapped onto them. All Hirshfeld surfaces were generated using the same color range from (for de + di smaller than the sum of the vdw radii - red) to 21 (de + di bigger than the sum of the vdw radii blue).

15 15 (a) 1 Ba HM (b) 2 Ba HM (c) 3 Ba HM (d) 4 Ba HM (e) K HM (f) PhAla HM Figure S3: Fingerprint plots

16 16 (a) Mg HM (b) 4AP HM (c) Ca HM (d) Li HM (e) Na HM (f) 8HQ HM Figure S4: Fingerprint plots

17 Figure S5: Percentage of different contact types mediated through the Hirshfeld surfaces. 17