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Free-energy relationship

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521: 235: 531: 124:, but at present there is little sign of acceptance of this change. The area of physical organic chemistry which deals with such relations is commonly referred to as 'linear free-energy relationships'. 138:
A typical LFER relation for predicting the equilibrium concentration of a compound or solute in the vapor phase to a condensed (or solvent) phase can be defined as follows (following
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Abraham MH, Ibrahim A, Zissimos AM, Zhao YH, Comer J, Reynolds DP (October 2002). "Application of hydrogen bonding calculations in property based drug design".
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can be determined. Free energy relationships are often used to calculate equilibrium constants since they are experimentally difficult to determine.
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with the logarithm of the rate or equilibrium constant for a related series of reactions. Free energy relationships establish the extent at which
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Poole CF, Atapattu SN, Poole SK, Bell AK (October 2009). "Determination of solute descriptors by chromatographic methods".
583: 851: 563: 543: 71: 516:{\displaystyle \log \mathrm {SP} =c+e\mathrm {E} +s\mathrm {S} +a\mathrm {A} +b\mathrm {B} +v\mathrm {V} } 420:= the contribution from hydrogen-bond acidity to the transfer of the solute from air to the aerosol phase. 230:{\displaystyle \log \mathrm {SP} =c+e\mathrm {E} +s\mathrm {S} +a\mathrm {A} +b\mathrm {B} +l\mathrm {L} } 20: 568: 558: 139: 70:
The most common form of free-energy relationships are linear free-energy relationships (LFER). The
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descriptors representing the complementary properties of the compounds. Specifically,
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of a series of catalysts and the reaction rate constant for a reaction on which the
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Relation between the equilibrium/reaction rate constants of two chemical reactions
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Similarly, the correlation of solvent–solvent partition coefficients as
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predicts the equilibrium constant or reaction rate of a reaction from a
249: 391: 384:= the contribution from cavity formation and dispersion interactions; 350:
by virtue of its capacity for orientation and induction interactions;
32: 370: 281: 79: 411: 360: 277: 410:= the contribution from hydrogen-bond basicity (because a basic 347: 305: 110:
is an example of a quadratic free-energy relationship (QFER).
113: 688: 276:) are system constants describing the contribution of the 758: 639: 723: 346:= the ability of a solute to stabilize a neighbouring 437: 377:
The complementary system constants are identified as
151: 127: 116:has suggested that this name should be replaced by 759:Bradley JC, Abraham MH, Acree WE, Lang AS (2015). 640:Lassila JK, Zalatan JG, Herschlag D (2011-06-15). 515: 256:, anesthetic potency, etc. The lowercase letters ( 229: 404:= the contribution from dipole-type interactions; 390:= the contribution from interactions with solute 838: 606: 604: 761:"Predicting Abraham model solvent coefficients" 534:in cubic centimeters per mole divided by 100. 601: 589:Quantitative structure–activity relationship 752: 786: 776: 665: 532:McGowan's characteristic molecular volume 414:will interact with an acidic solute); and 315:is the gas–liquid partition constant on 369:= the solute's effective hydrogen-bond 74:describes the relationship between the 59:of a reaction, and in combination with 839: 658:10.1146/annurev-biochem-060409-092741 134:LFER solvent coefficients (data page) 13: 819:Compendium of Chemical Terminology 616:Compendium of Chemical Terminology 509: 498: 487: 476: 465: 448: 445: 223: 212: 201: 190: 179: 162: 159: 98:relates the nucleophilic power to 14: 863: 807: 128:Chemical and physical properties 717: 682: 633: 284:process. The capital letters ( 1: 703:10.1016/s1359-6446(02)02478-9 646:Annual Review of Biochemistry 594: 248:related property, such as an 584:Bell–Evans–Polanyi principle 7: 824:linear free-energy relation 621:linear free-energy relation 544:Brønsted catalysis equation 537: 72:Brønsted catalysis equation 10: 868: 852:Physical organic chemistry 564:Grunwald–Winstein equation 131: 21:physical organic chemistry 778:10.1186/s13065-015-0085-4 765:Chemistry Central Journal 738:10.1016/j.aca.2009.04.038 356:= the solute's effective 252:or absorption constant, 25:free-energy relationship 832:10.1351/goldbook.L03551 629:10.1351/goldbook.L03551 726:Analytica Chimica Acta 517: 231: 92:reaction type constant 37:reaction rate constant 569:Yukawa–Tsuno equation 559:Swain–Lupton equation 518: 232: 29:Gibbs energy relation 691:Drug Discovery Today 435: 149: 88:substituent constant 41:equilibrium constant 76:ionization constant 513: 227: 65:reaction mechanism 45:chemical reactions 43:for one series of 142:and co-workers): 859: 801: 800: 790: 780: 756: 750: 749: 721: 715: 714: 686: 680: 679: 669: 637: 631: 608: 574:Edwards equation 549:Hammett equation 529: 522: 520: 519: 514: 512: 501: 490: 479: 468: 451: 427: 419: 409: 403: 389: 383: 368: 355: 345: 335: 330:molar refraction 327: 314: 303: 299: 295: 291: 287: 275: 271: 267: 263: 259: 255: 243: 236: 234: 233: 228: 226: 215: 204: 193: 182: 165: 96:Edwards equation 84:Hammett equation 57:transition state 867: 866: 862: 861: 860: 858: 857: 856: 837: 836: 810: 805: 804: 757: 753: 722: 718: 697:(20): 1056–63. 687: 683: 638: 634: 609: 602: 597: 579:Marcus equation 540: 527: 508: 497: 486: 475: 464: 444: 436: 433: 432: 425: 417: 407: 401: 387: 381: 366: 353: 343: 333: 325: 312: 301: 297: 293: 289: 285: 273: 269: 265: 261: 257: 253: 241: 222: 211: 200: 189: 178: 158: 150: 147: 146: 136: 130: 108:Marcus equation 61:kinetic isotope 17: 12: 11: 5: 865: 855: 854: 849: 835: 834: 809: 808:External links 806: 803: 802: 751: 732:(1–2): 32–53. 716: 681: 652:(1): 669–702. 632: 599: 598: 596: 593: 592: 591: 586: 581: 576: 571: 566: 561: 556: 551: 546: 539: 536: 524: 523: 511: 507: 504: 500: 496: 493: 489: 485: 482: 478: 474: 471: 467: 463: 460: 457: 454: 450: 447: 443: 440: 428:, is given by 422: 421: 415: 405: 399: 385: 375: 374: 364: 351: 341: 323: 322:at 298 K; 238: 237: 225: 221: 218: 214: 210: 207: 203: 199: 196: 192: 188: 185: 181: 177: 174: 171: 168: 164: 161: 157: 154: 132:Main article: 129: 126: 100:polarisability 82:operates. The 63:experiments a 55:happen in the 51:formation and 15: 9: 6: 4: 3: 2: 864: 853: 850: 848: 845: 844: 842: 833: 829: 825: 821: 820: 815: 812: 811: 798: 794: 789: 784: 779: 774: 770: 766: 762: 755: 747: 743: 739: 735: 731: 727: 720: 712: 708: 704: 700: 696: 692: 685: 677: 673: 668: 663: 659: 655: 651: 647: 643: 636: 630: 626: 622: 618: 617: 612: 607: 605: 600: 590: 587: 585: 582: 580: 577: 575: 572: 570: 567: 565: 562: 560: 557: 555: 554:Taft equation 552: 550: 547: 545: 542: 541: 535: 533: 505: 502: 494: 491: 483: 480: 472: 469: 461: 458: 455: 452: 441: 438: 431: 430: 429: 416: 413: 406: 400: 397: 393: 386: 380: 379: 378: 372: 365: 362: 359: 358:hydrogen bond 352: 349: 342: 339: 331: 328:= the excess 324: 321: 319: 311: 310: 309: 307: 283: 280:phase to the 279: 251: 247: 219: 216: 208: 205: 197: 194: 186: 183: 175: 172: 169: 166: 155: 152: 145: 144: 143: 141: 135: 125: 123: 121: 115: 111: 109: 105: 101: 97: 93: 89: 85: 81: 77: 73: 68: 66: 62: 58: 54: 50: 46: 42: 38: 34: 30: 26: 22: 817: 768: 764: 754: 729: 725: 719: 694: 690: 684: 649: 645: 635: 614: 525: 423: 396:pi electrons 376: 337: 317: 239: 140:M.H. Abraham 137: 120:Gibbs energy 117: 112: 103: 99: 91: 87: 69: 31:relates the 28: 24: 18: 392:n-electrons 320:-hexadecane 246:free-energy 841:Categories 595:References 340:-alkanes). 250:adsorption 847:Solutions 442:⁡ 156:⁡ 33:logarithm 797:25798192 746:19786169 711:12546895 676:21513457 538:See also 371:basicity 282:sorption 244:is some 122:relation 104:basicity 80:catalyst 53:breakage 788:4369285 667:3418923 412:sorbent 361:acidity 278:aerosol 118:linear 795:  785:  771:: 12. 744:  709:  674:  664:  526:where 426:log SP 348:dipole 306:solute 304:) are 240:where 106:. The 94:. The 90:and a 814:IUPAC 611:IUPAC 363:; and 334:E = 0 254:log K 114:IUPAC 35:of a 793:PMID 742:PMID 707:PMID 672:PMID 394:and 336:for 102:and 49:bond 23:, a 828:doi 826:". 783:PMC 773:doi 734:doi 730:652 699:doi 662:PMC 654:doi 625:doi 623:". 530:is 439:log 153:log 39:or 27:or 19:In 843:: 816:, 791:. 781:. 767:. 763:. 740:. 728:. 705:. 693:. 670:. 660:. 650:80 648:. 644:. 613:, 603:^ 300:, 296:, 292:, 288:, 272:, 268:, 264:, 260:, 242:SP 830:: 799:. 775:: 769:9 748:. 736:: 713:. 701:: 695:7 678:. 656:: 627:: 528:V 510:V 506:v 503:+ 499:B 495:b 492:+ 488:A 484:a 481:+ 477:S 473:s 470:+ 466:E 462:e 459:+ 456:c 453:= 449:P 446:S 418:b 408:a 402:s 398:; 388:e 382:l 373:. 367:B 354:A 344:S 338:n 332:( 326:E 318:n 313:L 302:L 298:B 294:A 290:S 286:E 274:l 270:b 266:a 262:s 258:e 224:L 220:l 217:+ 213:B 209:b 206:+ 202:A 198:a 195:+ 191:S 187:s 184:+ 180:E 176:e 173:+ 170:c 167:= 163:P 160:S

Index

physical organic chemistry
logarithm
reaction rate constant
equilibrium constant
chemical reactions
bond
breakage
transition state
kinetic isotope
reaction mechanism
Brønsted catalysis equation
ionization constant
catalyst
Hammett equation
Edwards equation
Marcus equation
IUPAC
Gibbs energy
LFER solvent coefficients (data page)
M.H. Abraham
free-energy
adsorption
aerosol
sorption
solute
n-hexadecane
molar refraction
dipole
hydrogen bond
acidity

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