4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene

C222H187B5N14 — CID 167675815

About 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene

4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene (PubChem CID 167675815) has the molecular formula C222H187B5N14 and a molecular weight of 3105.10 g/mol. Its IUPAC name is 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene.

Molecular Properties

• Compound Name: 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene
• PubChem CID: 167675815
• Molecular Formula: C222H187B5N14
• Molecular Weight: 3105.10 g/mol
• Exact Mass: 3103.55
• IUPAC Name: 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene
• SMILES: C1=CC2B3c4cc5c6c(N(c7ccccc7)c7ccccc7)cccc6n(-c6ccccc6)c5cc4N(c4ccccc4)c4cccc(c43)N(c3ccccc3)C2C=C1.CC(C)(C)c1ccc(N2c3ccc(C(C)(C)C)cc3B3c4cc(C(C)(C)C)ccc4N(c4ccc(C(C)(C)C)cc4)c4cccc2c43)cc1.CC(C)(C)c1ccc(N2c3ccc(C(C)(C)C)cc3B3c4ccccc4N(c4ccccc4)c4cccc2c43)cc1.c1ccc(N(c2ccccc2)c2ccc3c(c2)N(c2ccccc2)c2cccc4c2B3c2ccccc2N4c2ccccc2)cc1.c1ccc(N2c3ccccc3B3c4cc5c6ccccc6n(-c6ccccc6)c5cc4N(c4ccccc4)c4cccc2c43)cc1
• InChI: InChI=1S/C54H39BN4.C46H53BN2.C42H28BN3.C42H30BN3.C38H37BN2/c1-6-20-38(21-7-1)56(39-22-8-2-9-23-39)47-32-18-33-48-53(47)43-36-45-52(37-51(43)58(48)41-26-12-4-13-27-41)59(42-28-14-5-15-29-42)50-35-19-34-49-54(50)55(45)44-30-16-17-31-46(44)57(49)40-24-10-3-11-25-40;1-43(2,3)30-16-22-34(23-17-30)48-38-26-20-32(45(7,8)9)28-36(38)47-37-29-33(46(10,11)12)21-27-39(37)49(41-15-13-14-40(48)42(41)47)35-24-18-31(19-25-35)44(4,5)6;1-4-15-29(16-5-1)44-36-23-12-10-21-32(36)33-27-35-41(28-40(33)44)46(31-19-8-3-9-20-31)39-26-14-25-38-42(39)43(35)34-22-11-13-24-37(34)45(38)30-17-6-2-7-18-30;1-5-16-31(17-6-1)44(32-18-7-2-8-19-32)35-28-29-37-41(30-35)46(34-22-11-4-12-23-34)40-27-15-26-39-42(40)43(37)36-24-13-14-25-38(36)45(39)33-20-9-3-10-21-33;1-37(2,3)26-19-22-29(23-20-26)41-33-24-21-27(38(4,5)6)25-31(33)39-30-15-10-11-16-32(30)40(28-13-8-7-9-14-28)34-17-12-18-35(41)36(34)39/h1-37,44,46H;13-29H,1-12H3;1-28H;1-30H;7-25H,1-6H3
• InChIKey: UUHWXLRGKQOZJX-UHFFFAOYSA-N
• XLogP: 50.09
• TPSA: 48.74 Ų
• H-Bond Acceptors: 14
• Rotatable Bonds: 18
• Heavy Atoms: 241
• Complexity: —

Lipinski Rule of Five

3 violations

Rule	Value
MW ≤ 500	3105.10
LogP ≤ 5	50.09
H-Bond Donors ≤ 5	0
H-Bond Acceptors ≤ 10	14

Computed Properties (RDKit)

• Structural Alerts: {'alert_name': 'heavy_metal', 'substructure': 'N/A'}

Frequently Asked Questions

What is the IUPAC name of 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene?

The IUPAC name of 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene (CID 167675815) is 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene.

What is the SMILES notation for 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene?

The canonical SMILES for 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene is C1=CC2B3c4cc5c6c(N(c7ccccc7)c7ccccc7)cccc6n(-c6ccccc6)c5cc4N(c4ccccc4)c4cccc(c43)N(c3ccccc3)C2C=C1.CC(C)(C)c1ccc(N2c3ccc(C(C)(C)C)cc3B3c4cc(C(C)(C)C)ccc4N(c4ccc(C(C)(C)C)cc4)c4cccc2c43)cc1.CC(C)(C)c1ccc(N2c3ccc(C(C)(C)C)cc3B3c4ccccc4N(c4ccccc4)c4cccc2c43)cc1.c1ccc(N(c2ccccc2)c2ccc3c(c2)N(c2ccccc2)c2cccc4c2B3c2ccccc2N4c2ccccc2)cc1.c1ccc(N2c3ccccc3B3c4cc5c6ccccc6n(-c6ccccc6)c5cc4N(c4ccccc4)c4cccc2c43)cc1.

What is the InChIKey of 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene?

The InChIKey is UUHWXLRGKQOZJX-UHFFFAOYSA-N. The full InChI is InChI=1S/C54H39BN4.C46H53BN2.C42H28BN3.C42H30BN3.C38H37BN2/c1-6-20-38(21-7-1)56(39-22-8-2-9-23-39)47-32-18-33-48-53(47)43-36-45-52(37-51(43)58(48)41-26-12-4-13-27-41)59(42-28-14-5-15-29-42)50-35-19-34-49-54(50)55(45)44-30-16-17-31-46(44)57(49)40-24-10-3-11-25-40;1-43(2,3)30-16-22-34(23-17-30)48-38-26-20-32(45(7,8)9)28-36(38)47-37-29-33(46(10,11)12)21-27-39(37)49(41-15-13-14-40(48)42(41)47)35-24-18-31(19-25-35)44(4,5)6;1-4-15-29(16-5-1)44-36-23-12-10-21-32(36)33-27-35-41(28-40(33)44)46(31-19-8-3-9-20-31)39-26-14-25-38-42(39)43(35)34-22-11-13-24-37(34)45(38)30-17-6-2-7-18-30;1-5-16-31(17-6-1)44(32-18-7-2-8-19-32)35-28-29-37-41(30-35)46(34-22-11-4-12-23-34)40-27-15-26-39-42(40)43(37)36-24-13-14-25-38(36)45(39)33-20-9-3-10-21-33;1-37(2,3)26-19-22-29(23-20-26)41-33-24-21-27(38(4,5)6)25-31(33)39-30-15-10-11-16-32(30)40(28-13-8-7-9-14-28)34-17-12-18-35(41)36(34)39/h1-37,44,46H;13-29H,1-12H3;1-28H;1-30H;7-25H,1-6H3.

What are the key properties of 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene?

4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene has a molecular weight of 3105.10 g/mol, XLogP of 50.09, 18 rotatable bonds, 0 hydrogen bond donors, and 14 hydrogen bond acceptors.

Where does this data come from?

All data for 4-tert-butyl-8-(4-tert-butylphenyl)-14-phenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaene;4,18-ditert-butyl-8,14-bis(4-tert-butylphenyl)-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9(21),10,12,15(20),16,18-nonaene;N,N,11,15,21-pentakis-phenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5(10),6,8,13,16(28),17,19,23,25-undecaen-6-amine;N,N,8,14-tetraphenyl-8,14-diaza-1-borapentacyclo[11.7.1.02,7.09,21.015,20]henicosa-2(7),3,5,9,11,13(21),15,17,19-nonaen-5-amine;11,15,21-triphenyl-11,15,21-triaza-1-boraheptacyclo[14.11.1.02,14.04,12.05,10.020,28.022,27]octacosa-2,4(12),5,7,9,13,16,18,20(28),22,24,26-dodecaene is sourced from PubChem (CID 167675815), the world's largest open chemistry database maintained by the National Library of Medicine (NIH).